xref: /openbmc/linux/drivers/iio/light/rohm-bu27008.c (revision e2ad626f)
1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3  * ROHM Colour Sensor driver for
4  * - BU27008 RGBC sensor
5  * - BU27010 RGBC + Flickering sensor
6  *
7  * Copyright (c) 2023, ROHM Semiconductor.
8  */
9 
10 #include <linux/bitfield.h>
11 #include <linux/bitops.h>
12 #include <linux/device.h>
13 #include <linux/i2c.h>
14 #include <linux/interrupt.h>
15 #include <linux/module.h>
16 #include <linux/property.h>
17 #include <linux/regmap.h>
18 #include <linux/regulator/consumer.h>
19 #include <linux/units.h>
20 
21 #include <linux/iio/iio.h>
22 #include <linux/iio/iio-gts-helper.h>
23 #include <linux/iio/trigger.h>
24 #include <linux/iio/trigger_consumer.h>
25 #include <linux/iio/triggered_buffer.h>
26 
27 /*
28  * A word about register address and mask definitions.
29  *
30  * At a quick glance to the data-sheet register tables, the BU27010 has all the
31  * registers that the BU27008 has. On top of that the BU27010 adds couple of new
32  * ones.
33  *
34  * So, all definitions BU27008_REG_* are there also for BU27010 but none of the
35  * BU27010_REG_* are present on BU27008. This makes sense as BU27010 just adds
36  * some features (Flicker FIFO, more power control) on top of the BU27008.
37  *
38  * Unfortunately, some of the wheel has been re-invented. Even though the names
39  * of the registers have stayed the same, pretty much all of the functionality
40  * provided by the registers has changed place. Contents of all MODE_CONTROL
41  * registers on BU27008 and BU27010 are different.
42  *
43  * Chip-specific mapping from register addresses/bits to functionality is done
44  * in bu27_chip_data structures.
45  */
46 #define BU27008_REG_SYSTEM_CONTROL	0x40
47 #define BU27008_MASK_SW_RESET		BIT(7)
48 #define BU27008_MASK_PART_ID		GENMASK(5, 0)
49 #define BU27008_ID			0x1a
50 #define BU27008_REG_MODE_CONTROL1	0x41
51 #define BU27008_MASK_MEAS_MODE		GENMASK(2, 0)
52 #define BU27008_MASK_CHAN_SEL		GENMASK(3, 2)
53 
54 #define BU27008_REG_MODE_CONTROL2	0x42
55 #define BU27008_MASK_RGBC_GAIN		GENMASK(7, 3)
56 #define BU27008_MASK_IR_GAIN_LO		GENMASK(2, 0)
57 #define BU27008_SHIFT_IR_GAIN		3
58 
59 #define BU27008_REG_MODE_CONTROL3	0x43
60 #define BU27008_MASK_VALID		BIT(7)
61 #define BU27008_MASK_INT_EN		BIT(1)
62 #define BU27008_INT_EN			BU27008_MASK_INT_EN
63 #define BU27008_INT_DIS			0
64 #define BU27008_MASK_MEAS_EN		BIT(0)
65 #define BU27008_MEAS_EN			BIT(0)
66 #define BU27008_MEAS_DIS		0
67 
68 #define BU27008_REG_DATA0_LO		0x50
69 #define BU27008_REG_DATA1_LO		0x52
70 #define BU27008_REG_DATA2_LO		0x54
71 #define BU27008_REG_DATA3_LO		0x56
72 #define BU27008_REG_DATA3_HI		0x57
73 #define BU27008_REG_MANUFACTURER_ID	0x92
74 #define BU27008_REG_MAX BU27008_REG_MANUFACTURER_ID
75 
76 /* BU27010 specific definitions */
77 
78 #define BU27010_MASK_SW_RESET		BIT(7)
79 #define BU27010_ID			0x1b
80 #define BU27010_REG_POWER		0x3e
81 #define BU27010_MASK_POWER		BIT(0)
82 
83 #define BU27010_REG_RESET		0x3f
84 #define BU27010_MASK_RESET		BIT(0)
85 #define BU27010_RESET_RELEASE		BU27010_MASK_RESET
86 
87 #define BU27010_MASK_MEAS_EN		BIT(1)
88 
89 #define BU27010_MASK_CHAN_SEL		GENMASK(7, 6)
90 #define BU27010_MASK_MEAS_MODE		GENMASK(5, 4)
91 #define BU27010_MASK_RGBC_GAIN		GENMASK(3, 0)
92 
93 #define BU27010_MASK_DATA3_GAIN		GENMASK(7, 6)
94 #define BU27010_MASK_DATA2_GAIN		GENMASK(5, 4)
95 #define BU27010_MASK_DATA1_GAIN		GENMASK(3, 2)
96 #define BU27010_MASK_DATA0_GAIN		GENMASK(1, 0)
97 
98 #define BU27010_MASK_FLC_MODE		BIT(7)
99 #define BU27010_MASK_FLC_GAIN		GENMASK(4, 0)
100 
101 #define BU27010_REG_MODE_CONTROL4	0x44
102 /* If flicker is ever to be supported the IRQ must be handled as a field */
103 #define BU27010_IRQ_DIS_ALL		GENMASK(1, 0)
104 #define BU27010_DRDY_EN			BIT(0)
105 #define BU27010_MASK_INT_SEL		GENMASK(1, 0)
106 
107 #define BU27010_REG_MODE_CONTROL5	0x45
108 #define BU27010_MASK_RGB_VALID		BIT(7)
109 #define BU27010_MASK_FLC_VALID		BIT(6)
110 #define BU27010_MASK_WAIT_EN		BIT(3)
111 #define BU27010_MASK_FIFO_EN		BIT(2)
112 #define BU27010_MASK_RGB_EN		BIT(1)
113 #define BU27010_MASK_FLC_EN		BIT(0)
114 
115 #define BU27010_REG_DATA_FLICKER_LO	0x56
116 #define BU27010_MASK_DATA_FLICKER_HI	GENMASK(2, 0)
117 #define BU27010_REG_FLICKER_COUNT	0x5a
118 #define BU27010_REG_FIFO_LEVEL_LO	0x5b
119 #define BU27010_MASK_FIFO_LEVEL_HI	BIT(0)
120 #define BU27010_REG_FIFO_DATA_LO	0x5d
121 #define BU27010_REG_FIFO_DATA_HI	0x5e
122 #define BU27010_MASK_FIFO_DATA_HI	GENMASK(2, 0)
123 #define BU27010_REG_MANUFACTURER_ID	0x92
124 #define BU27010_REG_MAX BU27010_REG_MANUFACTURER_ID
125 
126 /**
127  * enum bu27008_chan_type - BU27008 channel types
128  * @BU27008_RED:	Red channel. Always via data0.
129  * @BU27008_GREEN:	Green channel. Always via data1.
130  * @BU27008_BLUE:	Blue channel. Via data2 (when used).
131  * @BU27008_CLEAR:	Clear channel. Via data2 or data3 (when used).
132  * @BU27008_IR:		IR channel. Via data3 (when used).
133  * @BU27008_NUM_CHANS:	Number of channel types.
134  */
135 enum bu27008_chan_type {
136 	BU27008_RED,
137 	BU27008_GREEN,
138 	BU27008_BLUE,
139 	BU27008_CLEAR,
140 	BU27008_IR,
141 	BU27008_NUM_CHANS
142 };
143 
144 /**
145  * enum bu27008_chan - BU27008 physical data channel
146  * @BU27008_DATA0:		Always red.
147  * @BU27008_DATA1:		Always green.
148  * @BU27008_DATA2:		Blue or clear.
149  * @BU27008_DATA3:		IR or clear.
150  * @BU27008_NUM_HW_CHANS:	Number of physical channels
151  */
152 enum bu27008_chan {
153 	BU27008_DATA0,
154 	BU27008_DATA1,
155 	BU27008_DATA2,
156 	BU27008_DATA3,
157 	BU27008_NUM_HW_CHANS
158 };
159 
160 /* We can always measure red and green at same time */
161 #define ALWAYS_SCANNABLE (BIT(BU27008_RED) | BIT(BU27008_GREEN))
162 
163 /* We use these data channel configs. Ensure scan_masks below follow them too */
164 #define BU27008_BLUE2_CLEAR3		0x0 /* buffer is R, G, B, C */
165 #define BU27008_CLEAR2_IR3		0x1 /* buffer is R, G, C, IR */
166 #define BU27008_BLUE2_IR3		0x2 /* buffer is R, G, B, IR */
167 
168 static const unsigned long bu27008_scan_masks[] = {
169 	/* buffer is R, G, B, C */
170 	ALWAYS_SCANNABLE | BIT(BU27008_BLUE) | BIT(BU27008_CLEAR),
171 	/* buffer is R, G, C, IR */
172 	ALWAYS_SCANNABLE | BIT(BU27008_CLEAR) | BIT(BU27008_IR),
173 	/* buffer is R, G, B, IR */
174 	ALWAYS_SCANNABLE | BIT(BU27008_BLUE) | BIT(BU27008_IR),
175 	0
176 };
177 
178 /*
179  * Available scales with gain 1x - 1024x, timings 55, 100, 200, 400 mS
180  * Time impacts to gain: 1x, 2x, 4x, 8x.
181  *
182  * => Max total gain is HWGAIN * gain by integration time (8 * 1024) = 8192
183  *
184  * Max amplification is (HWGAIN * MAX integration-time multiplier) 1024 * 8
185  * = 8192. With NANO scale we get rid of accuracy loss when we start with the
186  * scale 16.0 for HWGAIN1, INT-TIME 55 mS. This way the nano scale for MAX
187  * total gain 8192 will be 1953125
188  */
189 #define BU27008_SCALE_1X 16
190 
191 /*
192  * On BU27010 available scales with gain 1x - 4096x,
193  * timings 55, 100, 200, 400 mS. Time impacts to gain: 1x, 2x, 4x, 8x.
194  *
195  * => Max total gain is HWGAIN * gain by integration time (8 * 4096)
196  *
197  * Using NANO precision for scale we must use scale 64x corresponding gain 1x
198  * to avoid precision loss.
199  */
200 #define BU27010_SCALE_1X 64
201 
202 /* See the data sheet for the "Gain Setting" table */
203 #define BU27008_GSEL_1X		0x00
204 #define BU27008_GSEL_4X		0x08
205 #define BU27008_GSEL_8X		0x09
206 #define BU27008_GSEL_16X	0x0a
207 #define BU27008_GSEL_32X	0x0b
208 #define BU27008_GSEL_64X	0x0c
209 #define BU27008_GSEL_256X	0x18
210 #define BU27008_GSEL_512X	0x19
211 #define BU27008_GSEL_1024X	0x1a
212 
213 static const struct iio_gain_sel_pair bu27008_gains[] = {
214 	GAIN_SCALE_GAIN(1, BU27008_GSEL_1X),
215 	GAIN_SCALE_GAIN(4, BU27008_GSEL_4X),
216 	GAIN_SCALE_GAIN(8, BU27008_GSEL_8X),
217 	GAIN_SCALE_GAIN(16, BU27008_GSEL_16X),
218 	GAIN_SCALE_GAIN(32, BU27008_GSEL_32X),
219 	GAIN_SCALE_GAIN(64, BU27008_GSEL_64X),
220 	GAIN_SCALE_GAIN(256, BU27008_GSEL_256X),
221 	GAIN_SCALE_GAIN(512, BU27008_GSEL_512X),
222 	GAIN_SCALE_GAIN(1024, BU27008_GSEL_1024X),
223 };
224 
225 static const struct iio_gain_sel_pair bu27008_gains_ir[] = {
226 	GAIN_SCALE_GAIN(2, BU27008_GSEL_1X),
227 	GAIN_SCALE_GAIN(4, BU27008_GSEL_4X),
228 	GAIN_SCALE_GAIN(8, BU27008_GSEL_8X),
229 	GAIN_SCALE_GAIN(16, BU27008_GSEL_16X),
230 	GAIN_SCALE_GAIN(32, BU27008_GSEL_32X),
231 	GAIN_SCALE_GAIN(64, BU27008_GSEL_64X),
232 	GAIN_SCALE_GAIN(256, BU27008_GSEL_256X),
233 	GAIN_SCALE_GAIN(512, BU27008_GSEL_512X),
234 	GAIN_SCALE_GAIN(1024, BU27008_GSEL_1024X),
235 };
236 
237 #define BU27010_GSEL_1X		0x00	/* 000000 */
238 #define BU27010_GSEL_4X		0x08	/* 001000 */
239 #define BU27010_GSEL_16X	0x09	/* 001001 */
240 #define BU27010_GSEL_64X	0x0e	/* 001110 */
241 #define BU27010_GSEL_256X	0x1e	/* 011110 */
242 #define BU27010_GSEL_1024X	0x2e	/* 101110 */
243 #define BU27010_GSEL_4096X	0x3f	/* 111111 */
244 
245 static const struct iio_gain_sel_pair bu27010_gains[] = {
246 	GAIN_SCALE_GAIN(1, BU27010_GSEL_1X),
247 	GAIN_SCALE_GAIN(4, BU27010_GSEL_4X),
248 	GAIN_SCALE_GAIN(16, BU27010_GSEL_16X),
249 	GAIN_SCALE_GAIN(64, BU27010_GSEL_64X),
250 	GAIN_SCALE_GAIN(256, BU27010_GSEL_256X),
251 	GAIN_SCALE_GAIN(1024, BU27010_GSEL_1024X),
252 	GAIN_SCALE_GAIN(4096, BU27010_GSEL_4096X),
253 };
254 
255 static const struct iio_gain_sel_pair bu27010_gains_ir[] = {
256 	GAIN_SCALE_GAIN(2, BU27010_GSEL_1X),
257 	GAIN_SCALE_GAIN(4, BU27010_GSEL_4X),
258 	GAIN_SCALE_GAIN(16, BU27010_GSEL_16X),
259 	GAIN_SCALE_GAIN(64, BU27010_GSEL_64X),
260 	GAIN_SCALE_GAIN(256, BU27010_GSEL_256X),
261 	GAIN_SCALE_GAIN(1024, BU27010_GSEL_1024X),
262 	GAIN_SCALE_GAIN(4096, BU27010_GSEL_4096X),
263 };
264 
265 #define BU27008_MEAS_MODE_100MS		0x00
266 #define BU27008_MEAS_MODE_55MS		0x01
267 #define BU27008_MEAS_MODE_200MS		0x02
268 #define BU27008_MEAS_MODE_400MS		0x04
269 
270 #define BU27010_MEAS_MODE_100MS		0x00
271 #define BU27010_MEAS_MODE_55MS		0x03
272 #define BU27010_MEAS_MODE_200MS		0x01
273 #define BU27010_MEAS_MODE_400MS		0x02
274 
275 #define BU27008_MEAS_TIME_MAX_MS	400
276 
277 static const struct iio_itime_sel_mul bu27008_itimes[] = {
278 	GAIN_SCALE_ITIME_US(400000, BU27008_MEAS_MODE_400MS, 8),
279 	GAIN_SCALE_ITIME_US(200000, BU27008_MEAS_MODE_200MS, 4),
280 	GAIN_SCALE_ITIME_US(100000, BU27008_MEAS_MODE_100MS, 2),
281 	GAIN_SCALE_ITIME_US(55000, BU27008_MEAS_MODE_55MS, 1),
282 };
283 
284 static const struct iio_itime_sel_mul bu27010_itimes[] = {
285 	GAIN_SCALE_ITIME_US(400000, BU27010_MEAS_MODE_400MS, 8),
286 	GAIN_SCALE_ITIME_US(200000, BU27010_MEAS_MODE_200MS, 4),
287 	GAIN_SCALE_ITIME_US(100000, BU27010_MEAS_MODE_100MS, 2),
288 	GAIN_SCALE_ITIME_US(55000, BU27010_MEAS_MODE_55MS, 1),
289 };
290 
291 /*
292  * All the RGBC channels share the same gain.
293  * IR gain can be fine-tuned from the gain set for the RGBC by 2 bit, but this
294  * would yield quite complex gain setting. Especially since not all bit
295  * compinations are supported. And in any case setting GAIN for RGBC will
296  * always also change the IR-gain.
297  *
298  * On top of this, the selector '0' which corresponds to hw-gain 1X on RGBC,
299  * corresponds to gain 2X on IR. Rest of the selctors correspond to same gains
300  * though. This, however, makes it not possible to use shared gain for all
301  * RGBC and IR settings even though they are all changed at the one go.
302  */
303 #define BU27008_CHAN(color, data, separate_avail)				\
304 {										\
305 	.type = IIO_INTENSITY,							\
306 	.modified = 1,								\
307 	.channel2 = IIO_MOD_LIGHT_##color,					\
308 	.info_mask_separate = BIT(IIO_CHAN_INFO_RAW) |				\
309 			      BIT(IIO_CHAN_INFO_SCALE),				\
310 	.info_mask_separate_available = (separate_avail),			\
311 	.info_mask_shared_by_all = BIT(IIO_CHAN_INFO_INT_TIME),			\
312 	.info_mask_shared_by_all_available = BIT(IIO_CHAN_INFO_INT_TIME),	\
313 	.address = BU27008_REG_##data##_LO,					\
314 	.scan_index = BU27008_##color,						\
315 	.scan_type = {								\
316 		.sign = 'u',							\
317 		.realbits = 16,							\
318 		.storagebits = 16,						\
319 		.endianness = IIO_LE,						\
320 	},									\
321 }
322 
323 /* For raw reads we always configure DATA3 for CLEAR */
324 static const struct iio_chan_spec bu27008_channels[] = {
325 	BU27008_CHAN(RED, DATA0, BIT(IIO_CHAN_INFO_SCALE)),
326 	BU27008_CHAN(GREEN, DATA1, BIT(IIO_CHAN_INFO_SCALE)),
327 	BU27008_CHAN(BLUE, DATA2, BIT(IIO_CHAN_INFO_SCALE)),
328 	BU27008_CHAN(CLEAR, DATA2, BIT(IIO_CHAN_INFO_SCALE)),
329 	/*
330 	 * We don't allow setting scale for IR (because of shared gain bits).
331 	 * Hence we don't advertise available ones either.
332 	 */
333 	BU27008_CHAN(IR, DATA3, 0),
334 	IIO_CHAN_SOFT_TIMESTAMP(BU27008_NUM_CHANS),
335 };
336 
337 struct bu27008_data;
338 
339 struct bu27_chip_data {
340 	const char *name;
341 	int (*chip_init)(struct bu27008_data *data);
342 	int (*get_gain_sel)(struct bu27008_data *data, int *sel);
343 	int (*write_gain_sel)(struct bu27008_data *data, int sel);
344 	const struct regmap_config *regmap_cfg;
345 	const struct iio_gain_sel_pair *gains;
346 	const struct iio_gain_sel_pair *gains_ir;
347 	const struct iio_itime_sel_mul *itimes;
348 	int num_gains;
349 	int num_gains_ir;
350 	int num_itimes;
351 	int scale1x;
352 
353 	int drdy_en_reg;
354 	int drdy_en_mask;
355 	int meas_en_reg;
356 	int meas_en_mask;
357 	int valid_reg;
358 	int chan_sel_reg;
359 	int chan_sel_mask;
360 	int int_time_mask;
361 	u8 part_id;
362 };
363 
364 struct bu27008_data {
365 	const struct bu27_chip_data *cd;
366 	struct regmap *regmap;
367 	struct iio_trigger *trig;
368 	struct device *dev;
369 	struct iio_gts gts;
370 	struct iio_gts gts_ir;
371 	int irq;
372 
373 	/*
374 	 * Prevent changing gain/time config when scale is read/written.
375 	 * Similarly, protect the integration_time read/change sequence.
376 	 * Prevent changing gain/time when data is read.
377 	 */
378 	struct mutex mutex;
379 };
380 
381 static const struct regmap_range bu27008_volatile_ranges[] = {
382 	{
383 		.range_min = BU27008_REG_SYSTEM_CONTROL,	/* SWRESET */
384 		.range_max = BU27008_REG_SYSTEM_CONTROL,
385 	}, {
386 		.range_min = BU27008_REG_MODE_CONTROL3,		/* VALID */
387 		.range_max = BU27008_REG_MODE_CONTROL3,
388 	}, {
389 		.range_min = BU27008_REG_DATA0_LO,		/* DATA */
390 		.range_max = BU27008_REG_DATA3_HI,
391 	},
392 };
393 
394 static const struct regmap_range bu27010_volatile_ranges[] = {
395 	{
396 		.range_min = BU27010_REG_RESET,			/* RSTB */
397 		.range_max = BU27008_REG_SYSTEM_CONTROL,	/* RESET */
398 	}, {
399 		.range_min = BU27010_REG_MODE_CONTROL5,		/* VALID bits */
400 		.range_max = BU27010_REG_MODE_CONTROL5,
401 	}, {
402 		.range_min = BU27008_REG_DATA0_LO,
403 		.range_max = BU27010_REG_FIFO_DATA_HI,
404 	},
405 };
406 
407 static const struct regmap_access_table bu27008_volatile_regs = {
408 	.yes_ranges = &bu27008_volatile_ranges[0],
409 	.n_yes_ranges = ARRAY_SIZE(bu27008_volatile_ranges),
410 };
411 
412 static const struct regmap_access_table bu27010_volatile_regs = {
413 	.yes_ranges = &bu27010_volatile_ranges[0],
414 	.n_yes_ranges = ARRAY_SIZE(bu27010_volatile_ranges),
415 };
416 
417 static const struct regmap_range bu27008_read_only_ranges[] = {
418 	{
419 		.range_min = BU27008_REG_DATA0_LO,
420 		.range_max = BU27008_REG_DATA3_HI,
421 	}, {
422 		.range_min = BU27008_REG_MANUFACTURER_ID,
423 		.range_max = BU27008_REG_MANUFACTURER_ID,
424 	},
425 };
426 
427 static const struct regmap_range bu27010_read_only_ranges[] = {
428 	{
429 		.range_min = BU27008_REG_DATA0_LO,
430 		.range_max = BU27010_REG_FIFO_DATA_HI,
431 	}, {
432 		.range_min = BU27010_REG_MANUFACTURER_ID,
433 		.range_max = BU27010_REG_MANUFACTURER_ID,
434 	}
435 };
436 
437 static const struct regmap_access_table bu27008_ro_regs = {
438 	.no_ranges = &bu27008_read_only_ranges[0],
439 	.n_no_ranges = ARRAY_SIZE(bu27008_read_only_ranges),
440 };
441 
442 static const struct regmap_access_table bu27010_ro_regs = {
443 	.no_ranges = &bu27010_read_only_ranges[0],
444 	.n_no_ranges = ARRAY_SIZE(bu27010_read_only_ranges),
445 };
446 
447 static const struct regmap_config bu27008_regmap = {
448 	.reg_bits = 8,
449 	.val_bits = 8,
450 	.max_register = BU27008_REG_MAX,
451 	.cache_type = REGCACHE_RBTREE,
452 	.volatile_table = &bu27008_volatile_regs,
453 	.wr_table = &bu27008_ro_regs,
454 	/*
455 	 * All register writes are serialized by the mutex which protects the
456 	 * scale setting/getting. This is needed because scale is combined by
457 	 * gain and integration time settings and we need to ensure those are
458 	 * not read / written when scale is being computed.
459 	 *
460 	 * As a result of this serializing, we don't need regmap locking. Note,
461 	 * this is not true if we add any configurations which are not
462 	 * serialized by the mutex and which may need for example a protected
463 	 * read-modify-write cycle (eg. regmap_update_bits()). Please, revise
464 	 * this when adding features to the driver.
465 	 */
466 	.disable_locking = true,
467 };
468 
469 static const struct regmap_config bu27010_regmap = {
470 	.reg_bits	= 8,
471 	.val_bits	= 8,
472 
473 	.max_register	= BU27010_REG_MAX,
474 	.cache_type	= REGCACHE_RBTREE,
475 	.volatile_table = &bu27010_volatile_regs,
476 	.wr_table	= &bu27010_ro_regs,
477 	.disable_locking = true,
478 };
479 
480 static int bu27008_write_gain_sel(struct bu27008_data *data, int sel)
481 {
482 	int regval;
483 
484 	regval = FIELD_PREP(BU27008_MASK_RGBC_GAIN, sel);
485 
486 	/*
487 	 * We do always set also the LOW bits of IR-gain because othervice we
488 	 * would risk resulting an invalid GAIN register value.
489 	 *
490 	 * We could allow setting separate gains for RGBC and IR when the
491 	 * values were such that HW could support both gain settings.
492 	 * Eg, when the shared bits were same for both gain values.
493 	 *
494 	 * This, however, has a negligible benefit compared to the increased
495 	 * software complexity when we would need to go through the gains
496 	 * for both channels separately when the integration time changes.
497 	 * This would end up with nasty logic for computing gain values for
498 	 * both channels - and rejecting them if shared bits changed.
499 	 *
500 	 * We should then build the logic by guessing what a user prefers.
501 	 * RGBC or IR gains correctly set while other jumps to odd value?
502 	 * Maybe look-up a value where both gains are somehow optimized
503 	 * <what this somehow is, is ATM unknown to us>. Or maybe user would
504 	 * expect us to reject changes when optimal gains can't be set to both
505 	 * channels w/given integration time. At best that would result
506 	 * solution that works well for a very specific subset of
507 	 * configurations but causes unexpected corner-cases.
508 	 *
509 	 * So, we keep it simple. Always set same selector to IR and RGBC.
510 	 * We disallow setting IR (as I expect that most of the users are
511 	 * interested in RGBC). This way we can show the user that the scales
512 	 * for RGBC and IR channels are different (1X Vs 2X with sel 0) while
513 	 * still keeping the operation deterministic.
514 	 */
515 	regval |= FIELD_PREP(BU27008_MASK_IR_GAIN_LO, sel);
516 
517 	return regmap_update_bits(data->regmap, BU27008_REG_MODE_CONTROL2,
518 				  BU27008_MASK_RGBC_GAIN, regval);
519 }
520 
521 static int bu27010_write_gain_sel(struct bu27008_data *data, int sel)
522 {
523 	unsigned int regval;
524 	int ret, chan_selector;
525 
526 	/*
527 	 * Gain 'selector' is composed of two registers. Selector is 6bit value,
528 	 * 4 high bits being the RGBC gain fieild in MODE_CONTROL1 register and
529 	 * two low bits being the channel specific gain in MODE_CONTROL2.
530 	 *
531 	 * Let's take the 4 high bits of whole 6 bit selector, and prepare
532 	 * the MODE_CONTROL1 value (RGBC gain part).
533 	 */
534 	regval = FIELD_PREP(BU27010_MASK_RGBC_GAIN, (sel >> 2));
535 
536 	ret = regmap_update_bits(data->regmap, BU27008_REG_MODE_CONTROL1,
537 				  BU27010_MASK_RGBC_GAIN, regval);
538 	if (ret)
539 		return ret;
540 
541 	/*
542 	 * Two low two bits of the selector must be written for all 4
543 	 * channels in the MODE_CONTROL2 register. Copy these two bits for
544 	 * all channels.
545 	 */
546 	chan_selector = sel & GENMASK(1, 0);
547 
548 	regval = FIELD_PREP(BU27010_MASK_DATA0_GAIN, chan_selector);
549 	regval |= FIELD_PREP(BU27010_MASK_DATA1_GAIN, chan_selector);
550 	regval |= FIELD_PREP(BU27010_MASK_DATA2_GAIN, chan_selector);
551 	regval |= FIELD_PREP(BU27010_MASK_DATA3_GAIN, chan_selector);
552 
553 	return regmap_write(data->regmap, BU27008_REG_MODE_CONTROL2, regval);
554 }
555 
556 static int bu27008_get_gain_sel(struct bu27008_data *data, int *sel)
557 {
558 	int ret;
559 
560 	/*
561 	 * If we always "lock" the gain selectors for all channels to prevent
562 	 * unsupported configs, then it does not matter which channel is used
563 	 * we can just return selector from any of them.
564 	 *
565 	 * This, however is not true if we decide to support only 4X and 16X
566 	 * and then individual gains for channels. Currently this is not the
567 	 * case.
568 	 *
569 	 * If we some day decide to support individual gains, then we need to
570 	 * have channel information here.
571 	 */
572 
573 	ret = regmap_read(data->regmap, BU27008_REG_MODE_CONTROL2, sel);
574 	if (ret)
575 		return ret;
576 
577 	*sel = FIELD_GET(BU27008_MASK_RGBC_GAIN, *sel);
578 
579 	return 0;
580 }
581 
582 static int bu27010_get_gain_sel(struct bu27008_data *data, int *sel)
583 {
584 	int ret, tmp;
585 
586 	/*
587 	 * We always "lock" the gain selectors for all channels to prevent
588 	 * unsupported configs. It does not matter which channel is used
589 	 * we can just return selector from any of them.
590 	 *
591 	 * Read the channel0 gain.
592 	 */
593 	ret = regmap_read(data->regmap, BU27008_REG_MODE_CONTROL2, sel);
594 	if (ret)
595 		return ret;
596 
597 	*sel = FIELD_GET(BU27010_MASK_DATA0_GAIN, *sel);
598 
599 	/* Read the shared gain */
600 	ret = regmap_read(data->regmap, BU27008_REG_MODE_CONTROL1, &tmp);
601 	if (ret)
602 		return ret;
603 
604 	/*
605 	 * The gain selector is made as a combination of common RGBC gain and
606 	 * the channel specific gain. The channel specific gain forms the low
607 	 * bits of selector and RGBC gain is appended right after it.
608 	 *
609 	 * Compose the selector from channel0 gain and shared RGBC gain.
610 	 */
611 	*sel |= FIELD_GET(BU27010_MASK_RGBC_GAIN, tmp) << fls(BU27010_MASK_DATA0_GAIN);
612 
613 	return ret;
614 }
615 
616 static int bu27008_chip_init(struct bu27008_data *data)
617 {
618 	int ret;
619 
620 	ret = regmap_write_bits(data->regmap, BU27008_REG_SYSTEM_CONTROL,
621 				BU27008_MASK_SW_RESET, BU27008_MASK_SW_RESET);
622 	if (ret)
623 		return dev_err_probe(data->dev, ret, "Sensor reset failed\n");
624 
625 	/*
626 	 * The data-sheet does not tell how long performing the IC reset takes.
627 	 * However, the data-sheet says the minimum time it takes the IC to be
628 	 * able to take inputs after power is applied, is 100 uS. I'd assume
629 	 * > 1 mS is enough.
630 	 */
631 	msleep(1);
632 
633 	ret = regmap_reinit_cache(data->regmap, data->cd->regmap_cfg);
634 	if (ret)
635 		dev_err(data->dev, "Failed to reinit reg cache\n");
636 
637 	return ret;
638 }
639 
640 static int bu27010_chip_init(struct bu27008_data *data)
641 {
642 	int ret;
643 
644 	ret = regmap_write_bits(data->regmap, BU27008_REG_SYSTEM_CONTROL,
645 				BU27010_MASK_SW_RESET, BU27010_MASK_SW_RESET);
646 	if (ret)
647 		return dev_err_probe(data->dev, ret, "Sensor reset failed\n");
648 
649 	msleep(1);
650 
651 	/* Power ON*/
652 	ret = regmap_write_bits(data->regmap, BU27010_REG_POWER,
653 				BU27010_MASK_POWER, BU27010_MASK_POWER);
654 	if (ret)
655 		return dev_err_probe(data->dev, ret, "Sensor power-on failed\n");
656 
657 	msleep(1);
658 
659 	/* Release blocks from reset */
660 	ret = regmap_write_bits(data->regmap, BU27010_REG_RESET,
661 				BU27010_MASK_RESET, BU27010_RESET_RELEASE);
662 	if (ret)
663 		return dev_err_probe(data->dev, ret, "Sensor powering failed\n");
664 
665 	msleep(1);
666 
667 	/*
668 	 * The IRQ enabling on BU27010 is done in a peculiar way. The IRQ
669 	 * enabling is not a bit mask where individual IRQs could be enabled but
670 	 * a field which values are:
671 	 * 00 => IRQs disabled
672 	 * 01 => Data-ready (RGBC/IR)
673 	 * 10 => Data-ready (flicker)
674 	 * 11 => Flicker FIFO
675 	 *
676 	 * So, only one IRQ can be enabled at a time and enabling for example
677 	 * flicker FIFO would automagically disable data-ready IRQ.
678 	 *
679 	 * Currently the driver does not support the flicker. Hence, we can
680 	 * just treat the RGBC data-ready as single bit which can be enabled /
681 	 * disabled. This works for as long as the second bit in the field
682 	 * stays zero. Here we ensure it gets zeroed.
683 	 */
684 	return regmap_clear_bits(data->regmap, BU27010_REG_MODE_CONTROL4,
685 				 BU27010_IRQ_DIS_ALL);
686 }
687 
688 static const struct bu27_chip_data bu27010_chip = {
689 	.name = "bu27010",
690 	.chip_init = bu27010_chip_init,
691 	.get_gain_sel = bu27010_get_gain_sel,
692 	.write_gain_sel = bu27010_write_gain_sel,
693 	.regmap_cfg = &bu27010_regmap,
694 	.gains = &bu27010_gains[0],
695 	.gains_ir = &bu27010_gains_ir[0],
696 	.itimes = &bu27010_itimes[0],
697 	.num_gains = ARRAY_SIZE(bu27010_gains),
698 	.num_gains_ir = ARRAY_SIZE(bu27010_gains_ir),
699 	.num_itimes = ARRAY_SIZE(bu27010_itimes),
700 	.scale1x = BU27010_SCALE_1X,
701 	.drdy_en_reg = BU27010_REG_MODE_CONTROL4,
702 	.drdy_en_mask = BU27010_DRDY_EN,
703 	.meas_en_reg = BU27010_REG_MODE_CONTROL5,
704 	.meas_en_mask = BU27010_MASK_MEAS_EN,
705 	.valid_reg = BU27010_REG_MODE_CONTROL5,
706 	.chan_sel_reg = BU27008_REG_MODE_CONTROL1,
707 	.chan_sel_mask = BU27010_MASK_CHAN_SEL,
708 	.int_time_mask = BU27010_MASK_MEAS_MODE,
709 	.part_id = BU27010_ID,
710 };
711 
712 static const struct bu27_chip_data bu27008_chip = {
713 	.name = "bu27008",
714 	.chip_init = bu27008_chip_init,
715 	.get_gain_sel = bu27008_get_gain_sel,
716 	.write_gain_sel = bu27008_write_gain_sel,
717 	.regmap_cfg = &bu27008_regmap,
718 	.gains = &bu27008_gains[0],
719 	.gains_ir = &bu27008_gains_ir[0],
720 	.itimes = &bu27008_itimes[0],
721 	.num_gains = ARRAY_SIZE(bu27008_gains),
722 	.num_gains_ir = ARRAY_SIZE(bu27008_gains_ir),
723 	.num_itimes = ARRAY_SIZE(bu27008_itimes),
724 	.scale1x = BU27008_SCALE_1X,
725 	.drdy_en_reg = BU27008_REG_MODE_CONTROL3,
726 	.drdy_en_mask = BU27008_MASK_INT_EN,
727 	.valid_reg = BU27008_REG_MODE_CONTROL3,
728 	.meas_en_reg = BU27008_REG_MODE_CONTROL3,
729 	.meas_en_mask = BU27008_MASK_MEAS_EN,
730 	.chan_sel_reg = BU27008_REG_MODE_CONTROL3,
731 	.chan_sel_mask = BU27008_MASK_CHAN_SEL,
732 	.int_time_mask = BU27008_MASK_MEAS_MODE,
733 	.part_id = BU27008_ID,
734 };
735 
736 #define BU27008_MAX_VALID_RESULT_WAIT_US	50000
737 #define BU27008_VALID_RESULT_WAIT_QUANTA_US	1000
738 
739 static int bu27008_chan_read_data(struct bu27008_data *data, int reg, int *val)
740 {
741 	int ret, valid;
742 	__le16 tmp;
743 
744 	ret = regmap_read_poll_timeout(data->regmap, data->cd->valid_reg,
745 				       valid, (valid & BU27008_MASK_VALID),
746 				       BU27008_VALID_RESULT_WAIT_QUANTA_US,
747 				       BU27008_MAX_VALID_RESULT_WAIT_US);
748 	if (ret)
749 		return ret;
750 
751 	ret = regmap_bulk_read(data->regmap, reg, &tmp, sizeof(tmp));
752 	if (ret)
753 		dev_err(data->dev, "Reading channel data failed\n");
754 
755 	*val = le16_to_cpu(tmp);
756 
757 	return ret;
758 }
759 
760 static int bu27008_get_gain(struct bu27008_data *data, struct iio_gts *gts, int *gain)
761 {
762 	int ret, sel;
763 
764 	ret = data->cd->get_gain_sel(data, &sel);
765 	if (ret)
766 		return ret;
767 
768 	ret = iio_gts_find_gain_by_sel(gts, sel);
769 	if (ret < 0) {
770 		dev_err(data->dev, "unknown gain value 0x%x\n", sel);
771 		return ret;
772 	}
773 
774 	*gain = ret;
775 
776 	return 0;
777 }
778 
779 static int bu27008_set_gain(struct bu27008_data *data, int gain)
780 {
781 	int ret;
782 
783 	ret = iio_gts_find_sel_by_gain(&data->gts, gain);
784 	if (ret < 0)
785 		return ret;
786 
787 	return data->cd->write_gain_sel(data, ret);
788 }
789 
790 static int bu27008_get_int_time_sel(struct bu27008_data *data, int *sel)
791 {
792 	int ret, val;
793 
794 	ret = regmap_read(data->regmap, BU27008_REG_MODE_CONTROL1, &val);
795 	if (ret)
796 		return ret;
797 
798 	val &= data->cd->int_time_mask;
799 	val >>= ffs(data->cd->int_time_mask) - 1;
800 
801 	*sel = val;
802 
803 	return 0;
804 }
805 
806 static int bu27008_set_int_time_sel(struct bu27008_data *data, int sel)
807 {
808 	sel <<= ffs(data->cd->int_time_mask) - 1;
809 
810 	return regmap_update_bits(data->regmap, BU27008_REG_MODE_CONTROL1,
811 				  data->cd->int_time_mask, sel);
812 }
813 
814 static int bu27008_get_int_time_us(struct bu27008_data *data)
815 {
816 	int ret, sel;
817 
818 	ret = bu27008_get_int_time_sel(data, &sel);
819 	if (ret)
820 		return ret;
821 
822 	return iio_gts_find_int_time_by_sel(&data->gts, sel);
823 }
824 
825 static int _bu27008_get_scale(struct bu27008_data *data, bool ir, int *val,
826 			      int *val2)
827 {
828 	struct iio_gts *gts;
829 	int gain, ret;
830 
831 	if (ir)
832 		gts = &data->gts_ir;
833 	else
834 		gts = &data->gts;
835 
836 	ret = bu27008_get_gain(data, gts, &gain);
837 	if (ret)
838 		return ret;
839 
840 	ret = bu27008_get_int_time_us(data);
841 	if (ret < 0)
842 		return ret;
843 
844 	return iio_gts_get_scale(gts, gain, ret, val, val2);
845 }
846 
847 static int bu27008_get_scale(struct bu27008_data *data, bool ir, int *val,
848 			     int *val2)
849 {
850 	int ret;
851 
852 	mutex_lock(&data->mutex);
853 	ret = _bu27008_get_scale(data, ir, val, val2);
854 	mutex_unlock(&data->mutex);
855 
856 	return ret;
857 }
858 
859 static int bu27008_set_int_time(struct bu27008_data *data, int time)
860 {
861 	int ret;
862 
863 	ret = iio_gts_find_sel_by_int_time(&data->gts, time);
864 	if (ret < 0)
865 		return ret;
866 
867 	return bu27008_set_int_time_sel(data, ret);
868 }
869 
870 /* Try to change the time so that the scale is maintained */
871 static int bu27008_try_set_int_time(struct bu27008_data *data, int int_time_new)
872 {
873 	int ret, old_time_sel, new_time_sel,  old_gain, new_gain;
874 
875 	mutex_lock(&data->mutex);
876 
877 	ret = bu27008_get_int_time_sel(data, &old_time_sel);
878 	if (ret < 0)
879 		goto unlock_out;
880 
881 	if (!iio_gts_valid_time(&data->gts, int_time_new)) {
882 		dev_dbg(data->dev, "Unsupported integration time %u\n",
883 			int_time_new);
884 
885 		ret = -EINVAL;
886 		goto unlock_out;
887 	}
888 
889 	/* If we already use requested time, then we're done */
890 	new_time_sel = iio_gts_find_sel_by_int_time(&data->gts, int_time_new);
891 	if (new_time_sel == old_time_sel)
892 		goto unlock_out;
893 
894 	ret = bu27008_get_gain(data, &data->gts, &old_gain);
895 	if (ret)
896 		goto unlock_out;
897 
898 	ret = iio_gts_find_new_gain_sel_by_old_gain_time(&data->gts, old_gain,
899 				old_time_sel, new_time_sel, &new_gain);
900 	if (ret) {
901 		int scale1, scale2;
902 		bool ok;
903 
904 		_bu27008_get_scale(data, false, &scale1, &scale2);
905 		dev_dbg(data->dev,
906 			"Can't support time %u with current scale %u %u\n",
907 			int_time_new, scale1, scale2);
908 
909 		if (new_gain < 0)
910 			goto unlock_out;
911 
912 		/*
913 		 * If caller requests for integration time change and we
914 		 * can't support the scale - then the caller should be
915 		 * prepared to 'pick up the pieces and deal with the
916 		 * fact that the scale changed'.
917 		 */
918 		ret = iio_find_closest_gain_low(&data->gts, new_gain, &ok);
919 		if (!ok)
920 			dev_dbg(data->dev, "optimal gain out of range\n");
921 
922 		if (ret < 0) {
923 			dev_dbg(data->dev,
924 				 "Total gain increase. Risk of saturation");
925 			ret = iio_gts_get_min_gain(&data->gts);
926 			if (ret < 0)
927 				goto unlock_out;
928 		}
929 		new_gain = ret;
930 		dev_dbg(data->dev, "scale changed, new gain %u\n", new_gain);
931 	}
932 
933 	ret = bu27008_set_gain(data, new_gain);
934 	if (ret)
935 		goto unlock_out;
936 
937 	ret = bu27008_set_int_time(data, int_time_new);
938 
939 unlock_out:
940 	mutex_unlock(&data->mutex);
941 
942 	return ret;
943 }
944 
945 static int bu27008_meas_set(struct bu27008_data *data, bool enable)
946 {
947 	if (enable)
948 		return regmap_set_bits(data->regmap, data->cd->meas_en_reg,
949 				       data->cd->meas_en_mask);
950 	return regmap_clear_bits(data->regmap, data->cd->meas_en_reg,
951 				 data->cd->meas_en_mask);
952 }
953 
954 static int bu27008_chan_cfg(struct bu27008_data *data,
955 			    struct iio_chan_spec const *chan)
956 {
957 	int chan_sel;
958 
959 	if (chan->scan_index == BU27008_BLUE)
960 		chan_sel = BU27008_BLUE2_CLEAR3;
961 	else
962 		chan_sel = BU27008_CLEAR2_IR3;
963 
964 	/*
965 	 * prepare bitfield for channel sel. The FIELD_PREP works only when
966 	 * mask is constant. In our case the mask is assigned based on the
967 	 * chip type. Hence the open-coded FIELD_PREP here. We don't bother
968 	 * zeroing the irrelevant bits though - update_bits takes care of that.
969 	 */
970 	chan_sel <<= ffs(data->cd->chan_sel_mask) - 1;
971 
972 	return regmap_update_bits(data->regmap, data->cd->chan_sel_reg,
973 				  BU27008_MASK_CHAN_SEL, chan_sel);
974 }
975 
976 static int bu27008_read_one(struct bu27008_data *data, struct iio_dev *idev,
977 			    struct iio_chan_spec const *chan, int *val, int *val2)
978 {
979 	int ret, int_time;
980 
981 	ret = bu27008_chan_cfg(data, chan);
982 	if (ret)
983 		return ret;
984 
985 	ret = bu27008_meas_set(data, true);
986 	if (ret)
987 		return ret;
988 
989 	ret = bu27008_get_int_time_us(data);
990 	if (ret < 0)
991 		int_time = BU27008_MEAS_TIME_MAX_MS;
992 	else
993 		int_time = ret / USEC_PER_MSEC;
994 
995 	msleep(int_time);
996 
997 	ret = bu27008_chan_read_data(data, chan->address, val);
998 	if (!ret)
999 		ret = IIO_VAL_INT;
1000 
1001 	if (bu27008_meas_set(data, false))
1002 		dev_warn(data->dev, "measurement disabling failed\n");
1003 
1004 	return ret;
1005 }
1006 
1007 static int bu27008_read_raw(struct iio_dev *idev,
1008 			   struct iio_chan_spec const *chan,
1009 			   int *val, int *val2, long mask)
1010 {
1011 	struct bu27008_data *data = iio_priv(idev);
1012 	int busy, ret;
1013 
1014 	switch (mask) {
1015 	case IIO_CHAN_INFO_RAW:
1016 		busy = iio_device_claim_direct_mode(idev);
1017 		if (busy)
1018 			return -EBUSY;
1019 
1020 		mutex_lock(&data->mutex);
1021 		ret = bu27008_read_one(data, idev, chan, val, val2);
1022 		mutex_unlock(&data->mutex);
1023 
1024 		iio_device_release_direct_mode(idev);
1025 
1026 		return ret;
1027 
1028 	case IIO_CHAN_INFO_SCALE:
1029 		ret = bu27008_get_scale(data, chan->scan_index == BU27008_IR,
1030 					val, val2);
1031 		if (ret)
1032 			return ret;
1033 
1034 		return IIO_VAL_INT_PLUS_NANO;
1035 
1036 	case IIO_CHAN_INFO_INT_TIME:
1037 		ret = bu27008_get_int_time_us(data);
1038 		if (ret < 0)
1039 			return ret;
1040 
1041 		*val = 0;
1042 		*val2 = ret;
1043 
1044 		return IIO_VAL_INT_PLUS_MICRO;
1045 
1046 	default:
1047 		return -EINVAL;
1048 	}
1049 }
1050 
1051 /* Called if the new scale could not be supported with existing int-time */
1052 static int bu27008_try_find_new_time_gain(struct bu27008_data *data, int val,
1053 					  int val2, int *gain_sel)
1054 {
1055 	int i, ret, new_time_sel;
1056 
1057 	for (i = 0; i < data->gts.num_itime; i++) {
1058 		new_time_sel = data->gts.itime_table[i].sel;
1059 		ret = iio_gts_find_gain_sel_for_scale_using_time(&data->gts,
1060 					new_time_sel, val, val2, gain_sel);
1061 		if (!ret)
1062 			break;
1063 	}
1064 	if (i == data->gts.num_itime) {
1065 		dev_err(data->dev, "Can't support scale %u %u\n", val, val2);
1066 
1067 		return -EINVAL;
1068 	}
1069 
1070 	return bu27008_set_int_time_sel(data, new_time_sel);
1071 }
1072 
1073 static int bu27008_set_scale(struct bu27008_data *data,
1074 			     struct iio_chan_spec const *chan,
1075 			     int val, int val2)
1076 {
1077 	int ret, gain_sel, time_sel;
1078 
1079 	if (chan->scan_index == BU27008_IR)
1080 		return -EINVAL;
1081 
1082 	mutex_lock(&data->mutex);
1083 
1084 	ret = bu27008_get_int_time_sel(data, &time_sel);
1085 	if (ret < 0)
1086 		goto unlock_out;
1087 
1088 	ret = iio_gts_find_gain_sel_for_scale_using_time(&data->gts, time_sel,
1089 						val, val2, &gain_sel);
1090 	if (ret) {
1091 		ret = bu27008_try_find_new_time_gain(data, val, val2, &gain_sel);
1092 		if (ret)
1093 			goto unlock_out;
1094 
1095 	}
1096 	ret = data->cd->write_gain_sel(data, gain_sel);
1097 
1098 unlock_out:
1099 	mutex_unlock(&data->mutex);
1100 
1101 	return ret;
1102 }
1103 
1104 static int bu27008_write_raw_get_fmt(struct iio_dev *indio_dev,
1105 				     struct iio_chan_spec const *chan,
1106 				     long mask)
1107 {
1108 
1109 	switch (mask) {
1110 	case IIO_CHAN_INFO_SCALE:
1111 		return IIO_VAL_INT_PLUS_NANO;
1112 	case IIO_CHAN_INFO_INT_TIME:
1113 		return IIO_VAL_INT_PLUS_MICRO;
1114 	default:
1115 		return -EINVAL;
1116 	}
1117 }
1118 
1119 static int bu27008_write_raw(struct iio_dev *idev,
1120 			     struct iio_chan_spec const *chan,
1121 			     int val, int val2, long mask)
1122 {
1123 	struct bu27008_data *data = iio_priv(idev);
1124 	int ret;
1125 
1126 	/*
1127 	 * Do not allow changing scale when measurement is ongoing as doing so
1128 	 * could make values in the buffer inconsistent.
1129 	 */
1130 	ret = iio_device_claim_direct_mode(idev);
1131 	if (ret)
1132 		return ret;
1133 
1134 	switch (mask) {
1135 	case IIO_CHAN_INFO_SCALE:
1136 		ret = bu27008_set_scale(data, chan, val, val2);
1137 		break;
1138 	case IIO_CHAN_INFO_INT_TIME:
1139 		if (val) {
1140 			ret = -EINVAL;
1141 			break;
1142 		}
1143 		ret = bu27008_try_set_int_time(data, val2);
1144 		break;
1145 	default:
1146 		ret = -EINVAL;
1147 		break;
1148 	}
1149 	iio_device_release_direct_mode(idev);
1150 
1151 	return ret;
1152 }
1153 
1154 static int bu27008_read_avail(struct iio_dev *idev,
1155 			      struct iio_chan_spec const *chan, const int **vals,
1156 			      int *type, int *length, long mask)
1157 {
1158 	struct bu27008_data *data = iio_priv(idev);
1159 
1160 	switch (mask) {
1161 	case IIO_CHAN_INFO_INT_TIME:
1162 		return iio_gts_avail_times(&data->gts, vals, type, length);
1163 	case IIO_CHAN_INFO_SCALE:
1164 		if (chan->channel2 == IIO_MOD_LIGHT_IR)
1165 			return iio_gts_all_avail_scales(&data->gts_ir, vals,
1166 							type, length);
1167 		return iio_gts_all_avail_scales(&data->gts, vals, type, length);
1168 	default:
1169 		return -EINVAL;
1170 	}
1171 }
1172 
1173 static int bu27008_update_scan_mode(struct iio_dev *idev,
1174 				    const unsigned long *scan_mask)
1175 {
1176 	struct bu27008_data *data = iio_priv(idev);
1177 	int chan_sel;
1178 
1179 	/* Configure channel selection */
1180 	if (test_bit(BU27008_BLUE, idev->active_scan_mask)) {
1181 		if (test_bit(BU27008_CLEAR, idev->active_scan_mask))
1182 			chan_sel = BU27008_BLUE2_CLEAR3;
1183 		else
1184 			chan_sel = BU27008_BLUE2_IR3;
1185 	} else {
1186 		chan_sel = BU27008_CLEAR2_IR3;
1187 	}
1188 
1189 	chan_sel <<= ffs(data->cd->chan_sel_mask) - 1;
1190 
1191 	return regmap_update_bits(data->regmap, data->cd->chan_sel_reg,
1192 				  data->cd->chan_sel_mask, chan_sel);
1193 }
1194 
1195 static const struct iio_info bu27008_info = {
1196 	.read_raw = &bu27008_read_raw,
1197 	.write_raw = &bu27008_write_raw,
1198 	.write_raw_get_fmt = &bu27008_write_raw_get_fmt,
1199 	.read_avail = &bu27008_read_avail,
1200 	.update_scan_mode = bu27008_update_scan_mode,
1201 	.validate_trigger = iio_validate_own_trigger,
1202 };
1203 
1204 static int bu27008_trigger_set_state(struct iio_trigger *trig, bool state)
1205 {
1206 	struct bu27008_data *data = iio_trigger_get_drvdata(trig);
1207 	int ret;
1208 
1209 
1210 	if (state)
1211 		ret = regmap_set_bits(data->regmap, data->cd->drdy_en_reg,
1212 				      data->cd->drdy_en_mask);
1213 	else
1214 		ret = regmap_clear_bits(data->regmap, data->cd->drdy_en_reg,
1215 					data->cd->drdy_en_mask);
1216 	if (ret)
1217 		dev_err(data->dev, "Failed to set trigger state\n");
1218 
1219 	return ret;
1220 }
1221 
1222 static void bu27008_trigger_reenable(struct iio_trigger *trig)
1223 {
1224 	struct bu27008_data *data = iio_trigger_get_drvdata(trig);
1225 
1226 	enable_irq(data->irq);
1227 }
1228 
1229 static const struct iio_trigger_ops bu27008_trigger_ops = {
1230 	.set_trigger_state = bu27008_trigger_set_state,
1231 	.reenable = bu27008_trigger_reenable,
1232 };
1233 
1234 static irqreturn_t bu27008_trigger_handler(int irq, void *p)
1235 {
1236 	struct iio_poll_func *pf = p;
1237 	struct iio_dev *idev = pf->indio_dev;
1238 	struct bu27008_data *data = iio_priv(idev);
1239 	struct {
1240 		__le16 chan[BU27008_NUM_HW_CHANS];
1241 		s64 ts __aligned(8);
1242 	} raw;
1243 	int ret, dummy;
1244 
1245 	memset(&raw, 0, sizeof(raw));
1246 
1247 	/*
1248 	 * After some measurements, it seems reading the
1249 	 * BU27008_REG_MODE_CONTROL3 debounces the IRQ line
1250 	 */
1251 	ret = regmap_read(data->regmap, data->cd->valid_reg, &dummy);
1252 	if (ret < 0)
1253 		goto err_read;
1254 
1255 	ret = regmap_bulk_read(data->regmap, BU27008_REG_DATA0_LO, &raw.chan,
1256 			       sizeof(raw.chan));
1257 	if (ret < 0)
1258 		goto err_read;
1259 
1260 	iio_push_to_buffers_with_timestamp(idev, &raw, pf->timestamp);
1261 err_read:
1262 	iio_trigger_notify_done(idev->trig);
1263 
1264 	return IRQ_HANDLED;
1265 }
1266 
1267 static int bu27008_buffer_preenable(struct iio_dev *idev)
1268 {
1269 	struct bu27008_data *data = iio_priv(idev);
1270 
1271 	return bu27008_meas_set(data, true);
1272 }
1273 
1274 static int bu27008_buffer_postdisable(struct iio_dev *idev)
1275 {
1276 	struct bu27008_data *data = iio_priv(idev);
1277 
1278 	return bu27008_meas_set(data, false);
1279 }
1280 
1281 static const struct iio_buffer_setup_ops bu27008_buffer_ops = {
1282 	.preenable = bu27008_buffer_preenable,
1283 	.postdisable = bu27008_buffer_postdisable,
1284 };
1285 
1286 static irqreturn_t bu27008_data_rdy_poll(int irq, void *private)
1287 {
1288 	/*
1289 	 * The BU27008 keeps IRQ asserted until we read the VALID bit from
1290 	 * a register. We need to keep the IRQ disabled until then.
1291 	 */
1292 	disable_irq_nosync(irq);
1293 	iio_trigger_poll(private);
1294 
1295 	return IRQ_HANDLED;
1296 }
1297 
1298 static int bu27008_setup_trigger(struct bu27008_data *data, struct iio_dev *idev)
1299 {
1300 	struct iio_trigger *itrig;
1301 	char *name;
1302 	int ret;
1303 
1304 	ret = devm_iio_triggered_buffer_setup(data->dev, idev,
1305 					      &iio_pollfunc_store_time,
1306 					      bu27008_trigger_handler,
1307 					      &bu27008_buffer_ops);
1308 	if (ret)
1309 		return dev_err_probe(data->dev, ret,
1310 			     "iio_triggered_buffer_setup_ext FAIL\n");
1311 
1312 	itrig = devm_iio_trigger_alloc(data->dev, "%sdata-rdy-dev%d",
1313 				       idev->name, iio_device_id(idev));
1314 	if (!itrig)
1315 		return -ENOMEM;
1316 
1317 	data->trig = itrig;
1318 
1319 	itrig->ops = &bu27008_trigger_ops;
1320 	iio_trigger_set_drvdata(itrig, data);
1321 
1322 	name = devm_kasprintf(data->dev, GFP_KERNEL, "%s-bu27008",
1323 			      dev_name(data->dev));
1324 
1325 	ret = devm_request_irq(data->dev, data->irq,
1326 			       &bu27008_data_rdy_poll,
1327 			       0, name, itrig);
1328 	if (ret)
1329 		return dev_err_probe(data->dev, ret, "Could not request IRQ\n");
1330 
1331 	ret = devm_iio_trigger_register(data->dev, itrig);
1332 	if (ret)
1333 		return dev_err_probe(data->dev, ret,
1334 				     "Trigger registration failed\n");
1335 
1336 	/* set default trigger */
1337 	idev->trig = iio_trigger_get(itrig);
1338 
1339 	return 0;
1340 }
1341 
1342 static int bu27008_probe(struct i2c_client *i2c)
1343 {
1344 	struct device *dev = &i2c->dev;
1345 	struct bu27008_data *data;
1346 	struct regmap *regmap;
1347 	unsigned int part_id, reg;
1348 	struct iio_dev *idev;
1349 	int ret;
1350 
1351 	idev = devm_iio_device_alloc(dev, sizeof(*data));
1352 	if (!idev)
1353 		return -ENOMEM;
1354 
1355 	ret = devm_regulator_get_enable(dev, "vdd");
1356 	if (ret)
1357 		return dev_err_probe(dev, ret, "Failed to get regulator\n");
1358 
1359 	data = iio_priv(idev);
1360 
1361 	data->cd = device_get_match_data(&i2c->dev);
1362 	if (!data->cd)
1363 		return -ENODEV;
1364 
1365 	regmap = devm_regmap_init_i2c(i2c, data->cd->regmap_cfg);
1366 	if (IS_ERR(regmap))
1367 		return dev_err_probe(dev, PTR_ERR(regmap),
1368 				     "Failed to initialize Regmap\n");
1369 
1370 
1371 	ret = regmap_read(regmap, BU27008_REG_SYSTEM_CONTROL, &reg);
1372 	if (ret)
1373 		return dev_err_probe(dev, ret, "Failed to access sensor\n");
1374 
1375 	part_id = FIELD_GET(BU27008_MASK_PART_ID, reg);
1376 
1377 	if (part_id != data->cd->part_id)
1378 		dev_warn(dev, "unknown device 0x%x\n", part_id);
1379 
1380 	ret = devm_iio_init_iio_gts(dev, data->cd->scale1x, 0, data->cd->gains,
1381 				    data->cd->num_gains, data->cd->itimes,
1382 				    data->cd->num_itimes, &data->gts);
1383 	if (ret)
1384 		return ret;
1385 
1386 	ret = devm_iio_init_iio_gts(dev, data->cd->scale1x, 0, data->cd->gains_ir,
1387 				    data->cd->num_gains_ir, data->cd->itimes,
1388 				    data->cd->num_itimes, &data->gts_ir);
1389 	if (ret)
1390 		return ret;
1391 
1392 	mutex_init(&data->mutex);
1393 	data->regmap = regmap;
1394 	data->dev = dev;
1395 	data->irq = i2c->irq;
1396 
1397 	idev->channels = bu27008_channels;
1398 	idev->num_channels = ARRAY_SIZE(bu27008_channels);
1399 	idev->name = data->cd->name;
1400 	idev->info = &bu27008_info;
1401 	idev->modes = INDIO_DIRECT_MODE;
1402 	idev->available_scan_masks = bu27008_scan_masks;
1403 
1404 	ret = data->cd->chip_init(data);
1405 	if (ret)
1406 		return ret;
1407 
1408 	if (i2c->irq) {
1409 		ret = bu27008_setup_trigger(data, idev);
1410 		if (ret)
1411 			return ret;
1412 	} else {
1413 		dev_info(dev, "No IRQ, buffered mode disabled\n");
1414 	}
1415 
1416 	ret = devm_iio_device_register(dev, idev);
1417 	if (ret)
1418 		return dev_err_probe(dev, ret,
1419 				     "Unable to register iio device\n");
1420 
1421 	return 0;
1422 }
1423 
1424 static const struct of_device_id bu27008_of_match[] = {
1425 	{ .compatible = "rohm,bu27008", .data = &bu27008_chip },
1426 	{ .compatible = "rohm,bu27010", .data = &bu27010_chip },
1427 	{ }
1428 };
1429 MODULE_DEVICE_TABLE(of, bu27008_of_match);
1430 
1431 static struct i2c_driver bu27008_i2c_driver = {
1432 	.driver = {
1433 		.name = "bu27008",
1434 		.of_match_table = bu27008_of_match,
1435 		.probe_type = PROBE_PREFER_ASYNCHRONOUS,
1436 	},
1437 	.probe = bu27008_probe,
1438 };
1439 module_i2c_driver(bu27008_i2c_driver);
1440 
1441 MODULE_DESCRIPTION("ROHM BU27008 and BU27010 colour sensor driver");
1442 MODULE_AUTHOR("Matti Vaittinen <matti.vaittinen@fi.rohmeurope.com>");
1443 MODULE_LICENSE("GPL");
1444 MODULE_IMPORT_NS(IIO_GTS_HELPER);
1445