1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3  * Xilinx XADC driver
4  *
5  * Copyright 2013-2014 Analog Devices Inc.
6  *  Author: Lars-Peter Clauen <lars@metafoo.de>
7  *
8  * Documentation for the parts can be found at:
9  *  - XADC hardmacro: Xilinx UG480
10  *  - ZYNQ XADC interface: Xilinx UG585
11  *  - AXI XADC interface: Xilinx PG019
12  */
13 
14 #include <linux/clk.h>
15 #include <linux/device.h>
16 #include <linux/err.h>
17 #include <linux/interrupt.h>
18 #include <linux/io.h>
19 #include <linux/kernel.h>
20 #include <linux/module.h>
21 #include <linux/of.h>
22 #include <linux/platform_device.h>
23 #include <linux/slab.h>
24 #include <linux/sysfs.h>
25 
26 #include <linux/iio/buffer.h>
27 #include <linux/iio/events.h>
28 #include <linux/iio/iio.h>
29 #include <linux/iio/sysfs.h>
30 #include <linux/iio/trigger.h>
31 #include <linux/iio/trigger_consumer.h>
32 #include <linux/iio/triggered_buffer.h>
33 
34 #include "xilinx-xadc.h"
35 
36 static const unsigned int XADC_ZYNQ_UNMASK_TIMEOUT = 500;
37 
38 /* ZYNQ register definitions */
39 #define XADC_ZYNQ_REG_CFG	0x00
40 #define XADC_ZYNQ_REG_INTSTS	0x04
41 #define XADC_ZYNQ_REG_INTMSK	0x08
42 #define XADC_ZYNQ_REG_STATUS	0x0c
43 #define XADC_ZYNQ_REG_CFIFO	0x10
44 #define XADC_ZYNQ_REG_DFIFO	0x14
45 #define XADC_ZYNQ_REG_CTL		0x18
46 
47 #define XADC_ZYNQ_CFG_ENABLE		BIT(31)
48 #define XADC_ZYNQ_CFG_CFIFOTH_MASK	(0xf << 20)
49 #define XADC_ZYNQ_CFG_CFIFOTH_OFFSET	20
50 #define XADC_ZYNQ_CFG_DFIFOTH_MASK	(0xf << 16)
51 #define XADC_ZYNQ_CFG_DFIFOTH_OFFSET	16
52 #define XADC_ZYNQ_CFG_WEDGE		BIT(13)
53 #define XADC_ZYNQ_CFG_REDGE		BIT(12)
54 #define XADC_ZYNQ_CFG_TCKRATE_MASK	(0x3 << 8)
55 #define XADC_ZYNQ_CFG_TCKRATE_DIV2	(0x0 << 8)
56 #define XADC_ZYNQ_CFG_TCKRATE_DIV4	(0x1 << 8)
57 #define XADC_ZYNQ_CFG_TCKRATE_DIV8	(0x2 << 8)
58 #define XADC_ZYNQ_CFG_TCKRATE_DIV16	(0x3 << 8)
59 #define XADC_ZYNQ_CFG_IGAP_MASK		0x1f
60 #define XADC_ZYNQ_CFG_IGAP(x)		(x)
61 
62 #define XADC_ZYNQ_INT_CFIFO_LTH		BIT(9)
63 #define XADC_ZYNQ_INT_DFIFO_GTH		BIT(8)
64 #define XADC_ZYNQ_INT_ALARM_MASK	0xff
65 #define XADC_ZYNQ_INT_ALARM_OFFSET	0
66 
67 #define XADC_ZYNQ_STATUS_CFIFO_LVL_MASK	(0xf << 16)
68 #define XADC_ZYNQ_STATUS_CFIFO_LVL_OFFSET	16
69 #define XADC_ZYNQ_STATUS_DFIFO_LVL_MASK	(0xf << 12)
70 #define XADC_ZYNQ_STATUS_DFIFO_LVL_OFFSET	12
71 #define XADC_ZYNQ_STATUS_CFIFOF		BIT(11)
72 #define XADC_ZYNQ_STATUS_CFIFOE		BIT(10)
73 #define XADC_ZYNQ_STATUS_DFIFOF		BIT(9)
74 #define XADC_ZYNQ_STATUS_DFIFOE		BIT(8)
75 #define XADC_ZYNQ_STATUS_OT		BIT(7)
76 #define XADC_ZYNQ_STATUS_ALM(x)		BIT(x)
77 
78 #define XADC_ZYNQ_CTL_RESET		BIT(4)
79 
80 #define XADC_ZYNQ_CMD_NOP		0x00
81 #define XADC_ZYNQ_CMD_READ		0x01
82 #define XADC_ZYNQ_CMD_WRITE		0x02
83 
84 #define XADC_ZYNQ_CMD(cmd, addr, data) (((cmd) << 26) | ((addr) << 16) | (data))
85 
86 /* AXI register definitions */
87 #define XADC_AXI_REG_RESET		0x00
88 #define XADC_AXI_REG_STATUS		0x04
89 #define XADC_AXI_REG_ALARM_STATUS	0x08
90 #define XADC_AXI_REG_CONVST		0x0c
91 #define XADC_AXI_REG_XADC_RESET		0x10
92 #define XADC_AXI_REG_GIER		0x5c
93 #define XADC_AXI_REG_IPISR		0x60
94 #define XADC_AXI_REG_IPIER		0x68
95 #define XADC_AXI_ADC_REG_OFFSET		0x200
96 
97 #define XADC_AXI_RESET_MAGIC		0xa
98 #define XADC_AXI_GIER_ENABLE		BIT(31)
99 
100 #define XADC_AXI_INT_EOS		BIT(4)
101 #define XADC_AXI_INT_ALARM_MASK		0x3c0f
102 
103 #define XADC_FLAGS_BUFFERED BIT(0)
104 
105 static void xadc_write_reg(struct xadc *xadc, unsigned int reg,
106 	uint32_t val)
107 {
108 	writel(val, xadc->base + reg);
109 }
110 
111 static void xadc_read_reg(struct xadc *xadc, unsigned int reg,
112 	uint32_t *val)
113 {
114 	*val = readl(xadc->base + reg);
115 }
116 
117 /*
118  * The ZYNQ interface uses two asynchronous FIFOs for communication with the
119  * XADC. Reads and writes to the XADC register are performed by submitting a
120  * request to the command FIFO (CFIFO), once the request has been completed the
121  * result can be read from the data FIFO (DFIFO). The method currently used in
122  * this driver is to submit the request for a read/write operation, then go to
123  * sleep and wait for an interrupt that signals that a response is available in
124  * the data FIFO.
125  */
126 
127 static void xadc_zynq_write_fifo(struct xadc *xadc, uint32_t *cmd,
128 	unsigned int n)
129 {
130 	unsigned int i;
131 
132 	for (i = 0; i < n; i++)
133 		xadc_write_reg(xadc, XADC_ZYNQ_REG_CFIFO, cmd[i]);
134 }
135 
136 static void xadc_zynq_drain_fifo(struct xadc *xadc)
137 {
138 	uint32_t status, tmp;
139 
140 	xadc_read_reg(xadc, XADC_ZYNQ_REG_STATUS, &status);
141 
142 	while (!(status & XADC_ZYNQ_STATUS_DFIFOE)) {
143 		xadc_read_reg(xadc, XADC_ZYNQ_REG_DFIFO, &tmp);
144 		xadc_read_reg(xadc, XADC_ZYNQ_REG_STATUS, &status);
145 	}
146 }
147 
148 static void xadc_zynq_update_intmsk(struct xadc *xadc, unsigned int mask,
149 	unsigned int val)
150 {
151 	xadc->zynq_intmask &= ~mask;
152 	xadc->zynq_intmask |= val;
153 
154 	xadc_write_reg(xadc, XADC_ZYNQ_REG_INTMSK,
155 		xadc->zynq_intmask | xadc->zynq_masked_alarm);
156 }
157 
158 static int xadc_zynq_write_adc_reg(struct xadc *xadc, unsigned int reg,
159 	uint16_t val)
160 {
161 	uint32_t cmd[1];
162 	uint32_t tmp;
163 	int ret;
164 
165 	spin_lock_irq(&xadc->lock);
166 	xadc_zynq_update_intmsk(xadc, XADC_ZYNQ_INT_DFIFO_GTH,
167 			XADC_ZYNQ_INT_DFIFO_GTH);
168 
169 	reinit_completion(&xadc->completion);
170 
171 	cmd[0] = XADC_ZYNQ_CMD(XADC_ZYNQ_CMD_WRITE, reg, val);
172 	xadc_zynq_write_fifo(xadc, cmd, ARRAY_SIZE(cmd));
173 	xadc_read_reg(xadc, XADC_ZYNQ_REG_CFG, &tmp);
174 	tmp &= ~XADC_ZYNQ_CFG_DFIFOTH_MASK;
175 	tmp |= 0 << XADC_ZYNQ_CFG_DFIFOTH_OFFSET;
176 	xadc_write_reg(xadc, XADC_ZYNQ_REG_CFG, tmp);
177 
178 	xadc_zynq_update_intmsk(xadc, XADC_ZYNQ_INT_DFIFO_GTH, 0);
179 	spin_unlock_irq(&xadc->lock);
180 
181 	ret = wait_for_completion_interruptible_timeout(&xadc->completion, HZ);
182 	if (ret == 0)
183 		ret = -EIO;
184 	else
185 		ret = 0;
186 
187 	xadc_read_reg(xadc, XADC_ZYNQ_REG_DFIFO, &tmp);
188 
189 	return ret;
190 }
191 
192 static int xadc_zynq_read_adc_reg(struct xadc *xadc, unsigned int reg,
193 	uint16_t *val)
194 {
195 	uint32_t cmd[2];
196 	uint32_t resp, tmp;
197 	int ret;
198 
199 	cmd[0] = XADC_ZYNQ_CMD(XADC_ZYNQ_CMD_READ, reg, 0);
200 	cmd[1] = XADC_ZYNQ_CMD(XADC_ZYNQ_CMD_NOP, 0, 0);
201 
202 	spin_lock_irq(&xadc->lock);
203 	xadc_zynq_update_intmsk(xadc, XADC_ZYNQ_INT_DFIFO_GTH,
204 			XADC_ZYNQ_INT_DFIFO_GTH);
205 	xadc_zynq_drain_fifo(xadc);
206 	reinit_completion(&xadc->completion);
207 
208 	xadc_zynq_write_fifo(xadc, cmd, ARRAY_SIZE(cmd));
209 	xadc_read_reg(xadc, XADC_ZYNQ_REG_CFG, &tmp);
210 	tmp &= ~XADC_ZYNQ_CFG_DFIFOTH_MASK;
211 	tmp |= 1 << XADC_ZYNQ_CFG_DFIFOTH_OFFSET;
212 	xadc_write_reg(xadc, XADC_ZYNQ_REG_CFG, tmp);
213 
214 	xadc_zynq_update_intmsk(xadc, XADC_ZYNQ_INT_DFIFO_GTH, 0);
215 	spin_unlock_irq(&xadc->lock);
216 	ret = wait_for_completion_interruptible_timeout(&xadc->completion, HZ);
217 	if (ret == 0)
218 		ret = -EIO;
219 	if (ret < 0)
220 		return ret;
221 
222 	xadc_read_reg(xadc, XADC_ZYNQ_REG_DFIFO, &resp);
223 	xadc_read_reg(xadc, XADC_ZYNQ_REG_DFIFO, &resp);
224 
225 	*val = resp & 0xffff;
226 
227 	return 0;
228 }
229 
230 static unsigned int xadc_zynq_transform_alarm(unsigned int alarm)
231 {
232 	return ((alarm & 0x80) >> 4) |
233 		((alarm & 0x78) << 1) |
234 		(alarm & 0x07);
235 }
236 
237 /*
238  * The ZYNQ threshold interrupts are level sensitive. Since we can't make the
239  * threshold condition go way from within the interrupt handler, this means as
240  * soon as a threshold condition is present we would enter the interrupt handler
241  * again and again. To work around this we mask all active thresholds interrupts
242  * in the interrupt handler and start a timer. In this timer we poll the
243  * interrupt status and only if the interrupt is inactive we unmask it again.
244  */
245 static void xadc_zynq_unmask_worker(struct work_struct *work)
246 {
247 	struct xadc *xadc = container_of(work, struct xadc, zynq_unmask_work.work);
248 	unsigned int misc_sts, unmask;
249 
250 	xadc_read_reg(xadc, XADC_ZYNQ_REG_STATUS, &misc_sts);
251 
252 	misc_sts &= XADC_ZYNQ_INT_ALARM_MASK;
253 
254 	spin_lock_irq(&xadc->lock);
255 
256 	/* Clear those bits which are not active anymore */
257 	unmask = (xadc->zynq_masked_alarm ^ misc_sts) & xadc->zynq_masked_alarm;
258 	xadc->zynq_masked_alarm &= misc_sts;
259 
260 	/* Also clear those which are masked out anyway */
261 	xadc->zynq_masked_alarm &= ~xadc->zynq_intmask;
262 
263 	/* Clear the interrupts before we unmask them */
264 	xadc_write_reg(xadc, XADC_ZYNQ_REG_INTSTS, unmask);
265 
266 	xadc_zynq_update_intmsk(xadc, 0, 0);
267 
268 	spin_unlock_irq(&xadc->lock);
269 
270 	/* if still pending some alarm re-trigger the timer */
271 	if (xadc->zynq_masked_alarm) {
272 		schedule_delayed_work(&xadc->zynq_unmask_work,
273 				msecs_to_jiffies(XADC_ZYNQ_UNMASK_TIMEOUT));
274 	}
275 
276 }
277 
278 static irqreturn_t xadc_zynq_interrupt_handler(int irq, void *devid)
279 {
280 	struct iio_dev *indio_dev = devid;
281 	struct xadc *xadc = iio_priv(indio_dev);
282 	uint32_t status;
283 
284 	xadc_read_reg(xadc, XADC_ZYNQ_REG_INTSTS, &status);
285 
286 	status &= ~(xadc->zynq_intmask | xadc->zynq_masked_alarm);
287 
288 	if (!status)
289 		return IRQ_NONE;
290 
291 	spin_lock(&xadc->lock);
292 
293 	xadc_write_reg(xadc, XADC_ZYNQ_REG_INTSTS, status);
294 
295 	if (status & XADC_ZYNQ_INT_DFIFO_GTH) {
296 		xadc_zynq_update_intmsk(xadc, XADC_ZYNQ_INT_DFIFO_GTH,
297 			XADC_ZYNQ_INT_DFIFO_GTH);
298 		complete(&xadc->completion);
299 	}
300 
301 	status &= XADC_ZYNQ_INT_ALARM_MASK;
302 	if (status) {
303 		xadc->zynq_masked_alarm |= status;
304 		/*
305 		 * mask the current event interrupt,
306 		 * unmask it when the interrupt is no more active.
307 		 */
308 		xadc_zynq_update_intmsk(xadc, 0, 0);
309 
310 		xadc_handle_events(indio_dev,
311 				xadc_zynq_transform_alarm(status));
312 
313 		/* unmask the required interrupts in timer. */
314 		schedule_delayed_work(&xadc->zynq_unmask_work,
315 				msecs_to_jiffies(XADC_ZYNQ_UNMASK_TIMEOUT));
316 	}
317 	spin_unlock(&xadc->lock);
318 
319 	return IRQ_HANDLED;
320 }
321 
322 #define XADC_ZYNQ_TCK_RATE_MAX 50000000
323 #define XADC_ZYNQ_IGAP_DEFAULT 20
324 #define XADC_ZYNQ_PCAP_RATE_MAX 200000000
325 
326 static int xadc_zynq_setup(struct platform_device *pdev,
327 	struct iio_dev *indio_dev, int irq)
328 {
329 	struct xadc *xadc = iio_priv(indio_dev);
330 	unsigned long pcap_rate;
331 	unsigned int tck_div;
332 	unsigned int div;
333 	unsigned int igap;
334 	unsigned int tck_rate;
335 	int ret;
336 
337 	/* TODO: Figure out how to make igap and tck_rate configurable */
338 	igap = XADC_ZYNQ_IGAP_DEFAULT;
339 	tck_rate = XADC_ZYNQ_TCK_RATE_MAX;
340 
341 	xadc->zynq_intmask = ~0;
342 
343 	pcap_rate = clk_get_rate(xadc->clk);
344 	if (!pcap_rate)
345 		return -EINVAL;
346 
347 	if (pcap_rate > XADC_ZYNQ_PCAP_RATE_MAX) {
348 		ret = clk_set_rate(xadc->clk,
349 				   (unsigned long)XADC_ZYNQ_PCAP_RATE_MAX);
350 		if (ret)
351 			return ret;
352 	}
353 
354 	if (tck_rate > pcap_rate / 2) {
355 		div = 2;
356 	} else {
357 		div = pcap_rate / tck_rate;
358 		if (pcap_rate / div > XADC_ZYNQ_TCK_RATE_MAX)
359 			div++;
360 	}
361 
362 	if (div <= 3)
363 		tck_div = XADC_ZYNQ_CFG_TCKRATE_DIV2;
364 	else if (div <= 7)
365 		tck_div = XADC_ZYNQ_CFG_TCKRATE_DIV4;
366 	else if (div <= 15)
367 		tck_div = XADC_ZYNQ_CFG_TCKRATE_DIV8;
368 	else
369 		tck_div = XADC_ZYNQ_CFG_TCKRATE_DIV16;
370 
371 	xadc_write_reg(xadc, XADC_ZYNQ_REG_CTL, XADC_ZYNQ_CTL_RESET);
372 	xadc_write_reg(xadc, XADC_ZYNQ_REG_CTL, 0);
373 	xadc_write_reg(xadc, XADC_ZYNQ_REG_INTSTS, ~0);
374 	xadc_write_reg(xadc, XADC_ZYNQ_REG_INTMSK, xadc->zynq_intmask);
375 	xadc_write_reg(xadc, XADC_ZYNQ_REG_CFG, XADC_ZYNQ_CFG_ENABLE |
376 			XADC_ZYNQ_CFG_REDGE | XADC_ZYNQ_CFG_WEDGE |
377 			tck_div | XADC_ZYNQ_CFG_IGAP(igap));
378 
379 	if (pcap_rate > XADC_ZYNQ_PCAP_RATE_MAX) {
380 		ret = clk_set_rate(xadc->clk, pcap_rate);
381 		if (ret)
382 			return ret;
383 	}
384 
385 	return 0;
386 }
387 
388 static unsigned long xadc_zynq_get_dclk_rate(struct xadc *xadc)
389 {
390 	unsigned int div;
391 	uint32_t val;
392 
393 	xadc_read_reg(xadc, XADC_ZYNQ_REG_CFG, &val);
394 
395 	switch (val & XADC_ZYNQ_CFG_TCKRATE_MASK) {
396 	case XADC_ZYNQ_CFG_TCKRATE_DIV4:
397 		div = 4;
398 		break;
399 	case XADC_ZYNQ_CFG_TCKRATE_DIV8:
400 		div = 8;
401 		break;
402 	case XADC_ZYNQ_CFG_TCKRATE_DIV16:
403 		div = 16;
404 		break;
405 	default:
406 		div = 2;
407 		break;
408 	}
409 
410 	return clk_get_rate(xadc->clk) / div;
411 }
412 
413 static void xadc_zynq_update_alarm(struct xadc *xadc, unsigned int alarm)
414 {
415 	unsigned long flags;
416 	uint32_t status;
417 
418 	/* Move OT to bit 7 */
419 	alarm = ((alarm & 0x08) << 4) | ((alarm & 0xf0) >> 1) | (alarm & 0x07);
420 
421 	spin_lock_irqsave(&xadc->lock, flags);
422 
423 	/* Clear previous interrupts if any. */
424 	xadc_read_reg(xadc, XADC_ZYNQ_REG_INTSTS, &status);
425 	xadc_write_reg(xadc, XADC_ZYNQ_REG_INTSTS, status & alarm);
426 
427 	xadc_zynq_update_intmsk(xadc, XADC_ZYNQ_INT_ALARM_MASK,
428 		~alarm & XADC_ZYNQ_INT_ALARM_MASK);
429 
430 	spin_unlock_irqrestore(&xadc->lock, flags);
431 }
432 
433 static const struct xadc_ops xadc_zynq_ops = {
434 	.read = xadc_zynq_read_adc_reg,
435 	.write = xadc_zynq_write_adc_reg,
436 	.setup = xadc_zynq_setup,
437 	.get_dclk_rate = xadc_zynq_get_dclk_rate,
438 	.interrupt_handler = xadc_zynq_interrupt_handler,
439 	.update_alarm = xadc_zynq_update_alarm,
440 };
441 
442 static int xadc_axi_read_adc_reg(struct xadc *xadc, unsigned int reg,
443 	uint16_t *val)
444 {
445 	uint32_t val32;
446 
447 	xadc_read_reg(xadc, XADC_AXI_ADC_REG_OFFSET + reg * 4, &val32);
448 	*val = val32 & 0xffff;
449 
450 	return 0;
451 }
452 
453 static int xadc_axi_write_adc_reg(struct xadc *xadc, unsigned int reg,
454 	uint16_t val)
455 {
456 	xadc_write_reg(xadc, XADC_AXI_ADC_REG_OFFSET + reg * 4, val);
457 
458 	return 0;
459 }
460 
461 static int xadc_axi_setup(struct platform_device *pdev,
462 	struct iio_dev *indio_dev, int irq)
463 {
464 	struct xadc *xadc = iio_priv(indio_dev);
465 
466 	xadc_write_reg(xadc, XADC_AXI_REG_RESET, XADC_AXI_RESET_MAGIC);
467 	xadc_write_reg(xadc, XADC_AXI_REG_GIER, XADC_AXI_GIER_ENABLE);
468 
469 	return 0;
470 }
471 
472 static irqreturn_t xadc_axi_interrupt_handler(int irq, void *devid)
473 {
474 	struct iio_dev *indio_dev = devid;
475 	struct xadc *xadc = iio_priv(indio_dev);
476 	uint32_t status, mask;
477 	unsigned int events;
478 
479 	xadc_read_reg(xadc, XADC_AXI_REG_IPISR, &status);
480 	xadc_read_reg(xadc, XADC_AXI_REG_IPIER, &mask);
481 	status &= mask;
482 
483 	if (!status)
484 		return IRQ_NONE;
485 
486 	if ((status & XADC_AXI_INT_EOS) && xadc->trigger)
487 		iio_trigger_poll(xadc->trigger);
488 
489 	if (status & XADC_AXI_INT_ALARM_MASK) {
490 		/*
491 		 * The order of the bits in the AXI-XADC status register does
492 		 * not match the order of the bits in the XADC alarm enable
493 		 * register. xadc_handle_events() expects the events to be in
494 		 * the same order as the XADC alarm enable register.
495 		 */
496 		events = (status & 0x000e) >> 1;
497 		events |= (status & 0x0001) << 3;
498 		events |= (status & 0x3c00) >> 6;
499 		xadc_handle_events(indio_dev, events);
500 	}
501 
502 	xadc_write_reg(xadc, XADC_AXI_REG_IPISR, status);
503 
504 	return IRQ_HANDLED;
505 }
506 
507 static void xadc_axi_update_alarm(struct xadc *xadc, unsigned int alarm)
508 {
509 	uint32_t val;
510 	unsigned long flags;
511 
512 	/*
513 	 * The order of the bits in the AXI-XADC status register does not match
514 	 * the order of the bits in the XADC alarm enable register. We get
515 	 * passed the alarm mask in the same order as in the XADC alarm enable
516 	 * register.
517 	 */
518 	alarm = ((alarm & 0x07) << 1) | ((alarm & 0x08) >> 3) |
519 			((alarm & 0xf0) << 6);
520 
521 	spin_lock_irqsave(&xadc->lock, flags);
522 	xadc_read_reg(xadc, XADC_AXI_REG_IPIER, &val);
523 	val &= ~XADC_AXI_INT_ALARM_MASK;
524 	val |= alarm;
525 	xadc_write_reg(xadc, XADC_AXI_REG_IPIER, val);
526 	spin_unlock_irqrestore(&xadc->lock, flags);
527 }
528 
529 static unsigned long xadc_axi_get_dclk(struct xadc *xadc)
530 {
531 	return clk_get_rate(xadc->clk);
532 }
533 
534 static const struct xadc_ops xadc_axi_ops = {
535 	.read = xadc_axi_read_adc_reg,
536 	.write = xadc_axi_write_adc_reg,
537 	.setup = xadc_axi_setup,
538 	.get_dclk_rate = xadc_axi_get_dclk,
539 	.update_alarm = xadc_axi_update_alarm,
540 	.interrupt_handler = xadc_axi_interrupt_handler,
541 	.flags = XADC_FLAGS_BUFFERED,
542 };
543 
544 static int _xadc_update_adc_reg(struct xadc *xadc, unsigned int reg,
545 	uint16_t mask, uint16_t val)
546 {
547 	uint16_t tmp;
548 	int ret;
549 
550 	ret = _xadc_read_adc_reg(xadc, reg, &tmp);
551 	if (ret)
552 		return ret;
553 
554 	return _xadc_write_adc_reg(xadc, reg, (tmp & ~mask) | val);
555 }
556 
557 static int xadc_update_adc_reg(struct xadc *xadc, unsigned int reg,
558 	uint16_t mask, uint16_t val)
559 {
560 	int ret;
561 
562 	mutex_lock(&xadc->mutex);
563 	ret = _xadc_update_adc_reg(xadc, reg, mask, val);
564 	mutex_unlock(&xadc->mutex);
565 
566 	return ret;
567 }
568 
569 static unsigned long xadc_get_dclk_rate(struct xadc *xadc)
570 {
571 	return xadc->ops->get_dclk_rate(xadc);
572 }
573 
574 static int xadc_update_scan_mode(struct iio_dev *indio_dev,
575 	const unsigned long *mask)
576 {
577 	struct xadc *xadc = iio_priv(indio_dev);
578 	unsigned int n;
579 
580 	n = bitmap_weight(mask, indio_dev->masklength);
581 
582 	kfree(xadc->data);
583 	xadc->data = kcalloc(n, sizeof(*xadc->data), GFP_KERNEL);
584 	if (!xadc->data)
585 		return -ENOMEM;
586 
587 	return 0;
588 }
589 
590 static unsigned int xadc_scan_index_to_channel(unsigned int scan_index)
591 {
592 	switch (scan_index) {
593 	case 5:
594 		return XADC_REG_VCCPINT;
595 	case 6:
596 		return XADC_REG_VCCPAUX;
597 	case 7:
598 		return XADC_REG_VCCO_DDR;
599 	case 8:
600 		return XADC_REG_TEMP;
601 	case 9:
602 		return XADC_REG_VCCINT;
603 	case 10:
604 		return XADC_REG_VCCAUX;
605 	case 11:
606 		return XADC_REG_VPVN;
607 	case 12:
608 		return XADC_REG_VREFP;
609 	case 13:
610 		return XADC_REG_VREFN;
611 	case 14:
612 		return XADC_REG_VCCBRAM;
613 	default:
614 		return XADC_REG_VAUX(scan_index - 16);
615 	}
616 }
617 
618 static irqreturn_t xadc_trigger_handler(int irq, void *p)
619 {
620 	struct iio_poll_func *pf = p;
621 	struct iio_dev *indio_dev = pf->indio_dev;
622 	struct xadc *xadc = iio_priv(indio_dev);
623 	unsigned int chan;
624 	int i, j;
625 
626 	if (!xadc->data)
627 		goto out;
628 
629 	j = 0;
630 	for_each_set_bit(i, indio_dev->active_scan_mask,
631 		indio_dev->masklength) {
632 		chan = xadc_scan_index_to_channel(i);
633 		xadc_read_adc_reg(xadc, chan, &xadc->data[j]);
634 		j++;
635 	}
636 
637 	iio_push_to_buffers(indio_dev, xadc->data);
638 
639 out:
640 	iio_trigger_notify_done(indio_dev->trig);
641 
642 	return IRQ_HANDLED;
643 }
644 
645 static int xadc_trigger_set_state(struct iio_trigger *trigger, bool state)
646 {
647 	struct xadc *xadc = iio_trigger_get_drvdata(trigger);
648 	unsigned long flags;
649 	unsigned int convst;
650 	unsigned int val;
651 	int ret = 0;
652 
653 	mutex_lock(&xadc->mutex);
654 
655 	if (state) {
656 		/* Only one of the two triggers can be active at the a time. */
657 		if (xadc->trigger != NULL) {
658 			ret = -EBUSY;
659 			goto err_out;
660 		} else {
661 			xadc->trigger = trigger;
662 			if (trigger == xadc->convst_trigger)
663 				convst = XADC_CONF0_EC;
664 			else
665 				convst = 0;
666 		}
667 		ret = _xadc_update_adc_reg(xadc, XADC_REG_CONF1, XADC_CONF0_EC,
668 					convst);
669 		if (ret)
670 			goto err_out;
671 	} else {
672 		xadc->trigger = NULL;
673 	}
674 
675 	spin_lock_irqsave(&xadc->lock, flags);
676 	xadc_read_reg(xadc, XADC_AXI_REG_IPIER, &val);
677 	xadc_write_reg(xadc, XADC_AXI_REG_IPISR, val & XADC_AXI_INT_EOS);
678 	if (state)
679 		val |= XADC_AXI_INT_EOS;
680 	else
681 		val &= ~XADC_AXI_INT_EOS;
682 	xadc_write_reg(xadc, XADC_AXI_REG_IPIER, val);
683 	spin_unlock_irqrestore(&xadc->lock, flags);
684 
685 err_out:
686 	mutex_unlock(&xadc->mutex);
687 
688 	return ret;
689 }
690 
691 static const struct iio_trigger_ops xadc_trigger_ops = {
692 	.set_trigger_state = &xadc_trigger_set_state,
693 };
694 
695 static struct iio_trigger *xadc_alloc_trigger(struct iio_dev *indio_dev,
696 	const char *name)
697 {
698 	struct iio_trigger *trig;
699 	int ret;
700 
701 	trig = iio_trigger_alloc("%s%d-%s", indio_dev->name,
702 				indio_dev->id, name);
703 	if (trig == NULL)
704 		return ERR_PTR(-ENOMEM);
705 
706 	trig->dev.parent = indio_dev->dev.parent;
707 	trig->ops = &xadc_trigger_ops;
708 	iio_trigger_set_drvdata(trig, iio_priv(indio_dev));
709 
710 	ret = iio_trigger_register(trig);
711 	if (ret)
712 		goto error_free_trig;
713 
714 	return trig;
715 
716 error_free_trig:
717 	iio_trigger_free(trig);
718 	return ERR_PTR(ret);
719 }
720 
721 static int xadc_power_adc_b(struct xadc *xadc, unsigned int seq_mode)
722 {
723 	uint16_t val;
724 
725 	switch (seq_mode) {
726 	case XADC_CONF1_SEQ_SIMULTANEOUS:
727 	case XADC_CONF1_SEQ_INDEPENDENT:
728 		val = XADC_CONF2_PD_ADC_B;
729 		break;
730 	default:
731 		val = 0;
732 		break;
733 	}
734 
735 	return xadc_update_adc_reg(xadc, XADC_REG_CONF2, XADC_CONF2_PD_MASK,
736 		val);
737 }
738 
739 static int xadc_get_seq_mode(struct xadc *xadc, unsigned long scan_mode)
740 {
741 	unsigned int aux_scan_mode = scan_mode >> 16;
742 
743 	if (xadc->external_mux_mode == XADC_EXTERNAL_MUX_DUAL)
744 		return XADC_CONF1_SEQ_SIMULTANEOUS;
745 
746 	if ((aux_scan_mode & 0xff00) == 0 ||
747 		(aux_scan_mode & 0x00ff) == 0)
748 		return XADC_CONF1_SEQ_CONTINUOUS;
749 
750 	return XADC_CONF1_SEQ_SIMULTANEOUS;
751 }
752 
753 static int xadc_postdisable(struct iio_dev *indio_dev)
754 {
755 	struct xadc *xadc = iio_priv(indio_dev);
756 	unsigned long scan_mask;
757 	int ret;
758 	int i;
759 
760 	scan_mask = 1; /* Run calibration as part of the sequence */
761 	for (i = 0; i < indio_dev->num_channels; i++)
762 		scan_mask |= BIT(indio_dev->channels[i].scan_index);
763 
764 	/* Enable all channels and calibration */
765 	ret = xadc_write_adc_reg(xadc, XADC_REG_SEQ(0), scan_mask & 0xffff);
766 	if (ret)
767 		return ret;
768 
769 	ret = xadc_write_adc_reg(xadc, XADC_REG_SEQ(1), scan_mask >> 16);
770 	if (ret)
771 		return ret;
772 
773 	ret = xadc_update_adc_reg(xadc, XADC_REG_CONF1, XADC_CONF1_SEQ_MASK,
774 		XADC_CONF1_SEQ_CONTINUOUS);
775 	if (ret)
776 		return ret;
777 
778 	return xadc_power_adc_b(xadc, XADC_CONF1_SEQ_CONTINUOUS);
779 }
780 
781 static int xadc_preenable(struct iio_dev *indio_dev)
782 {
783 	struct xadc *xadc = iio_priv(indio_dev);
784 	unsigned long scan_mask;
785 	int seq_mode;
786 	int ret;
787 
788 	ret = xadc_update_adc_reg(xadc, XADC_REG_CONF1, XADC_CONF1_SEQ_MASK,
789 		XADC_CONF1_SEQ_DEFAULT);
790 	if (ret)
791 		goto err;
792 
793 	scan_mask = *indio_dev->active_scan_mask;
794 	seq_mode = xadc_get_seq_mode(xadc, scan_mask);
795 
796 	ret = xadc_write_adc_reg(xadc, XADC_REG_SEQ(0), scan_mask & 0xffff);
797 	if (ret)
798 		goto err;
799 
800 	ret = xadc_write_adc_reg(xadc, XADC_REG_SEQ(1), scan_mask >> 16);
801 	if (ret)
802 		goto err;
803 
804 	ret = xadc_power_adc_b(xadc, seq_mode);
805 	if (ret)
806 		goto err;
807 
808 	ret = xadc_update_adc_reg(xadc, XADC_REG_CONF1, XADC_CONF1_SEQ_MASK,
809 		seq_mode);
810 	if (ret)
811 		goto err;
812 
813 	return 0;
814 err:
815 	xadc_postdisable(indio_dev);
816 	return ret;
817 }
818 
819 static const struct iio_buffer_setup_ops xadc_buffer_ops = {
820 	.preenable = &xadc_preenable,
821 	.postenable = &iio_triggered_buffer_postenable,
822 	.predisable = &iio_triggered_buffer_predisable,
823 	.postdisable = &xadc_postdisable,
824 };
825 
826 static int xadc_read_raw(struct iio_dev *indio_dev,
827 	struct iio_chan_spec const *chan, int *val, int *val2, long info)
828 {
829 	struct xadc *xadc = iio_priv(indio_dev);
830 	unsigned int div;
831 	uint16_t val16;
832 	int ret;
833 
834 	switch (info) {
835 	case IIO_CHAN_INFO_RAW:
836 		if (iio_buffer_enabled(indio_dev))
837 			return -EBUSY;
838 		ret = xadc_read_adc_reg(xadc, chan->address, &val16);
839 		if (ret < 0)
840 			return ret;
841 
842 		val16 >>= 4;
843 		if (chan->scan_type.sign == 'u')
844 			*val = val16;
845 		else
846 			*val = sign_extend32(val16, 11);
847 
848 		return IIO_VAL_INT;
849 	case IIO_CHAN_INFO_SCALE:
850 		switch (chan->type) {
851 		case IIO_VOLTAGE:
852 			/* V = (val * 3.0) / 4096 */
853 			switch (chan->address) {
854 			case XADC_REG_VCCINT:
855 			case XADC_REG_VCCAUX:
856 			case XADC_REG_VREFP:
857 			case XADC_REG_VREFN:
858 			case XADC_REG_VCCBRAM:
859 			case XADC_REG_VCCPINT:
860 			case XADC_REG_VCCPAUX:
861 			case XADC_REG_VCCO_DDR:
862 				*val = 3000;
863 				break;
864 			default:
865 				*val = 1000;
866 				break;
867 			}
868 			*val2 = 12;
869 			return IIO_VAL_FRACTIONAL_LOG2;
870 		case IIO_TEMP:
871 			/* Temp in C = (val * 503.975) / 4096 - 273.15 */
872 			*val = 503975;
873 			*val2 = 12;
874 			return IIO_VAL_FRACTIONAL_LOG2;
875 		default:
876 			return -EINVAL;
877 		}
878 	case IIO_CHAN_INFO_OFFSET:
879 		/* Only the temperature channel has an offset */
880 		*val = -((273150 << 12) / 503975);
881 		return IIO_VAL_INT;
882 	case IIO_CHAN_INFO_SAMP_FREQ:
883 		ret = xadc_read_adc_reg(xadc, XADC_REG_CONF2, &val16);
884 		if (ret)
885 			return ret;
886 
887 		div = (val16 & XADC_CONF2_DIV_MASK) >> XADC_CONF2_DIV_OFFSET;
888 		if (div < 2)
889 			div = 2;
890 
891 		*val = xadc_get_dclk_rate(xadc) / div / 26;
892 
893 		return IIO_VAL_INT;
894 	default:
895 		return -EINVAL;
896 	}
897 }
898 
899 static int xadc_write_raw(struct iio_dev *indio_dev,
900 	struct iio_chan_spec const *chan, int val, int val2, long info)
901 {
902 	struct xadc *xadc = iio_priv(indio_dev);
903 	unsigned long clk_rate = xadc_get_dclk_rate(xadc);
904 	unsigned int div;
905 
906 	if (!clk_rate)
907 		return -EINVAL;
908 
909 	if (info != IIO_CHAN_INFO_SAMP_FREQ)
910 		return -EINVAL;
911 
912 	if (val <= 0)
913 		return -EINVAL;
914 
915 	/* Max. 150 kSPS */
916 	if (val > 150000)
917 		val = 150000;
918 
919 	val *= 26;
920 
921 	/* Min 1MHz */
922 	if (val < 1000000)
923 		val = 1000000;
924 
925 	/*
926 	 * We want to round down, but only if we do not exceed the 150 kSPS
927 	 * limit.
928 	 */
929 	div = clk_rate / val;
930 	if (clk_rate / div / 26 > 150000)
931 		div++;
932 	if (div < 2)
933 		div = 2;
934 	else if (div > 0xff)
935 		div = 0xff;
936 
937 	return xadc_update_adc_reg(xadc, XADC_REG_CONF2, XADC_CONF2_DIV_MASK,
938 		div << XADC_CONF2_DIV_OFFSET);
939 }
940 
941 static const struct iio_event_spec xadc_temp_events[] = {
942 	{
943 		.type = IIO_EV_TYPE_THRESH,
944 		.dir = IIO_EV_DIR_RISING,
945 		.mask_separate = BIT(IIO_EV_INFO_ENABLE) |
946 				BIT(IIO_EV_INFO_VALUE) |
947 				BIT(IIO_EV_INFO_HYSTERESIS),
948 	},
949 };
950 
951 /* Separate values for upper and lower thresholds, but only a shared enabled */
952 static const struct iio_event_spec xadc_voltage_events[] = {
953 	{
954 		.type = IIO_EV_TYPE_THRESH,
955 		.dir = IIO_EV_DIR_RISING,
956 		.mask_separate = BIT(IIO_EV_INFO_VALUE),
957 	}, {
958 		.type = IIO_EV_TYPE_THRESH,
959 		.dir = IIO_EV_DIR_FALLING,
960 		.mask_separate = BIT(IIO_EV_INFO_VALUE),
961 	}, {
962 		.type = IIO_EV_TYPE_THRESH,
963 		.dir = IIO_EV_DIR_EITHER,
964 		.mask_separate = BIT(IIO_EV_INFO_ENABLE),
965 	},
966 };
967 
968 #define XADC_CHAN_TEMP(_chan, _scan_index, _addr) { \
969 	.type = IIO_TEMP, \
970 	.indexed = 1, \
971 	.channel = (_chan), \
972 	.address = (_addr), \
973 	.info_mask_separate = BIT(IIO_CHAN_INFO_RAW) | \
974 		BIT(IIO_CHAN_INFO_SCALE) | \
975 		BIT(IIO_CHAN_INFO_OFFSET), \
976 	.info_mask_shared_by_all = BIT(IIO_CHAN_INFO_SAMP_FREQ), \
977 	.event_spec = xadc_temp_events, \
978 	.num_event_specs = ARRAY_SIZE(xadc_temp_events), \
979 	.scan_index = (_scan_index), \
980 	.scan_type = { \
981 		.sign = 'u', \
982 		.realbits = 12, \
983 		.storagebits = 16, \
984 		.shift = 4, \
985 		.endianness = IIO_CPU, \
986 	}, \
987 }
988 
989 #define XADC_CHAN_VOLTAGE(_chan, _scan_index, _addr, _ext, _alarm) { \
990 	.type = IIO_VOLTAGE, \
991 	.indexed = 1, \
992 	.channel = (_chan), \
993 	.address = (_addr), \
994 	.info_mask_separate = BIT(IIO_CHAN_INFO_RAW) | \
995 		BIT(IIO_CHAN_INFO_SCALE), \
996 	.info_mask_shared_by_all = BIT(IIO_CHAN_INFO_SAMP_FREQ), \
997 	.event_spec = (_alarm) ? xadc_voltage_events : NULL, \
998 	.num_event_specs = (_alarm) ? ARRAY_SIZE(xadc_voltage_events) : 0, \
999 	.scan_index = (_scan_index), \
1000 	.scan_type = { \
1001 		.sign = ((_addr) == XADC_REG_VREFN) ? 's' : 'u', \
1002 		.realbits = 12, \
1003 		.storagebits = 16, \
1004 		.shift = 4, \
1005 		.endianness = IIO_CPU, \
1006 	}, \
1007 	.extend_name = _ext, \
1008 }
1009 
1010 static const struct iio_chan_spec xadc_channels[] = {
1011 	XADC_CHAN_TEMP(0, 8, XADC_REG_TEMP),
1012 	XADC_CHAN_VOLTAGE(0, 9, XADC_REG_VCCINT, "vccint", true),
1013 	XADC_CHAN_VOLTAGE(1, 10, XADC_REG_VCCAUX, "vccaux", true),
1014 	XADC_CHAN_VOLTAGE(2, 14, XADC_REG_VCCBRAM, "vccbram", true),
1015 	XADC_CHAN_VOLTAGE(3, 5, XADC_REG_VCCPINT, "vccpint", true),
1016 	XADC_CHAN_VOLTAGE(4, 6, XADC_REG_VCCPAUX, "vccpaux", true),
1017 	XADC_CHAN_VOLTAGE(5, 7, XADC_REG_VCCO_DDR, "vccoddr", true),
1018 	XADC_CHAN_VOLTAGE(6, 12, XADC_REG_VREFP, "vrefp", false),
1019 	XADC_CHAN_VOLTAGE(7, 13, XADC_REG_VREFN, "vrefn", false),
1020 	XADC_CHAN_VOLTAGE(8, 11, XADC_REG_VPVN, NULL, false),
1021 	XADC_CHAN_VOLTAGE(9, 16, XADC_REG_VAUX(0), NULL, false),
1022 	XADC_CHAN_VOLTAGE(10, 17, XADC_REG_VAUX(1), NULL, false),
1023 	XADC_CHAN_VOLTAGE(11, 18, XADC_REG_VAUX(2), NULL, false),
1024 	XADC_CHAN_VOLTAGE(12, 19, XADC_REG_VAUX(3), NULL, false),
1025 	XADC_CHAN_VOLTAGE(13, 20, XADC_REG_VAUX(4), NULL, false),
1026 	XADC_CHAN_VOLTAGE(14, 21, XADC_REG_VAUX(5), NULL, false),
1027 	XADC_CHAN_VOLTAGE(15, 22, XADC_REG_VAUX(6), NULL, false),
1028 	XADC_CHAN_VOLTAGE(16, 23, XADC_REG_VAUX(7), NULL, false),
1029 	XADC_CHAN_VOLTAGE(17, 24, XADC_REG_VAUX(8), NULL, false),
1030 	XADC_CHAN_VOLTAGE(18, 25, XADC_REG_VAUX(9), NULL, false),
1031 	XADC_CHAN_VOLTAGE(19, 26, XADC_REG_VAUX(10), NULL, false),
1032 	XADC_CHAN_VOLTAGE(20, 27, XADC_REG_VAUX(11), NULL, false),
1033 	XADC_CHAN_VOLTAGE(21, 28, XADC_REG_VAUX(12), NULL, false),
1034 	XADC_CHAN_VOLTAGE(22, 29, XADC_REG_VAUX(13), NULL, false),
1035 	XADC_CHAN_VOLTAGE(23, 30, XADC_REG_VAUX(14), NULL, false),
1036 	XADC_CHAN_VOLTAGE(24, 31, XADC_REG_VAUX(15), NULL, false),
1037 };
1038 
1039 static const struct iio_info xadc_info = {
1040 	.read_raw = &xadc_read_raw,
1041 	.write_raw = &xadc_write_raw,
1042 	.read_event_config = &xadc_read_event_config,
1043 	.write_event_config = &xadc_write_event_config,
1044 	.read_event_value = &xadc_read_event_value,
1045 	.write_event_value = &xadc_write_event_value,
1046 	.update_scan_mode = &xadc_update_scan_mode,
1047 };
1048 
1049 static const struct of_device_id xadc_of_match_table[] = {
1050 	{ .compatible = "xlnx,zynq-xadc-1.00.a", (void *)&xadc_zynq_ops },
1051 	{ .compatible = "xlnx,axi-xadc-1.00.a", (void *)&xadc_axi_ops },
1052 	{ },
1053 };
1054 MODULE_DEVICE_TABLE(of, xadc_of_match_table);
1055 
1056 static int xadc_parse_dt(struct iio_dev *indio_dev, struct device_node *np,
1057 	unsigned int *conf)
1058 {
1059 	struct xadc *xadc = iio_priv(indio_dev);
1060 	struct iio_chan_spec *channels, *chan;
1061 	struct device_node *chan_node, *child;
1062 	unsigned int num_channels;
1063 	const char *external_mux;
1064 	u32 ext_mux_chan;
1065 	u32 reg;
1066 	int ret;
1067 
1068 	*conf = 0;
1069 
1070 	ret = of_property_read_string(np, "xlnx,external-mux", &external_mux);
1071 	if (ret < 0 || strcasecmp(external_mux, "none") == 0)
1072 		xadc->external_mux_mode = XADC_EXTERNAL_MUX_NONE;
1073 	else if (strcasecmp(external_mux, "single") == 0)
1074 		xadc->external_mux_mode = XADC_EXTERNAL_MUX_SINGLE;
1075 	else if (strcasecmp(external_mux, "dual") == 0)
1076 		xadc->external_mux_mode = XADC_EXTERNAL_MUX_DUAL;
1077 	else
1078 		return -EINVAL;
1079 
1080 	if (xadc->external_mux_mode != XADC_EXTERNAL_MUX_NONE) {
1081 		ret = of_property_read_u32(np, "xlnx,external-mux-channel",
1082 					&ext_mux_chan);
1083 		if (ret < 0)
1084 			return ret;
1085 
1086 		if (xadc->external_mux_mode == XADC_EXTERNAL_MUX_SINGLE) {
1087 			if (ext_mux_chan == 0)
1088 				ext_mux_chan = XADC_REG_VPVN;
1089 			else if (ext_mux_chan <= 16)
1090 				ext_mux_chan = XADC_REG_VAUX(ext_mux_chan - 1);
1091 			else
1092 				return -EINVAL;
1093 		} else {
1094 			if (ext_mux_chan > 0 && ext_mux_chan <= 8)
1095 				ext_mux_chan = XADC_REG_VAUX(ext_mux_chan - 1);
1096 			else
1097 				return -EINVAL;
1098 		}
1099 
1100 		*conf |= XADC_CONF0_MUX | XADC_CONF0_CHAN(ext_mux_chan);
1101 	}
1102 
1103 	channels = kmemdup(xadc_channels, sizeof(xadc_channels), GFP_KERNEL);
1104 	if (!channels)
1105 		return -ENOMEM;
1106 
1107 	num_channels = 9;
1108 	chan = &channels[9];
1109 
1110 	chan_node = of_get_child_by_name(np, "xlnx,channels");
1111 	if (chan_node) {
1112 		for_each_child_of_node(chan_node, child) {
1113 			if (num_channels >= ARRAY_SIZE(xadc_channels)) {
1114 				of_node_put(child);
1115 				break;
1116 			}
1117 
1118 			ret = of_property_read_u32(child, "reg", &reg);
1119 			if (ret || reg > 16)
1120 				continue;
1121 
1122 			if (of_property_read_bool(child, "xlnx,bipolar"))
1123 				chan->scan_type.sign = 's';
1124 
1125 			if (reg == 0) {
1126 				chan->scan_index = 11;
1127 				chan->address = XADC_REG_VPVN;
1128 			} else {
1129 				chan->scan_index = 15 + reg;
1130 				chan->address = XADC_REG_VAUX(reg - 1);
1131 			}
1132 			num_channels++;
1133 			chan++;
1134 		}
1135 	}
1136 	of_node_put(chan_node);
1137 
1138 	indio_dev->num_channels = num_channels;
1139 	indio_dev->channels = krealloc(channels, sizeof(*channels) *
1140 					num_channels, GFP_KERNEL);
1141 	/* If we can't resize the channels array, just use the original */
1142 	if (!indio_dev->channels)
1143 		indio_dev->channels = channels;
1144 
1145 	return 0;
1146 }
1147 
1148 static int xadc_probe(struct platform_device *pdev)
1149 {
1150 	const struct of_device_id *id;
1151 	struct iio_dev *indio_dev;
1152 	unsigned int bipolar_mask;
1153 	struct resource *mem;
1154 	unsigned int conf0;
1155 	struct xadc *xadc;
1156 	int ret;
1157 	int irq;
1158 	int i;
1159 
1160 	if (!pdev->dev.of_node)
1161 		return -ENODEV;
1162 
1163 	id = of_match_node(xadc_of_match_table, pdev->dev.of_node);
1164 	if (!id)
1165 		return -EINVAL;
1166 
1167 	irq = platform_get_irq(pdev, 0);
1168 	if (irq <= 0)
1169 		return -ENXIO;
1170 
1171 	indio_dev = devm_iio_device_alloc(&pdev->dev, sizeof(*xadc));
1172 	if (!indio_dev)
1173 		return -ENOMEM;
1174 
1175 	xadc = iio_priv(indio_dev);
1176 	xadc->ops = id->data;
1177 	xadc->irq = irq;
1178 	init_completion(&xadc->completion);
1179 	mutex_init(&xadc->mutex);
1180 	spin_lock_init(&xadc->lock);
1181 	INIT_DELAYED_WORK(&xadc->zynq_unmask_work, xadc_zynq_unmask_worker);
1182 
1183 	mem = platform_get_resource(pdev, IORESOURCE_MEM, 0);
1184 	xadc->base = devm_ioremap_resource(&pdev->dev, mem);
1185 	if (IS_ERR(xadc->base))
1186 		return PTR_ERR(xadc->base);
1187 
1188 	indio_dev->dev.parent = &pdev->dev;
1189 	indio_dev->dev.of_node = pdev->dev.of_node;
1190 	indio_dev->name = "xadc";
1191 	indio_dev->modes = INDIO_DIRECT_MODE;
1192 	indio_dev->info = &xadc_info;
1193 
1194 	ret = xadc_parse_dt(indio_dev, pdev->dev.of_node, &conf0);
1195 	if (ret)
1196 		goto err_device_free;
1197 
1198 	if (xadc->ops->flags & XADC_FLAGS_BUFFERED) {
1199 		ret = iio_triggered_buffer_setup(indio_dev,
1200 			&iio_pollfunc_store_time, &xadc_trigger_handler,
1201 			&xadc_buffer_ops);
1202 		if (ret)
1203 			goto err_device_free;
1204 
1205 		xadc->convst_trigger = xadc_alloc_trigger(indio_dev, "convst");
1206 		if (IS_ERR(xadc->convst_trigger)) {
1207 			ret = PTR_ERR(xadc->convst_trigger);
1208 			goto err_triggered_buffer_cleanup;
1209 		}
1210 		xadc->samplerate_trigger = xadc_alloc_trigger(indio_dev,
1211 			"samplerate");
1212 		if (IS_ERR(xadc->samplerate_trigger)) {
1213 			ret = PTR_ERR(xadc->samplerate_trigger);
1214 			goto err_free_convst_trigger;
1215 		}
1216 	}
1217 
1218 	xadc->clk = devm_clk_get(&pdev->dev, NULL);
1219 	if (IS_ERR(xadc->clk)) {
1220 		ret = PTR_ERR(xadc->clk);
1221 		goto err_free_samplerate_trigger;
1222 	}
1223 
1224 	ret = clk_prepare_enable(xadc->clk);
1225 	if (ret)
1226 		goto err_free_samplerate_trigger;
1227 
1228 	ret = request_irq(xadc->irq, xadc->ops->interrupt_handler, 0,
1229 			dev_name(&pdev->dev), indio_dev);
1230 	if (ret)
1231 		goto err_clk_disable_unprepare;
1232 
1233 	ret = xadc->ops->setup(pdev, indio_dev, xadc->irq);
1234 	if (ret)
1235 		goto err_free_irq;
1236 
1237 	for (i = 0; i < 16; i++)
1238 		xadc_read_adc_reg(xadc, XADC_REG_THRESHOLD(i),
1239 			&xadc->threshold[i]);
1240 
1241 	ret = xadc_write_adc_reg(xadc, XADC_REG_CONF0, conf0);
1242 	if (ret)
1243 		goto err_free_irq;
1244 
1245 	bipolar_mask = 0;
1246 	for (i = 0; i < indio_dev->num_channels; i++) {
1247 		if (indio_dev->channels[i].scan_type.sign == 's')
1248 			bipolar_mask |= BIT(indio_dev->channels[i].scan_index);
1249 	}
1250 
1251 	ret = xadc_write_adc_reg(xadc, XADC_REG_INPUT_MODE(0), bipolar_mask);
1252 	if (ret)
1253 		goto err_free_irq;
1254 	ret = xadc_write_adc_reg(xadc, XADC_REG_INPUT_MODE(1),
1255 		bipolar_mask >> 16);
1256 	if (ret)
1257 		goto err_free_irq;
1258 
1259 	/* Disable all alarms */
1260 	ret = xadc_update_adc_reg(xadc, XADC_REG_CONF1, XADC_CONF1_ALARM_MASK,
1261 				  XADC_CONF1_ALARM_MASK);
1262 	if (ret)
1263 		goto err_free_irq;
1264 
1265 	/* Set thresholds to min/max */
1266 	for (i = 0; i < 16; i++) {
1267 		/*
1268 		 * Set max voltage threshold and both temperature thresholds to
1269 		 * 0xffff, min voltage threshold to 0.
1270 		 */
1271 		if (i % 8 < 4 || i == 7)
1272 			xadc->threshold[i] = 0xffff;
1273 		else
1274 			xadc->threshold[i] = 0;
1275 		ret = xadc_write_adc_reg(xadc, XADC_REG_THRESHOLD(i),
1276 			xadc->threshold[i]);
1277 		if (ret)
1278 			goto err_free_irq;
1279 	}
1280 
1281 	/* Go to non-buffered mode */
1282 	xadc_postdisable(indio_dev);
1283 
1284 	ret = iio_device_register(indio_dev);
1285 	if (ret)
1286 		goto err_free_irq;
1287 
1288 	platform_set_drvdata(pdev, indio_dev);
1289 
1290 	return 0;
1291 
1292 err_free_irq:
1293 	free_irq(xadc->irq, indio_dev);
1294 	cancel_delayed_work_sync(&xadc->zynq_unmask_work);
1295 err_clk_disable_unprepare:
1296 	clk_disable_unprepare(xadc->clk);
1297 err_free_samplerate_trigger:
1298 	if (xadc->ops->flags & XADC_FLAGS_BUFFERED)
1299 		iio_trigger_free(xadc->samplerate_trigger);
1300 err_free_convst_trigger:
1301 	if (xadc->ops->flags & XADC_FLAGS_BUFFERED)
1302 		iio_trigger_free(xadc->convst_trigger);
1303 err_triggered_buffer_cleanup:
1304 	if (xadc->ops->flags & XADC_FLAGS_BUFFERED)
1305 		iio_triggered_buffer_cleanup(indio_dev);
1306 err_device_free:
1307 	kfree(indio_dev->channels);
1308 
1309 	return ret;
1310 }
1311 
1312 static int xadc_remove(struct platform_device *pdev)
1313 {
1314 	struct iio_dev *indio_dev = platform_get_drvdata(pdev);
1315 	struct xadc *xadc = iio_priv(indio_dev);
1316 
1317 	iio_device_unregister(indio_dev);
1318 	if (xadc->ops->flags & XADC_FLAGS_BUFFERED) {
1319 		iio_trigger_free(xadc->samplerate_trigger);
1320 		iio_trigger_free(xadc->convst_trigger);
1321 		iio_triggered_buffer_cleanup(indio_dev);
1322 	}
1323 	free_irq(xadc->irq, indio_dev);
1324 	cancel_delayed_work_sync(&xadc->zynq_unmask_work);
1325 	clk_disable_unprepare(xadc->clk);
1326 	kfree(xadc->data);
1327 	kfree(indio_dev->channels);
1328 
1329 	return 0;
1330 }
1331 
1332 static struct platform_driver xadc_driver = {
1333 	.probe = xadc_probe,
1334 	.remove = xadc_remove,
1335 	.driver = {
1336 		.name = "xadc",
1337 		.of_match_table = xadc_of_match_table,
1338 	},
1339 };
1340 module_platform_driver(xadc_driver);
1341 
1342 MODULE_LICENSE("GPL v2");
1343 MODULE_AUTHOR("Lars-Peter Clausen <lars@metafoo.de>");
1344 MODULE_DESCRIPTION("Xilinx XADC IIO driver");
1345