1 // SPDX-License-Identifier: GPL-2.0
2 /*
3  * TI Bandgap temperature sensor driver for J72XX SoC Family
4  *
5  * Copyright (C) 2021 Texas Instruments Incorporated - http://www.ti.com/
6  */
7 
8 #include <linux/math.h>
9 #include <linux/math64.h>
10 #include <linux/module.h>
11 #include <linux/init.h>
12 #include <linux/kernel.h>
13 #include <linux/pm_runtime.h>
14 #include <linux/err.h>
15 #include <linux/types.h>
16 #include <linux/of_platform.h>
17 #include <linux/io.h>
18 #include <linux/thermal.h>
19 #include <linux/of.h>
20 #include <linux/delay.h>
21 #include <linux/slab.h>
22 
23 #define K3_VTM_DEVINFO_PWR0_OFFSET		0x4
24 #define K3_VTM_DEVINFO_PWR0_TEMPSENS_CT_MASK	0xf0
25 #define K3_VTM_TMPSENS0_CTRL_OFFSET		0x300
26 #define K3_VTM_MISC_CTRL_OFFSET			0xc
27 #define K3_VTM_TMPSENS_STAT_OFFSET		0x8
28 #define K3_VTM_ANYMAXT_OUTRG_ALERT_EN		0x1
29 #define K3_VTM_MISC_CTRL2_OFFSET		0x10
30 #define K3_VTM_TS_STAT_DTEMP_MASK		0x3ff
31 #define K3_VTM_MAX_NUM_TS			8
32 #define K3_VTM_TMPSENS_CTRL_SOC			BIT(5)
33 #define K3_VTM_TMPSENS_CTRL_CLRZ		BIT(6)
34 #define K3_VTM_TMPSENS_CTRL_CLKON_REQ		BIT(7)
35 #define K3_VTM_TMPSENS_CTRL_MAXT_OUTRG_EN	BIT(11)
36 
37 #define K3_VTM_CORRECTION_TEMP_CNT		3
38 
39 #define MINUS40CREF				5
40 #define PLUS30CREF				253
41 #define PLUS125CREF				730
42 #define PLUS150CREF				940
43 
44 #define TABLE_SIZE				1024
45 #define MAX_TEMP				123000
46 #define COOL_DOWN_TEMP				105000
47 
48 #define FACTORS_REDUCTION			13
49 static int *derived_table;
50 
51 static int compute_value(int index, const s64 *factors, int nr_factors,
52 			 int reduction)
53 {
54 	s64 value = 0;
55 	int i;
56 
57 	for (i = 0; i < nr_factors; i++)
58 		value += factors[i] * int_pow(index, i);
59 
60 	return (int)div64_s64(value, int_pow(10, reduction));
61 }
62 
63 static void init_table(int factors_size, int *table, const s64 *factors)
64 {
65 	int i;
66 
67 	for (i = 0; i < TABLE_SIZE; i++)
68 		table[i] = compute_value(i, factors, factors_size,
69 					 FACTORS_REDUCTION);
70 }
71 
72 /**
73  * struct err_values - structure containing error/reference values
74  * @refs: reference error values for -40C, 30C, 125C & 150C
75  * @errs: Actual error values for -40C, 30C, 125C & 150C read from the efuse
76  */
77 struct err_values {
78 	int refs[4];
79 	int errs[4];
80 };
81 
82 static void create_table_segments(struct err_values *err_vals, int seg,
83 				  int *ref_table)
84 {
85 	int m = 0, c, num, den, i, err, idx1, idx2, err1, err2, ref1, ref2;
86 
87 	if (seg == 0)
88 		idx1 = 0;
89 	else
90 		idx1 = err_vals->refs[seg];
91 
92 	idx2 = err_vals->refs[seg + 1];
93 	err1 = err_vals->errs[seg];
94 	err2 = err_vals->errs[seg + 1];
95 	ref1 = err_vals->refs[seg];
96 	ref2 = err_vals->refs[seg + 1];
97 
98 	/*
99 	 * Calculate the slope with adc values read from the register
100 	 * as the y-axis param and err in adc value as x-axis param
101 	 */
102 	num = ref2 - ref1;
103 	den = err2 - err1;
104 	if (den)
105 		m = num / den;
106 	c = ref2 - m * err2;
107 
108 	/*
109 	 * Take care of divide by zero error if error values are same
110 	 * Or when the slope is 0
111 	 */
112 	if (den != 0 && m != 0) {
113 		for (i = idx1; i <= idx2; i++) {
114 			err = (i - c) / m;
115 			if (((i + err) < 0) || ((i + err) >= TABLE_SIZE))
116 				continue;
117 			derived_table[i] = ref_table[i + err];
118 		}
119 	} else { /* Constant error take care of divide by zero */
120 		for (i = idx1; i <= idx2; i++) {
121 			if (((i + err1) < 0) || ((i + err1) >= TABLE_SIZE))
122 				continue;
123 			derived_table[i] = ref_table[i + err1];
124 		}
125 	}
126 }
127 
128 static int prep_lookup_table(struct err_values *err_vals, int *ref_table)
129 {
130 	int inc, i, seg;
131 
132 	/*
133 	 * Fill up the lookup table under 3 segments
134 	 * region -40C to +30C
135 	 * region +30C to +125C
136 	 * region +125C to +150C
137 	 */
138 	for (seg = 0; seg < 3; seg++)
139 		create_table_segments(err_vals, seg, ref_table);
140 
141 	/* Get to the first valid temperature */
142 	i = 0;
143 	while (!derived_table[i])
144 		i++;
145 
146 	/*
147 	 * Get to the last zero index and back fill the temperature for
148 	 * sake of continuity
149 	 */
150 	if (i) {
151 		/* 300 milli celsius steps */
152 		while (i--)
153 			derived_table[i] = derived_table[i + 1] - 300;
154 	}
155 
156 	/*
157 	 * Fill the last trailing 0s which are unfilled with increments of
158 	 * 100 milli celsius till 1023 code
159 	 */
160 	i = TABLE_SIZE - 1;
161 	while (!derived_table[i])
162 		i--;
163 
164 	i++;
165 	inc = 1;
166 	while (i < TABLE_SIZE) {
167 		derived_table[i] = derived_table[i - 1] + inc * 100;
168 		i++;
169 	}
170 
171 	return 0;
172 }
173 
174 struct k3_thermal_data;
175 
176 struct k3_j72xx_bandgap {
177 	struct device *dev;
178 	void __iomem *base;
179 	void __iomem *cfg2_base;
180 	void __iomem *fuse_base;
181 	struct k3_thermal_data *ts_data[K3_VTM_MAX_NUM_TS];
182 };
183 
184 /* common data structures */
185 struct k3_thermal_data {
186 	struct k3_j72xx_bandgap *bgp;
187 	u32 ctrl_offset;
188 	u32 stat_offset;
189 };
190 
191 static int two_cmp(int tmp, int mask)
192 {
193 	tmp = ~(tmp);
194 	tmp &= mask;
195 	tmp += 1;
196 
197 	/* Return negative value */
198 	return (0 - tmp);
199 }
200 
201 static unsigned int vtm_get_best_value(unsigned int s0, unsigned int s1,
202 				       unsigned int s2)
203 {
204 	int d01 = abs(s0 - s1);
205 	int d02 = abs(s0 - s2);
206 	int d12 = abs(s1 - s2);
207 
208 	if (d01 <= d02 && d01 <= d12)
209 		return (s0 + s1) / 2;
210 
211 	if (d02 <= d01 && d02 <= d12)
212 		return (s0 + s2) / 2;
213 
214 	return (s1 + s2) / 2;
215 }
216 
217 static inline int k3_bgp_read_temp(struct k3_thermal_data *devdata,
218 				   int *temp)
219 {
220 	struct k3_j72xx_bandgap *bgp;
221 	unsigned int dtemp, s0, s1, s2;
222 
223 	bgp = devdata->bgp;
224 	/*
225 	 * Errata is applicable for am654 pg 1.0 silicon/J7ES. There
226 	 * is a variation of the order for certain degree centigrade on AM654.
227 	 * Work around that by getting the average of two closest
228 	 * readings out of three readings everytime we want to
229 	 * report temperatures.
230 	 *
231 	 * Errata workaround.
232 	 */
233 	s0 = readl(bgp->base + devdata->stat_offset) &
234 		K3_VTM_TS_STAT_DTEMP_MASK;
235 	s1 = readl(bgp->base + devdata->stat_offset) &
236 		K3_VTM_TS_STAT_DTEMP_MASK;
237 	s2 = readl(bgp->base + devdata->stat_offset) &
238 		K3_VTM_TS_STAT_DTEMP_MASK;
239 	dtemp = vtm_get_best_value(s0, s1, s2);
240 
241 	if (dtemp < 0 || dtemp >= TABLE_SIZE)
242 		return -EINVAL;
243 
244 	*temp = derived_table[dtemp];
245 
246 	return 0;
247 }
248 
249 /* Get temperature callback function for thermal zone */
250 static int k3_thermal_get_temp(void *devdata, int *temp)
251 {
252 	struct k3_thermal_data *data = devdata;
253 	int ret = 0;
254 
255 	ret = k3_bgp_read_temp(data, temp);
256 	if (ret)
257 		return ret;
258 
259 	return ret;
260 }
261 
262 static const struct thermal_zone_of_device_ops k3_of_thermal_ops = {
263 	.get_temp = k3_thermal_get_temp,
264 };
265 
266 static int k3_j72xx_bandgap_temp_to_adc_code(int temp)
267 {
268 	int low = 0, high = TABLE_SIZE - 1, mid;
269 
270 	if (temp > 160000 || temp < -50000)
271 		return -EINVAL;
272 
273 	/* Binary search to find the adc code */
274 	while (low < (high - 1)) {
275 		mid = (low + high) / 2;
276 		if (temp <= derived_table[mid])
277 			high = mid;
278 		else
279 			low = mid;
280 	}
281 
282 	return mid;
283 }
284 
285 static void get_efuse_values(int id, struct k3_thermal_data *data, int *err,
286 			     struct k3_j72xx_bandgap *bgp)
287 {
288 	int i, tmp, pow;
289 	int ct_offsets[5][K3_VTM_CORRECTION_TEMP_CNT] = {
290 		{ 0x0, 0x8, 0x4 },
291 		{ 0x0, 0x8, 0x4 },
292 		{ 0x0, -1,  0x4 },
293 		{ 0x0, 0xC, -1 },
294 		{ 0x0, 0xc, 0x8 }
295 	};
296 	int ct_bm[5][K3_VTM_CORRECTION_TEMP_CNT] = {
297 		{ 0x3f, 0x1fe000, 0x1ff },
298 		{ 0xfc0, 0x1fe000, 0x3fe00 },
299 		{ 0x3f000, 0x7f800000, 0x7fc0000 },
300 		{ 0xfc0000, 0x1fe0, 0x1f800000 },
301 		{ 0x3f000000, 0x1fe000, 0x1ff0 }
302 	};
303 
304 	for (i = 0; i < 3; i++) {
305 		/* Extract the offset value using bit-mask */
306 		if (ct_offsets[id][i] == -1 && i == 1) {
307 			/* 25C offset Case of Sensor 2 split between 2 regs */
308 			tmp = (readl(bgp->fuse_base + 0x8) & 0xE0000000) >> (29);
309 			tmp |= ((readl(bgp->fuse_base + 0xC) & 0x1F) << 3);
310 			pow = tmp & 0x80;
311 		} else if (ct_offsets[id][i] == -1 && i == 2) {
312 			/* 125C Case of Sensor 3 split between 2 regs */
313 			tmp = (readl(bgp->fuse_base + 0x4) & 0xF8000000) >> (27);
314 			tmp |= ((readl(bgp->fuse_base + 0x8) & 0xF) << 5);
315 			pow = tmp & 0x100;
316 		} else {
317 			tmp = readl(bgp->fuse_base + ct_offsets[id][i]);
318 			tmp &= ct_bm[id][i];
319 			tmp = tmp >> __ffs(ct_bm[id][i]);
320 
321 			/* Obtain the sign bit pow*/
322 			pow = ct_bm[id][i] >> __ffs(ct_bm[id][i]);
323 			pow += 1;
324 			pow /= 2;
325 		}
326 
327 		/* Check for negative value */
328 		if (tmp & pow) {
329 			/* 2's complement value */
330 			tmp = two_cmp(tmp, ct_bm[id][i] >> __ffs(ct_bm[id][i]));
331 		}
332 		err[i] = tmp;
333 	}
334 
335 	/* Err value for 150C is set to 0 */
336 	err[i] = 0;
337 }
338 
339 static void print_look_up_table(struct device *dev, int *ref_table)
340 {
341 	int i;
342 
343 	dev_dbg(dev, "The contents of derived array\n");
344 	dev_dbg(dev, "Code   Temperature\n");
345 	for (i = 0; i < TABLE_SIZE; i++)
346 		dev_dbg(dev, "%d       %d %d\n", i, derived_table[i], ref_table[i]);
347 }
348 
349 struct k3_j72xx_bandgap_data {
350 	unsigned int has_errata_i2128;
351 };
352 
353 static int k3_j72xx_bandgap_probe(struct platform_device *pdev)
354 {
355 	int ret = 0, cnt, val, id;
356 	int high_max, low_temp;
357 	struct resource *res;
358 	struct device *dev = &pdev->dev;
359 	struct k3_j72xx_bandgap *bgp;
360 	struct k3_thermal_data *data;
361 	int workaround_needed = 0;
362 	const struct k3_j72xx_bandgap_data *driver_data;
363 	struct thermal_zone_device *ti_thermal;
364 	int *ref_table;
365 	struct err_values err_vals;
366 
367 	const s64 golden_factors[] = {
368 		-490019999999999936,
369 		3251200000000000,
370 		-1705800000000,
371 		603730000,
372 		-92627,
373 	};
374 
375 	const s64 pvt_wa_factors[] = {
376 		-415230000000000000,
377 		3126600000000000,
378 		-1157800000000,
379 	};
380 
381 	bgp = devm_kzalloc(&pdev->dev, sizeof(*bgp), GFP_KERNEL);
382 	if (!bgp)
383 		return -ENOMEM;
384 
385 	bgp->dev = dev;
386 	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
387 	bgp->base = devm_ioremap_resource(dev, res);
388 	if (IS_ERR(bgp->base))
389 		return PTR_ERR(bgp->base);
390 
391 	res = platform_get_resource(pdev, IORESOURCE_MEM, 1);
392 	bgp->cfg2_base = devm_ioremap_resource(dev, res);
393 	if (IS_ERR(bgp->cfg2_base))
394 		return PTR_ERR(bgp->cfg2_base);
395 
396 	res = platform_get_resource(pdev, IORESOURCE_MEM, 2);
397 	bgp->fuse_base = devm_ioremap_resource(dev, res);
398 	if (IS_ERR(bgp->fuse_base))
399 		return PTR_ERR(bgp->fuse_base);
400 
401 	driver_data = of_device_get_match_data(dev);
402 	if (driver_data)
403 		workaround_needed = driver_data->has_errata_i2128;
404 
405 	pm_runtime_enable(dev);
406 	ret = pm_runtime_get_sync(dev);
407 	if (ret < 0) {
408 		pm_runtime_put_noidle(dev);
409 		pm_runtime_disable(dev);
410 		return ret;
411 	}
412 
413 	/* Get the sensor count in the VTM */
414 	val = readl(bgp->base + K3_VTM_DEVINFO_PWR0_OFFSET);
415 	cnt = val & K3_VTM_DEVINFO_PWR0_TEMPSENS_CT_MASK;
416 	cnt >>= __ffs(K3_VTM_DEVINFO_PWR0_TEMPSENS_CT_MASK);
417 
418 	data = devm_kcalloc(bgp->dev, cnt, sizeof(*data), GFP_KERNEL);
419 	if (!data) {
420 		ret = -ENOMEM;
421 		goto err_alloc;
422 	}
423 
424 	ref_table = kzalloc(sizeof(*ref_table) * TABLE_SIZE, GFP_KERNEL);
425 	if (!ref_table) {
426 		ret = -ENOMEM;
427 		goto err_alloc;
428 	}
429 
430 	derived_table = devm_kzalloc(bgp->dev, sizeof(*derived_table) * TABLE_SIZE,
431 				     GFP_KERNEL);
432 	if (!derived_table) {
433 		ret = -ENOMEM;
434 		goto err_free_ref_table;
435 	}
436 
437 	/* Workaround not needed if bit30/bit31 is set even for J721e */
438 	if (workaround_needed && (readl(bgp->fuse_base + 0x0) & 0xc0000000) == 0xc0000000)
439 		workaround_needed = false;
440 
441 	dev_dbg(bgp->dev, "Work around %sneeded\n",
442 		workaround_needed ? "not " : "");
443 
444 	if (!workaround_needed)
445 		init_table(5, ref_table, golden_factors);
446 	else
447 		init_table(3, ref_table, pvt_wa_factors);
448 
449 	/* Register the thermal sensors */
450 	for (id = 0; id < cnt; id++) {
451 		data[id].bgp = bgp;
452 		data[id].ctrl_offset = K3_VTM_TMPSENS0_CTRL_OFFSET + id * 0x20;
453 		data[id].stat_offset = data[id].ctrl_offset +
454 					K3_VTM_TMPSENS_STAT_OFFSET;
455 
456 		if (workaround_needed) {
457 			/* ref adc values for -40C, 30C & 125C respectively */
458 			err_vals.refs[0] = MINUS40CREF;
459 			err_vals.refs[1] = PLUS30CREF;
460 			err_vals.refs[2] = PLUS125CREF;
461 			err_vals.refs[3] = PLUS150CREF;
462 			get_efuse_values(id, &data[id], err_vals.errs, bgp);
463 		}
464 
465 		if (id == 0 && workaround_needed)
466 			prep_lookup_table(&err_vals, ref_table);
467 		else if (id == 0 && !workaround_needed)
468 			memcpy(derived_table, ref_table, TABLE_SIZE * 4);
469 
470 		val = readl(data[id].bgp->cfg2_base + data[id].ctrl_offset);
471 		val |= (K3_VTM_TMPSENS_CTRL_MAXT_OUTRG_EN |
472 			K3_VTM_TMPSENS_CTRL_SOC |
473 			K3_VTM_TMPSENS_CTRL_CLRZ | BIT(4));
474 		writel(val, data[id].bgp->cfg2_base + data[id].ctrl_offset);
475 
476 		bgp->ts_data[id] = &data[id];
477 		ti_thermal =
478 		devm_thermal_zone_of_sensor_register(bgp->dev, id,
479 						     &data[id],
480 						     &k3_of_thermal_ops);
481 		if (IS_ERR(ti_thermal)) {
482 			dev_err(bgp->dev, "thermal zone device is NULL\n");
483 			ret = PTR_ERR(ti_thermal);
484 			goto err_free_ref_table;
485 		}
486 	}
487 
488 	/*
489 	 * Program TSHUT thresholds
490 	 * Step 1: set the thresholds to ~123C and 105C WKUP_VTM_MISC_CTRL2
491 	 * Step 2: WKUP_VTM_TMPSENS_CTRL_j set the MAXT_OUTRG_EN  bit
492 	 *         This is already taken care as per of init
493 	 * Step 3: WKUP_VTM_MISC_CTRL set the ANYMAXT_OUTRG_ALERT_EN  bit
494 	 */
495 	high_max = k3_j72xx_bandgap_temp_to_adc_code(MAX_TEMP);
496 	low_temp = k3_j72xx_bandgap_temp_to_adc_code(COOL_DOWN_TEMP);
497 
498 	writel((low_temp << 16) | high_max, data[0].bgp->cfg2_base +
499 	       K3_VTM_MISC_CTRL2_OFFSET);
500 	mdelay(100);
501 	writel(K3_VTM_ANYMAXT_OUTRG_ALERT_EN, data[0].bgp->cfg2_base +
502 	       K3_VTM_MISC_CTRL_OFFSET);
503 
504 	platform_set_drvdata(pdev, bgp);
505 
506 	print_look_up_table(dev, ref_table);
507 	/*
508 	 * Now that the derived_table has the appropriate look up values
509 	 * Free up the ref_table
510 	 */
511 	kfree(ref_table);
512 
513 	return 0;
514 
515 err_free_ref_table:
516 	kfree(ref_table);
517 
518 err_alloc:
519 	pm_runtime_put_sync(&pdev->dev);
520 	pm_runtime_disable(&pdev->dev);
521 
522 	return ret;
523 }
524 
525 static int k3_j72xx_bandgap_remove(struct platform_device *pdev)
526 {
527 	pm_runtime_put_sync(&pdev->dev);
528 	pm_runtime_disable(&pdev->dev);
529 
530 	return 0;
531 }
532 
533 static const struct k3_j72xx_bandgap_data k3_j72xx_bandgap_j721e_data = {
534 	.has_errata_i2128 = 1,
535 };
536 
537 static const struct k3_j72xx_bandgap_data k3_j72xx_bandgap_j7200_data = {
538 	.has_errata_i2128 = 0,
539 };
540 
541 static const struct of_device_id of_k3_j72xx_bandgap_match[] = {
542 	{
543 		.compatible = "ti,j721e-vtm",
544 		.data = &k3_j72xx_bandgap_j721e_data,
545 	},
546 	{
547 		.compatible = "ti,j7200-vtm",
548 		.data = &k3_j72xx_bandgap_j7200_data,
549 	},
550 	{ /* sentinel */ },
551 };
552 MODULE_DEVICE_TABLE(of, of_k3_j72xx_bandgap_match);
553 
554 static struct platform_driver k3_j72xx_bandgap_sensor_driver = {
555 	.probe = k3_j72xx_bandgap_probe,
556 	.remove = k3_j72xx_bandgap_remove,
557 	.driver = {
558 		.name = "k3-j72xx-soc-thermal",
559 		.of_match_table	= of_k3_j72xx_bandgap_match,
560 	},
561 };
562 
563 module_platform_driver(k3_j72xx_bandgap_sensor_driver);
564 
565 MODULE_DESCRIPTION("K3 bandgap temperature sensor driver");
566 MODULE_LICENSE("GPL");
567 MODULE_AUTHOR("J Keerthy <j-keerthy@ti.com>");
568