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2024-02-20 ea08eeccae9297f7aabd2ef7f0c2517ac4549acc 
 kernel/drivers/pwm/pwm-fsl-ftm.c
....@@ -1,12 +1,8 @@
1
+// SPDX-License-Identifier: GPL-2.0-or-later
12 /*
23  *  Freescale FlexTimer Module (FTM) PWM Driver
34  *
45  *  Copyright 2012-2013 Freescale Semiconductor, Inc.
5
- *
6
- * This program is free software; you can redistribute it and/or modify
7
- * it under the terms of the GNU General Public License as published by
8
- * the Free Software Foundation; either version 2 of the License, or
9
- * (at your option) any later version.
106  */
117 
128 #include <linux/clk.h>
....@@ -22,51 +18,9 @@
2218 #include <linux/pwm.h>
2319 #include <linux/regmap.h>
2420 #include <linux/slab.h>
21
+#include <linux/fsl/ftm.h>
2522 
26
-#define FTM_SC		0x00
27
-#define FTM_SC_CLK_MASK_SHIFT	3
28
-#define FTM_SC_CLK_MASK	(3 << FTM_SC_CLK_MASK_SHIFT)
2923 #define FTM_SC_CLK(c)	(((c) + 1) << FTM_SC_CLK_MASK_SHIFT)
30
-#define FTM_SC_PS_MASK	0x7
31
-
32
-#define FTM_CNT		0x04
33
-#define FTM_MOD		0x08
34
-
35
-#define FTM_CSC_BASE	0x0C
36
-#define FTM_CSC_MSB	BIT(5)
37
-#define FTM_CSC_MSA	BIT(4)
38
-#define FTM_CSC_ELSB	BIT(3)
39
-#define FTM_CSC_ELSA	BIT(2)
40
-#define FTM_CSC(_channel)	(FTM_CSC_BASE + ((_channel) * 8))
41
-
42
-#define FTM_CV_BASE	0x10
43
-#define FTM_CV(_channel)	(FTM_CV_BASE + ((_channel) * 8))
44
-
45
-#define FTM_CNTIN	0x4C
46
-#define FTM_STATUS	0x50
47
-
48
-#define FTM_MODE	0x54
49
-#define FTM_MODE_FTMEN	BIT(0)
50
-#define FTM_MODE_INIT	BIT(2)
51
-#define FTM_MODE_PWMSYNC	BIT(3)
52
-
53
-#define FTM_SYNC	0x58
54
-#define FTM_OUTINIT	0x5C
55
-#define FTM_OUTMASK	0x60
56
-#define FTM_COMBINE	0x64
57
-#define FTM_DEADTIME	0x68
58
-#define FTM_EXTTRIG	0x6C
59
-#define FTM_POL		0x70
60
-#define FTM_FMS		0x74
61
-#define FTM_FILTER	0x78
62
-#define FTM_FLTCTRL	0x7C
63
-#define FTM_QDCTRL	0x80
64
-#define FTM_CONF	0x84
65
-#define FTM_FLTPOL	0x88
66
-#define FTM_SYNCONF	0x8C
67
-#define FTM_INVCTRL	0x90
68
-#define FTM_SWOCTRL	0x94
69
-#define FTM_PWMLOAD	0x98
7024 
7125 enum fsl_pwm_clk {
7226 	FSL_PWM_CLK_SYS,
....@@ -80,17 +34,19 @@
8034 	bool has_enable_bits;
8135 };
8236 
37
+struct fsl_pwm_periodcfg {
38
+	enum fsl_pwm_clk clk_select;
39
+	unsigned int clk_ps;
40
+	unsigned int mod_period;
41
+};
42
+
8343 struct fsl_pwm_chip {
8444 	struct pwm_chip chip;
85
-
8645 	struct mutex lock;
87
-
88
-	unsigned int cnt_select;
89
-	unsigned int clk_ps;
90
-
9146 	struct regmap *regmap;
9247 
93
-	int period_ns;
48
+	/* This value is valid iff a pwm is running */
49
+	struct fsl_pwm_periodcfg period;
9450 
9551 	struct clk *ipg_clk;
9652 	struct clk *clk[FSL_PWM_CLK_MAX];
....@@ -101,6 +57,33 @@
10157 static inline struct fsl_pwm_chip *to_fsl_chip(struct pwm_chip *chip)
10258 {
10359 	return container_of(chip, struct fsl_pwm_chip, chip);
60
+}
61
+
62
+static void ftm_clear_write_protection(struct fsl_pwm_chip *fpc)
63
+{
64
+	u32 val;
65
+
66
+	regmap_read(fpc->regmap, FTM_FMS, &val);
67
+	if (val & FTM_FMS_WPEN)
68
+		regmap_update_bits(fpc->regmap, FTM_MODE, FTM_MODE_WPDIS,
69
+				   FTM_MODE_WPDIS);
70
+}
71
+
72
+static void ftm_set_write_protection(struct fsl_pwm_chip *fpc)
73
+{
74
+	regmap_update_bits(fpc->regmap, FTM_FMS, FTM_FMS_WPEN, FTM_FMS_WPEN);
75
+}
76
+
77
+static bool fsl_pwm_periodcfg_are_equal(const struct fsl_pwm_periodcfg *a,
78
+					const struct fsl_pwm_periodcfg *b)
79
+{
80
+	if (a->clk_select != b->clk_select)
81
+		return false;
82
+	if (a->clk_ps != b->clk_ps)
83
+		return false;
84
+	if (a->mod_period != b->mod_period)
85
+		return false;
86
+	return true;
10487 }
10588 
10689 static int fsl_pwm_request(struct pwm_chip *chip, struct pwm_device *pwm)
....@@ -133,89 +116,58 @@
133116 	clk_disable_unprepare(fpc->ipg_clk);
134117 }
135118 
136
-static int fsl_pwm_calculate_default_ps(struct fsl_pwm_chip *fpc,
137
-					enum fsl_pwm_clk index)
119
+static unsigned int fsl_pwm_ticks_to_ns(struct fsl_pwm_chip *fpc,
120
+					  unsigned int ticks)
138121 {
139
-	unsigned long sys_rate, cnt_rate;
140
-	unsigned long long ratio;
122
+	unsigned long rate;
123
+	unsigned long long exval;
141124 
142
-	sys_rate = clk_get_rate(fpc->clk[FSL_PWM_CLK_SYS]);
143
-	if (!sys_rate)
144
-		return -EINVAL;
145
-
146
-	cnt_rate = clk_get_rate(fpc->clk[fpc->cnt_select]);
147
-	if (!cnt_rate)
148
-		return -EINVAL;
149
-
150
-	switch (index) {
151
-	case FSL_PWM_CLK_SYS:
152
-		fpc->clk_ps = 1;
153
-		break;
154
-	case FSL_PWM_CLK_FIX:
155
-		ratio = 2 * cnt_rate - 1;
156
-		do_div(ratio, sys_rate);
157
-		fpc->clk_ps = ratio;
158
-		break;
159
-	case FSL_PWM_CLK_EXT:
160
-		ratio = 4 * cnt_rate - 1;
161
-		do_div(ratio, sys_rate);
162
-		fpc->clk_ps = ratio;
163
-		break;
164
-	default:
165
-		return -EINVAL;
166
-	}
167
-
168
-	return 0;
125
+	rate = clk_get_rate(fpc->clk[fpc->period.clk_select]);
126
+	exval = ticks;
127
+	exval *= 1000000000UL;
128
+	do_div(exval, rate >> fpc->period.clk_ps);
129
+	return exval;
169130 }
170131 
171
-static unsigned long fsl_pwm_calculate_cycles(struct fsl_pwm_chip *fpc,
172
-					      unsigned long period_ns)
132
+static bool fsl_pwm_calculate_period_clk(struct fsl_pwm_chip *fpc,
133
+					 unsigned int period_ns,
134
+					 enum fsl_pwm_clk index,
135
+					 struct fsl_pwm_periodcfg *periodcfg
136
+					 )
173137 {
174
-	unsigned long long c, c0;
138
+	unsigned long long c;
139
+	unsigned int ps;
175140 
176
-	c = clk_get_rate(fpc->clk[fpc->cnt_select]);
141
+	c = clk_get_rate(fpc->clk[index]);
177142 	c = c * period_ns;
178143 	do_div(c, 1000000000UL);
179144 
180
-	do {
181
-		c0 = c;
182
-		do_div(c0, (1 << fpc->clk_ps));
183
-		if (c0 <= 0xFFFF)
184
-			return (unsigned long)c0;
185
-	} while (++fpc->clk_ps < 8);
145
+	if (c == 0)
146
+		return false;
186147 
187
-	return 0;
188
-}
189
-
190
-static unsigned long fsl_pwm_calculate_period_cycles(struct fsl_pwm_chip *fpc,
191
-						     unsigned long period_ns,
192
-						     enum fsl_pwm_clk index)
193
-{
194
-	int ret;
195
-
196
-	ret = fsl_pwm_calculate_default_ps(fpc, index);
197
-	if (ret) {
198
-		dev_err(fpc->chip.dev,
199
-			"failed to calculate default prescaler: %d\n",
200
-			ret);
201
-		return 0;
148
+	for (ps = 0; ps < 8 ; ++ps, c >>= 1) {
149
+		if (c <= 0x10000) {
150
+			periodcfg->clk_select = index;
151
+			periodcfg->clk_ps = ps;
152
+			periodcfg->mod_period = c - 1;
153
+			return true;
154
+		}
202155 	}
203
-
204
-	return fsl_pwm_calculate_cycles(fpc, period_ns);
156
+	return false;
205157 }
206158 
207
-static unsigned long fsl_pwm_calculate_period(struct fsl_pwm_chip *fpc,
208
-					      unsigned long period_ns)
159
+static bool fsl_pwm_calculate_period(struct fsl_pwm_chip *fpc,
160
+				     unsigned int period_ns,
161
+				     struct fsl_pwm_periodcfg *periodcfg)
209162 {
210163 	enum fsl_pwm_clk m0, m1;
211
-	unsigned long fix_rate, ext_rate, cycles;
164
+	unsigned long fix_rate, ext_rate;
165
+	bool ret;
212166 
213
-	cycles = fsl_pwm_calculate_period_cycles(fpc, period_ns,
214
-			FSL_PWM_CLK_SYS);
215
-	if (cycles) {
216
-		fpc->cnt_select = FSL_PWM_CLK_SYS;
217
-		return cycles;
218
-	}
167
+	ret = fsl_pwm_calculate_period_clk(fpc, period_ns, FSL_PWM_CLK_SYS,
168
+					   periodcfg);
169
+	if (ret)
170
+		return true;
219171 
220172 	fix_rate = clk_get_rate(fpc->clk[FSL_PWM_CLK_FIX]);
221173 	ext_rate = clk_get_rate(fpc->clk[FSL_PWM_CLK_EXT]);
....@@ -228,158 +180,181 @@
228180 		m1 = FSL_PWM_CLK_FIX;
229181 	}
230182 
231
-	cycles = fsl_pwm_calculate_period_cycles(fpc, period_ns, m0);
232
-	if (cycles) {
233
-		fpc->cnt_select = m0;
234
-		return cycles;
235
-	}
183
+	ret = fsl_pwm_calculate_period_clk(fpc, period_ns, m0, periodcfg);
184
+	if (ret)
185
+		return true;
236186 
237
-	fpc->cnt_select = m1;
238
-
239
-	return fsl_pwm_calculate_period_cycles(fpc, period_ns, m1);
187
+	return fsl_pwm_calculate_period_clk(fpc, period_ns, m1, periodcfg);
240188 }
241189 
242
-static unsigned long fsl_pwm_calculate_duty(struct fsl_pwm_chip *fpc,
243
-					    unsigned long period_ns,
244
-					    unsigned long duty_ns)
190
+static unsigned int fsl_pwm_calculate_duty(struct fsl_pwm_chip *fpc,
191
+					   unsigned int duty_ns)
245192 {
246193 	unsigned long long duty;
247
-	u32 val;
248194 
249
-	regmap_read(fpc->regmap, FTM_MOD, &val);
250
-	duty = (unsigned long long)duty_ns * (val + 1);
195
+	unsigned int period = fpc->period.mod_period + 1;
196
+	unsigned int period_ns = fsl_pwm_ticks_to_ns(fpc, period);
197
+
198
+	duty = (unsigned long long)duty_ns * period;
251199 	do_div(duty, period_ns);
252200 
253
-	return (unsigned long)duty;
201
+	return (unsigned int)duty;
254202 }
255203 
256
-static int fsl_pwm_config(struct pwm_chip *chip, struct pwm_device *pwm,
257
-			  int duty_ns, int period_ns)
204
+static bool fsl_pwm_is_any_pwm_enabled(struct fsl_pwm_chip *fpc,
205
+				       struct pwm_device *pwm)
258206 {
259
-	struct fsl_pwm_chip *fpc = to_fsl_chip(chip);
260
-	u32 period, duty;
207
+	u32 val;
261208 
262
-	mutex_lock(&fpc->lock);
209
+	regmap_read(fpc->regmap, FTM_OUTMASK, &val);
210
+	if (~val & 0xFF)
211
+		return true;
212
+	else
213
+		return false;
214
+}
263215 
216
+static bool fsl_pwm_is_other_pwm_enabled(struct fsl_pwm_chip *fpc,
217
+					 struct pwm_device *pwm)
218
+{
219
+	u32 val;
220
+
221
+	regmap_read(fpc->regmap, FTM_OUTMASK, &val);
222
+	if (~(val | BIT(pwm->hwpwm)) & 0xFF)
223
+		return true;
224
+	else
225
+		return false;
226
+}
227
+
228
+static int fsl_pwm_apply_config(struct fsl_pwm_chip *fpc,
229
+				struct pwm_device *pwm,
230
+				const struct pwm_state *newstate)
231
+{
232
+	unsigned int duty;
233
+	u32 reg_polarity;
234
+
235
+	struct fsl_pwm_periodcfg periodcfg;
236
+	bool do_write_period = false;
237
+
238
+	if (!fsl_pwm_calculate_period(fpc, newstate->period, &periodcfg)) {
239
+		dev_err(fpc->chip.dev, "failed to calculate new period\n");
240
+		return -EINVAL;
241
+	}
242
+
243
+	if (!fsl_pwm_is_any_pwm_enabled(fpc, pwm))
244
+		do_write_period = true;
264245 	/*
265246 	 * The Freescale FTM controller supports only a single period for
266
-	 * all PWM channels, therefore incompatible changes need to be
267
-	 * refused.
247
+	 * all PWM channels, therefore verify if the newly computed period
248
+	 * is different than the current period being used. In such case
249
+	 * we allow to change the period only if no other pwm is running.
268250 	 */
269
-	if (fpc->period_ns && fpc->period_ns != period_ns) {
270
-		dev_err(fpc->chip.dev,
271
-			"conflicting period requested for PWM %u\n",
272
-			pwm->hwpwm);
273
-		mutex_unlock(&fpc->lock);
274
-		return -EBUSY;
275
-	}
276
-
277
-	if (!fpc->period_ns && duty_ns) {
278
-		period = fsl_pwm_calculate_period(fpc, period_ns);
279
-		if (!period) {
280
-			dev_err(fpc->chip.dev, "failed to calculate period\n");
281
-			mutex_unlock(&fpc->lock);
282
-			return -EINVAL;
251
+	else if (!fsl_pwm_periodcfg_are_equal(&fpc->period, &periodcfg)) {
252
+		if (fsl_pwm_is_other_pwm_enabled(fpc, pwm)) {
253
+			dev_err(fpc->chip.dev,
254
+				"Cannot change period for PWM %u, disable other PWMs first\n",
255
+				pwm->hwpwm);
256
+			return -EBUSY;
283257 		}
258
+		if (fpc->period.clk_select != periodcfg.clk_select) {
259
+			int ret;
260
+			enum fsl_pwm_clk oldclk = fpc->period.clk_select;
261
+			enum fsl_pwm_clk newclk = periodcfg.clk_select;
284262 
285
-		regmap_update_bits(fpc->regmap, FTM_SC, FTM_SC_PS_MASK,
286
-				   fpc->clk_ps);
287
-		regmap_write(fpc->regmap, FTM_MOD, period - 1);
288
-
289
-		fpc->period_ns = period_ns;
263
+			ret = clk_prepare_enable(fpc->clk[newclk]);
264
+			if (ret)
265
+				return ret;
266
+			clk_disable_unprepare(fpc->clk[oldclk]);
267
+		}
268
+		do_write_period = true;
290269 	}
291270 
292
-	mutex_unlock(&fpc->lock);
271
+	ftm_clear_write_protection(fpc);
293272 
294
-	duty = fsl_pwm_calculate_duty(fpc, period_ns, duty_ns);
273
+	if (do_write_period) {
274
+		regmap_update_bits(fpc->regmap, FTM_SC, FTM_SC_CLK_MASK,
275
+				   FTM_SC_CLK(periodcfg.clk_select));
276
+		regmap_update_bits(fpc->regmap, FTM_SC, FTM_SC_PS_MASK,
277
+				   periodcfg.clk_ps);
278
+		regmap_write(fpc->regmap, FTM_MOD, periodcfg.mod_period);
279
+
280
+		fpc->period = periodcfg;
281
+	}
282
+
283
+	duty = fsl_pwm_calculate_duty(fpc, newstate->duty_cycle);
295284 
296285 	regmap_write(fpc->regmap, FTM_CSC(pwm->hwpwm),
297286 		     FTM_CSC_MSB | FTM_CSC_ELSB);
298287 	regmap_write(fpc->regmap, FTM_CV(pwm->hwpwm), duty);
299288 
289
+	reg_polarity = 0;
290
+	if (newstate->polarity == PWM_POLARITY_INVERSED)
291
+		reg_polarity = BIT(pwm->hwpwm);
292
+
293
+	regmap_update_bits(fpc->regmap, FTM_POL, BIT(pwm->hwpwm), reg_polarity);
294
+
295
+	ftm_set_write_protection(fpc);
296
+
300297 	return 0;
301298 }
302299 
303
-static int fsl_pwm_set_polarity(struct pwm_chip *chip,
304
-				struct pwm_device *pwm,
305
-				enum pwm_polarity polarity)
300
+static int fsl_pwm_apply(struct pwm_chip *chip, struct pwm_device *pwm,
301
+			 const struct pwm_state *newstate)
306302 {
307303 	struct fsl_pwm_chip *fpc = to_fsl_chip(chip);
308
-	u32 val;
304
+	struct pwm_state *oldstate = &pwm->state;
305
+	int ret = 0;
309306 
310
-	regmap_read(fpc->regmap, FTM_POL, &val);
307
+	/*
308
+	 * oldstate to newstate : action
309
+	 *
310
+	 * disabled to disabled : ignore
311
+	 * enabled to disabled : disable
312
+	 * enabled to enabled : update settings
313
+	 * disabled to enabled : update settings + enable
314
+	 */
311315 
312
-	if (polarity == PWM_POLARITY_INVERSED)
313
-		val |= BIT(pwm->hwpwm);
314
-	else
315
-		val &= ~BIT(pwm->hwpwm);
316
+	mutex_lock(&fpc->lock);
316317 
317
-	regmap_write(fpc->regmap, FTM_POL, val);
318
+	if (!newstate->enabled) {
319
+		if (oldstate->enabled) {
320
+			regmap_update_bits(fpc->regmap, FTM_OUTMASK,
321
+					   BIT(pwm->hwpwm), BIT(pwm->hwpwm));
322
+			clk_disable_unprepare(fpc->clk[FSL_PWM_CLK_CNTEN]);
323
+			clk_disable_unprepare(fpc->clk[fpc->period.clk_select]);
324
+		}
318325 
319
-	return 0;
320
-}
321
-
322
-static int fsl_counter_clock_enable(struct fsl_pwm_chip *fpc)
323
-{
324
-	int ret;
325
-
326
-	/* select counter clock source */
327
-	regmap_update_bits(fpc->regmap, FTM_SC, FTM_SC_CLK_MASK,
328
-			   FTM_SC_CLK(fpc->cnt_select));
329
-
330
-	ret = clk_prepare_enable(fpc->clk[fpc->cnt_select]);
331
-	if (ret)
332
-		return ret;
333
-
334
-	ret = clk_prepare_enable(fpc->clk[FSL_PWM_CLK_CNTEN]);
335
-	if (ret) {
336
-		clk_disable_unprepare(fpc->clk[fpc->cnt_select]);
337
-		return ret;
326
+		goto end_mutex;
338327 	}
339328 
340
-	return 0;
341
-}
329
+	ret = fsl_pwm_apply_config(fpc, pwm, newstate);
330
+	if (ret)
331
+		goto end_mutex;
342332 
343
-static int fsl_pwm_enable(struct pwm_chip *chip, struct pwm_device *pwm)
344
-{
345
-	struct fsl_pwm_chip *fpc = to_fsl_chip(chip);
346
-	int ret;
333
+	/* check if need to enable */
334
+	if (!oldstate->enabled) {
335
+		ret = clk_prepare_enable(fpc->clk[fpc->period.clk_select]);
336
+		if (ret)
337
+			goto end_mutex;
347338 
348
-	mutex_lock(&fpc->lock);
349
-	regmap_update_bits(fpc->regmap, FTM_OUTMASK, BIT(pwm->hwpwm), 0);
339
+		ret = clk_prepare_enable(fpc->clk[FSL_PWM_CLK_CNTEN]);
340
+		if (ret) {
341
+			clk_disable_unprepare(fpc->clk[fpc->period.clk_select]);
342
+			goto end_mutex;
343
+		}
350344 
351
-	ret = fsl_counter_clock_enable(fpc);
345
+		regmap_update_bits(fpc->regmap, FTM_OUTMASK, BIT(pwm->hwpwm),
346
+				   0);
347
+	}
348
+
349
+end_mutex:
352350 	mutex_unlock(&fpc->lock);
353
-
354351 	return ret;
355
-}
356
-
357
-static void fsl_pwm_disable(struct pwm_chip *chip, struct pwm_device *pwm)
358
-{
359
-	struct fsl_pwm_chip *fpc = to_fsl_chip(chip);
360
-	u32 val;
361
-
362
-	mutex_lock(&fpc->lock);
363
-	regmap_update_bits(fpc->regmap, FTM_OUTMASK, BIT(pwm->hwpwm),
364
-			   BIT(pwm->hwpwm));
365
-
366
-	clk_disable_unprepare(fpc->clk[FSL_PWM_CLK_CNTEN]);
367
-	clk_disable_unprepare(fpc->clk[fpc->cnt_select]);
368
-
369
-	regmap_read(fpc->regmap, FTM_OUTMASK, &val);
370
-	if ((val & 0xFF) == 0xFF)
371
-		fpc->period_ns = 0;
372
-
373
-	mutex_unlock(&fpc->lock);
374352 }
375353 
376354 static const struct pwm_ops fsl_pwm_ops = {
377355 	.request = fsl_pwm_request,
378356 	.free = fsl_pwm_free,
379
-	.config = fsl_pwm_config,
380
-	.set_polarity = fsl_pwm_set_polarity,
381
-	.enable = fsl_pwm_enable,
382
-	.disable = fsl_pwm_disable,
357
+	.apply = fsl_pwm_apply,
383358 	.owner = THIS_MODULE,
384359 };
385360 
....@@ -403,6 +378,8 @@
403378 static bool fsl_pwm_volatile_reg(struct device *dev, unsigned int reg)
404379 {
405380 	switch (reg) {
381
+	case FTM_FMS:
382
+	case FTM_MODE:
406383 	case FTM_CNT:
407384 		return true;
408385 	}
....@@ -520,7 +497,7 @@
520497 			continue;
521498 
522499 		clk_disable_unprepare(fpc->clk[FSL_PWM_CLK_CNTEN]);
523
-		clk_disable_unprepare(fpc->clk[fpc->cnt_select]);
500
+		clk_disable_unprepare(fpc->clk[fpc->period.clk_select]);
524501 	}
525502 
526503 	return 0;
....@@ -542,7 +519,7 @@
542519 		if (!pwm_is_enabled(pwm))
543520 			continue;
544521 
545
-		clk_prepare_enable(fpc->clk[fpc->cnt_select]);
522
+		clk_prepare_enable(fpc->clk[fpc->period.clk_select]);
546523 		clk_prepare_enable(fpc->clk[FSL_PWM_CLK_CNTEN]);
547524 	}
548525