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1// SPDX-License-Identifier: GPL-2.0-only
2/*
3 * Driver for Atmel Pulse Width Modulation Controller
4 *
5 * Copyright (C) 2013 Atmel Corporation
6 * Bo Shen <voice.shen@atmel.com>
7 */
8
9#include <linux/clk.h>
10#include <linux/delay.h>
11#include <linux/err.h>
12#include <linux/io.h>
13#include <linux/module.h>
14#include <linux/mutex.h>
15#include <linux/of.h>
16#include <linux/of_device.h>
17#include <linux/platform_device.h>
18#include <linux/pwm.h>
19#include <linux/slab.h>
20
21/* The following is global registers for PWM controller */
22#define PWM_ENA 0x04
23#define PWM_DIS 0x08
24#define PWM_SR 0x0C
25#define PWM_ISR 0x1C
26/* Bit field in SR */
27#define PWM_SR_ALL_CH_ON 0x0F
28
29/* The following register is PWM channel related registers */
30#define PWM_CH_REG_OFFSET 0x200
31#define PWM_CH_REG_SIZE 0x20
32
33#define PWM_CMR 0x0
34/* Bit field in CMR */
35#define PWM_CMR_CPOL (1 << 9)
36#define PWM_CMR_UPD_CDTY (1 << 10)
37#define PWM_CMR_CPRE_MSK 0xF
38
39/* The following registers for PWM v1 */
40#define PWMV1_CDTY 0x04
41#define PWMV1_CPRD 0x08
42#define PWMV1_CUPD 0x10
43
44/* The following registers for PWM v2 */
45#define PWMV2_CDTY 0x04
46#define PWMV2_CDTYUPD 0x08
47#define PWMV2_CPRD 0x0C
48#define PWMV2_CPRDUPD 0x10
49
50struct atmel_pwm_registers {
51 u8 period;
52 u8 period_upd;
53 u8 duty;
54 u8 duty_upd;
55};
56
57struct atmel_pwm_config {
58 u32 max_period;
59 u32 max_pres;
60};
61
62struct atmel_pwm_data {
63 struct atmel_pwm_registers regs;
64 struct atmel_pwm_config cfg;
65};
66
67struct atmel_pwm_chip {
68 struct pwm_chip chip;
69 struct clk *clk;
70 void __iomem *base;
71 const struct atmel_pwm_data *data;
72
73 unsigned int updated_pwms;
74 /* ISR is cleared when read, ensure only one thread does that */
75 struct mutex isr_lock;
76};
77
78static inline struct atmel_pwm_chip *to_atmel_pwm_chip(struct pwm_chip *chip)
79{
80 return container_of(chip, struct atmel_pwm_chip, chip);
81}
82
83static inline u32 atmel_pwm_readl(struct atmel_pwm_chip *chip,
84 unsigned long offset)
85{
86 return readl_relaxed(chip->base + offset);
87}
88
89static inline void atmel_pwm_writel(struct atmel_pwm_chip *chip,
90 unsigned long offset, unsigned long val)
91{
92 writel_relaxed(val, chip->base + offset);
93}
94
95static inline u32 atmel_pwm_ch_readl(struct atmel_pwm_chip *chip,
96 unsigned int ch, unsigned long offset)
97{
98 unsigned long base = PWM_CH_REG_OFFSET + ch * PWM_CH_REG_SIZE;
99
100 return readl_relaxed(chip->base + base + offset);
101}
102
103static inline void atmel_pwm_ch_writel(struct atmel_pwm_chip *chip,
104 unsigned int ch, unsigned long offset,
105 unsigned long val)
106{
107 unsigned long base = PWM_CH_REG_OFFSET + ch * PWM_CH_REG_SIZE;
108
109 writel_relaxed(val, chip->base + base + offset);
110}
111
112static int atmel_pwm_calculate_cprd_and_pres(struct pwm_chip *chip,
113 const struct pwm_state *state,
114 unsigned long *cprd, u32 *pres)
115{
116 struct atmel_pwm_chip *atmel_pwm = to_atmel_pwm_chip(chip);
117 unsigned long long cycles = state->period;
118
119 /* Calculate the period cycles and prescale value */
120 cycles *= clk_get_rate(atmel_pwm->clk);
121 do_div(cycles, NSEC_PER_SEC);
122
123 for (*pres = 0; cycles > atmel_pwm->data->cfg.max_period; cycles >>= 1)
124 (*pres)++;
125
126 if (*pres > atmel_pwm->data->cfg.max_pres) {
127 dev_err(chip->dev, "pres exceeds the maximum value\n");
128 return -EINVAL;
129 }
130
131 *cprd = cycles;
132
133 return 0;
134}
135
136static void atmel_pwm_calculate_cdty(const struct pwm_state *state,
137 unsigned long cprd, unsigned long *cdty)
138{
139 unsigned long long cycles = state->duty_cycle;
140
141 cycles *= cprd;
142 do_div(cycles, state->period);
143 *cdty = cprd - cycles;
144}
145
146static void atmel_pwm_update_cdty(struct pwm_chip *chip, struct pwm_device *pwm,
147 unsigned long cdty)
148{
149 struct atmel_pwm_chip *atmel_pwm = to_atmel_pwm_chip(chip);
150 u32 val;
151
152 if (atmel_pwm->data->regs.duty_upd ==
153 atmel_pwm->data->regs.period_upd) {
154 val = atmel_pwm_ch_readl(atmel_pwm, pwm->hwpwm, PWM_CMR);
155 val &= ~PWM_CMR_UPD_CDTY;
156 atmel_pwm_ch_writel(atmel_pwm, pwm->hwpwm, PWM_CMR, val);
157 }
158
159 atmel_pwm_ch_writel(atmel_pwm, pwm->hwpwm,
160 atmel_pwm->data->regs.duty_upd, cdty);
161}
162
163static void atmel_pwm_set_cprd_cdty(struct pwm_chip *chip,
164 struct pwm_device *pwm,
165 unsigned long cprd, unsigned long cdty)
166{
167 struct atmel_pwm_chip *atmel_pwm = to_atmel_pwm_chip(chip);
168
169 atmel_pwm_ch_writel(atmel_pwm, pwm->hwpwm,
170 atmel_pwm->data->regs.duty, cdty);
171 atmel_pwm_ch_writel(atmel_pwm, pwm->hwpwm,
172 atmel_pwm->data->regs.period, cprd);
173}
174
175static void atmel_pwm_disable(struct pwm_chip *chip, struct pwm_device *pwm,
176 bool disable_clk)
177{
178 struct atmel_pwm_chip *atmel_pwm = to_atmel_pwm_chip(chip);
179 unsigned long timeout = jiffies + 2 * HZ;
180
181 /*
182 * Wait for at least a complete period to have passed before disabling a
183 * channel to be sure that CDTY has been updated
184 */
185 mutex_lock(&atmel_pwm->isr_lock);
186 atmel_pwm->updated_pwms |= atmel_pwm_readl(atmel_pwm, PWM_ISR);
187
188 while (!(atmel_pwm->updated_pwms & (1 << pwm->hwpwm)) &&
189 time_before(jiffies, timeout)) {
190 usleep_range(10, 100);
191 atmel_pwm->updated_pwms |= atmel_pwm_readl(atmel_pwm, PWM_ISR);
192 }
193
194 mutex_unlock(&atmel_pwm->isr_lock);
195 atmel_pwm_writel(atmel_pwm, PWM_DIS, 1 << pwm->hwpwm);
196
197 /*
198 * Wait for the PWM channel disable operation to be effective before
199 * stopping the clock.
200 */
201 timeout = jiffies + 2 * HZ;
202
203 while ((atmel_pwm_readl(atmel_pwm, PWM_SR) & (1 << pwm->hwpwm)) &&
204 time_before(jiffies, timeout))
205 usleep_range(10, 100);
206
207 if (disable_clk)
208 clk_disable(atmel_pwm->clk);
209}
210
211static int atmel_pwm_apply(struct pwm_chip *chip, struct pwm_device *pwm,
212 const struct pwm_state *state)
213{
214 struct atmel_pwm_chip *atmel_pwm = to_atmel_pwm_chip(chip);
215 struct pwm_state cstate;
216 unsigned long cprd, cdty;
217 u32 pres, val;
218 int ret;
219
220 pwm_get_state(pwm, &cstate);
221
222 if (state->enabled) {
223 if (cstate.enabled &&
224 cstate.polarity == state->polarity &&
225 cstate.period == state->period) {
226 cprd = atmel_pwm_ch_readl(atmel_pwm, pwm->hwpwm,
227 atmel_pwm->data->regs.period);
228 atmel_pwm_calculate_cdty(state, cprd, &cdty);
229 atmel_pwm_update_cdty(chip, pwm, cdty);
230 return 0;
231 }
232
233 ret = atmel_pwm_calculate_cprd_and_pres(chip, state, &cprd,
234 &pres);
235 if (ret) {
236 dev_err(chip->dev,
237 "failed to calculate cprd and prescaler\n");
238 return ret;
239 }
240
241 atmel_pwm_calculate_cdty(state, cprd, &cdty);
242
243 if (cstate.enabled) {
244 atmel_pwm_disable(chip, pwm, false);
245 } else {
246 ret = clk_enable(atmel_pwm->clk);
247 if (ret) {
248 dev_err(chip->dev, "failed to enable clock\n");
249 return ret;
250 }
251 }
252
253 /* It is necessary to preserve CPOL, inside CMR */
254 val = atmel_pwm_ch_readl(atmel_pwm, pwm->hwpwm, PWM_CMR);
255 val = (val & ~PWM_CMR_CPRE_MSK) | (pres & PWM_CMR_CPRE_MSK);
256 if (state->polarity == PWM_POLARITY_NORMAL)
257 val &= ~PWM_CMR_CPOL;
258 else
259 val |= PWM_CMR_CPOL;
260 atmel_pwm_ch_writel(atmel_pwm, pwm->hwpwm, PWM_CMR, val);
261 atmel_pwm_set_cprd_cdty(chip, pwm, cprd, cdty);
262 mutex_lock(&atmel_pwm->isr_lock);
263 atmel_pwm->updated_pwms |= atmel_pwm_readl(atmel_pwm, PWM_ISR);
264 atmel_pwm->updated_pwms &= ~(1 << pwm->hwpwm);
265 mutex_unlock(&atmel_pwm->isr_lock);
266 atmel_pwm_writel(atmel_pwm, PWM_ENA, 1 << pwm->hwpwm);
267 } else if (cstate.enabled) {
268 atmel_pwm_disable(chip, pwm, true);
269 }
270
271 return 0;
272}
273
274static const struct pwm_ops atmel_pwm_ops = {
275 .apply = atmel_pwm_apply,
276 .owner = THIS_MODULE,
277};
278
279static const struct atmel_pwm_data atmel_sam9rl_pwm_data = {
280 .regs = {
281 .period = PWMV1_CPRD,
282 .period_upd = PWMV1_CUPD,
283 .duty = PWMV1_CDTY,
284 .duty_upd = PWMV1_CUPD,
285 },
286 .cfg = {
287 /* 16 bits to keep period and duty. */
288 .max_period = 0xffff,
289 .max_pres = 10,
290 },
291};
292
293static const struct atmel_pwm_data atmel_sama5_pwm_data = {
294 .regs = {
295 .period = PWMV2_CPRD,
296 .period_upd = PWMV2_CPRDUPD,
297 .duty = PWMV2_CDTY,
298 .duty_upd = PWMV2_CDTYUPD,
299 },
300 .cfg = {
301 /* 16 bits to keep period and duty. */
302 .max_period = 0xffff,
303 .max_pres = 10,
304 },
305};
306
307static const struct atmel_pwm_data mchp_sam9x60_pwm_data = {
308 .regs = {
309 .period = PWMV1_CPRD,
310 .period_upd = PWMV1_CUPD,
311 .duty = PWMV1_CDTY,
312 .duty_upd = PWMV1_CUPD,
313 },
314 .cfg = {
315 /* 32 bits to keep period and duty. */
316 .max_period = 0xffffffff,
317 .max_pres = 10,
318 },
319};
320
321static const struct of_device_id atmel_pwm_dt_ids[] = {
322 {
323 .compatible = "atmel,at91sam9rl-pwm",
324 .data = &atmel_sam9rl_pwm_data,
325 }, {
326 .compatible = "atmel,sama5d3-pwm",
327 .data = &atmel_sama5_pwm_data,
328 }, {
329 .compatible = "atmel,sama5d2-pwm",
330 .data = &atmel_sama5_pwm_data,
331 }, {
332 .compatible = "microchip,sam9x60-pwm",
333 .data = &mchp_sam9x60_pwm_data,
334 }, {
335 /* sentinel */
336 },
337};
338MODULE_DEVICE_TABLE(of, atmel_pwm_dt_ids);
339
340static int atmel_pwm_probe(struct platform_device *pdev)
341{
342 struct atmel_pwm_chip *atmel_pwm;
343 struct resource *res;
344 int ret;
345
346 atmel_pwm = devm_kzalloc(&pdev->dev, sizeof(*atmel_pwm), GFP_KERNEL);
347 if (!atmel_pwm)
348 return -ENOMEM;
349
350 mutex_init(&atmel_pwm->isr_lock);
351 atmel_pwm->data = of_device_get_match_data(&pdev->dev);
352 atmel_pwm->updated_pwms = 0;
353
354 res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
355 atmel_pwm->base = devm_ioremap_resource(&pdev->dev, res);
356 if (IS_ERR(atmel_pwm->base))
357 return PTR_ERR(atmel_pwm->base);
358
359 atmel_pwm->clk = devm_clk_get(&pdev->dev, NULL);
360 if (IS_ERR(atmel_pwm->clk))
361 return PTR_ERR(atmel_pwm->clk);
362
363 ret = clk_prepare(atmel_pwm->clk);
364 if (ret) {
365 dev_err(&pdev->dev, "failed to prepare PWM clock\n");
366 return ret;
367 }
368
369 atmel_pwm->chip.dev = &pdev->dev;
370 atmel_pwm->chip.ops = &atmel_pwm_ops;
371 atmel_pwm->chip.of_xlate = of_pwm_xlate_with_flags;
372 atmel_pwm->chip.of_pwm_n_cells = 3;
373 atmel_pwm->chip.base = -1;
374 atmel_pwm->chip.npwm = 4;
375
376 ret = pwmchip_add(&atmel_pwm->chip);
377 if (ret < 0) {
378 dev_err(&pdev->dev, "failed to add PWM chip %d\n", ret);
379 goto unprepare_clk;
380 }
381
382 platform_set_drvdata(pdev, atmel_pwm);
383
384 return ret;
385
386unprepare_clk:
387 clk_unprepare(atmel_pwm->clk);
388 return ret;
389}
390
391static int atmel_pwm_remove(struct platform_device *pdev)
392{
393 struct atmel_pwm_chip *atmel_pwm = platform_get_drvdata(pdev);
394
395 clk_unprepare(atmel_pwm->clk);
396 mutex_destroy(&atmel_pwm->isr_lock);
397
398 return pwmchip_remove(&atmel_pwm->chip);
399}
400
401static struct platform_driver atmel_pwm_driver = {
402 .driver = {
403 .name = "atmel-pwm",
404 .of_match_table = of_match_ptr(atmel_pwm_dt_ids),
405 },
406 .probe = atmel_pwm_probe,
407 .remove = atmel_pwm_remove,
408};
409module_platform_driver(atmel_pwm_driver);
410
411MODULE_ALIAS("platform:atmel-pwm");
412MODULE_AUTHOR("Bo Shen <voice.shen@atmel.com>");
413MODULE_DESCRIPTION("Atmel PWM driver");
414MODULE_LICENSE("GPL v2");