2 * PWM device driver for ST SoCs.
3 * Author: Ajit Pal Singh <ajitpal.singh@st.com>
5 * Copyright (C) 2013-2014 STMicroelectronics (R&D) Limited
7 * This program is free software; you can redistribute it and/or modify
8 * it under the terms of the GNU General Public License as published by
9 * the Free Software Foundation; either version 2 of the License, or
10 * (at your option) any later version.
13 #include <linux/clk.h>
14 #include <linux/interrupt.h>
15 #include <linux/math64.h>
16 #include <linux/mfd/syscon.h>
17 #include <linux/module.h>
19 #include <linux/platform_device.h>
20 #include <linux/pwm.h>
21 #include <linux/regmap.h>
22 #include <linux/sched.h>
23 #include <linux/slab.h>
24 #include <linux/time.h>
25 #include <linux/wait.h>
27 #define PWM_OUT_VAL(x) (0x00 + (4 * (x))) /* Device's Duty Cycle register */
28 #define PWM_CPT_VAL(x) (0x10 + (4 * (x))) /* Capture value */
29 #define PWM_CPT_EDGE(x) (0x30 + (4 * (x))) /* Edge to capture on */
31 #define STI_PWM_CTRL 0x50 /* Control/Config register */
32 #define STI_INT_EN 0x54 /* Interrupt Enable/Disable register */
33 #define STI_INT_STA 0x58 /* Interrupt Status register */
34 #define PWM_INT_ACK 0x5c
35 #define PWM_PRESCALE_LOW_MASK 0x0f
36 #define PWM_PRESCALE_HIGH_MASK 0xf0
37 #define PWM_CPT_EDGE_MASK 0x03
38 #define PWM_INT_ACK_MASK 0x1ff
40 #define STI_MAX_CPT_DEVS 4
41 #define CPT_DC_MAX 0xff
60 /* Each capture input can be programmed to detect rising-edge, falling-edge,
61 * either edge or neither egde
70 struct sti_cpt_ddata {
74 wait_queue_head_t wait;
77 struct sti_pwm_compat_data {
78 const struct reg_field *reg_fields;
79 unsigned int pwm_num_devs;
80 unsigned int cpt_num_devs;
81 unsigned int max_pwm_cnt;
82 unsigned int max_prescale;
89 struct regmap *regmap;
90 struct sti_pwm_compat_data *cdata;
91 struct regmap_field *prescale_low;
92 struct regmap_field *prescale_high;
93 struct regmap_field *pwm_out_en;
94 struct regmap_field *pwm_cpt_int_en;
96 struct pwm_device *cur;
97 unsigned long configured;
98 unsigned int en_count;
99 struct mutex sti_pwm_lock; /* To sync between enable/disable calls */
103 static const struct reg_field sti_pwm_regfields[MAX_REGFIELDS] = {
104 [PWMCLK_PRESCALE_LOW] = REG_FIELD(STI_PWM_CTRL, 0, 3),
105 [PWMCLK_PRESCALE_HIGH] = REG_FIELD(STI_PWM_CTRL, 11, 14),
106 [CPTCLK_PRESCALE] = REG_FIELD(STI_PWM_CTRL, 4, 8),
107 [PWM_OUT_EN] = REG_FIELD(STI_PWM_CTRL, 9, 9),
108 [PWM_CPT_EN] = REG_FIELD(STI_PWM_CTRL, 10, 10),
109 [PWM_CPT_INT_EN] = REG_FIELD(STI_INT_EN, 1, 4),
110 [PWM_CPT_INT_STAT] = REG_FIELD(STI_INT_STA, 1, 4),
113 static inline struct sti_pwm_chip *to_sti_pwmchip(struct pwm_chip *chip)
115 return container_of(chip, struct sti_pwm_chip, chip);
119 * Calculate the prescaler value corresponding to the period.
121 static int sti_pwm_get_prescale(struct sti_pwm_chip *pc, unsigned long period,
122 unsigned int *prescale)
124 struct sti_pwm_compat_data *cdata = pc->cdata;
125 unsigned long clk_rate;
129 clk_rate = clk_get_rate(pc->pwm_clk);
131 dev_err(pc->dev, "failed to get clock rate\n");
136 * prescale = ((period_ns * clk_rate) / (10^9 * (max_pwm_count + 1)) - 1
138 val = NSEC_PER_SEC / clk_rate;
139 val *= cdata->max_pwm_cnt + 1;
144 ps = period / val - 1;
145 if (ps > cdata->max_prescale)
154 * For STiH4xx PWM IP, the PWM period is fixed to 256 local clock cycles.
155 * The only way to change the period (apart from changing the PWM input clock)
156 * is to change the PWM clock prescaler.
157 * The prescaler is of 8 bits, so 256 prescaler values and hence
158 * 256 possible period values are supported (for a particular clock rate).
159 * The requested period will be applied only if it matches one of these
162 static int sti_pwm_config(struct pwm_chip *chip, struct pwm_device *pwm,
163 int duty_ns, int period_ns)
165 struct sti_pwm_chip *pc = to_sti_pwmchip(chip);
166 struct sti_pwm_compat_data *cdata = pc->cdata;
167 struct pwm_device *cur = pc->cur;
168 struct device *dev = pc->dev;
169 unsigned int prescale = 0, pwmvalx;
172 bool period_same = false;
174 ncfg = hweight_long(pc->configured);
176 period_same = (period_ns == pwm_get_period(cur));
178 /* Allow configuration changes if one of the
179 * following conditions satisfy.
180 * 1. No devices have been configured.
181 * 2. Only one device has been configured and the new request
182 * is for the same device.
183 * 3. Only one device has been configured and the new request is
184 * for a new device and period of the new device is same as
185 * the current configured period.
186 * 4. More than one devices are configured and period of the new
187 * requestis the same as the current period.
190 ((ncfg == 1) && (pwm->hwpwm == cur->hwpwm)) ||
191 ((ncfg == 1) && (pwm->hwpwm != cur->hwpwm) && period_same) ||
192 ((ncfg > 1) && period_same)) {
193 /* Enable clock before writing to PWM registers. */
194 ret = clk_enable(pc->pwm_clk);
198 ret = clk_enable(pc->cpt_clk);
203 ret = sti_pwm_get_prescale(pc, period_ns, &prescale);
208 regmap_field_write(pc->prescale_low,
209 prescale & PWM_PRESCALE_LOW_MASK);
214 regmap_field_write(pc->prescale_high,
215 (prescale & PWM_PRESCALE_HIGH_MASK) >> 4);
221 * When PWMVal == 0, PWM pulse = 1 local clock cycle.
222 * When PWMVal == max_pwm_count,
223 * PWM pulse = (max_pwm_count + 1) local cycles,
224 * that is continuous pulse: signal never goes low.
226 pwmvalx = cdata->max_pwm_cnt * duty_ns / period_ns;
228 ret = regmap_write(pc->regmap,
229 PWM_OUT_VAL(pwm->hwpwm), pwmvalx);
233 ret = regmap_field_write(pc->pwm_cpt_int_en, 0);
235 set_bit(pwm->hwpwm, &pc->configured);
238 dev_dbg(dev, "prescale:%u, period:%i, duty:%i, pwmvalx:%u\n",
239 prescale, period_ns, duty_ns, pwmvalx);
245 clk_disable(pc->pwm_clk);
246 clk_disable(pc->cpt_clk);
250 static int sti_pwm_enable(struct pwm_chip *chip, struct pwm_device *pwm)
252 struct sti_pwm_chip *pc = to_sti_pwmchip(chip);
253 struct device *dev = pc->dev;
257 * Since we have a common enable for all PWM devices,
258 * do not enable if already enabled.
260 mutex_lock(&pc->sti_pwm_lock);
262 ret = clk_enable(pc->pwm_clk);
266 ret = clk_enable(pc->cpt_clk);
270 ret = regmap_field_write(pc->pwm_out_en, 1);
272 dev_err(dev, "failed to enable PWM device:%d\n",
279 mutex_unlock(&pc->sti_pwm_lock);
283 static void sti_pwm_disable(struct pwm_chip *chip, struct pwm_device *pwm)
285 struct sti_pwm_chip *pc = to_sti_pwmchip(chip);
287 mutex_lock(&pc->sti_pwm_lock);
288 if (--pc->en_count) {
289 mutex_unlock(&pc->sti_pwm_lock);
292 regmap_field_write(pc->pwm_out_en, 0);
294 clk_disable(pc->pwm_clk);
295 clk_disable(pc->cpt_clk);
296 mutex_unlock(&pc->sti_pwm_lock);
299 static void sti_pwm_free(struct pwm_chip *chip, struct pwm_device *pwm)
301 struct sti_pwm_chip *pc = to_sti_pwmchip(chip);
303 clear_bit(pwm->hwpwm, &pc->configured);
306 static const struct pwm_ops sti_pwm_ops = {
307 .config = sti_pwm_config,
308 .enable = sti_pwm_enable,
309 .disable = sti_pwm_disable,
310 .free = sti_pwm_free,
311 .owner = THIS_MODULE,
314 static int sti_pwm_probe_dt(struct sti_pwm_chip *pc)
316 struct device *dev = pc->dev;
317 const struct reg_field *reg_fields;
318 struct device_node *np = dev->of_node;
319 struct sti_pwm_compat_data *cdata = pc->cdata;
323 ret = of_property_read_u32(np, "st,pwm-num-chan", &num_devs);
325 cdata->pwm_num_devs = num_devs;
327 ret = of_property_read_u32(np, "st,capture-num-chan", &num_devs);
329 cdata->cpt_num_devs = num_devs;
331 reg_fields = cdata->reg_fields;
333 pc->prescale_low = devm_regmap_field_alloc(dev, pc->regmap,
334 reg_fields[PWMCLK_PRESCALE_LOW]);
335 if (IS_ERR(pc->prescale_low))
336 return PTR_ERR(pc->prescale_low);
338 pc->prescale_high = devm_regmap_field_alloc(dev, pc->regmap,
339 reg_fields[PWMCLK_PRESCALE_HIGH]);
340 if (IS_ERR(pc->prescale_high))
341 return PTR_ERR(pc->prescale_high);
344 pc->pwm_out_en = devm_regmap_field_alloc(dev, pc->regmap,
345 reg_fields[PWM_OUT_EN]);
346 if (IS_ERR(pc->pwm_out_en))
347 return PTR_ERR(pc->pwm_out_en);
349 pc->pwm_cpt_int_en = devm_regmap_field_alloc(dev, pc->regmap,
350 reg_fields[PWM_CPT_INT_EN]);
351 if (IS_ERR(pc->pwm_cpt_int_en))
352 return PTR_ERR(pc->pwm_cpt_int_en);
357 static const struct regmap_config sti_pwm_regmap_config = {
363 static int sti_pwm_probe(struct platform_device *pdev)
365 struct device *dev = &pdev->dev;
366 struct sti_pwm_compat_data *cdata;
367 struct sti_pwm_chip *pc;
368 struct resource *res;
372 pc = devm_kzalloc(dev, sizeof(*pc), GFP_KERNEL);
376 cdata = devm_kzalloc(dev, sizeof(*cdata), GFP_KERNEL);
380 res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
382 pc->mmio = devm_ioremap_resource(dev, res);
383 if (IS_ERR(pc->mmio))
384 return PTR_ERR(pc->mmio);
386 pc->regmap = devm_regmap_init_mmio(dev, pc->mmio,
387 &sti_pwm_regmap_config);
388 if (IS_ERR(pc->regmap))
389 return PTR_ERR(pc->regmap);
392 * Setup PWM data with default values: some values could be replaced
393 * with specific ones provided from Device Tree.
395 cdata->reg_fields = &sti_pwm_regfields[0];
396 cdata->max_prescale = 0xff;
397 cdata->max_pwm_cnt = 255;
398 cdata->pwm_num_devs = 1;
399 cdata->cpt_num_devs = 0;
404 mutex_init(&pc->sti_pwm_lock);
406 ret = sti_pwm_probe_dt(pc);
410 pc->pwm_clk = of_clk_get_by_name(dev->of_node, "pwm");
411 if (IS_ERR(pc->pwm_clk)) {
412 dev_err(dev, "failed to get PWM clock\n");
413 return PTR_ERR(pc->pwm_clk);
416 ret = clk_prepare(pc->pwm_clk);
418 dev_err(dev, "failed to prepare clock\n");
422 pc->cpt_clk = of_clk_get_by_name(dev->of_node, "capture");
423 if (IS_ERR(pc->cpt_clk)) {
424 dev_err(dev, "failed to get PWM capture clock\n");
425 return PTR_ERR(pc->cpt_clk);
428 ret = clk_prepare(pc->cpt_clk);
430 dev_err(dev, "failed to prepare clock\n");
435 pc->chip.ops = &sti_pwm_ops;
437 pc->chip.npwm = pc->cdata->pwm_num_devs;
438 pc->chip.can_sleep = true;
440 ret = pwmchip_add(&pc->chip);
442 clk_unprepare(pc->pwm_clk);
443 clk_unprepare(pc->cpt_clk);
447 for (i = 0; i < cdata->cpt_num_devs; i++) {
448 struct sti_cpt_ddata *ddata;
450 ddata = devm_kzalloc(dev, sizeof(*ddata), GFP_KERNEL);
454 init_waitqueue_head(&ddata->wait);
455 mutex_init(&ddata->lock);
457 pwm_set_chip_data(&pc->chip.pwms[i], ddata);
460 platform_set_drvdata(pdev, pc);
465 static int sti_pwm_remove(struct platform_device *pdev)
467 struct sti_pwm_chip *pc = platform_get_drvdata(pdev);
470 for (i = 0; i < pc->cdata->pwm_num_devs; i++)
471 pwm_disable(&pc->chip.pwms[i]);
473 clk_unprepare(pc->pwm_clk);
474 clk_unprepare(pc->cpt_clk);
476 return pwmchip_remove(&pc->chip);
479 static const struct of_device_id sti_pwm_of_match[] = {
480 { .compatible = "st,sti-pwm", },
483 MODULE_DEVICE_TABLE(of, sti_pwm_of_match);
485 static struct platform_driver sti_pwm_driver = {
488 .of_match_table = sti_pwm_of_match,
490 .probe = sti_pwm_probe,
491 .remove = sti_pwm_remove,
493 module_platform_driver(sti_pwm_driver);
495 MODULE_AUTHOR("Ajit Pal Singh <ajitpal.singh@st.com>");
496 MODULE_DESCRIPTION("STMicroelectronics ST PWM driver");
497 MODULE_LICENSE("GPL");