1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3 * Imagination Technologies Pulse Width Modulator driver
4 *
5 * Copyright (c) 2014-2015, Imagination Technologies
6 *
7 * Based on drivers/pwm/pwm-tegra.c, Copyright (c) 2010, NVIDIA Corporation
8 */
9
10 #include <linux/clk.h>
11 #include <linux/err.h>
12 #include <linux/io.h>
13 #include <linux/mfd/syscon.h>
14 #include <linux/module.h>
15 #include <linux/of.h>
16 #include <linux/platform_device.h>
17 #include <linux/pm_runtime.h>
18 #include <linux/property.h>
19 #include <linux/pwm.h>
20 #include <linux/regmap.h>
21 #include <linux/slab.h>
22
23 /* PWM registers */
24 #define PWM_CTRL_CFG 0x0000
25 #define PWM_CTRL_CFG_NO_SUB_DIV 0
26 #define PWM_CTRL_CFG_SUB_DIV0 1
27 #define PWM_CTRL_CFG_SUB_DIV1 2
28 #define PWM_CTRL_CFG_SUB_DIV0_DIV1 3
29 #define PWM_CTRL_CFG_DIV_SHIFT(ch) ((ch) * 2 + 4)
30 #define PWM_CTRL_CFG_DIV_MASK 0x3
31
32 #define PWM_CH_CFG(ch) (0x4 + (ch) * 4)
33 #define PWM_CH_CFG_TMBASE_SHIFT 0
34 #define PWM_CH_CFG_DUTY_SHIFT 16
35
36 #define PERIP_PWM_PDM_CONTROL 0x0140
37 #define PERIP_PWM_PDM_CONTROL_CH_MASK 0x1
38 #define PERIP_PWM_PDM_CONTROL_CH_SHIFT(ch) ((ch) * 4)
39
40 #define IMG_PWM_PM_TIMEOUT 1000 /* ms */
41
42 /*
43 * PWM period is specified with a timebase register,
44 * in number of step periods. The PWM duty cycle is also
45 * specified in step periods, in the [0, $timebase] range.
46 * In other words, the timebase imposes the duty cycle
47 * resolution. Therefore, let's constraint the timebase to
48 * a minimum value to allow a sane range of duty cycle values.
49 * Imposing a minimum timebase, will impose a maximum PWM frequency.
50 *
51 * The value chosen is completely arbitrary.
52 */
53 #define MIN_TMBASE_STEPS 16
54
55 #define IMG_PWM_NPWM 4
56
57 struct img_pwm_soc_data {
58 u32 max_timebase;
59 };
60
61 struct img_pwm_chip {
62 struct clk *pwm_clk;
63 struct clk *sys_clk;
64 void __iomem *base;
65 struct regmap *periph_regs;
66 int max_period_ns;
67 int min_period_ns;
68 const struct img_pwm_soc_data *data;
69 u32 suspend_ctrl_cfg;
70 u32 suspend_ch_cfg[IMG_PWM_NPWM];
71 };
72
to_img_pwm_chip(struct pwm_chip * chip)73 static inline struct img_pwm_chip *to_img_pwm_chip(struct pwm_chip *chip)
74 {
75 return pwmchip_get_drvdata(chip);
76 }
77
img_pwm_writel(struct img_pwm_chip * imgchip,u32 reg,u32 val)78 static inline void img_pwm_writel(struct img_pwm_chip *imgchip,
79 u32 reg, u32 val)
80 {
81 writel(val, imgchip->base + reg);
82 }
83
img_pwm_readl(struct img_pwm_chip * imgchip,u32 reg)84 static inline u32 img_pwm_readl(struct img_pwm_chip *imgchip, u32 reg)
85 {
86 return readl(imgchip->base + reg);
87 }
88
img_pwm_config(struct pwm_chip * chip,struct pwm_device * pwm,int duty_ns,int period_ns)89 static int img_pwm_config(struct pwm_chip *chip, struct pwm_device *pwm,
90 int duty_ns, int period_ns)
91 {
92 u32 val, div, duty, timebase;
93 unsigned long mul, output_clk_hz, input_clk_hz;
94 struct img_pwm_chip *imgchip = to_img_pwm_chip(chip);
95 unsigned int max_timebase = imgchip->data->max_timebase;
96 int ret;
97
98 if (period_ns < imgchip->min_period_ns ||
99 period_ns > imgchip->max_period_ns) {
100 dev_err(pwmchip_parent(chip), "configured period not in range\n");
101 return -ERANGE;
102 }
103
104 input_clk_hz = clk_get_rate(imgchip->pwm_clk);
105 output_clk_hz = DIV_ROUND_UP(NSEC_PER_SEC, period_ns);
106
107 mul = DIV_ROUND_UP(input_clk_hz, output_clk_hz);
108 if (mul <= max_timebase) {
109 div = PWM_CTRL_CFG_NO_SUB_DIV;
110 timebase = DIV_ROUND_UP(mul, 1);
111 } else if (mul <= max_timebase * 8) {
112 div = PWM_CTRL_CFG_SUB_DIV0;
113 timebase = DIV_ROUND_UP(mul, 8);
114 } else if (mul <= max_timebase * 64) {
115 div = PWM_CTRL_CFG_SUB_DIV1;
116 timebase = DIV_ROUND_UP(mul, 64);
117 } else if (mul <= max_timebase * 512) {
118 div = PWM_CTRL_CFG_SUB_DIV0_DIV1;
119 timebase = DIV_ROUND_UP(mul, 512);
120 } else {
121 dev_err(pwmchip_parent(chip),
122 "failed to configure timebase steps/divider value\n");
123 return -EINVAL;
124 }
125
126 duty = DIV_ROUND_UP(timebase * duty_ns, period_ns);
127
128 ret = pm_runtime_resume_and_get(pwmchip_parent(chip));
129 if (ret < 0)
130 return ret;
131
132 val = img_pwm_readl(imgchip, PWM_CTRL_CFG);
133 val &= ~(PWM_CTRL_CFG_DIV_MASK << PWM_CTRL_CFG_DIV_SHIFT(pwm->hwpwm));
134 val |= (div & PWM_CTRL_CFG_DIV_MASK) <<
135 PWM_CTRL_CFG_DIV_SHIFT(pwm->hwpwm);
136 img_pwm_writel(imgchip, PWM_CTRL_CFG, val);
137
138 val = (duty << PWM_CH_CFG_DUTY_SHIFT) |
139 (timebase << PWM_CH_CFG_TMBASE_SHIFT);
140 img_pwm_writel(imgchip, PWM_CH_CFG(pwm->hwpwm), val);
141
142 pm_runtime_mark_last_busy(pwmchip_parent(chip));
143 pm_runtime_put_autosuspend(pwmchip_parent(chip));
144
145 return 0;
146 }
147
img_pwm_enable(struct pwm_chip * chip,struct pwm_device * pwm)148 static int img_pwm_enable(struct pwm_chip *chip, struct pwm_device *pwm)
149 {
150 u32 val;
151 struct img_pwm_chip *imgchip = to_img_pwm_chip(chip);
152 int ret;
153
154 ret = pm_runtime_resume_and_get(pwmchip_parent(chip));
155 if (ret < 0)
156 return ret;
157
158 val = img_pwm_readl(imgchip, PWM_CTRL_CFG);
159 val |= BIT(pwm->hwpwm);
160 img_pwm_writel(imgchip, PWM_CTRL_CFG, val);
161
162 regmap_clear_bits(imgchip->periph_regs, PERIP_PWM_PDM_CONTROL,
163 PERIP_PWM_PDM_CONTROL_CH_MASK <<
164 PERIP_PWM_PDM_CONTROL_CH_SHIFT(pwm->hwpwm));
165
166 return 0;
167 }
168
img_pwm_disable(struct pwm_chip * chip,struct pwm_device * pwm)169 static void img_pwm_disable(struct pwm_chip *chip, struct pwm_device *pwm)
170 {
171 u32 val;
172 struct img_pwm_chip *imgchip = to_img_pwm_chip(chip);
173
174 val = img_pwm_readl(imgchip, PWM_CTRL_CFG);
175 val &= ~BIT(pwm->hwpwm);
176 img_pwm_writel(imgchip, PWM_CTRL_CFG, val);
177
178 pm_runtime_mark_last_busy(pwmchip_parent(chip));
179 pm_runtime_put_autosuspend(pwmchip_parent(chip));
180 }
181
img_pwm_apply(struct pwm_chip * chip,struct pwm_device * pwm,const struct pwm_state * state)182 static int img_pwm_apply(struct pwm_chip *chip, struct pwm_device *pwm,
183 const struct pwm_state *state)
184 {
185 int err;
186
187 if (state->polarity != PWM_POLARITY_NORMAL)
188 return -EINVAL;
189
190 if (!state->enabled) {
191 if (pwm->state.enabled)
192 img_pwm_disable(chip, pwm);
193
194 return 0;
195 }
196
197 err = img_pwm_config(chip, pwm, state->duty_cycle, state->period);
198 if (err)
199 return err;
200
201 if (!pwm->state.enabled)
202 err = img_pwm_enable(chip, pwm);
203
204 return err;
205 }
206
207 static const struct pwm_ops img_pwm_ops = {
208 .apply = img_pwm_apply,
209 };
210
211 static const struct img_pwm_soc_data pistachio_pwm = {
212 .max_timebase = 255,
213 };
214
215 static const struct of_device_id img_pwm_of_match[] = {
216 {
217 .compatible = "img,pistachio-pwm",
218 .data = &pistachio_pwm,
219 },
220 { }
221 };
222 MODULE_DEVICE_TABLE(of, img_pwm_of_match);
223
img_pwm_runtime_suspend(struct device * dev)224 static int img_pwm_runtime_suspend(struct device *dev)
225 {
226 struct pwm_chip *chip = dev_get_drvdata(dev);
227 struct img_pwm_chip *imgchip = to_img_pwm_chip(chip);
228
229 clk_disable_unprepare(imgchip->pwm_clk);
230 clk_disable_unprepare(imgchip->sys_clk);
231
232 return 0;
233 }
234
img_pwm_runtime_resume(struct device * dev)235 static int img_pwm_runtime_resume(struct device *dev)
236 {
237 struct pwm_chip *chip = dev_get_drvdata(dev);
238 struct img_pwm_chip *imgchip = to_img_pwm_chip(chip);
239 int ret;
240
241 ret = clk_prepare_enable(imgchip->sys_clk);
242 if (ret < 0) {
243 dev_err(dev, "could not prepare or enable sys clock\n");
244 return ret;
245 }
246
247 ret = clk_prepare_enable(imgchip->pwm_clk);
248 if (ret < 0) {
249 dev_err(dev, "could not prepare or enable pwm clock\n");
250 clk_disable_unprepare(imgchip->sys_clk);
251 return ret;
252 }
253
254 return 0;
255 }
256
img_pwm_probe(struct platform_device * pdev)257 static int img_pwm_probe(struct platform_device *pdev)
258 {
259 int ret;
260 u64 val;
261 unsigned long clk_rate;
262 struct pwm_chip *chip;
263 struct img_pwm_chip *imgchip;
264
265 chip = devm_pwmchip_alloc(&pdev->dev, IMG_PWM_NPWM, sizeof(*imgchip));
266 if (IS_ERR(chip))
267 return PTR_ERR(chip);
268 imgchip = to_img_pwm_chip(chip);
269
270 imgchip->base = devm_platform_ioremap_resource(pdev, 0);
271 if (IS_ERR(imgchip->base))
272 return PTR_ERR(imgchip->base);
273
274 imgchip->data = device_get_match_data(&pdev->dev);
275
276 imgchip->periph_regs = syscon_regmap_lookup_by_phandle(pdev->dev.of_node,
277 "img,cr-periph");
278 if (IS_ERR(imgchip->periph_regs))
279 return PTR_ERR(imgchip->periph_regs);
280
281 imgchip->sys_clk = devm_clk_get(&pdev->dev, "sys");
282 if (IS_ERR(imgchip->sys_clk)) {
283 dev_err(&pdev->dev, "failed to get system clock\n");
284 return PTR_ERR(imgchip->sys_clk);
285 }
286
287 imgchip->pwm_clk = devm_clk_get(&pdev->dev, "pwm");
288 if (IS_ERR(imgchip->pwm_clk)) {
289 dev_err(&pdev->dev, "failed to get pwm clock\n");
290 return PTR_ERR(imgchip->pwm_clk);
291 }
292
293 platform_set_drvdata(pdev, chip);
294
295 pm_runtime_set_autosuspend_delay(&pdev->dev, IMG_PWM_PM_TIMEOUT);
296 pm_runtime_use_autosuspend(&pdev->dev);
297 pm_runtime_enable(&pdev->dev);
298 if (!pm_runtime_enabled(&pdev->dev)) {
299 ret = img_pwm_runtime_resume(&pdev->dev);
300 if (ret)
301 goto err_pm_disable;
302 }
303
304 clk_rate = clk_get_rate(imgchip->pwm_clk);
305 if (!clk_rate) {
306 dev_err(&pdev->dev, "imgchip clock has no frequency\n");
307 ret = -EINVAL;
308 goto err_suspend;
309 }
310
311 /* The maximum input clock divider is 512 */
312 val = (u64)NSEC_PER_SEC * 512 * imgchip->data->max_timebase;
313 do_div(val, clk_rate);
314 imgchip->max_period_ns = val;
315
316 val = (u64)NSEC_PER_SEC * MIN_TMBASE_STEPS;
317 do_div(val, clk_rate);
318 imgchip->min_period_ns = val;
319
320 chip->ops = &img_pwm_ops;
321
322 ret = pwmchip_add(chip);
323 if (ret < 0) {
324 dev_err(&pdev->dev, "pwmchip_add failed: %d\n", ret);
325 goto err_suspend;
326 }
327
328 return 0;
329
330 err_suspend:
331 if (!pm_runtime_enabled(&pdev->dev))
332 img_pwm_runtime_suspend(&pdev->dev);
333 err_pm_disable:
334 pm_runtime_disable(&pdev->dev);
335 pm_runtime_dont_use_autosuspend(&pdev->dev);
336 return ret;
337 }
338
img_pwm_remove(struct platform_device * pdev)339 static void img_pwm_remove(struct platform_device *pdev)
340 {
341 struct pwm_chip *chip = platform_get_drvdata(pdev);
342
343 pm_runtime_disable(&pdev->dev);
344 if (!pm_runtime_status_suspended(&pdev->dev))
345 img_pwm_runtime_suspend(&pdev->dev);
346
347 pwmchip_remove(chip);
348 }
349
350 #ifdef CONFIG_PM_SLEEP
img_pwm_suspend(struct device * dev)351 static int img_pwm_suspend(struct device *dev)
352 {
353 struct pwm_chip *chip = dev_get_drvdata(dev);
354 struct img_pwm_chip *imgchip = to_img_pwm_chip(chip);
355 int i, ret;
356
357 if (pm_runtime_status_suspended(dev)) {
358 ret = img_pwm_runtime_resume(dev);
359 if (ret)
360 return ret;
361 }
362
363 for (i = 0; i < chip->npwm; i++)
364 imgchip->suspend_ch_cfg[i] = img_pwm_readl(imgchip,
365 PWM_CH_CFG(i));
366
367 imgchip->suspend_ctrl_cfg = img_pwm_readl(imgchip, PWM_CTRL_CFG);
368
369 img_pwm_runtime_suspend(dev);
370
371 return 0;
372 }
373
img_pwm_resume(struct device * dev)374 static int img_pwm_resume(struct device *dev)
375 {
376 struct pwm_chip *chip = dev_get_drvdata(dev);
377 struct img_pwm_chip *imgchip = to_img_pwm_chip(chip);
378 int ret;
379 int i;
380
381 ret = img_pwm_runtime_resume(dev);
382 if (ret)
383 return ret;
384
385 for (i = 0; i < chip->npwm; i++)
386 img_pwm_writel(imgchip, PWM_CH_CFG(i),
387 imgchip->suspend_ch_cfg[i]);
388
389 img_pwm_writel(imgchip, PWM_CTRL_CFG, imgchip->suspend_ctrl_cfg);
390
391 for (i = 0; i < chip->npwm; i++)
392 if (imgchip->suspend_ctrl_cfg & BIT(i))
393 regmap_clear_bits(imgchip->periph_regs,
394 PERIP_PWM_PDM_CONTROL,
395 PERIP_PWM_PDM_CONTROL_CH_MASK <<
396 PERIP_PWM_PDM_CONTROL_CH_SHIFT(i));
397
398 if (pm_runtime_status_suspended(dev))
399 img_pwm_runtime_suspend(dev);
400
401 return 0;
402 }
403 #endif /* CONFIG_PM */
404
405 static const struct dev_pm_ops img_pwm_pm_ops = {
406 SET_RUNTIME_PM_OPS(img_pwm_runtime_suspend,
407 img_pwm_runtime_resume,
408 NULL)
409 SET_SYSTEM_SLEEP_PM_OPS(img_pwm_suspend, img_pwm_resume)
410 };
411
412 static struct platform_driver img_pwm_driver = {
413 .driver = {
414 .name = "img-pwm",
415 .pm = &img_pwm_pm_ops,
416 .of_match_table = img_pwm_of_match,
417 },
418 .probe = img_pwm_probe,
419 .remove = img_pwm_remove,
420 };
421 module_platform_driver(img_pwm_driver);
422
423 MODULE_AUTHOR("Sai Masarapu <Sai.Masarapu@imgtec.com>");
424 MODULE_DESCRIPTION("Imagination Technologies PWM DAC driver");
425 MODULE_LICENSE("GPL v2");
426