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/of_device.h>
17 #include <linux/platform_device.h>
18 #include <linux/pm_runtime.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 device *dev;
63 struct pwm_chip chip;
64 struct clk *pwm_clk;
65 struct clk *sys_clk;
66 void __iomem *base;
67 struct regmap *periph_regs;
68 int max_period_ns;
69 int min_period_ns;
70 const struct img_pwm_soc_data *data;
71 u32 suspend_ctrl_cfg;
72 u32 suspend_ch_cfg[IMG_PWM_NPWM];
73 };
74
to_img_pwm_chip(struct pwm_chip * chip)75 static inline struct img_pwm_chip *to_img_pwm_chip(struct pwm_chip *chip)
76 {
77 return container_of(chip, struct img_pwm_chip, chip);
78 }
79
img_pwm_writel(struct img_pwm_chip * imgchip,u32 reg,u32 val)80 static inline void img_pwm_writel(struct img_pwm_chip *imgchip,
81 u32 reg, u32 val)
82 {
83 writel(val, imgchip->base + reg);
84 }
85
img_pwm_readl(struct img_pwm_chip * imgchip,u32 reg)86 static inline u32 img_pwm_readl(struct img_pwm_chip *imgchip, u32 reg)
87 {
88 return readl(imgchip->base + reg);
89 }
90
img_pwm_config(struct pwm_chip * chip,struct pwm_device * pwm,int duty_ns,int period_ns)91 static int img_pwm_config(struct pwm_chip *chip, struct pwm_device *pwm,
92 int duty_ns, int period_ns)
93 {
94 u32 val, div, duty, timebase;
95 unsigned long mul, output_clk_hz, input_clk_hz;
96 struct img_pwm_chip *imgchip = to_img_pwm_chip(chip);
97 unsigned int max_timebase = imgchip->data->max_timebase;
98 int ret;
99
100 if (period_ns < imgchip->min_period_ns ||
101 period_ns > imgchip->max_period_ns) {
102 dev_err(chip->dev, "configured period not in range\n");
103 return -ERANGE;
104 }
105
106 input_clk_hz = clk_get_rate(imgchip->pwm_clk);
107 output_clk_hz = DIV_ROUND_UP(NSEC_PER_SEC, period_ns);
108
109 mul = DIV_ROUND_UP(input_clk_hz, output_clk_hz);
110 if (mul <= max_timebase) {
111 div = PWM_CTRL_CFG_NO_SUB_DIV;
112 timebase = DIV_ROUND_UP(mul, 1);
113 } else if (mul <= max_timebase * 8) {
114 div = PWM_CTRL_CFG_SUB_DIV0;
115 timebase = DIV_ROUND_UP(mul, 8);
116 } else if (mul <= max_timebase * 64) {
117 div = PWM_CTRL_CFG_SUB_DIV1;
118 timebase = DIV_ROUND_UP(mul, 64);
119 } else if (mul <= max_timebase * 512) {
120 div = PWM_CTRL_CFG_SUB_DIV0_DIV1;
121 timebase = DIV_ROUND_UP(mul, 512);
122 } else {
123 dev_err(chip->dev,
124 "failed to configure timebase steps/divider value\n");
125 return -EINVAL;
126 }
127
128 duty = DIV_ROUND_UP(timebase * duty_ns, period_ns);
129
130 ret = pm_runtime_resume_and_get(chip->dev);
131 if (ret < 0)
132 return ret;
133
134 val = img_pwm_readl(imgchip, PWM_CTRL_CFG);
135 val &= ~(PWM_CTRL_CFG_DIV_MASK << PWM_CTRL_CFG_DIV_SHIFT(pwm->hwpwm));
136 val |= (div & PWM_CTRL_CFG_DIV_MASK) <<
137 PWM_CTRL_CFG_DIV_SHIFT(pwm->hwpwm);
138 img_pwm_writel(imgchip, PWM_CTRL_CFG, val);
139
140 val = (duty << PWM_CH_CFG_DUTY_SHIFT) |
141 (timebase << PWM_CH_CFG_TMBASE_SHIFT);
142 img_pwm_writel(imgchip, PWM_CH_CFG(pwm->hwpwm), val);
143
144 pm_runtime_mark_last_busy(chip->dev);
145 pm_runtime_put_autosuspend(chip->dev);
146
147 return 0;
148 }
149
img_pwm_enable(struct pwm_chip * chip,struct pwm_device * pwm)150 static int img_pwm_enable(struct pwm_chip *chip, struct pwm_device *pwm)
151 {
152 u32 val;
153 struct img_pwm_chip *imgchip = to_img_pwm_chip(chip);
154 int ret;
155
156 ret = pm_runtime_resume_and_get(chip->dev);
157 if (ret < 0)
158 return ret;
159
160 val = img_pwm_readl(imgchip, PWM_CTRL_CFG);
161 val |= BIT(pwm->hwpwm);
162 img_pwm_writel(imgchip, PWM_CTRL_CFG, val);
163
164 regmap_clear_bits(imgchip->periph_regs, PERIP_PWM_PDM_CONTROL,
165 PERIP_PWM_PDM_CONTROL_CH_MASK <<
166 PERIP_PWM_PDM_CONTROL_CH_SHIFT(pwm->hwpwm));
167
168 return 0;
169 }
170
img_pwm_disable(struct pwm_chip * chip,struct pwm_device * pwm)171 static void img_pwm_disable(struct pwm_chip *chip, struct pwm_device *pwm)
172 {
173 u32 val;
174 struct img_pwm_chip *imgchip = to_img_pwm_chip(chip);
175
176 val = img_pwm_readl(imgchip, PWM_CTRL_CFG);
177 val &= ~BIT(pwm->hwpwm);
178 img_pwm_writel(imgchip, PWM_CTRL_CFG, val);
179
180 pm_runtime_mark_last_busy(chip->dev);
181 pm_runtime_put_autosuspend(chip->dev);
182 }
183
img_pwm_apply(struct pwm_chip * chip,struct pwm_device * pwm,const struct pwm_state * state)184 static int img_pwm_apply(struct pwm_chip *chip, struct pwm_device *pwm,
185 const struct pwm_state *state)
186 {
187 int err;
188
189 if (state->polarity != PWM_POLARITY_NORMAL)
190 return -EINVAL;
191
192 if (!state->enabled) {
193 if (pwm->state.enabled)
194 img_pwm_disable(chip, pwm);
195
196 return 0;
197 }
198
199 err = img_pwm_config(pwm->chip, pwm, state->duty_cycle, state->period);
200 if (err)
201 return err;
202
203 if (!pwm->state.enabled)
204 err = img_pwm_enable(chip, pwm);
205
206 return err;
207 }
208
209 static const struct pwm_ops img_pwm_ops = {
210 .apply = img_pwm_apply,
211 .owner = THIS_MODULE,
212 };
213
214 static const struct img_pwm_soc_data pistachio_pwm = {
215 .max_timebase = 255,
216 };
217
218 static const struct of_device_id img_pwm_of_match[] = {
219 {
220 .compatible = "img,pistachio-pwm",
221 .data = &pistachio_pwm,
222 },
223 { }
224 };
225 MODULE_DEVICE_TABLE(of, img_pwm_of_match);
226
img_pwm_runtime_suspend(struct device * dev)227 static int img_pwm_runtime_suspend(struct device *dev)
228 {
229 struct img_pwm_chip *imgchip = dev_get_drvdata(dev);
230
231 clk_disable_unprepare(imgchip->pwm_clk);
232 clk_disable_unprepare(imgchip->sys_clk);
233
234 return 0;
235 }
236
img_pwm_runtime_resume(struct device * dev)237 static int img_pwm_runtime_resume(struct device *dev)
238 {
239 struct img_pwm_chip *imgchip = dev_get_drvdata(dev);
240 int ret;
241
242 ret = clk_prepare_enable(imgchip->sys_clk);
243 if (ret < 0) {
244 dev_err(dev, "could not prepare or enable sys clock\n");
245 return ret;
246 }
247
248 ret = clk_prepare_enable(imgchip->pwm_clk);
249 if (ret < 0) {
250 dev_err(dev, "could not prepare or enable pwm clock\n");
251 clk_disable_unprepare(imgchip->sys_clk);
252 return ret;
253 }
254
255 return 0;
256 }
257
img_pwm_probe(struct platform_device * pdev)258 static int img_pwm_probe(struct platform_device *pdev)
259 {
260 int ret;
261 u64 val;
262 unsigned long clk_rate;
263 struct img_pwm_chip *imgchip;
264 const struct of_device_id *of_dev_id;
265
266 imgchip = devm_kzalloc(&pdev->dev, sizeof(*imgchip), GFP_KERNEL);
267 if (!imgchip)
268 return -ENOMEM;
269
270 imgchip->dev = &pdev->dev;
271
272 imgchip->base = devm_platform_ioremap_resource(pdev, 0);
273 if (IS_ERR(imgchip->base))
274 return PTR_ERR(imgchip->base);
275
276 of_dev_id = of_match_device(img_pwm_of_match, &pdev->dev);
277 if (!of_dev_id)
278 return -ENODEV;
279 imgchip->data = of_dev_id->data;
280
281 imgchip->periph_regs = syscon_regmap_lookup_by_phandle(pdev->dev.of_node,
282 "img,cr-periph");
283 if (IS_ERR(imgchip->periph_regs))
284 return PTR_ERR(imgchip->periph_regs);
285
286 imgchip->sys_clk = devm_clk_get(&pdev->dev, "sys");
287 if (IS_ERR(imgchip->sys_clk)) {
288 dev_err(&pdev->dev, "failed to get system clock\n");
289 return PTR_ERR(imgchip->sys_clk);
290 }
291
292 imgchip->pwm_clk = devm_clk_get(&pdev->dev, "pwm");
293 if (IS_ERR(imgchip->pwm_clk)) {
294 dev_err(&pdev->dev, "failed to get pwm clock\n");
295 return PTR_ERR(imgchip->pwm_clk);
296 }
297
298 platform_set_drvdata(pdev, imgchip);
299
300 pm_runtime_set_autosuspend_delay(&pdev->dev, IMG_PWM_PM_TIMEOUT);
301 pm_runtime_use_autosuspend(&pdev->dev);
302 pm_runtime_enable(&pdev->dev);
303 if (!pm_runtime_enabled(&pdev->dev)) {
304 ret = img_pwm_runtime_resume(&pdev->dev);
305 if (ret)
306 goto err_pm_disable;
307 }
308
309 clk_rate = clk_get_rate(imgchip->pwm_clk);
310 if (!clk_rate) {
311 dev_err(&pdev->dev, "imgchip clock has no frequency\n");
312 ret = -EINVAL;
313 goto err_suspend;
314 }
315
316 /* The maximum input clock divider is 512 */
317 val = (u64)NSEC_PER_SEC * 512 * imgchip->data->max_timebase;
318 do_div(val, clk_rate);
319 imgchip->max_period_ns = val;
320
321 val = (u64)NSEC_PER_SEC * MIN_TMBASE_STEPS;
322 do_div(val, clk_rate);
323 imgchip->min_period_ns = val;
324
325 imgchip->chip.dev = &pdev->dev;
326 imgchip->chip.ops = &img_pwm_ops;
327 imgchip->chip.npwm = IMG_PWM_NPWM;
328
329 ret = pwmchip_add(&imgchip->chip);
330 if (ret < 0) {
331 dev_err(&pdev->dev, "pwmchip_add failed: %d\n", ret);
332 goto err_suspend;
333 }
334
335 return 0;
336
337 err_suspend:
338 if (!pm_runtime_enabled(&pdev->dev))
339 img_pwm_runtime_suspend(&pdev->dev);
340 err_pm_disable:
341 pm_runtime_disable(&pdev->dev);
342 pm_runtime_dont_use_autosuspend(&pdev->dev);
343 return ret;
344 }
345
img_pwm_remove(struct platform_device * pdev)346 static void img_pwm_remove(struct platform_device *pdev)
347 {
348 struct img_pwm_chip *imgchip = platform_get_drvdata(pdev);
349
350 pm_runtime_disable(&pdev->dev);
351 if (!pm_runtime_status_suspended(&pdev->dev))
352 img_pwm_runtime_suspend(&pdev->dev);
353
354 pwmchip_remove(&imgchip->chip);
355 }
356
357 #ifdef CONFIG_PM_SLEEP
img_pwm_suspend(struct device * dev)358 static int img_pwm_suspend(struct device *dev)
359 {
360 struct img_pwm_chip *imgchip = dev_get_drvdata(dev);
361 int i, ret;
362
363 if (pm_runtime_status_suspended(dev)) {
364 ret = img_pwm_runtime_resume(dev);
365 if (ret)
366 return ret;
367 }
368
369 for (i = 0; i < imgchip->chip.npwm; i++)
370 imgchip->suspend_ch_cfg[i] = img_pwm_readl(imgchip,
371 PWM_CH_CFG(i));
372
373 imgchip->suspend_ctrl_cfg = img_pwm_readl(imgchip, PWM_CTRL_CFG);
374
375 img_pwm_runtime_suspend(dev);
376
377 return 0;
378 }
379
img_pwm_resume(struct device * dev)380 static int img_pwm_resume(struct device *dev)
381 {
382 struct img_pwm_chip *imgchip = dev_get_drvdata(dev);
383 int ret;
384 int i;
385
386 ret = img_pwm_runtime_resume(dev);
387 if (ret)
388 return ret;
389
390 for (i = 0; i < imgchip->chip.npwm; i++)
391 img_pwm_writel(imgchip, PWM_CH_CFG(i),
392 imgchip->suspend_ch_cfg[i]);
393
394 img_pwm_writel(imgchip, PWM_CTRL_CFG, imgchip->suspend_ctrl_cfg);
395
396 for (i = 0; i < imgchip->chip.npwm; i++)
397 if (imgchip->suspend_ctrl_cfg & BIT(i))
398 regmap_clear_bits(imgchip->periph_regs,
399 PERIP_PWM_PDM_CONTROL,
400 PERIP_PWM_PDM_CONTROL_CH_MASK <<
401 PERIP_PWM_PDM_CONTROL_CH_SHIFT(i));
402
403 if (pm_runtime_status_suspended(dev))
404 img_pwm_runtime_suspend(dev);
405
406 return 0;
407 }
408 #endif /* CONFIG_PM */
409
410 static const struct dev_pm_ops img_pwm_pm_ops = {
411 SET_RUNTIME_PM_OPS(img_pwm_runtime_suspend,
412 img_pwm_runtime_resume,
413 NULL)
414 SET_SYSTEM_SLEEP_PM_OPS(img_pwm_suspend, img_pwm_resume)
415 };
416
417 static struct platform_driver img_pwm_driver = {
418 .driver = {
419 .name = "img-pwm",
420 .pm = &img_pwm_pm_ops,
421 .of_match_table = img_pwm_of_match,
422 },
423 .probe = img_pwm_probe,
424 .remove_new = img_pwm_remove,
425 };
426 module_platform_driver(img_pwm_driver);
427
428 MODULE_AUTHOR("Sai Masarapu <Sai.Masarapu@imgtec.com>");
429 MODULE_DESCRIPTION("Imagination Technologies PWM DAC driver");
430 MODULE_LICENSE("GPL v2");
431