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32b16d46 BS |
1 | /* |
2 | * Driver for Atmel Pulse Width Modulation Controller | |
3 | * | |
4 | * Copyright (C) 2013 Atmel Corporation | |
5 | * Bo Shen <voice.shen@atmel.com> | |
6 | * | |
7 | * Licensed under GPLv2. | |
8 | */ | |
9 | ||
10 | #include <linux/clk.h> | |
472ac3dc | 11 | #include <linux/delay.h> |
32b16d46 BS |
12 | #include <linux/err.h> |
13 | #include <linux/io.h> | |
14 | #include <linux/module.h> | |
472ac3dc | 15 | #include <linux/mutex.h> |
32b16d46 BS |
16 | #include <linux/of.h> |
17 | #include <linux/of_device.h> | |
18 | #include <linux/platform_device.h> | |
19 | #include <linux/pwm.h> | |
20 | #include <linux/slab.h> | |
21 | ||
22 | /* The following is global registers for PWM controller */ | |
23 | #define PWM_ENA 0x04 | |
24 | #define PWM_DIS 0x08 | |
25 | #define PWM_SR 0x0C | |
472ac3dc | 26 | #define PWM_ISR 0x1C |
32b16d46 BS |
27 | /* Bit field in SR */ |
28 | #define PWM_SR_ALL_CH_ON 0x0F | |
29 | ||
30 | /* The following register is PWM channel related registers */ | |
31 | #define PWM_CH_REG_OFFSET 0x200 | |
32 | #define PWM_CH_REG_SIZE 0x20 | |
33 | ||
34 | #define PWM_CMR 0x0 | |
35 | /* Bit field in CMR */ | |
36 | #define PWM_CMR_CPOL (1 << 9) | |
37 | #define PWM_CMR_UPD_CDTY (1 << 10) | |
8db9e29f | 38 | #define PWM_CMR_CPRE_MSK 0xF |
32b16d46 BS |
39 | |
40 | /* The following registers for PWM v1 */ | |
41 | #define PWMV1_CDTY 0x04 | |
42 | #define PWMV1_CPRD 0x08 | |
43 | #define PWMV1_CUPD 0x10 | |
44 | ||
45 | /* The following registers for PWM v2 */ | |
46 | #define PWMV2_CDTY 0x04 | |
47 | #define PWMV2_CDTYUPD 0x08 | |
48 | #define PWMV2_CPRD 0x0C | |
49 | #define PWMV2_CPRDUPD 0x10 | |
50 | ||
51 | /* | |
52 | * Max value for duty and period | |
53 | * | |
54 | * Although the duty and period register is 32 bit, | |
55 | * however only the LSB 16 bits are significant. | |
56 | */ | |
57 | #define PWM_MAX_DTY 0xFFFF | |
58 | #define PWM_MAX_PRD 0xFFFF | |
59 | #define PRD_MAX_PRES 10 | |
60 | ||
1a722aad CB |
61 | struct atmel_pwm_registers { |
62 | u8 period; | |
63 | u8 period_upd; | |
64 | u8 duty; | |
65 | u8 duty_upd; | |
66 | }; | |
67 | ||
32b16d46 BS |
68 | struct atmel_pwm_chip { |
69 | struct pwm_chip chip; | |
70 | struct clk *clk; | |
71 | void __iomem *base; | |
1a722aad | 72 | const struct atmel_pwm_registers *regs; |
32b16d46 | 73 | |
472ac3dc | 74 | unsigned int updated_pwms; |
313b78ef TR |
75 | /* ISR is cleared when read, ensure only one thread does that */ |
76 | struct mutex isr_lock; | |
32b16d46 BS |
77 | }; |
78 | ||
79 | static inline struct atmel_pwm_chip *to_atmel_pwm_chip(struct pwm_chip *chip) | |
80 | { | |
81 | return container_of(chip, struct atmel_pwm_chip, chip); | |
82 | } | |
83 | ||
84 | static inline u32 atmel_pwm_readl(struct atmel_pwm_chip *chip, | |
85 | unsigned long offset) | |
86 | { | |
87 | return readl_relaxed(chip->base + offset); | |
88 | } | |
89 | ||
90 | static inline void atmel_pwm_writel(struct atmel_pwm_chip *chip, | |
91 | unsigned long offset, unsigned long val) | |
92 | { | |
93 | writel_relaxed(val, chip->base + offset); | |
94 | } | |
95 | ||
96 | static inline u32 atmel_pwm_ch_readl(struct atmel_pwm_chip *chip, | |
97 | unsigned int ch, unsigned long offset) | |
98 | { | |
99 | unsigned long base = PWM_CH_REG_OFFSET + ch * PWM_CH_REG_SIZE; | |
100 | ||
101 | return readl_relaxed(chip->base + base + offset); | |
102 | } | |
103 | ||
104 | static inline void atmel_pwm_ch_writel(struct atmel_pwm_chip *chip, | |
105 | unsigned int ch, unsigned long offset, | |
106 | unsigned long val) | |
107 | { | |
108 | unsigned long base = PWM_CH_REG_OFFSET + ch * PWM_CH_REG_SIZE; | |
109 | ||
110 | writel_relaxed(val, chip->base + base + offset); | |
111 | } | |
112 | ||
1a722aad CB |
113 | static int atmel_pwm_calculate_cprd_and_pres(struct pwm_chip *chip, |
114 | const struct pwm_state *state, | |
115 | unsigned long *cprd, u32 *pres) | |
32b16d46 BS |
116 | { |
117 | struct atmel_pwm_chip *atmel_pwm = to_atmel_pwm_chip(chip); | |
1a722aad | 118 | unsigned long long cycles = state->period; |
32b16d46 | 119 | |
e2e08970 | 120 | /* Calculate the period cycles and prescale value */ |
1a722aad CB |
121 | cycles *= clk_get_rate(atmel_pwm->clk); |
122 | do_div(cycles, NSEC_PER_SEC); | |
32b16d46 | 123 | |
1a722aad CB |
124 | for (*pres = 0; cycles > PWM_MAX_PRD; cycles >>= 1) |
125 | (*pres)++; | |
e2e08970 | 126 | |
1a722aad | 127 | if (*pres > PRD_MAX_PRES) { |
e2e08970 NV |
128 | dev_err(chip->dev, "pres exceeds the maximum value\n"); |
129 | return -EINVAL; | |
32b16d46 BS |
130 | } |
131 | ||
1a722aad | 132 | *cprd = cycles; |
32b16d46 | 133 | |
1a722aad | 134 | return 0; |
32b16d46 BS |
135 | } |
136 | ||
1a722aad CB |
137 | static void atmel_pwm_calculate_cdty(const struct pwm_state *state, |
138 | unsigned long cprd, unsigned long *cdty) | |
32b16d46 | 139 | { |
1a722aad | 140 | unsigned long long cycles = state->duty_cycle; |
32b16d46 | 141 | |
1a722aad CB |
142 | cycles *= cprd; |
143 | do_div(cycles, state->period); | |
144 | *cdty = cprd - cycles; | |
32b16d46 BS |
145 | } |
146 | ||
1a722aad CB |
147 | static void atmel_pwm_update_cdty(struct pwm_chip *chip, struct pwm_device *pwm, |
148 | unsigned long cdty) | |
32b16d46 BS |
149 | { |
150 | struct atmel_pwm_chip *atmel_pwm = to_atmel_pwm_chip(chip); | |
151 | u32 val; | |
32b16d46 | 152 | |
1a722aad CB |
153 | if (atmel_pwm->regs->duty_upd == |
154 | atmel_pwm->regs->period_upd) { | |
155 | val = atmel_pwm_ch_readl(atmel_pwm, pwm->hwpwm, PWM_CMR); | |
156 | val &= ~PWM_CMR_UPD_CDTY; | |
157 | atmel_pwm_ch_writel(atmel_pwm, pwm->hwpwm, PWM_CMR, val); | |
32b16d46 BS |
158 | } |
159 | ||
1a722aad CB |
160 | atmel_pwm_ch_writel(atmel_pwm, pwm->hwpwm, |
161 | atmel_pwm->regs->duty_upd, cdty); | |
32b16d46 BS |
162 | } |
163 | ||
1a722aad CB |
164 | static void atmel_pwm_set_cprd_cdty(struct pwm_chip *chip, |
165 | struct pwm_device *pwm, | |
166 | unsigned long cprd, unsigned long cdty) | |
32b16d46 BS |
167 | { |
168 | struct atmel_pwm_chip *atmel_pwm = to_atmel_pwm_chip(chip); | |
32b16d46 | 169 | |
1a722aad CB |
170 | atmel_pwm_ch_writel(atmel_pwm, pwm->hwpwm, |
171 | atmel_pwm->regs->duty, cdty); | |
172 | atmel_pwm_ch_writel(atmel_pwm, pwm->hwpwm, | |
173 | atmel_pwm->regs->period, cprd); | |
32b16d46 BS |
174 | } |
175 | ||
1a722aad CB |
176 | static void atmel_pwm_disable(struct pwm_chip *chip, struct pwm_device *pwm, |
177 | bool disable_clk) | |
32b16d46 BS |
178 | { |
179 | struct atmel_pwm_chip *atmel_pwm = to_atmel_pwm_chip(chip); | |
472ac3dc AB |
180 | unsigned long timeout = jiffies + 2 * HZ; |
181 | ||
182 | /* | |
183 | * Wait for at least a complete period to have passed before disabling a | |
184 | * channel to be sure that CDTY has been updated | |
185 | */ | |
186 | mutex_lock(&atmel_pwm->isr_lock); | |
187 | atmel_pwm->updated_pwms |= atmel_pwm_readl(atmel_pwm, PWM_ISR); | |
188 | ||
189 | while (!(atmel_pwm->updated_pwms & (1 << pwm->hwpwm)) && | |
190 | time_before(jiffies, timeout)) { | |
191 | usleep_range(10, 100); | |
192 | atmel_pwm->updated_pwms |= atmel_pwm_readl(atmel_pwm, PWM_ISR); | |
193 | } | |
32b16d46 | 194 | |
472ac3dc | 195 | mutex_unlock(&atmel_pwm->isr_lock); |
32b16d46 BS |
196 | atmel_pwm_writel(atmel_pwm, PWM_DIS, 1 << pwm->hwpwm); |
197 | ||
f718c54c GR |
198 | /* |
199 | * Wait for the PWM channel disable operation to be effective before | |
200 | * stopping the clock. | |
201 | */ | |
202 | timeout = jiffies + 2 * HZ; | |
203 | ||
204 | while ((atmel_pwm_readl(atmel_pwm, PWM_SR) & (1 << pwm->hwpwm)) && | |
205 | time_before(jiffies, timeout)) | |
206 | usleep_range(10, 100); | |
207 | ||
1a722aad CB |
208 | if (disable_clk) |
209 | clk_disable(atmel_pwm->clk); | |
210 | } | |
211 | ||
212 | static int atmel_pwm_apply(struct pwm_chip *chip, struct pwm_device *pwm, | |
213 | struct pwm_state *state) | |
214 | { | |
215 | struct atmel_pwm_chip *atmel_pwm = to_atmel_pwm_chip(chip); | |
216 | struct pwm_state cstate; | |
217 | unsigned long cprd, cdty; | |
218 | u32 pres, val; | |
219 | int ret; | |
220 | ||
221 | pwm_get_state(pwm, &cstate); | |
222 | ||
223 | if (state->enabled) { | |
224 | if (cstate.enabled && | |
225 | cstate.polarity == state->polarity && | |
226 | cstate.period == state->period) { | |
227 | cprd = atmel_pwm_ch_readl(atmel_pwm, pwm->hwpwm, | |
228 | atmel_pwm->regs->period); | |
229 | atmel_pwm_calculate_cdty(state, cprd, &cdty); | |
230 | atmel_pwm_update_cdty(chip, pwm, cdty); | |
231 | return 0; | |
232 | } | |
233 | ||
234 | ret = atmel_pwm_calculate_cprd_and_pres(chip, state, &cprd, | |
235 | &pres); | |
236 | if (ret) { | |
237 | dev_err(chip->dev, | |
238 | "failed to calculate cprd and prescaler\n"); | |
239 | return ret; | |
240 | } | |
241 | ||
242 | atmel_pwm_calculate_cdty(state, cprd, &cdty); | |
243 | ||
244 | if (cstate.enabled) { | |
245 | atmel_pwm_disable(chip, pwm, false); | |
246 | } else { | |
247 | ret = clk_enable(atmel_pwm->clk); | |
248 | if (ret) { | |
249 | dev_err(chip->dev, "failed to enable clock\n"); | |
250 | return ret; | |
251 | } | |
252 | } | |
253 | ||
254 | /* It is necessary to preserve CPOL, inside CMR */ | |
255 | val = atmel_pwm_ch_readl(atmel_pwm, pwm->hwpwm, PWM_CMR); | |
256 | val = (val & ~PWM_CMR_CPRE_MSK) | (pres & PWM_CMR_CPRE_MSK); | |
257 | if (state->polarity == PWM_POLARITY_NORMAL) | |
258 | val &= ~PWM_CMR_CPOL; | |
259 | else | |
260 | val |= PWM_CMR_CPOL; | |
261 | atmel_pwm_ch_writel(atmel_pwm, pwm->hwpwm, PWM_CMR, val); | |
262 | atmel_pwm_set_cprd_cdty(chip, pwm, cprd, cdty); | |
263 | mutex_lock(&atmel_pwm->isr_lock); | |
264 | atmel_pwm->updated_pwms |= atmel_pwm_readl(atmel_pwm, PWM_ISR); | |
265 | atmel_pwm->updated_pwms &= ~(1 << pwm->hwpwm); | |
266 | mutex_unlock(&atmel_pwm->isr_lock); | |
267 | atmel_pwm_writel(atmel_pwm, PWM_ENA, 1 << pwm->hwpwm); | |
268 | } else if (cstate.enabled) { | |
269 | atmel_pwm_disable(chip, pwm, true); | |
270 | } | |
271 | ||
272 | return 0; | |
32b16d46 BS |
273 | } |
274 | ||
275 | static const struct pwm_ops atmel_pwm_ops = { | |
1a722aad | 276 | .apply = atmel_pwm_apply, |
32b16d46 BS |
277 | .owner = THIS_MODULE, |
278 | }; | |
279 | ||
1a722aad CB |
280 | static const struct atmel_pwm_registers atmel_pwm_regs_v1 = { |
281 | .period = PWMV1_CPRD, | |
282 | .period_upd = PWMV1_CUPD, | |
283 | .duty = PWMV1_CDTY, | |
284 | .duty_upd = PWMV1_CUPD, | |
32b16d46 BS |
285 | }; |
286 | ||
1a722aad CB |
287 | static const struct atmel_pwm_registers atmel_pwm_regs_v2 = { |
288 | .period = PWMV2_CPRD, | |
289 | .period_upd = PWMV2_CPRDUPD, | |
290 | .duty = PWMV2_CDTY, | |
291 | .duty_upd = PWMV2_CDTYUPD, | |
32b16d46 BS |
292 | }; |
293 | ||
294 | static const struct platform_device_id atmel_pwm_devtypes[] = { | |
295 | { | |
296 | .name = "at91sam9rl-pwm", | |
1a722aad | 297 | .driver_data = (kernel_ulong_t)&atmel_pwm_regs_v1, |
32b16d46 BS |
298 | }, { |
299 | .name = "sama5d3-pwm", | |
1a722aad | 300 | .driver_data = (kernel_ulong_t)&atmel_pwm_regs_v2, |
32b16d46 BS |
301 | }, { |
302 | /* sentinel */ | |
303 | }, | |
304 | }; | |
305 | MODULE_DEVICE_TABLE(platform, atmel_pwm_devtypes); | |
306 | ||
307 | static const struct of_device_id atmel_pwm_dt_ids[] = { | |
308 | { | |
309 | .compatible = "atmel,at91sam9rl-pwm", | |
1a722aad | 310 | .data = &atmel_pwm_regs_v1, |
32b16d46 BS |
311 | }, { |
312 | .compatible = "atmel,sama5d3-pwm", | |
1a722aad | 313 | .data = &atmel_pwm_regs_v2, |
44521afa CB |
314 | }, { |
315 | .compatible = "atmel,sama5d2-pwm", | |
316 | .data = &atmel_pwm_regs_v2, | |
32b16d46 BS |
317 | }, { |
318 | /* sentinel */ | |
319 | }, | |
320 | }; | |
321 | MODULE_DEVICE_TABLE(of, atmel_pwm_dt_ids); | |
322 | ||
1a722aad | 323 | static inline const struct atmel_pwm_registers * |
32b16d46 BS |
324 | atmel_pwm_get_driver_data(struct platform_device *pdev) |
325 | { | |
313b78ef TR |
326 | const struct platform_device_id *id; |
327 | ||
017bb04e TR |
328 | if (pdev->dev.of_node) |
329 | return of_device_get_match_data(&pdev->dev); | |
32b16d46 | 330 | |
313b78ef | 331 | id = platform_get_device_id(pdev); |
32b16d46 | 332 | |
1a722aad | 333 | return (struct atmel_pwm_registers *)id->driver_data; |
32b16d46 BS |
334 | } |
335 | ||
336 | static int atmel_pwm_probe(struct platform_device *pdev) | |
337 | { | |
1a722aad | 338 | const struct atmel_pwm_registers *regs; |
32b16d46 BS |
339 | struct atmel_pwm_chip *atmel_pwm; |
340 | struct resource *res; | |
341 | int ret; | |
342 | ||
1a722aad CB |
343 | regs = atmel_pwm_get_driver_data(pdev); |
344 | if (!regs) | |
32b16d46 BS |
345 | return -ENODEV; |
346 | ||
347 | atmel_pwm = devm_kzalloc(&pdev->dev, sizeof(*atmel_pwm), GFP_KERNEL); | |
348 | if (!atmel_pwm) | |
349 | return -ENOMEM; | |
350 | ||
351 | res = platform_get_resource(pdev, IORESOURCE_MEM, 0); | |
352 | atmel_pwm->base = devm_ioremap_resource(&pdev->dev, res); | |
353 | if (IS_ERR(atmel_pwm->base)) | |
354 | return PTR_ERR(atmel_pwm->base); | |
355 | ||
356 | atmel_pwm->clk = devm_clk_get(&pdev->dev, NULL); | |
357 | if (IS_ERR(atmel_pwm->clk)) | |
358 | return PTR_ERR(atmel_pwm->clk); | |
359 | ||
360 | ret = clk_prepare(atmel_pwm->clk); | |
361 | if (ret) { | |
362 | dev_err(&pdev->dev, "failed to prepare PWM clock\n"); | |
363 | return ret; | |
364 | } | |
365 | ||
366 | atmel_pwm->chip.dev = &pdev->dev; | |
367 | atmel_pwm->chip.ops = &atmel_pwm_ops; | |
368 | ||
369 | if (pdev->dev.of_node) { | |
370 | atmel_pwm->chip.of_xlate = of_pwm_xlate_with_flags; | |
371 | atmel_pwm->chip.of_pwm_n_cells = 3; | |
372 | } | |
373 | ||
374 | atmel_pwm->chip.base = -1; | |
375 | atmel_pwm->chip.npwm = 4; | |
1a722aad | 376 | atmel_pwm->regs = regs; |
472ac3dc AB |
377 | atmel_pwm->updated_pwms = 0; |
378 | mutex_init(&atmel_pwm->isr_lock); | |
32b16d46 BS |
379 | |
380 | ret = pwmchip_add(&atmel_pwm->chip); | |
381 | if (ret < 0) { | |
382 | dev_err(&pdev->dev, "failed to add PWM chip %d\n", ret); | |
383 | goto unprepare_clk; | |
384 | } | |
385 | ||
386 | platform_set_drvdata(pdev, atmel_pwm); | |
387 | ||
6a683356 BS |
388 | return ret; |
389 | ||
32b16d46 BS |
390 | unprepare_clk: |
391 | clk_unprepare(atmel_pwm->clk); | |
392 | return ret; | |
393 | } | |
394 | ||
395 | static int atmel_pwm_remove(struct platform_device *pdev) | |
396 | { | |
397 | struct atmel_pwm_chip *atmel_pwm = platform_get_drvdata(pdev); | |
398 | ||
399 | clk_unprepare(atmel_pwm->clk); | |
472ac3dc | 400 | mutex_destroy(&atmel_pwm->isr_lock); |
32b16d46 BS |
401 | |
402 | return pwmchip_remove(&atmel_pwm->chip); | |
403 | } | |
404 | ||
405 | static struct platform_driver atmel_pwm_driver = { | |
406 | .driver = { | |
407 | .name = "atmel-pwm", | |
408 | .of_match_table = of_match_ptr(atmel_pwm_dt_ids), | |
409 | }, | |
410 | .id_table = atmel_pwm_devtypes, | |
411 | .probe = atmel_pwm_probe, | |
412 | .remove = atmel_pwm_remove, | |
413 | }; | |
414 | module_platform_driver(atmel_pwm_driver); | |
415 | ||
416 | MODULE_ALIAS("platform:atmel-pwm"); | |
417 | MODULE_AUTHOR("Bo Shen <voice.shen@atmel.com>"); | |
418 | MODULE_DESCRIPTION("Atmel PWM driver"); | |
419 | MODULE_LICENSE("GPL v2"); |