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1/*
2 * Driver for Allwinner sun4i Pulse Width Modulation Controller
3 *
4 * Copyright (C) 2014 Alexandre Belloni <alexandre.belloni@free-electrons.com>
5 *
6 * Licensed under GPLv2.
7 */
8
9#include <linux/bitops.h>
10#include <linux/clk.h>
11#include <linux/delay.h>
12#include <linux/err.h>
13#include <linux/io.h>
14#include <linux/jiffies.h>
15#include <linux/module.h>
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#include <linux/spinlock.h>
22#include <linux/time.h>
23
24#define PWM_CTRL_REG 0x0
25
26#define PWM_CH_PRD_BASE 0x4
27#define PWM_CH_PRD_OFFSET 0x4
28#define PWM_CH_PRD(ch) (PWM_CH_PRD_BASE + PWM_CH_PRD_OFFSET * (ch))
29
30#define PWMCH_OFFSET 15
31#define PWM_PRESCAL_MASK GENMASK(3, 0)
32#define PWM_PRESCAL_OFF 0
33#define PWM_EN BIT(4)
34#define PWM_ACT_STATE BIT(5)
35#define PWM_CLK_GATING BIT(6)
36#define PWM_MODE BIT(7)
37#define PWM_PULSE BIT(8)
38#define PWM_BYPASS BIT(9)
39
40#define PWM_RDY_BASE 28
41#define PWM_RDY_OFFSET 1
42#define PWM_RDY(ch) BIT(PWM_RDY_BASE + PWM_RDY_OFFSET * (ch))
43
44#define PWM_PRD(prd) (((prd) - 1) << 16)
45#define PWM_PRD_MASK GENMASK(15, 0)
46
47#define PWM_DTY_MASK GENMASK(15, 0)
48
49#define PWM_REG_PRD(reg) ((((reg) >> 16) & PWM_PRD_MASK) + 1)
50#define PWM_REG_DTY(reg) ((reg) & PWM_DTY_MASK)
51#define PWM_REG_PRESCAL(reg, chan) (((reg) >> ((chan) * PWMCH_OFFSET)) & PWM_PRESCAL_MASK)
52
53#define BIT_CH(bit, chan) ((bit) << ((chan) * PWMCH_OFFSET))
54
55static const u32 prescaler_table[] = {
56 120,
57 180,
58 240,
59 360,
60 480,
61 0,
62 0,
63 0,
64 12000,
65 24000,
66 36000,
67 48000,
68 72000,
69 0,
70 0,
71 0, /* Actually 1 but tested separately */
72};
73
74struct sun4i_pwm_data {
75 bool has_prescaler_bypass;
76 unsigned int npwm;
77};
78
79struct sun4i_pwm_chip {
80 struct pwm_chip chip;
81 struct clk *clk;
82 void __iomem *base;
83 spinlock_t ctrl_lock;
84 const struct sun4i_pwm_data *data;
85 unsigned long next_period[2];
86 bool needs_delay[2];
87};
88
89static inline struct sun4i_pwm_chip *to_sun4i_pwm_chip(struct pwm_chip *chip)
90{
91 return container_of(chip, struct sun4i_pwm_chip, chip);
92}
93
94static inline u32 sun4i_pwm_readl(struct sun4i_pwm_chip *chip,
95 unsigned long offset)
96{
97 return readl(chip->base + offset);
98}
99
100static inline void sun4i_pwm_writel(struct sun4i_pwm_chip *chip,
101 u32 val, unsigned long offset)
102{
103 writel(val, chip->base + offset);
104}
105
106static void sun4i_pwm_get_state(struct pwm_chip *chip,
107 struct pwm_device *pwm,
108 struct pwm_state *state)
109{
110 struct sun4i_pwm_chip *sun4i_pwm = to_sun4i_pwm_chip(chip);
111 u64 clk_rate, tmp;
112 u32 val;
113 unsigned int prescaler;
114
115 clk_rate = clk_get_rate(sun4i_pwm->clk);
116
117 val = sun4i_pwm_readl(sun4i_pwm, PWM_CTRL_REG);
118
119 if ((PWM_REG_PRESCAL(val, pwm->hwpwm) == PWM_PRESCAL_MASK) &&
120 sun4i_pwm->data->has_prescaler_bypass)
121 prescaler = 1;
122 else
123 prescaler = prescaler_table[PWM_REG_PRESCAL(val, pwm->hwpwm)];
124
125 if (prescaler == 0)
126 return;
127
128 if (val & BIT_CH(PWM_ACT_STATE, pwm->hwpwm))
129 state->polarity = PWM_POLARITY_NORMAL;
130 else
131 state->polarity = PWM_POLARITY_INVERSED;
132
133 if ((val & BIT_CH(PWM_CLK_GATING | PWM_EN, pwm->hwpwm)) ==
134 BIT_CH(PWM_CLK_GATING | PWM_EN, pwm->hwpwm))
135 state->enabled = true;
136 else
137 state->enabled = false;
138
139 val = sun4i_pwm_readl(sun4i_pwm, PWM_CH_PRD(pwm->hwpwm));
140
141 tmp = prescaler * NSEC_PER_SEC * PWM_REG_DTY(val);
142 state->duty_cycle = DIV_ROUND_CLOSEST_ULL(tmp, clk_rate);
143
144 tmp = prescaler * NSEC_PER_SEC * PWM_REG_PRD(val);
145 state->period = DIV_ROUND_CLOSEST_ULL(tmp, clk_rate);
146}
147
148static int sun4i_pwm_calculate(struct sun4i_pwm_chip *sun4i_pwm,
149 struct pwm_state *state,
150 u32 *dty, u32 *prd, unsigned int *prsclr)
151{
152 u64 clk_rate, div = 0;
153 unsigned int pval, prescaler = 0;
154
155 clk_rate = clk_get_rate(sun4i_pwm->clk);
156
157 if (sun4i_pwm->data->has_prescaler_bypass) {
158 /* First, test without any prescaler when available */
159 prescaler = PWM_PRESCAL_MASK;
160 pval = 1;
161 /*
162 * When not using any prescaler, the clock period in nanoseconds
163 * is not an integer so round it half up instead of
164 * truncating to get less surprising values.
165 */
166 div = clk_rate * state->period + NSEC_PER_SEC / 2;
167 do_div(div, NSEC_PER_SEC);
168 if (div - 1 > PWM_PRD_MASK)
169 prescaler = 0;
170 }
171
172 if (prescaler == 0) {
173 /* Go up from the first divider */
174 for (prescaler = 0; prescaler < PWM_PRESCAL_MASK; prescaler++) {
175 if (!prescaler_table[prescaler])
176 continue;
177 pval = prescaler_table[prescaler];
178 div = clk_rate;
179 do_div(div, pval);
180 div = div * state->period;
181 do_div(div, NSEC_PER_SEC);
182 if (div - 1 <= PWM_PRD_MASK)
183 break;
184 }
185
186 if (div - 1 > PWM_PRD_MASK)
187 return -EINVAL;
188 }
189
190 *prd = div;
191 div *= state->duty_cycle;
192 do_div(div, state->period);
193 *dty = div;
194 *prsclr = prescaler;
195
196 div = (u64)pval * NSEC_PER_SEC * *prd;
197 state->period = DIV_ROUND_CLOSEST_ULL(div, clk_rate);
198
199 div = (u64)pval * NSEC_PER_SEC * *dty;
200 state->duty_cycle = DIV_ROUND_CLOSEST_ULL(div, clk_rate);
201
202 return 0;
203}
204
205static int sun4i_pwm_apply(struct pwm_chip *chip, struct pwm_device *pwm,
206 struct pwm_state *state)
207{
208 struct sun4i_pwm_chip *sun4i_pwm = to_sun4i_pwm_chip(chip);
209 struct pwm_state cstate;
210 u32 ctrl;
211 int ret;
212 unsigned int delay_us;
213 unsigned long now;
214
215 pwm_get_state(pwm, &cstate);
216
217 if (!cstate.enabled) {
218 ret = clk_prepare_enable(sun4i_pwm->clk);
219 if (ret) {
220 dev_err(chip->dev, "failed to enable PWM clock\n");
221 return ret;
222 }
223 }
224
225 spin_lock(&sun4i_pwm->ctrl_lock);
226 ctrl = sun4i_pwm_readl(sun4i_pwm, PWM_CTRL_REG);
227
228 if ((cstate.period != state->period) ||
229 (cstate.duty_cycle != state->duty_cycle)) {
230 u32 period, duty, val;
231 unsigned int prescaler;
232
233 ret = sun4i_pwm_calculate(sun4i_pwm, state,
234 &duty, &period, &prescaler);
235 if (ret) {
236 dev_err(chip->dev, "period exceeds the maximum value\n");
237 spin_unlock(&sun4i_pwm->ctrl_lock);
238 if (!cstate.enabled)
239 clk_disable_unprepare(sun4i_pwm->clk);
240 return ret;
241 }
242
243 if (PWM_REG_PRESCAL(ctrl, pwm->hwpwm) != prescaler) {
244 /* Prescaler changed, the clock has to be gated */
245 ctrl &= ~BIT_CH(PWM_CLK_GATING, pwm->hwpwm);
246 sun4i_pwm_writel(sun4i_pwm, ctrl, PWM_CTRL_REG);
247
248 ctrl &= ~BIT_CH(PWM_PRESCAL_MASK, pwm->hwpwm);
249 ctrl |= BIT_CH(prescaler, pwm->hwpwm);
250 }
251
252 val = (duty & PWM_DTY_MASK) | PWM_PRD(period);
253 sun4i_pwm_writel(sun4i_pwm, val, PWM_CH_PRD(pwm->hwpwm));
254 sun4i_pwm->next_period[pwm->hwpwm] = jiffies +
255 usecs_to_jiffies(cstate.period / 1000 + 1);
256 sun4i_pwm->needs_delay[pwm->hwpwm] = true;
257 }
258
259 if (state->polarity != PWM_POLARITY_NORMAL)
260 ctrl &= ~BIT_CH(PWM_ACT_STATE, pwm->hwpwm);
261 else
262 ctrl |= BIT_CH(PWM_ACT_STATE, pwm->hwpwm);
263
264 ctrl |= BIT_CH(PWM_CLK_GATING, pwm->hwpwm);
265 if (state->enabled) {
266 ctrl |= BIT_CH(PWM_EN, pwm->hwpwm);
267 } else if (!sun4i_pwm->needs_delay[pwm->hwpwm]) {
268 ctrl &= ~BIT_CH(PWM_EN, pwm->hwpwm);
269 ctrl &= ~BIT_CH(PWM_CLK_GATING, pwm->hwpwm);
270 }
271
272 sun4i_pwm_writel(sun4i_pwm, ctrl, PWM_CTRL_REG);
273
274 spin_unlock(&sun4i_pwm->ctrl_lock);
275
276 if (state->enabled)
277 return 0;
278
279 if (!sun4i_pwm->needs_delay[pwm->hwpwm]) {
280 clk_disable_unprepare(sun4i_pwm->clk);
281 return 0;
282 }
283
284 /* We need a full period to elapse before disabling the channel. */
285 now = jiffies;
286 if (sun4i_pwm->needs_delay[pwm->hwpwm] &&
287 time_before(now, sun4i_pwm->next_period[pwm->hwpwm])) {
288 delay_us = jiffies_to_usecs(sun4i_pwm->next_period[pwm->hwpwm] -
289 now);
290 if ((delay_us / 500) > MAX_UDELAY_MS)
291 msleep(delay_us / 1000 + 1);
292 else
293 usleep_range(delay_us, delay_us * 2);
294 }
295 sun4i_pwm->needs_delay[pwm->hwpwm] = false;
296
297 spin_lock(&sun4i_pwm->ctrl_lock);
298 ctrl = sun4i_pwm_readl(sun4i_pwm, PWM_CTRL_REG);
299 ctrl &= ~BIT_CH(PWM_CLK_GATING, pwm->hwpwm);
300 ctrl &= ~BIT_CH(PWM_EN, pwm->hwpwm);
301 sun4i_pwm_writel(sun4i_pwm, ctrl, PWM_CTRL_REG);
302 spin_unlock(&sun4i_pwm->ctrl_lock);
303
304 clk_disable_unprepare(sun4i_pwm->clk);
305
306 return 0;
307}
308
309static const struct pwm_ops sun4i_pwm_ops = {
310 .apply = sun4i_pwm_apply,
311 .get_state = sun4i_pwm_get_state,
312 .owner = THIS_MODULE,
313};
314
315static const struct sun4i_pwm_data sun4i_pwm_dual_nobypass = {
316 .has_prescaler_bypass = false,
317 .npwm = 2,
318};
319
320static const struct sun4i_pwm_data sun4i_pwm_dual_bypass = {
321 .has_prescaler_bypass = true,
322 .npwm = 2,
323};
324
325static const struct sun4i_pwm_data sun4i_pwm_single_bypass = {
326 .has_prescaler_bypass = true,
327 .npwm = 1,
328};
329
330static const struct of_device_id sun4i_pwm_dt_ids[] = {
331 {
332 .compatible = "allwinner,sun4i-a10-pwm",
333 .data = &sun4i_pwm_dual_nobypass,
334 }, {
335 .compatible = "allwinner,sun5i-a10s-pwm",
336 .data = &sun4i_pwm_dual_bypass,
337 }, {
338 .compatible = "allwinner,sun5i-a13-pwm",
339 .data = &sun4i_pwm_single_bypass,
340 }, {
341 .compatible = "allwinner,sun7i-a20-pwm",
342 .data = &sun4i_pwm_dual_bypass,
343 }, {
344 .compatible = "allwinner,sun8i-h3-pwm",
345 .data = &sun4i_pwm_single_bypass,
346 }, {
347 /* sentinel */
348 },
349};
350MODULE_DEVICE_TABLE(of, sun4i_pwm_dt_ids);
351
352static int sun4i_pwm_probe(struct platform_device *pdev)
353{
354 struct sun4i_pwm_chip *pwm;
355 struct resource *res;
356 int ret;
357
358 pwm = devm_kzalloc(&pdev->dev, sizeof(*pwm), GFP_KERNEL);
359 if (!pwm)
360 return -ENOMEM;
361
362 pwm->data = of_device_get_match_data(&pdev->dev);
363 if (!pwm->data)
364 return -ENODEV;
365
366 res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
367 pwm->base = devm_ioremap_resource(&pdev->dev, res);
368 if (IS_ERR(pwm->base))
369 return PTR_ERR(pwm->base);
370
371 pwm->clk = devm_clk_get(&pdev->dev, NULL);
372 if (IS_ERR(pwm->clk))
373 return PTR_ERR(pwm->clk);
374
375 pwm->chip.dev = &pdev->dev;
376 pwm->chip.ops = &sun4i_pwm_ops;
377 pwm->chip.base = -1;
378 pwm->chip.npwm = pwm->data->npwm;
379 pwm->chip.of_xlate = of_pwm_xlate_with_flags;
380 pwm->chip.of_pwm_n_cells = 3;
381
382 spin_lock_init(&pwm->ctrl_lock);
383
384 ret = pwmchip_add(&pwm->chip);
385 if (ret < 0) {
386 dev_err(&pdev->dev, "failed to add PWM chip: %d\n", ret);
387 return ret;
388 }
389
390 platform_set_drvdata(pdev, pwm);
391
392 return 0;
393}
394
395static int sun4i_pwm_remove(struct platform_device *pdev)
396{
397 struct sun4i_pwm_chip *pwm = platform_get_drvdata(pdev);
398
399 return pwmchip_remove(&pwm->chip);
400}
401
402static struct platform_driver sun4i_pwm_driver = {
403 .driver = {
404 .name = "sun4i-pwm",
405 .of_match_table = sun4i_pwm_dt_ids,
406 },
407 .probe = sun4i_pwm_probe,
408 .remove = sun4i_pwm_remove,
409};
410module_platform_driver(sun4i_pwm_driver);
411
412MODULE_ALIAS("platform:sun4i-pwm");
413MODULE_AUTHOR("Alexandre Belloni <alexandre.belloni@free-electrons.com>");
414MODULE_DESCRIPTION("Allwinner sun4i PWM driver");
415MODULE_LICENSE("GPL v2");
1// SPDX-License-Identifier: GPL-2.0-only
2/*
3 * Driver for Allwinner sun4i Pulse Width Modulation Controller
4 *
5 * Copyright (C) 2014 Alexandre Belloni <alexandre.belloni@free-electrons.com>
6 *
7 * Limitations:
8 * - When outputing the source clock directly, the PWM logic will be bypassed
9 * and the currently running period is not guaranteed to be completed
10 */
11
12#include <linux/bitops.h>
13#include <linux/clk.h>
14#include <linux/delay.h>
15#include <linux/err.h>
16#include <linux/io.h>
17#include <linux/jiffies.h>
18#include <linux/module.h>
19#include <linux/of.h>
20#include <linux/of_device.h>
21#include <linux/platform_device.h>
22#include <linux/pwm.h>
23#include <linux/reset.h>
24#include <linux/slab.h>
25#include <linux/spinlock.h>
26#include <linux/time.h>
27
28#define PWM_CTRL_REG 0x0
29
30#define PWM_CH_PRD_BASE 0x4
31#define PWM_CH_PRD_OFFSET 0x4
32#define PWM_CH_PRD(ch) (PWM_CH_PRD_BASE + PWM_CH_PRD_OFFSET * (ch))
33
34#define PWMCH_OFFSET 15
35#define PWM_PRESCAL_MASK GENMASK(3, 0)
36#define PWM_PRESCAL_OFF 0
37#define PWM_EN BIT(4)
38#define PWM_ACT_STATE BIT(5)
39#define PWM_CLK_GATING BIT(6)
40#define PWM_MODE BIT(7)
41#define PWM_PULSE BIT(8)
42#define PWM_BYPASS BIT(9)
43
44#define PWM_RDY_BASE 28
45#define PWM_RDY_OFFSET 1
46#define PWM_RDY(ch) BIT(PWM_RDY_BASE + PWM_RDY_OFFSET * (ch))
47
48#define PWM_PRD(prd) (((prd) - 1) << 16)
49#define PWM_PRD_MASK GENMASK(15, 0)
50
51#define PWM_DTY_MASK GENMASK(15, 0)
52
53#define PWM_REG_PRD(reg) ((((reg) >> 16) & PWM_PRD_MASK) + 1)
54#define PWM_REG_DTY(reg) ((reg) & PWM_DTY_MASK)
55#define PWM_REG_PRESCAL(reg, chan) (((reg) >> ((chan) * PWMCH_OFFSET)) & PWM_PRESCAL_MASK)
56
57#define BIT_CH(bit, chan) ((bit) << ((chan) * PWMCH_OFFSET))
58
59static const u32 prescaler_table[] = {
60 120,
61 180,
62 240,
63 360,
64 480,
65 0,
66 0,
67 0,
68 12000,
69 24000,
70 36000,
71 48000,
72 72000,
73 0,
74 0,
75 0, /* Actually 1 but tested separately */
76};
77
78struct sun4i_pwm_data {
79 bool has_prescaler_bypass;
80 bool has_direct_mod_clk_output;
81 unsigned int npwm;
82};
83
84struct sun4i_pwm_chip {
85 struct pwm_chip chip;
86 struct clk *bus_clk;
87 struct clk *clk;
88 struct reset_control *rst;
89 void __iomem *base;
90 spinlock_t ctrl_lock;
91 const struct sun4i_pwm_data *data;
92};
93
94static inline struct sun4i_pwm_chip *to_sun4i_pwm_chip(struct pwm_chip *chip)
95{
96 return container_of(chip, struct sun4i_pwm_chip, chip);
97}
98
99static inline u32 sun4i_pwm_readl(struct sun4i_pwm_chip *chip,
100 unsigned long offset)
101{
102 return readl(chip->base + offset);
103}
104
105static inline void sun4i_pwm_writel(struct sun4i_pwm_chip *chip,
106 u32 val, unsigned long offset)
107{
108 writel(val, chip->base + offset);
109}
110
111static int sun4i_pwm_get_state(struct pwm_chip *chip,
112 struct pwm_device *pwm,
113 struct pwm_state *state)
114{
115 struct sun4i_pwm_chip *sun4i_pwm = to_sun4i_pwm_chip(chip);
116 u64 clk_rate, tmp;
117 u32 val;
118 unsigned int prescaler;
119
120 clk_rate = clk_get_rate(sun4i_pwm->clk);
121 if (!clk_rate)
122 return -EINVAL;
123
124 val = sun4i_pwm_readl(sun4i_pwm, PWM_CTRL_REG);
125
126 /*
127 * PWM chapter in H6 manual has a diagram which explains that if bypass
128 * bit is set, no other setting has any meaning. Even more, experiment
129 * proved that also enable bit is ignored in this case.
130 */
131 if ((val & BIT_CH(PWM_BYPASS, pwm->hwpwm)) &&
132 sun4i_pwm->data->has_direct_mod_clk_output) {
133 state->period = DIV_ROUND_UP_ULL(NSEC_PER_SEC, clk_rate);
134 state->duty_cycle = DIV_ROUND_UP_ULL(state->period, 2);
135 state->polarity = PWM_POLARITY_NORMAL;
136 state->enabled = true;
137 return 0;
138 }
139
140 if ((PWM_REG_PRESCAL(val, pwm->hwpwm) == PWM_PRESCAL_MASK) &&
141 sun4i_pwm->data->has_prescaler_bypass)
142 prescaler = 1;
143 else
144 prescaler = prescaler_table[PWM_REG_PRESCAL(val, pwm->hwpwm)];
145
146 if (prescaler == 0)
147 return -EINVAL;
148
149 if (val & BIT_CH(PWM_ACT_STATE, pwm->hwpwm))
150 state->polarity = PWM_POLARITY_NORMAL;
151 else
152 state->polarity = PWM_POLARITY_INVERSED;
153
154 if ((val & BIT_CH(PWM_CLK_GATING | PWM_EN, pwm->hwpwm)) ==
155 BIT_CH(PWM_CLK_GATING | PWM_EN, pwm->hwpwm))
156 state->enabled = true;
157 else
158 state->enabled = false;
159
160 val = sun4i_pwm_readl(sun4i_pwm, PWM_CH_PRD(pwm->hwpwm));
161
162 tmp = (u64)prescaler * NSEC_PER_SEC * PWM_REG_DTY(val);
163 state->duty_cycle = DIV_ROUND_CLOSEST_ULL(tmp, clk_rate);
164
165 tmp = (u64)prescaler * NSEC_PER_SEC * PWM_REG_PRD(val);
166 state->period = DIV_ROUND_CLOSEST_ULL(tmp, clk_rate);
167
168 return 0;
169}
170
171static int sun4i_pwm_calculate(struct sun4i_pwm_chip *sun4i_pwm,
172 const struct pwm_state *state,
173 u32 *dty, u32 *prd, unsigned int *prsclr,
174 bool *bypass)
175{
176 u64 clk_rate, div = 0;
177 unsigned int prescaler = 0;
178
179 clk_rate = clk_get_rate(sun4i_pwm->clk);
180
181 *bypass = sun4i_pwm->data->has_direct_mod_clk_output &&
182 state->enabled &&
183 (state->period * clk_rate >= NSEC_PER_SEC) &&
184 (state->period * clk_rate < 2 * NSEC_PER_SEC) &&
185 (state->duty_cycle * clk_rate * 2 >= NSEC_PER_SEC);
186
187 /* Skip calculation of other parameters if we bypass them */
188 if (*bypass)
189 return 0;
190
191 if (sun4i_pwm->data->has_prescaler_bypass) {
192 /* First, test without any prescaler when available */
193 prescaler = PWM_PRESCAL_MASK;
194 /*
195 * When not using any prescaler, the clock period in nanoseconds
196 * is not an integer so round it half up instead of
197 * truncating to get less surprising values.
198 */
199 div = clk_rate * state->period + NSEC_PER_SEC / 2;
200 do_div(div, NSEC_PER_SEC);
201 if (div - 1 > PWM_PRD_MASK)
202 prescaler = 0;
203 }
204
205 if (prescaler == 0) {
206 /* Go up from the first divider */
207 for (prescaler = 0; prescaler < PWM_PRESCAL_MASK; prescaler++) {
208 unsigned int pval = prescaler_table[prescaler];
209
210 if (!pval)
211 continue;
212
213 div = clk_rate;
214 do_div(div, pval);
215 div = div * state->period;
216 do_div(div, NSEC_PER_SEC);
217 if (div - 1 <= PWM_PRD_MASK)
218 break;
219 }
220
221 if (div - 1 > PWM_PRD_MASK)
222 return -EINVAL;
223 }
224
225 *prd = div;
226 div *= state->duty_cycle;
227 do_div(div, state->period);
228 *dty = div;
229 *prsclr = prescaler;
230
231 return 0;
232}
233
234static int sun4i_pwm_apply(struct pwm_chip *chip, struct pwm_device *pwm,
235 const struct pwm_state *state)
236{
237 struct sun4i_pwm_chip *sun4i_pwm = to_sun4i_pwm_chip(chip);
238 struct pwm_state cstate;
239 u32 ctrl, duty = 0, period = 0, val;
240 int ret;
241 unsigned int delay_us, prescaler = 0;
242 bool bypass;
243
244 pwm_get_state(pwm, &cstate);
245
246 if (!cstate.enabled) {
247 ret = clk_prepare_enable(sun4i_pwm->clk);
248 if (ret) {
249 dev_err(chip->dev, "failed to enable PWM clock\n");
250 return ret;
251 }
252 }
253
254 ret = sun4i_pwm_calculate(sun4i_pwm, state, &duty, &period, &prescaler,
255 &bypass);
256 if (ret) {
257 dev_err(chip->dev, "period exceeds the maximum value\n");
258 if (!cstate.enabled)
259 clk_disable_unprepare(sun4i_pwm->clk);
260 return ret;
261 }
262
263 spin_lock(&sun4i_pwm->ctrl_lock);
264 ctrl = sun4i_pwm_readl(sun4i_pwm, PWM_CTRL_REG);
265
266 if (sun4i_pwm->data->has_direct_mod_clk_output) {
267 if (bypass) {
268 ctrl |= BIT_CH(PWM_BYPASS, pwm->hwpwm);
269 /* We can skip other parameter */
270 sun4i_pwm_writel(sun4i_pwm, ctrl, PWM_CTRL_REG);
271 spin_unlock(&sun4i_pwm->ctrl_lock);
272 return 0;
273 }
274
275 ctrl &= ~BIT_CH(PWM_BYPASS, pwm->hwpwm);
276 }
277
278 if (PWM_REG_PRESCAL(ctrl, pwm->hwpwm) != prescaler) {
279 /* Prescaler changed, the clock has to be gated */
280 ctrl &= ~BIT_CH(PWM_CLK_GATING, pwm->hwpwm);
281 sun4i_pwm_writel(sun4i_pwm, ctrl, PWM_CTRL_REG);
282
283 ctrl &= ~BIT_CH(PWM_PRESCAL_MASK, pwm->hwpwm);
284 ctrl |= BIT_CH(prescaler, pwm->hwpwm);
285 }
286
287 val = (duty & PWM_DTY_MASK) | PWM_PRD(period);
288 sun4i_pwm_writel(sun4i_pwm, val, PWM_CH_PRD(pwm->hwpwm));
289
290 if (state->polarity != PWM_POLARITY_NORMAL)
291 ctrl &= ~BIT_CH(PWM_ACT_STATE, pwm->hwpwm);
292 else
293 ctrl |= BIT_CH(PWM_ACT_STATE, pwm->hwpwm);
294
295 ctrl |= BIT_CH(PWM_CLK_GATING, pwm->hwpwm);
296
297 if (state->enabled)
298 ctrl |= BIT_CH(PWM_EN, pwm->hwpwm);
299
300 sun4i_pwm_writel(sun4i_pwm, ctrl, PWM_CTRL_REG);
301
302 spin_unlock(&sun4i_pwm->ctrl_lock);
303
304 if (state->enabled)
305 return 0;
306
307 /* We need a full period to elapse before disabling the channel. */
308 delay_us = DIV_ROUND_UP_ULL(cstate.period, NSEC_PER_USEC);
309 if ((delay_us / 500) > MAX_UDELAY_MS)
310 msleep(delay_us / 1000 + 1);
311 else
312 usleep_range(delay_us, delay_us * 2);
313
314 spin_lock(&sun4i_pwm->ctrl_lock);
315 ctrl = sun4i_pwm_readl(sun4i_pwm, PWM_CTRL_REG);
316 ctrl &= ~BIT_CH(PWM_CLK_GATING, pwm->hwpwm);
317 ctrl &= ~BIT_CH(PWM_EN, pwm->hwpwm);
318 sun4i_pwm_writel(sun4i_pwm, ctrl, PWM_CTRL_REG);
319 spin_unlock(&sun4i_pwm->ctrl_lock);
320
321 clk_disable_unprepare(sun4i_pwm->clk);
322
323 return 0;
324}
325
326static const struct pwm_ops sun4i_pwm_ops = {
327 .apply = sun4i_pwm_apply,
328 .get_state = sun4i_pwm_get_state,
329 .owner = THIS_MODULE,
330};
331
332static const struct sun4i_pwm_data sun4i_pwm_dual_nobypass = {
333 .has_prescaler_bypass = false,
334 .npwm = 2,
335};
336
337static const struct sun4i_pwm_data sun4i_pwm_dual_bypass = {
338 .has_prescaler_bypass = true,
339 .npwm = 2,
340};
341
342static const struct sun4i_pwm_data sun4i_pwm_single_bypass = {
343 .has_prescaler_bypass = true,
344 .npwm = 1,
345};
346
347static const struct sun4i_pwm_data sun50i_a64_pwm_data = {
348 .has_prescaler_bypass = true,
349 .has_direct_mod_clk_output = true,
350 .npwm = 1,
351};
352
353static const struct sun4i_pwm_data sun50i_h6_pwm_data = {
354 .has_prescaler_bypass = true,
355 .has_direct_mod_clk_output = true,
356 .npwm = 2,
357};
358
359static const struct of_device_id sun4i_pwm_dt_ids[] = {
360 {
361 .compatible = "allwinner,sun4i-a10-pwm",
362 .data = &sun4i_pwm_dual_nobypass,
363 }, {
364 .compatible = "allwinner,sun5i-a10s-pwm",
365 .data = &sun4i_pwm_dual_bypass,
366 }, {
367 .compatible = "allwinner,sun5i-a13-pwm",
368 .data = &sun4i_pwm_single_bypass,
369 }, {
370 .compatible = "allwinner,sun7i-a20-pwm",
371 .data = &sun4i_pwm_dual_bypass,
372 }, {
373 .compatible = "allwinner,sun8i-h3-pwm",
374 .data = &sun4i_pwm_single_bypass,
375 }, {
376 .compatible = "allwinner,sun50i-a64-pwm",
377 .data = &sun50i_a64_pwm_data,
378 }, {
379 .compatible = "allwinner,sun50i-h6-pwm",
380 .data = &sun50i_h6_pwm_data,
381 }, {
382 /* sentinel */
383 },
384};
385MODULE_DEVICE_TABLE(of, sun4i_pwm_dt_ids);
386
387static int sun4i_pwm_probe(struct platform_device *pdev)
388{
389 struct sun4i_pwm_chip *sun4ichip;
390 int ret;
391
392 sun4ichip = devm_kzalloc(&pdev->dev, sizeof(*sun4ichip), GFP_KERNEL);
393 if (!sun4ichip)
394 return -ENOMEM;
395
396 sun4ichip->data = of_device_get_match_data(&pdev->dev);
397 if (!sun4ichip->data)
398 return -ENODEV;
399
400 sun4ichip->base = devm_platform_ioremap_resource(pdev, 0);
401 if (IS_ERR(sun4ichip->base))
402 return PTR_ERR(sun4ichip->base);
403
404 /*
405 * All hardware variants need a source clock that is divided and
406 * then feeds the counter that defines the output wave form. In the
407 * device tree this clock is either unnamed or called "mod".
408 * Some variants (e.g. H6) need another clock to access the
409 * hardware registers; this is called "bus".
410 * So we request "mod" first (and ignore the corner case that a
411 * parent provides a "mod" clock while the right one would be the
412 * unnamed one of the PWM device) and if this is not found we fall
413 * back to the first clock of the PWM.
414 */
415 sun4ichip->clk = devm_clk_get_optional(&pdev->dev, "mod");
416 if (IS_ERR(sun4ichip->clk))
417 return dev_err_probe(&pdev->dev, PTR_ERR(sun4ichip->clk),
418 "get mod clock failed\n");
419
420 if (!sun4ichip->clk) {
421 sun4ichip->clk = devm_clk_get(&pdev->dev, NULL);
422 if (IS_ERR(sun4ichip->clk))
423 return dev_err_probe(&pdev->dev, PTR_ERR(sun4ichip->clk),
424 "get unnamed clock failed\n");
425 }
426
427 sun4ichip->bus_clk = devm_clk_get_optional(&pdev->dev, "bus");
428 if (IS_ERR(sun4ichip->bus_clk))
429 return dev_err_probe(&pdev->dev, PTR_ERR(sun4ichip->bus_clk),
430 "get bus clock failed\n");
431
432 sun4ichip->rst = devm_reset_control_get_optional_shared(&pdev->dev, NULL);
433 if (IS_ERR(sun4ichip->rst))
434 return dev_err_probe(&pdev->dev, PTR_ERR(sun4ichip->rst),
435 "get reset failed\n");
436
437 /* Deassert reset */
438 ret = reset_control_deassert(sun4ichip->rst);
439 if (ret) {
440 dev_err(&pdev->dev, "cannot deassert reset control: %pe\n",
441 ERR_PTR(ret));
442 return ret;
443 }
444
445 /*
446 * We're keeping the bus clock on for the sake of simplicity.
447 * Actually it only needs to be on for hardware register accesses.
448 */
449 ret = clk_prepare_enable(sun4ichip->bus_clk);
450 if (ret) {
451 dev_err(&pdev->dev, "cannot prepare and enable bus_clk %pe\n",
452 ERR_PTR(ret));
453 goto err_bus;
454 }
455
456 sun4ichip->chip.dev = &pdev->dev;
457 sun4ichip->chip.ops = &sun4i_pwm_ops;
458 sun4ichip->chip.npwm = sun4ichip->data->npwm;
459
460 spin_lock_init(&sun4ichip->ctrl_lock);
461
462 ret = pwmchip_add(&sun4ichip->chip);
463 if (ret < 0) {
464 dev_err(&pdev->dev, "failed to add PWM chip: %d\n", ret);
465 goto err_pwm_add;
466 }
467
468 platform_set_drvdata(pdev, sun4ichip);
469
470 return 0;
471
472err_pwm_add:
473 clk_disable_unprepare(sun4ichip->bus_clk);
474err_bus:
475 reset_control_assert(sun4ichip->rst);
476
477 return ret;
478}
479
480static int sun4i_pwm_remove(struct platform_device *pdev)
481{
482 struct sun4i_pwm_chip *sun4ichip = platform_get_drvdata(pdev);
483
484 pwmchip_remove(&sun4ichip->chip);
485
486 clk_disable_unprepare(sun4ichip->bus_clk);
487 reset_control_assert(sun4ichip->rst);
488
489 return 0;
490}
491
492static struct platform_driver sun4i_pwm_driver = {
493 .driver = {
494 .name = "sun4i-pwm",
495 .of_match_table = sun4i_pwm_dt_ids,
496 },
497 .probe = sun4i_pwm_probe,
498 .remove = sun4i_pwm_remove,
499};
500module_platform_driver(sun4i_pwm_driver);
501
502MODULE_ALIAS("platform:sun4i-pwm");
503MODULE_AUTHOR("Alexandre Belloni <alexandre.belloni@free-electrons.com>");
504MODULE_DESCRIPTION("Allwinner sun4i PWM driver");
505MODULE_LICENSE("GPL v2");