Loading...
1// SPDX-License-Identifier: GPL-2.0-or-later
2/*
3 * Copyright (C) 2010, Lars-Peter Clausen <lars@metafoo.de>
4 * JZ4740 platform PWM support
5 *
6 * Limitations:
7 * - The .apply callback doesn't complete the currently running period before
8 * reconfiguring the hardware.
9 */
10
11#include <linux/clk.h>
12#include <linux/err.h>
13#include <linux/gpio.h>
14#include <linux/kernel.h>
15#include <linux/mfd/ingenic-tcu.h>
16#include <linux/mfd/syscon.h>
17#include <linux/module.h>
18#include <linux/of.h>
19#include <linux/platform_device.h>
20#include <linux/pwm.h>
21#include <linux/regmap.h>
22
23struct soc_info {
24 unsigned int num_pwms;
25};
26
27struct jz4740_pwm_chip {
28 struct pwm_chip chip;
29 struct regmap *map;
30 struct clk *clk[];
31};
32
33static inline struct jz4740_pwm_chip *to_jz4740(struct pwm_chip *chip)
34{
35 return container_of(chip, struct jz4740_pwm_chip, chip);
36}
37
38static bool jz4740_pwm_can_use_chn(struct jz4740_pwm_chip *jz,
39 unsigned int channel)
40{
41 /* Enable all TCU channels for PWM use by default except channels 0/1 */
42 u32 pwm_channels_mask = GENMASK(jz->chip.npwm - 1, 2);
43
44 device_property_read_u32(jz->chip.dev->parent,
45 "ingenic,pwm-channels-mask",
46 &pwm_channels_mask);
47
48 return !!(pwm_channels_mask & BIT(channel));
49}
50
51static int jz4740_pwm_request(struct pwm_chip *chip, struct pwm_device *pwm)
52{
53 struct jz4740_pwm_chip *jz = to_jz4740(chip);
54 struct clk *clk;
55 char name[16];
56 int err;
57
58 if (!jz4740_pwm_can_use_chn(jz, pwm->hwpwm))
59 return -EBUSY;
60
61 snprintf(name, sizeof(name), "timer%u", pwm->hwpwm);
62
63 clk = clk_get(chip->dev, name);
64 if (IS_ERR(clk)) {
65 dev_err(chip->dev, "error %pe: Failed to get clock\n", clk);
66 return PTR_ERR(clk);
67 }
68
69 err = clk_prepare_enable(clk);
70 if (err < 0) {
71 clk_put(clk);
72 return err;
73 }
74
75 jz->clk[pwm->hwpwm] = clk;
76
77 return 0;
78}
79
80static void jz4740_pwm_free(struct pwm_chip *chip, struct pwm_device *pwm)
81{
82 struct jz4740_pwm_chip *jz = to_jz4740(chip);
83 struct clk *clk = jz->clk[pwm->hwpwm];
84
85 clk_disable_unprepare(clk);
86 clk_put(clk);
87}
88
89static int jz4740_pwm_enable(struct pwm_chip *chip, struct pwm_device *pwm)
90{
91 struct jz4740_pwm_chip *jz = to_jz4740(chip);
92
93 /* Enable PWM output */
94 regmap_set_bits(jz->map, TCU_REG_TCSRc(pwm->hwpwm), TCU_TCSR_PWM_EN);
95
96 /* Start counter */
97 regmap_write(jz->map, TCU_REG_TESR, BIT(pwm->hwpwm));
98
99 return 0;
100}
101
102static void jz4740_pwm_disable(struct pwm_chip *chip, struct pwm_device *pwm)
103{
104 struct jz4740_pwm_chip *jz = to_jz4740(chip);
105
106 /*
107 * Set duty > period. This trick allows the TCU channels in TCU2 mode to
108 * properly return to their init level.
109 */
110 regmap_write(jz->map, TCU_REG_TDHRc(pwm->hwpwm), 0xffff);
111 regmap_write(jz->map, TCU_REG_TDFRc(pwm->hwpwm), 0x0);
112
113 /*
114 * Disable PWM output.
115 * In TCU2 mode (channel 1/2 on JZ4750+), this must be done before the
116 * counter is stopped, while in TCU1 mode the order does not matter.
117 */
118 regmap_clear_bits(jz->map, TCU_REG_TCSRc(pwm->hwpwm), TCU_TCSR_PWM_EN);
119
120 /* Stop counter */
121 regmap_write(jz->map, TCU_REG_TECR, BIT(pwm->hwpwm));
122}
123
124static int jz4740_pwm_apply(struct pwm_chip *chip, struct pwm_device *pwm,
125 const struct pwm_state *state)
126{
127 struct jz4740_pwm_chip *jz = to_jz4740(chip);
128 unsigned long long tmp = 0xffffull * NSEC_PER_SEC;
129 struct clk *clk = jz->clk[pwm->hwpwm];
130 unsigned long period, duty;
131 long rate;
132 int err;
133
134 /*
135 * Limit the clock to a maximum rate that still gives us a period value
136 * which fits in 16 bits.
137 */
138 do_div(tmp, state->period);
139
140 /*
141 * /!\ IMPORTANT NOTE:
142 * -------------------
143 * This code relies on the fact that clk_round_rate() will always round
144 * down, which is not a valid assumption given by the clk API, but only
145 * happens to be true with the clk drivers used for Ingenic SoCs.
146 *
147 * Right now, there is no alternative as the clk API does not have a
148 * round-down function (and won't have one for a while), but if it ever
149 * comes to light, a round-down function should be used instead.
150 */
151 rate = clk_round_rate(clk, tmp);
152 if (rate < 0) {
153 dev_err(chip->dev, "Unable to round rate: %ld\n", rate);
154 return rate;
155 }
156
157 /* Calculate period value */
158 tmp = (unsigned long long)rate * state->period;
159 do_div(tmp, NSEC_PER_SEC);
160 period = tmp;
161
162 /* Calculate duty value */
163 tmp = (unsigned long long)rate * state->duty_cycle;
164 do_div(tmp, NSEC_PER_SEC);
165 duty = tmp;
166
167 if (duty >= period)
168 duty = period - 1;
169
170 jz4740_pwm_disable(chip, pwm);
171
172 err = clk_set_rate(clk, rate);
173 if (err) {
174 dev_err(chip->dev, "Unable to set rate: %d\n", err);
175 return err;
176 }
177
178 /* Reset counter to 0 */
179 regmap_write(jz->map, TCU_REG_TCNTc(pwm->hwpwm), 0);
180
181 /* Set duty */
182 regmap_write(jz->map, TCU_REG_TDHRc(pwm->hwpwm), duty);
183
184 /* Set period */
185 regmap_write(jz->map, TCU_REG_TDFRc(pwm->hwpwm), period);
186
187 /* Set abrupt shutdown */
188 regmap_set_bits(jz->map, TCU_REG_TCSRc(pwm->hwpwm),
189 TCU_TCSR_PWM_SD);
190
191 /*
192 * Set polarity.
193 *
194 * The PWM starts in inactive state until the internal timer reaches the
195 * duty value, then becomes active until the timer reaches the period
196 * value. In theory, we should then use (period - duty) as the real duty
197 * value, as a high duty value would otherwise result in the PWM pin
198 * being inactive most of the time.
199 *
200 * Here, we don't do that, and instead invert the polarity of the PWM
201 * when it is active. This trick makes the PWM start with its active
202 * state instead of its inactive state.
203 */
204 if ((state->polarity == PWM_POLARITY_NORMAL) ^ state->enabled)
205 regmap_update_bits(jz->map, TCU_REG_TCSRc(pwm->hwpwm),
206 TCU_TCSR_PWM_INITL_HIGH, 0);
207 else
208 regmap_update_bits(jz->map, TCU_REG_TCSRc(pwm->hwpwm),
209 TCU_TCSR_PWM_INITL_HIGH,
210 TCU_TCSR_PWM_INITL_HIGH);
211
212 if (state->enabled)
213 jz4740_pwm_enable(chip, pwm);
214
215 return 0;
216}
217
218static const struct pwm_ops jz4740_pwm_ops = {
219 .request = jz4740_pwm_request,
220 .free = jz4740_pwm_free,
221 .apply = jz4740_pwm_apply,
222};
223
224static int jz4740_pwm_probe(struct platform_device *pdev)
225{
226 struct device *dev = &pdev->dev;
227 struct jz4740_pwm_chip *jz;
228 const struct soc_info *info;
229
230 info = device_get_match_data(dev);
231 if (!info)
232 return -EINVAL;
233
234 jz = devm_kzalloc(dev, struct_size(jz, clk, info->num_pwms),
235 GFP_KERNEL);
236 if (!jz)
237 return -ENOMEM;
238
239 jz->map = device_node_to_regmap(dev->parent->of_node);
240 if (IS_ERR(jz->map)) {
241 dev_err(dev, "regmap not found: %ld\n", PTR_ERR(jz->map));
242 return PTR_ERR(jz->map);
243 }
244
245 jz->chip.dev = dev;
246 jz->chip.ops = &jz4740_pwm_ops;
247 jz->chip.npwm = info->num_pwms;
248
249 return devm_pwmchip_add(dev, &jz->chip);
250}
251
252static const struct soc_info jz4740_soc_info = {
253 .num_pwms = 8,
254};
255
256static const struct soc_info jz4725b_soc_info = {
257 .num_pwms = 6,
258};
259
260static const struct soc_info x1000_soc_info = {
261 .num_pwms = 5,
262};
263
264static const struct of_device_id jz4740_pwm_dt_ids[] = {
265 { .compatible = "ingenic,jz4740-pwm", .data = &jz4740_soc_info },
266 { .compatible = "ingenic,jz4725b-pwm", .data = &jz4725b_soc_info },
267 { .compatible = "ingenic,x1000-pwm", .data = &x1000_soc_info },
268 {},
269};
270MODULE_DEVICE_TABLE(of, jz4740_pwm_dt_ids);
271
272static struct platform_driver jz4740_pwm_driver = {
273 .driver = {
274 .name = "jz4740-pwm",
275 .of_match_table = jz4740_pwm_dt_ids,
276 },
277 .probe = jz4740_pwm_probe,
278};
279module_platform_driver(jz4740_pwm_driver);
280
281MODULE_AUTHOR("Lars-Peter Clausen <lars@metafoo.de>");
282MODULE_DESCRIPTION("Ingenic JZ4740 PWM driver");
283MODULE_ALIAS("platform:jz4740-pwm");
284MODULE_LICENSE("GPL");
1// SPDX-License-Identifier: GPL-2.0-or-later
2/*
3 * Copyright (C) 2010, Lars-Peter Clausen <lars@metafoo.de>
4 * JZ4740 platform PWM support
5 *
6 * Limitations:
7 * - The .apply callback doesn't complete the currently running period before
8 * reconfiguring the hardware.
9 */
10
11#include <linux/clk.h>
12#include <linux/err.h>
13#include <linux/gpio.h>
14#include <linux/kernel.h>
15#include <linux/mfd/ingenic-tcu.h>
16#include <linux/mfd/syscon.h>
17#include <linux/module.h>
18#include <linux/of_device.h>
19#include <linux/platform_device.h>
20#include <linux/pwm.h>
21#include <linux/regmap.h>
22
23struct soc_info {
24 unsigned int num_pwms;
25};
26
27struct jz4740_pwm_chip {
28 struct pwm_chip chip;
29 struct regmap *map;
30};
31
32static inline struct jz4740_pwm_chip *to_jz4740(struct pwm_chip *chip)
33{
34 return container_of(chip, struct jz4740_pwm_chip, chip);
35}
36
37static bool jz4740_pwm_can_use_chn(struct jz4740_pwm_chip *jz,
38 unsigned int channel)
39{
40 /* Enable all TCU channels for PWM use by default except channels 0/1 */
41 u32 pwm_channels_mask = GENMASK(jz->chip.npwm - 1, 2);
42
43 device_property_read_u32(jz->chip.dev->parent,
44 "ingenic,pwm-channels-mask",
45 &pwm_channels_mask);
46
47 return !!(pwm_channels_mask & BIT(channel));
48}
49
50static int jz4740_pwm_request(struct pwm_chip *chip, struct pwm_device *pwm)
51{
52 struct jz4740_pwm_chip *jz = to_jz4740(chip);
53 struct clk *clk;
54 char name[16];
55 int err;
56
57 if (!jz4740_pwm_can_use_chn(jz, pwm->hwpwm))
58 return -EBUSY;
59
60 snprintf(name, sizeof(name), "timer%u", pwm->hwpwm);
61
62 clk = clk_get(chip->dev, name);
63 if (IS_ERR(clk))
64 return dev_err_probe(chip->dev, PTR_ERR(clk),
65 "Failed to get clock\n");
66
67 err = clk_prepare_enable(clk);
68 if (err < 0) {
69 clk_put(clk);
70 return err;
71 }
72
73 pwm_set_chip_data(pwm, clk);
74
75 return 0;
76}
77
78static void jz4740_pwm_free(struct pwm_chip *chip, struct pwm_device *pwm)
79{
80 struct clk *clk = pwm_get_chip_data(pwm);
81
82 clk_disable_unprepare(clk);
83 clk_put(clk);
84}
85
86static int jz4740_pwm_enable(struct pwm_chip *chip, struct pwm_device *pwm)
87{
88 struct jz4740_pwm_chip *jz = to_jz4740(chip);
89
90 /* Enable PWM output */
91 regmap_update_bits(jz->map, TCU_REG_TCSRc(pwm->hwpwm),
92 TCU_TCSR_PWM_EN, TCU_TCSR_PWM_EN);
93
94 /* Start counter */
95 regmap_write(jz->map, TCU_REG_TESR, BIT(pwm->hwpwm));
96
97 return 0;
98}
99
100static void jz4740_pwm_disable(struct pwm_chip *chip, struct pwm_device *pwm)
101{
102 struct jz4740_pwm_chip *jz = to_jz4740(chip);
103
104 /*
105 * Set duty > period. This trick allows the TCU channels in TCU2 mode to
106 * properly return to their init level.
107 */
108 regmap_write(jz->map, TCU_REG_TDHRc(pwm->hwpwm), 0xffff);
109 regmap_write(jz->map, TCU_REG_TDFRc(pwm->hwpwm), 0x0);
110
111 /*
112 * Disable PWM output.
113 * In TCU2 mode (channel 1/2 on JZ4750+), this must be done before the
114 * counter is stopped, while in TCU1 mode the order does not matter.
115 */
116 regmap_update_bits(jz->map, TCU_REG_TCSRc(pwm->hwpwm),
117 TCU_TCSR_PWM_EN, 0);
118
119 /* Stop counter */
120 regmap_write(jz->map, TCU_REG_TECR, BIT(pwm->hwpwm));
121}
122
123static int jz4740_pwm_apply(struct pwm_chip *chip, struct pwm_device *pwm,
124 const struct pwm_state *state)
125{
126 struct jz4740_pwm_chip *jz4740 = to_jz4740(pwm->chip);
127 unsigned long long tmp = 0xffffull * NSEC_PER_SEC;
128 struct clk *clk = pwm_get_chip_data(pwm);
129 unsigned long period, duty;
130 long rate;
131 int err;
132
133 /*
134 * Limit the clock to a maximum rate that still gives us a period value
135 * which fits in 16 bits.
136 */
137 do_div(tmp, state->period);
138
139 /*
140 * /!\ IMPORTANT NOTE:
141 * -------------------
142 * This code relies on the fact that clk_round_rate() will always round
143 * down, which is not a valid assumption given by the clk API, but only
144 * happens to be true with the clk drivers used for Ingenic SoCs.
145 *
146 * Right now, there is no alternative as the clk API does not have a
147 * round-down function (and won't have one for a while), but if it ever
148 * comes to light, a round-down function should be used instead.
149 */
150 rate = clk_round_rate(clk, tmp);
151 if (rate < 0) {
152 dev_err(chip->dev, "Unable to round rate: %ld", rate);
153 return rate;
154 }
155
156 /* Calculate period value */
157 tmp = (unsigned long long)rate * state->period;
158 do_div(tmp, NSEC_PER_SEC);
159 period = tmp;
160
161 /* Calculate duty value */
162 tmp = (unsigned long long)rate * state->duty_cycle;
163 do_div(tmp, NSEC_PER_SEC);
164 duty = tmp;
165
166 if (duty >= period)
167 duty = period - 1;
168
169 jz4740_pwm_disable(chip, pwm);
170
171 err = clk_set_rate(clk, rate);
172 if (err) {
173 dev_err(chip->dev, "Unable to set rate: %d", err);
174 return err;
175 }
176
177 /* Reset counter to 0 */
178 regmap_write(jz4740->map, TCU_REG_TCNTc(pwm->hwpwm), 0);
179
180 /* Set duty */
181 regmap_write(jz4740->map, TCU_REG_TDHRc(pwm->hwpwm), duty);
182
183 /* Set period */
184 regmap_write(jz4740->map, TCU_REG_TDFRc(pwm->hwpwm), period);
185
186 /* Set abrupt shutdown */
187 regmap_update_bits(jz4740->map, TCU_REG_TCSRc(pwm->hwpwm),
188 TCU_TCSR_PWM_SD, TCU_TCSR_PWM_SD);
189
190 /*
191 * Set polarity.
192 *
193 * The PWM starts in inactive state until the internal timer reaches the
194 * duty value, then becomes active until the timer reaches the period
195 * value. In theory, we should then use (period - duty) as the real duty
196 * value, as a high duty value would otherwise result in the PWM pin
197 * being inactive most of the time.
198 *
199 * Here, we don't do that, and instead invert the polarity of the PWM
200 * when it is active. This trick makes the PWM start with its active
201 * state instead of its inactive state.
202 */
203 if ((state->polarity == PWM_POLARITY_NORMAL) ^ state->enabled)
204 regmap_update_bits(jz4740->map, TCU_REG_TCSRc(pwm->hwpwm),
205 TCU_TCSR_PWM_INITL_HIGH, 0);
206 else
207 regmap_update_bits(jz4740->map, TCU_REG_TCSRc(pwm->hwpwm),
208 TCU_TCSR_PWM_INITL_HIGH,
209 TCU_TCSR_PWM_INITL_HIGH);
210
211 if (state->enabled)
212 jz4740_pwm_enable(chip, pwm);
213
214 return 0;
215}
216
217static const struct pwm_ops jz4740_pwm_ops = {
218 .request = jz4740_pwm_request,
219 .free = jz4740_pwm_free,
220 .apply = jz4740_pwm_apply,
221 .owner = THIS_MODULE,
222};
223
224static int jz4740_pwm_probe(struct platform_device *pdev)
225{
226 struct device *dev = &pdev->dev;
227 struct jz4740_pwm_chip *jz4740;
228 const struct soc_info *info;
229
230 info = device_get_match_data(dev);
231 if (!info)
232 return -EINVAL;
233
234 jz4740 = devm_kzalloc(dev, sizeof(*jz4740), GFP_KERNEL);
235 if (!jz4740)
236 return -ENOMEM;
237
238 jz4740->map = device_node_to_regmap(dev->parent->of_node);
239 if (IS_ERR(jz4740->map)) {
240 dev_err(dev, "regmap not found: %ld\n", PTR_ERR(jz4740->map));
241 return PTR_ERR(jz4740->map);
242 }
243
244 jz4740->chip.dev = dev;
245 jz4740->chip.ops = &jz4740_pwm_ops;
246 jz4740->chip.npwm = info->num_pwms;
247
248 platform_set_drvdata(pdev, jz4740);
249
250 return pwmchip_add(&jz4740->chip);
251}
252
253static int jz4740_pwm_remove(struct platform_device *pdev)
254{
255 struct jz4740_pwm_chip *jz4740 = platform_get_drvdata(pdev);
256
257 return pwmchip_remove(&jz4740->chip);
258}
259
260static const struct soc_info __maybe_unused jz4740_soc_info = {
261 .num_pwms = 8,
262};
263
264static const struct soc_info __maybe_unused jz4725b_soc_info = {
265 .num_pwms = 6,
266};
267
268#ifdef CONFIG_OF
269static const struct of_device_id jz4740_pwm_dt_ids[] = {
270 { .compatible = "ingenic,jz4740-pwm", .data = &jz4740_soc_info },
271 { .compatible = "ingenic,jz4725b-pwm", .data = &jz4725b_soc_info },
272 {},
273};
274MODULE_DEVICE_TABLE(of, jz4740_pwm_dt_ids);
275#endif
276
277static struct platform_driver jz4740_pwm_driver = {
278 .driver = {
279 .name = "jz4740-pwm",
280 .of_match_table = of_match_ptr(jz4740_pwm_dt_ids),
281 },
282 .probe = jz4740_pwm_probe,
283 .remove = jz4740_pwm_remove,
284};
285module_platform_driver(jz4740_pwm_driver);
286
287MODULE_AUTHOR("Lars-Peter Clausen <lars@metafoo.de>");
288MODULE_DESCRIPTION("Ingenic JZ4740 PWM driver");
289MODULE_ALIAS("platform:jz4740-pwm");
290MODULE_LICENSE("GPL");