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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_set_bits(jz->map, TCU_REG_TCSRc(pwm->hwpwm), TCU_TCSR_PWM_EN);
92
93 /* Start counter */
94 regmap_write(jz->map, TCU_REG_TESR, BIT(pwm->hwpwm));
95
96 return 0;
97}
98
99static void jz4740_pwm_disable(struct pwm_chip *chip, struct pwm_device *pwm)
100{
101 struct jz4740_pwm_chip *jz = to_jz4740(chip);
102
103 /*
104 * Set duty > period. This trick allows the TCU channels in TCU2 mode to
105 * properly return to their init level.
106 */
107 regmap_write(jz->map, TCU_REG_TDHRc(pwm->hwpwm), 0xffff);
108 regmap_write(jz->map, TCU_REG_TDFRc(pwm->hwpwm), 0x0);
109
110 /*
111 * Disable PWM output.
112 * In TCU2 mode (channel 1/2 on JZ4750+), this must be done before the
113 * counter is stopped, while in TCU1 mode the order does not matter.
114 */
115 regmap_clear_bits(jz->map, TCU_REG_TCSRc(pwm->hwpwm), TCU_TCSR_PWM_EN);
116
117 /* Stop counter */
118 regmap_write(jz->map, TCU_REG_TECR, BIT(pwm->hwpwm));
119}
120
121static int jz4740_pwm_apply(struct pwm_chip *chip, struct pwm_device *pwm,
122 const struct pwm_state *state)
123{
124 struct jz4740_pwm_chip *jz4740 = to_jz4740(pwm->chip);
125 unsigned long long tmp = 0xffffull * NSEC_PER_SEC;
126 struct clk *clk = pwm_get_chip_data(pwm);
127 unsigned long period, duty;
128 long rate;
129 int err;
130
131 /*
132 * Limit the clock to a maximum rate that still gives us a period value
133 * which fits in 16 bits.
134 */
135 do_div(tmp, state->period);
136
137 /*
138 * /!\ IMPORTANT NOTE:
139 * -------------------
140 * This code relies on the fact that clk_round_rate() will always round
141 * down, which is not a valid assumption given by the clk API, but only
142 * happens to be true with the clk drivers used for Ingenic SoCs.
143 *
144 * Right now, there is no alternative as the clk API does not have a
145 * round-down function (and won't have one for a while), but if it ever
146 * comes to light, a round-down function should be used instead.
147 */
148 rate = clk_round_rate(clk, tmp);
149 if (rate < 0) {
150 dev_err(chip->dev, "Unable to round rate: %ld", rate);
151 return rate;
152 }
153
154 /* Calculate period value */
155 tmp = (unsigned long long)rate * state->period;
156 do_div(tmp, NSEC_PER_SEC);
157 period = tmp;
158
159 /* Calculate duty value */
160 tmp = (unsigned long long)rate * state->duty_cycle;
161 do_div(tmp, NSEC_PER_SEC);
162 duty = tmp;
163
164 if (duty >= period)
165 duty = period - 1;
166
167 jz4740_pwm_disable(chip, pwm);
168
169 err = clk_set_rate(clk, rate);
170 if (err) {
171 dev_err(chip->dev, "Unable to set rate: %d", err);
172 return err;
173 }
174
175 /* Reset counter to 0 */
176 regmap_write(jz4740->map, TCU_REG_TCNTc(pwm->hwpwm), 0);
177
178 /* Set duty */
179 regmap_write(jz4740->map, TCU_REG_TDHRc(pwm->hwpwm), duty);
180
181 /* Set period */
182 regmap_write(jz4740->map, TCU_REG_TDFRc(pwm->hwpwm), period);
183
184 /* Set abrupt shutdown */
185 regmap_set_bits(jz4740->map, TCU_REG_TCSRc(pwm->hwpwm),
186 TCU_TCSR_PWM_SD);
187
188 /*
189 * Set polarity.
190 *
191 * The PWM starts in inactive state until the internal timer reaches the
192 * duty value, then becomes active until the timer reaches the period
193 * value. In theory, we should then use (period - duty) as the real duty
194 * value, as a high duty value would otherwise result in the PWM pin
195 * being inactive most of the time.
196 *
197 * Here, we don't do that, and instead invert the polarity of the PWM
198 * when it is active. This trick makes the PWM start with its active
199 * state instead of its inactive state.
200 */
201 if ((state->polarity == PWM_POLARITY_NORMAL) ^ state->enabled)
202 regmap_update_bits(jz4740->map, TCU_REG_TCSRc(pwm->hwpwm),
203 TCU_TCSR_PWM_INITL_HIGH, 0);
204 else
205 regmap_update_bits(jz4740->map, TCU_REG_TCSRc(pwm->hwpwm),
206 TCU_TCSR_PWM_INITL_HIGH,
207 TCU_TCSR_PWM_INITL_HIGH);
208
209 if (state->enabled)
210 jz4740_pwm_enable(chip, pwm);
211
212 return 0;
213}
214
215static const struct pwm_ops jz4740_pwm_ops = {
216 .request = jz4740_pwm_request,
217 .free = jz4740_pwm_free,
218 .apply = jz4740_pwm_apply,
219 .owner = THIS_MODULE,
220};
221
222static int jz4740_pwm_probe(struct platform_device *pdev)
223{
224 struct device *dev = &pdev->dev;
225 struct jz4740_pwm_chip *jz4740;
226 const struct soc_info *info;
227
228 info = device_get_match_data(dev);
229 if (!info)
230 return -EINVAL;
231
232 jz4740 = devm_kzalloc(dev, sizeof(*jz4740), GFP_KERNEL);
233 if (!jz4740)
234 return -ENOMEM;
235
236 jz4740->map = device_node_to_regmap(dev->parent->of_node);
237 if (IS_ERR(jz4740->map)) {
238 dev_err(dev, "regmap not found: %ld\n", PTR_ERR(jz4740->map));
239 return PTR_ERR(jz4740->map);
240 }
241
242 jz4740->chip.dev = dev;
243 jz4740->chip.ops = &jz4740_pwm_ops;
244 jz4740->chip.npwm = info->num_pwms;
245
246 return devm_pwmchip_add(dev, &jz4740->chip);
247}
248
249static const struct soc_info jz4740_soc_info = {
250 .num_pwms = 8,
251};
252
253static const struct soc_info jz4725b_soc_info = {
254 .num_pwms = 6,
255};
256
257static const struct soc_info x1000_soc_info = {
258 .num_pwms = 5,
259};
260
261static const struct of_device_id jz4740_pwm_dt_ids[] = {
262 { .compatible = "ingenic,jz4740-pwm", .data = &jz4740_soc_info },
263 { .compatible = "ingenic,jz4725b-pwm", .data = &jz4725b_soc_info },
264 { .compatible = "ingenic,x1000-pwm", .data = &x1000_soc_info },
265 {},
266};
267MODULE_DEVICE_TABLE(of, jz4740_pwm_dt_ids);
268
269static struct platform_driver jz4740_pwm_driver = {
270 .driver = {
271 .name = "jz4740-pwm",
272 .of_match_table = jz4740_pwm_dt_ids,
273 },
274 .probe = jz4740_pwm_probe,
275};
276module_platform_driver(jz4740_pwm_driver);
277
278MODULE_AUTHOR("Lars-Peter Clausen <lars@metafoo.de>");
279MODULE_DESCRIPTION("Ingenic JZ4740 PWM driver");
280MODULE_ALIAS("platform:jz4740-pwm");
281MODULE_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 * - Each period starts with the inactive part.
10 */
11
12#include <linux/clk.h>
13#include <linux/err.h>
14#include <linux/gpio.h>
15#include <linux/kernel.h>
16#include <linux/module.h>
17#include <linux/of_device.h>
18#include <linux/platform_device.h>
19#include <linux/pwm.h>
20
21#include <asm/mach-jz4740/timer.h>
22
23#define NUM_PWM 8
24
25struct jz4740_pwm_chip {
26 struct pwm_chip chip;
27 struct clk *clk;
28};
29
30static inline struct jz4740_pwm_chip *to_jz4740(struct pwm_chip *chip)
31{
32 return container_of(chip, struct jz4740_pwm_chip, chip);
33}
34
35static int jz4740_pwm_request(struct pwm_chip *chip, struct pwm_device *pwm)
36{
37 /*
38 * Timers 0 and 1 are used for system tasks, so they are unavailable
39 * for use as PWMs.
40 */
41 if (pwm->hwpwm < 2)
42 return -EBUSY;
43
44 jz4740_timer_start(pwm->hwpwm);
45
46 return 0;
47}
48
49static void jz4740_pwm_free(struct pwm_chip *chip, struct pwm_device *pwm)
50{
51 jz4740_timer_set_ctrl(pwm->hwpwm, 0);
52
53 jz4740_timer_stop(pwm->hwpwm);
54}
55
56static int jz4740_pwm_enable(struct pwm_chip *chip, struct pwm_device *pwm)
57{
58 uint32_t ctrl = jz4740_timer_get_ctrl(pwm->pwm);
59
60 ctrl |= JZ_TIMER_CTRL_PWM_ENABLE;
61 jz4740_timer_set_ctrl(pwm->hwpwm, ctrl);
62 jz4740_timer_enable(pwm->hwpwm);
63
64 return 0;
65}
66
67static void jz4740_pwm_disable(struct pwm_chip *chip, struct pwm_device *pwm)
68{
69 uint32_t ctrl = jz4740_timer_get_ctrl(pwm->hwpwm);
70
71 /*
72 * Set duty > period. This trick allows the TCU channels in TCU2 mode to
73 * properly return to their init level.
74 */
75 jz4740_timer_set_duty(pwm->hwpwm, 0xffff);
76 jz4740_timer_set_period(pwm->hwpwm, 0x0);
77
78 /*
79 * Disable PWM output.
80 * In TCU2 mode (channel 1/2 on JZ4750+), this must be done before the
81 * counter is stopped, while in TCU1 mode the order does not matter.
82 */
83 ctrl &= ~JZ_TIMER_CTRL_PWM_ENABLE;
84 jz4740_timer_set_ctrl(pwm->hwpwm, ctrl);
85
86 /* Stop counter */
87 jz4740_timer_disable(pwm->hwpwm);
88}
89
90static int jz4740_pwm_apply(struct pwm_chip *chip, struct pwm_device *pwm,
91 const struct pwm_state *state)
92{
93 struct jz4740_pwm_chip *jz4740 = to_jz4740(pwm->chip);
94 unsigned long long tmp;
95 unsigned long period, duty;
96 unsigned int prescaler = 0;
97 uint16_t ctrl;
98
99 tmp = (unsigned long long)clk_get_rate(jz4740->clk) * state->period;
100 do_div(tmp, 1000000000);
101 period = tmp;
102
103 while (period > 0xffff && prescaler < 6) {
104 period >>= 2;
105 ++prescaler;
106 }
107
108 if (prescaler == 6)
109 return -EINVAL;
110
111 tmp = (unsigned long long)period * state->duty_cycle;
112 do_div(tmp, state->period);
113 duty = period - tmp;
114
115 if (duty >= period)
116 duty = period - 1;
117
118 jz4740_pwm_disable(chip, pwm);
119
120 jz4740_timer_set_count(pwm->hwpwm, 0);
121 jz4740_timer_set_duty(pwm->hwpwm, duty);
122 jz4740_timer_set_period(pwm->hwpwm, period);
123
124 ctrl = JZ_TIMER_CTRL_PRESCALER(prescaler) | JZ_TIMER_CTRL_SRC_EXT |
125 JZ_TIMER_CTRL_PWM_ABBRUPT_SHUTDOWN;
126
127 jz4740_timer_set_ctrl(pwm->hwpwm, ctrl);
128
129 switch (state->polarity) {
130 case PWM_POLARITY_NORMAL:
131 ctrl &= ~JZ_TIMER_CTRL_PWM_ACTIVE_LOW;
132 break;
133 case PWM_POLARITY_INVERSED:
134 ctrl |= JZ_TIMER_CTRL_PWM_ACTIVE_LOW;
135 break;
136 }
137
138 jz4740_timer_set_ctrl(pwm->hwpwm, ctrl);
139
140 if (state->enabled)
141 jz4740_pwm_enable(chip, pwm);
142
143 return 0;
144}
145
146static const struct pwm_ops jz4740_pwm_ops = {
147 .request = jz4740_pwm_request,
148 .free = jz4740_pwm_free,
149 .apply = jz4740_pwm_apply,
150 .owner = THIS_MODULE,
151};
152
153static int jz4740_pwm_probe(struct platform_device *pdev)
154{
155 struct jz4740_pwm_chip *jz4740;
156
157 jz4740 = devm_kzalloc(&pdev->dev, sizeof(*jz4740), GFP_KERNEL);
158 if (!jz4740)
159 return -ENOMEM;
160
161 jz4740->clk = devm_clk_get(&pdev->dev, "ext");
162 if (IS_ERR(jz4740->clk))
163 return PTR_ERR(jz4740->clk);
164
165 jz4740->chip.dev = &pdev->dev;
166 jz4740->chip.ops = &jz4740_pwm_ops;
167 jz4740->chip.npwm = NUM_PWM;
168 jz4740->chip.base = -1;
169 jz4740->chip.of_xlate = of_pwm_xlate_with_flags;
170 jz4740->chip.of_pwm_n_cells = 3;
171
172 platform_set_drvdata(pdev, jz4740);
173
174 return pwmchip_add(&jz4740->chip);
175}
176
177static int jz4740_pwm_remove(struct platform_device *pdev)
178{
179 struct jz4740_pwm_chip *jz4740 = platform_get_drvdata(pdev);
180
181 return pwmchip_remove(&jz4740->chip);
182}
183
184#ifdef CONFIG_OF
185static const struct of_device_id jz4740_pwm_dt_ids[] = {
186 { .compatible = "ingenic,jz4740-pwm", },
187 {},
188};
189MODULE_DEVICE_TABLE(of, jz4740_pwm_dt_ids);
190#endif
191
192static struct platform_driver jz4740_pwm_driver = {
193 .driver = {
194 .name = "jz4740-pwm",
195 .of_match_table = of_match_ptr(jz4740_pwm_dt_ids),
196 },
197 .probe = jz4740_pwm_probe,
198 .remove = jz4740_pwm_remove,
199};
200module_platform_driver(jz4740_pwm_driver);
201
202MODULE_AUTHOR("Lars-Peter Clausen <lars@metafoo.de>");
203MODULE_DESCRIPTION("Ingenic JZ4740 PWM driver");
204MODULE_ALIAS("platform:jz4740-pwm");
205MODULE_LICENSE("GPL");