xref: /openbmc/linux/drivers/pwm/pwm-lp3943.c (revision 0a41b0c5)
1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3  * TI/National Semiconductor LP3943 PWM driver
4  *
5  * Copyright 2013 Texas Instruments
6  *
7  * Author: Milo Kim <milo.kim@ti.com>
8  */
9 
10 #include <linux/err.h>
11 #include <linux/mfd/lp3943.h>
12 #include <linux/module.h>
13 #include <linux/of.h>
14 #include <linux/platform_device.h>
15 #include <linux/pwm.h>
16 #include <linux/slab.h>
17 
18 #define LP3943_MAX_DUTY			255
19 #define LP3943_MIN_PERIOD		6250
20 #define LP3943_MAX_PERIOD		1600000
21 
22 struct lp3943_pwm {
23 	struct pwm_chip chip;
24 	struct lp3943 *lp3943;
25 	struct lp3943_platform_data *pdata;
26 };
27 
to_lp3943_pwm(struct pwm_chip * chip)28 static inline struct lp3943_pwm *to_lp3943_pwm(struct pwm_chip *chip)
29 {
30 	return container_of(chip, struct lp3943_pwm, chip);
31 }
32 
33 static struct lp3943_pwm_map *
lp3943_pwm_request_map(struct lp3943_pwm * lp3943_pwm,int hwpwm)34 lp3943_pwm_request_map(struct lp3943_pwm *lp3943_pwm, int hwpwm)
35 {
36 	struct lp3943_platform_data *pdata = lp3943_pwm->pdata;
37 	struct lp3943 *lp3943 = lp3943_pwm->lp3943;
38 	struct lp3943_pwm_map *pwm_map;
39 	int i, offset;
40 
41 	pwm_map = kzalloc(sizeof(*pwm_map), GFP_KERNEL);
42 	if (!pwm_map)
43 		return ERR_PTR(-ENOMEM);
44 
45 	pwm_map->output = pdata->pwms[hwpwm]->output;
46 	pwm_map->num_outputs = pdata->pwms[hwpwm]->num_outputs;
47 
48 	for (i = 0; i < pwm_map->num_outputs; i++) {
49 		offset = pwm_map->output[i];
50 
51 		/* Return an error if the pin is already assigned */
52 		if (test_and_set_bit(offset, &lp3943->pin_used)) {
53 			kfree(pwm_map);
54 			return ERR_PTR(-EBUSY);
55 		}
56 	}
57 
58 	return pwm_map;
59 }
60 
lp3943_pwm_request(struct pwm_chip * chip,struct pwm_device * pwm)61 static int lp3943_pwm_request(struct pwm_chip *chip, struct pwm_device *pwm)
62 {
63 	struct lp3943_pwm *lp3943_pwm = to_lp3943_pwm(chip);
64 	struct lp3943_pwm_map *pwm_map;
65 
66 	pwm_map = lp3943_pwm_request_map(lp3943_pwm, pwm->hwpwm);
67 	if (IS_ERR(pwm_map))
68 		return PTR_ERR(pwm_map);
69 
70 	return pwm_set_chip_data(pwm, pwm_map);
71 }
72 
lp3943_pwm_free_map(struct lp3943_pwm * lp3943_pwm,struct lp3943_pwm_map * pwm_map)73 static void lp3943_pwm_free_map(struct lp3943_pwm *lp3943_pwm,
74 				struct lp3943_pwm_map *pwm_map)
75 {
76 	struct lp3943 *lp3943 = lp3943_pwm->lp3943;
77 	int i, offset;
78 
79 	for (i = 0; i < pwm_map->num_outputs; i++) {
80 		offset = pwm_map->output[i];
81 		clear_bit(offset, &lp3943->pin_used);
82 	}
83 
84 	kfree(pwm_map);
85 }
86 
lp3943_pwm_free(struct pwm_chip * chip,struct pwm_device * pwm)87 static void lp3943_pwm_free(struct pwm_chip *chip, struct pwm_device *pwm)
88 {
89 	struct lp3943_pwm *lp3943_pwm = to_lp3943_pwm(chip);
90 	struct lp3943_pwm_map *pwm_map = pwm_get_chip_data(pwm);
91 
92 	lp3943_pwm_free_map(lp3943_pwm, pwm_map);
93 }
94 
lp3943_pwm_config(struct pwm_chip * chip,struct pwm_device * pwm,u64 duty_ns,u64 period_ns)95 static int lp3943_pwm_config(struct pwm_chip *chip, struct pwm_device *pwm,
96 			     u64 duty_ns, u64 period_ns)
97 {
98 	struct lp3943_pwm *lp3943_pwm = to_lp3943_pwm(chip);
99 	struct lp3943 *lp3943 = lp3943_pwm->lp3943;
100 	u8 val, reg_duty, reg_prescale;
101 	int err;
102 
103 	/*
104 	 * How to configure the LP3943 PWMs
105 	 *
106 	 * 1) Period = 6250 ~ 1600000
107 	 * 2) Prescale = period / 6250 -1
108 	 * 3) Duty = input duty
109 	 *
110 	 * Prescale and duty are register values
111 	 */
112 
113 	if (pwm->hwpwm == 0) {
114 		reg_prescale = LP3943_REG_PRESCALE0;
115 		reg_duty     = LP3943_REG_PWM0;
116 	} else {
117 		reg_prescale = LP3943_REG_PRESCALE1;
118 		reg_duty     = LP3943_REG_PWM1;
119 	}
120 
121 	/*
122 	 * Note that after this clamping, period_ns fits into an int. This is
123 	 * helpful because we can resort to integer division below instead of
124 	 * the (more expensive) 64 bit division.
125 	 */
126 	period_ns = clamp(period_ns, (u64)LP3943_MIN_PERIOD, (u64)LP3943_MAX_PERIOD);
127 	val       = (u8)((int)period_ns / LP3943_MIN_PERIOD - 1);
128 
129 	err = lp3943_write_byte(lp3943, reg_prescale, val);
130 	if (err)
131 		return err;
132 
133 	duty_ns = min(duty_ns, period_ns);
134 	val = (u8)((int)duty_ns * LP3943_MAX_DUTY / (int)period_ns);
135 
136 	return lp3943_write_byte(lp3943, reg_duty, val);
137 }
138 
lp3943_pwm_set_mode(struct lp3943_pwm * lp3943_pwm,struct lp3943_pwm_map * pwm_map,u8 val)139 static int lp3943_pwm_set_mode(struct lp3943_pwm *lp3943_pwm,
140 			       struct lp3943_pwm_map *pwm_map,
141 			       u8 val)
142 {
143 	struct lp3943 *lp3943 = lp3943_pwm->lp3943;
144 	const struct lp3943_reg_cfg *mux = lp3943->mux_cfg;
145 	int i, index, err;
146 
147 	for (i = 0; i < pwm_map->num_outputs; i++) {
148 		index = pwm_map->output[i];
149 		err = lp3943_update_bits(lp3943, mux[index].reg,
150 					 mux[index].mask,
151 					 val << mux[index].shift);
152 		if (err)
153 			return err;
154 	}
155 
156 	return 0;
157 }
158 
lp3943_pwm_enable(struct pwm_chip * chip,struct pwm_device * pwm)159 static int lp3943_pwm_enable(struct pwm_chip *chip, struct pwm_device *pwm)
160 {
161 	struct lp3943_pwm *lp3943_pwm = to_lp3943_pwm(chip);
162 	struct lp3943_pwm_map *pwm_map = pwm_get_chip_data(pwm);
163 	u8 val;
164 
165 	if (pwm->hwpwm == 0)
166 		val = LP3943_DIM_PWM0;
167 	else
168 		val = LP3943_DIM_PWM1;
169 
170 	/*
171 	 * Each PWM generator is set to control any of outputs of LP3943.
172 	 * To enable/disable the PWM, these output pins should be configured.
173 	 */
174 
175 	return lp3943_pwm_set_mode(lp3943_pwm, pwm_map, val);
176 }
177 
lp3943_pwm_disable(struct pwm_chip * chip,struct pwm_device * pwm)178 static void lp3943_pwm_disable(struct pwm_chip *chip, struct pwm_device *pwm)
179 {
180 	struct lp3943_pwm *lp3943_pwm = to_lp3943_pwm(chip);
181 	struct lp3943_pwm_map *pwm_map = pwm_get_chip_data(pwm);
182 
183 	/*
184 	 * LP3943 outputs are open-drain, so the pin should be configured
185 	 * when the PWM is disabled.
186 	 */
187 
188 	lp3943_pwm_set_mode(lp3943_pwm, pwm_map, LP3943_GPIO_OUT_HIGH);
189 }
190 
lp3943_pwm_apply(struct pwm_chip * chip,struct pwm_device * pwm,const struct pwm_state * state)191 static int lp3943_pwm_apply(struct pwm_chip *chip, struct pwm_device *pwm,
192 			    const struct pwm_state *state)
193 {
194 	int err;
195 
196 	if (state->polarity != PWM_POLARITY_NORMAL)
197 		return -EINVAL;
198 
199 	if (!state->enabled) {
200 		if (pwm->state.enabled)
201 			lp3943_pwm_disable(chip, pwm);
202 		return 0;
203 	}
204 
205 	err = lp3943_pwm_config(chip, pwm, state->duty_cycle, state->period);
206 	if (err)
207 		return err;
208 
209 	if (!pwm->state.enabled)
210 		err = lp3943_pwm_enable(chip, pwm);
211 
212 	return err;
213 }
214 
215 static const struct pwm_ops lp3943_pwm_ops = {
216 	.request	= lp3943_pwm_request,
217 	.free		= lp3943_pwm_free,
218 	.apply		= lp3943_pwm_apply,
219 	.owner		= THIS_MODULE,
220 };
221 
lp3943_pwm_parse_dt(struct device * dev,struct lp3943_pwm * lp3943_pwm)222 static int lp3943_pwm_parse_dt(struct device *dev,
223 			       struct lp3943_pwm *lp3943_pwm)
224 {
225 	static const char * const name[] = { "ti,pwm0", "ti,pwm1", };
226 	struct device_node *node = dev->of_node;
227 	struct lp3943_platform_data *pdata;
228 	struct lp3943_pwm_map *pwm_map;
229 	enum lp3943_pwm_output *output;
230 	int i, err, proplen, count = 0;
231 	u32 num_outputs;
232 
233 	if (!node)
234 		return -EINVAL;
235 
236 	pdata = devm_kzalloc(dev, sizeof(*pdata), GFP_KERNEL);
237 	if (!pdata)
238 		return -ENOMEM;
239 
240 	/*
241 	 * Read the output map configuration from the device tree.
242 	 * Each of the two PWM generators can drive zero or more outputs.
243 	 */
244 
245 	for (i = 0; i < LP3943_NUM_PWMS; i++) {
246 		if (!of_get_property(node, name[i], &proplen))
247 			continue;
248 
249 		num_outputs = proplen / sizeof(u32);
250 		if (num_outputs == 0)
251 			continue;
252 
253 		output = devm_kcalloc(dev, num_outputs, sizeof(*output),
254 				      GFP_KERNEL);
255 		if (!output)
256 			return -ENOMEM;
257 
258 		err = of_property_read_u32_array(node, name[i], output,
259 						 num_outputs);
260 		if (err)
261 			return err;
262 
263 		pwm_map = devm_kzalloc(dev, sizeof(*pwm_map), GFP_KERNEL);
264 		if (!pwm_map)
265 			return -ENOMEM;
266 
267 		pwm_map->output = output;
268 		pwm_map->num_outputs = num_outputs;
269 		pdata->pwms[i] = pwm_map;
270 
271 		count++;
272 	}
273 
274 	if (count == 0)
275 		return -ENODATA;
276 
277 	lp3943_pwm->pdata = pdata;
278 	return 0;
279 }
280 
lp3943_pwm_probe(struct platform_device * pdev)281 static int lp3943_pwm_probe(struct platform_device *pdev)
282 {
283 	struct lp3943 *lp3943 = dev_get_drvdata(pdev->dev.parent);
284 	struct lp3943_pwm *lp3943_pwm;
285 	int ret;
286 
287 	lp3943_pwm = devm_kzalloc(&pdev->dev, sizeof(*lp3943_pwm), GFP_KERNEL);
288 	if (!lp3943_pwm)
289 		return -ENOMEM;
290 
291 	lp3943_pwm->pdata = lp3943->pdata;
292 	if (!lp3943_pwm->pdata) {
293 		if (IS_ENABLED(CONFIG_OF))
294 			ret = lp3943_pwm_parse_dt(&pdev->dev, lp3943_pwm);
295 		else
296 			ret = -ENODEV;
297 
298 		if (ret)
299 			return ret;
300 	}
301 
302 	lp3943_pwm->lp3943 = lp3943;
303 	lp3943_pwm->chip.dev = &pdev->dev;
304 	lp3943_pwm->chip.ops = &lp3943_pwm_ops;
305 	lp3943_pwm->chip.npwm = LP3943_NUM_PWMS;
306 
307 	return devm_pwmchip_add(&pdev->dev, &lp3943_pwm->chip);
308 }
309 
310 #ifdef CONFIG_OF
311 static const struct of_device_id lp3943_pwm_of_match[] = {
312 	{ .compatible = "ti,lp3943-pwm", },
313 	{ }
314 };
315 MODULE_DEVICE_TABLE(of, lp3943_pwm_of_match);
316 #endif
317 
318 static struct platform_driver lp3943_pwm_driver = {
319 	.probe = lp3943_pwm_probe,
320 	.driver = {
321 		.name = "lp3943-pwm",
322 		.of_match_table = of_match_ptr(lp3943_pwm_of_match),
323 	},
324 };
325 module_platform_driver(lp3943_pwm_driver);
326 
327 MODULE_DESCRIPTION("LP3943 PWM driver");
328 MODULE_ALIAS("platform:lp3943-pwm");
329 MODULE_AUTHOR("Milo Kim");
330 MODULE_LICENSE("GPL");
331