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/i2c.h>
12#include <linux/mfd/lp3943.h>
13#include <linux/module.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
22struct lp3943_pwm {
23	struct pwm_chip chip;
24	struct lp3943 *lp3943;
25	struct lp3943_platform_data *pdata;
26};
27
28static inline struct lp3943_pwm *to_lp3943_pwm(struct pwm_chip *_chip)
29{
30	return container_of(_chip, struct lp3943_pwm, chip);
31}
32
33static struct lp3943_pwm_map *
34lp3943_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
61static 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
73static 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
87static 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
95static int lp3943_pwm_config(struct pwm_chip *chip, struct pwm_device *pwm,
96			     int duty_ns, int 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	period_ns = clamp(period_ns, LP3943_MIN_PERIOD, LP3943_MAX_PERIOD);
122	val       = (u8)(period_ns / LP3943_MIN_PERIOD - 1);
123
124	err = lp3943_write_byte(lp3943, reg_prescale, val);
125	if (err)
126		return err;
127
128	duty_ns = min(duty_ns, period_ns);
129	val = (u8)(duty_ns * LP3943_MAX_DUTY / period_ns);
130
131	return lp3943_write_byte(lp3943, reg_duty, val);
132}
133
134static int lp3943_pwm_set_mode(struct lp3943_pwm *lp3943_pwm,
135			       struct lp3943_pwm_map *pwm_map,
136			       u8 val)
137{
138	struct lp3943 *lp3943 = lp3943_pwm->lp3943;
139	const struct lp3943_reg_cfg *mux = lp3943->mux_cfg;
140	int i, index, err;
141
142	for (i = 0; i < pwm_map->num_outputs; i++) {
143		index = pwm_map->output[i];
144		err = lp3943_update_bits(lp3943, mux[index].reg,
145					 mux[index].mask,
146					 val << mux[index].shift);
147		if (err)
148			return err;
149	}
150
151	return 0;
152}
153
154static int lp3943_pwm_enable(struct pwm_chip *chip, struct pwm_device *pwm)
155{
156	struct lp3943_pwm *lp3943_pwm = to_lp3943_pwm(chip);
157	struct lp3943_pwm_map *pwm_map = pwm_get_chip_data(pwm);
158	u8 val;
159
160	if (pwm->hwpwm == 0)
161		val = LP3943_DIM_PWM0;
162	else
163		val = LP3943_DIM_PWM1;
164
165	/*
166	 * Each PWM generator is set to control any of outputs of LP3943.
167	 * To enable/disable the PWM, these output pins should be configured.
168	 */
169
170	return lp3943_pwm_set_mode(lp3943_pwm, pwm_map, val);
171}
172
173static void lp3943_pwm_disable(struct pwm_chip *chip, struct pwm_device *pwm)
174{
175	struct lp3943_pwm *lp3943_pwm = to_lp3943_pwm(chip);
176	struct lp3943_pwm_map *pwm_map = pwm_get_chip_data(pwm);
177
178	/*
179	 * LP3943 outputs are open-drain, so the pin should be configured
180	 * when the PWM is disabled.
181	 */
182
183	lp3943_pwm_set_mode(lp3943_pwm, pwm_map, LP3943_GPIO_OUT_HIGH);
184}
185
186static const struct pwm_ops lp3943_pwm_ops = {
187	.request	= lp3943_pwm_request,
188	.free		= lp3943_pwm_free,
189	.config		= lp3943_pwm_config,
190	.enable		= lp3943_pwm_enable,
191	.disable	= lp3943_pwm_disable,
192	.owner		= THIS_MODULE,
193};
194
195static int lp3943_pwm_parse_dt(struct device *dev,
196			       struct lp3943_pwm *lp3943_pwm)
197{
198	static const char * const name[] = { "ti,pwm0", "ti,pwm1", };
199	struct device_node *node = dev->of_node;
200	struct lp3943_platform_data *pdata;
201	struct lp3943_pwm_map *pwm_map;
202	enum lp3943_pwm_output *output;
203	int i, err, proplen, count = 0;
204	u32 num_outputs;
205
206	if (!node)
207		return -EINVAL;
208
209	pdata = devm_kzalloc(dev, sizeof(*pdata), GFP_KERNEL);
210	if (!pdata)
211		return -ENOMEM;
212
213	/*
214	 * Read the output map configuration from the device tree.
215	 * Each of the two PWM generators can drive zero or more outputs.
216	 */
217
218	for (i = 0; i < LP3943_NUM_PWMS; i++) {
219		if (!of_get_property(node, name[i], &proplen))
220			continue;
221
222		num_outputs = proplen / sizeof(u32);
223		if (num_outputs == 0)
224			continue;
225
226		output = devm_kcalloc(dev, num_outputs, sizeof(*output),
227				      GFP_KERNEL);
228		if (!output)
229			return -ENOMEM;
230
231		err = of_property_read_u32_array(node, name[i], output,
232						 num_outputs);
233		if (err)
234			return err;
235
236		pwm_map = devm_kzalloc(dev, sizeof(*pwm_map), GFP_KERNEL);
237		if (!pwm_map)
238			return -ENOMEM;
239
240		pwm_map->output = output;
241		pwm_map->num_outputs = num_outputs;
242		pdata->pwms[i] = pwm_map;
243
244		count++;
245	}
246
247	if (count == 0)
248		return -ENODATA;
249
250	lp3943_pwm->pdata = pdata;
251	return 0;
252}
253
254static int lp3943_pwm_probe(struct platform_device *pdev)
255{
256	struct lp3943 *lp3943 = dev_get_drvdata(pdev->dev.parent);
257	struct lp3943_pwm *lp3943_pwm;
258	int ret;
259
260	lp3943_pwm = devm_kzalloc(&pdev->dev, sizeof(*lp3943_pwm), GFP_KERNEL);
261	if (!lp3943_pwm)
262		return -ENOMEM;
263
264	lp3943_pwm->pdata = lp3943->pdata;
265	if (!lp3943_pwm->pdata) {
266		if (IS_ENABLED(CONFIG_OF))
267			ret = lp3943_pwm_parse_dt(&pdev->dev, lp3943_pwm);
268		else
269			ret = -ENODEV;
270
271		if (ret)
272			return ret;
273	}
274
275	lp3943_pwm->lp3943 = lp3943;
276	lp3943_pwm->chip.dev = &pdev->dev;
277	lp3943_pwm->chip.ops = &lp3943_pwm_ops;
278	lp3943_pwm->chip.npwm = LP3943_NUM_PWMS;
279	lp3943_pwm->chip.base = -1;
280
281	platform_set_drvdata(pdev, lp3943_pwm);
282
283	return pwmchip_add(&lp3943_pwm->chip);
284}
285
286static int lp3943_pwm_remove(struct platform_device *pdev)
287{
288	struct lp3943_pwm *lp3943_pwm = platform_get_drvdata(pdev);
289
290	return pwmchip_remove(&lp3943_pwm->chip);
291}
292
293#ifdef CONFIG_OF
294static const struct of_device_id lp3943_pwm_of_match[] = {
295	{ .compatible = "ti,lp3943-pwm", },
296	{ }
297};
298MODULE_DEVICE_TABLE(of, lp3943_pwm_of_match);
299#endif
300
301static struct platform_driver lp3943_pwm_driver = {
302	.probe = lp3943_pwm_probe,
303	.remove = lp3943_pwm_remove,
304	.driver = {
305		.name = "lp3943-pwm",
306		.of_match_table = of_match_ptr(lp3943_pwm_of_match),
307	},
308};
309module_platform_driver(lp3943_pwm_driver);
310
311MODULE_DESCRIPTION("LP3943 PWM driver");
312MODULE_ALIAS("platform:lp3943-pwm");
313MODULE_AUTHOR("Milo Kim");
314MODULE_LICENSE("GPL");
315