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
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			     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
139static 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
159static 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
178static 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
191static 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
215static 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
222static 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
281static 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
311static const struct of_device_id lp3943_pwm_of_match[] = {
312	{ .compatible = "ti,lp3943-pwm", },
313	{ }
314};
315MODULE_DEVICE_TABLE(of, lp3943_pwm_of_match);
316#endif
317
318static 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};
325module_platform_driver(lp3943_pwm_driver);
326
327MODULE_DESCRIPTION("LP3943 PWM driver");
328MODULE_ALIAS("platform:lp3943-pwm");
329MODULE_AUTHOR("Milo Kim");
330MODULE_LICENSE("GPL");
331