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