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189 lines · 4.8 KiB

1// SPDX-License-Identifier: GPL-2.0-only
2/*
3 * Copyright (C) 2015 Intel Corporation. All rights reserved.
4 *
5 * Author: Shobhit Kumar <[email protected]>
6 */
7
8#include <linux/platform_device.h>
9#include <linux/regmap.h>
10#include <linux/mfd/intel_soc_pmic.h>
11#include <linux/pwm.h>
12
13#define PWM0_CLK_DIV 0x4B
14#define PWM_OUTPUT_ENABLE BIT(7)
15#define PWM_DIV_CLK_0 0x00 /* DIVIDECLK = BASECLK */
16#define PWM_DIV_CLK_100 0x63 /* DIVIDECLK = BASECLK/100 */
17#define PWM_DIV_CLK_128 0x7F /* DIVIDECLK = BASECLK/128 */
18
19#define PWM0_DUTY_CYCLE 0x4E
20#define BACKLIGHT_EN 0x51
21
22#define PWM_MAX_LEVEL 0xFF
23
24#define PWM_BASE_CLK_MHZ 6 /* 6 MHz */
25#define PWM_MAX_PERIOD_NS 5461334 /* 183 Hz */
26
27/**
28 * struct crystalcove_pwm - Crystal Cove PWM controller
29 * @regmap: the regmap from the parent device.
30 */
31struct crystalcove_pwm {
32 struct regmap *regmap;
33};
34
35static inline struct crystalcove_pwm *to_crc_pwm(struct pwm_chip *chip)
36{
37 return pwmchip_get_drvdata(chip);
38}
39
40static int crc_pwm_calc_clk_div(int period_ns)
41{
42 int clk_div;
43
44 clk_div = PWM_BASE_CLK_MHZ * period_ns / (256 * NSEC_PER_USEC);
45 /* clk_div 1 - 128, maps to register values 0-127 */
46 if (clk_div > 0)
47 clk_div--;
48
49 return clk_div;
50}
51
52static int crc_pwm_apply(struct pwm_chip *chip, struct pwm_device *pwm,
53 const struct pwm_state *state)
54{
55 struct crystalcove_pwm *crc_pwm = to_crc_pwm(chip);
56 struct device *dev = pwmchip_parent(chip);
57 int err;
58
59 if (state->period > PWM_MAX_PERIOD_NS) {
60 dev_err(dev, "un-supported period_ns\n");
61 return -EINVAL;
62 }
63
64 if (state->polarity != PWM_POLARITY_NORMAL)
65 return -EINVAL;
66
67 if (pwm_is_enabled(pwm) && !state->enabled) {
68 err = regmap_write(crc_pwm->regmap, BACKLIGHT_EN, 0);
69 if (err) {
70 dev_err(dev, "Error writing BACKLIGHT_EN %d\n", err);
71 return err;
72 }
73 }
74
75 if (pwm_get_duty_cycle(pwm) != state->duty_cycle ||
76 pwm_get_period(pwm) != state->period) {
77 u64 level = state->duty_cycle * PWM_MAX_LEVEL;
78
79 do_div(level, state->period);
80
81 err = regmap_write(crc_pwm->regmap, PWM0_DUTY_CYCLE, level);
82 if (err) {
83 dev_err(dev, "Error writing PWM0_DUTY_CYCLE %d\n", err);
84 return err;
85 }
86 }
87
88 if (pwm_is_enabled(pwm) && state->enabled &&
89 pwm_get_period(pwm) != state->period) {
90 /* changing the clk divisor, clear PWM_OUTPUT_ENABLE first */
91 err = regmap_write(crc_pwm->regmap, PWM0_CLK_DIV, 0);
92 if (err) {
93 dev_err(dev, "Error writing PWM0_CLK_DIV %d\n", err);
94 return err;
95 }
96 }
97
98 if (pwm_get_period(pwm) != state->period ||
99 pwm_is_enabled(pwm) != state->enabled) {
100 int clk_div = crc_pwm_calc_clk_div(state->period);
101 int pwm_output_enable = state->enabled ? PWM_OUTPUT_ENABLE : 0;
102
103 err = regmap_write(crc_pwm->regmap, PWM0_CLK_DIV,
104 clk_div | pwm_output_enable);
105 if (err) {
106 dev_err(dev, "Error writing PWM0_CLK_DIV %d\n", err);
107 return err;
108 }
109 }
110
111 if (!pwm_is_enabled(pwm) && state->enabled) {
112 err = regmap_write(crc_pwm->regmap, BACKLIGHT_EN, 1);
113 if (err) {
114 dev_err(dev, "Error writing BACKLIGHT_EN %d\n", err);
115 return err;
116 }
117 }
118
119 return 0;
120}
121
122static int crc_pwm_get_state(struct pwm_chip *chip, struct pwm_device *pwm,
123 struct pwm_state *state)
124{
125 struct crystalcove_pwm *crc_pwm = to_crc_pwm(chip);
126 struct device *dev = pwmchip_parent(chip);
127 unsigned int clk_div, clk_div_reg, duty_cycle_reg;
128 int error;
129
130 error = regmap_read(crc_pwm->regmap, PWM0_CLK_DIV, &clk_div_reg);
131 if (error) {
132 dev_err(dev, "Error reading PWM0_CLK_DIV %d\n", error);
133 return error;
134 }
135
136 error = regmap_read(crc_pwm->regmap, PWM0_DUTY_CYCLE, &duty_cycle_reg);
137 if (error) {
138 dev_err(dev, "Error reading PWM0_DUTY_CYCLE %d\n", error);
139 return error;
140 }
141
142 clk_div = (clk_div_reg & ~PWM_OUTPUT_ENABLE) + 1;
143
144 state->period =
145 DIV_ROUND_UP(clk_div * NSEC_PER_USEC * 256, PWM_BASE_CLK_MHZ);
146 state->duty_cycle =
147 DIV_ROUND_UP_ULL(duty_cycle_reg * state->period, PWM_MAX_LEVEL);
148 state->polarity = PWM_POLARITY_NORMAL;
149 state->enabled = !!(clk_div_reg & PWM_OUTPUT_ENABLE);
150
151 return 0;
152}
153
154static const struct pwm_ops crc_pwm_ops = {
155 .apply = crc_pwm_apply,
156 .get_state = crc_pwm_get_state,
157};
158
159static int crystalcove_pwm_probe(struct platform_device *pdev)
160{
161 struct pwm_chip *chip;
162 struct crystalcove_pwm *crc_pwm;
163 struct device *dev = pdev->dev.parent;
164 struct intel_soc_pmic *pmic = dev_get_drvdata(dev);
165
166 chip = devm_pwmchip_alloc(&pdev->dev, 1, sizeof(*crc_pwm));
167 if (IS_ERR(chip))
168 return PTR_ERR(chip);
169 crc_pwm = to_crc_pwm(chip);
170
171 chip->ops = &crc_pwm_ops;
172
173 /* get the PMIC regmap */
174 crc_pwm->regmap = pmic->regmap;
175
176 return devm_pwmchip_add(&pdev->dev, chip);
177}
178
179static struct platform_driver crystalcove_pwm_driver = {
180 .probe = crystalcove_pwm_probe,
181 .driver = {
182 .name = "crystal_cove_pwm",
183 },
184};
185module_platform_driver(crystalcove_pwm_driver);
186
187MODULE_ALIAS("platform:crystal_cove_pwm");
188MODULE_DESCRIPTION("Intel Crystalcove (CRC) PWM support");
189MODULE_LICENSE("GPL");