tjh.dev
Linux kernel mirror (for testing)
git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
kernel
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linux
1// SPDX-License-Identifier: GPL-2.0-only
2/*
3 * Copyright (C) 2015 Intel Corporation. All rights reserved.
4 *
5 * Author: Shobhit Kumar <shobhit.kumar@intel.com>
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 6000000 /* 6 MHz */
25#define PWM_MAX_PERIOD_NS 21333 /* 46.875KHz */
26
27/**
28 * struct crystalcove_pwm - Crystal Cove PWM controller
29 * @chip: the abstract pwm_chip structure.
30 * @regmap: the regmap from the parent device.
31 */
32struct crystalcove_pwm {
33 struct pwm_chip chip;
34 struct regmap *regmap;
35};
36
37static inline struct crystalcove_pwm *to_crc_pwm(struct pwm_chip *pc)
38{
39 return container_of(pc, struct crystalcove_pwm, chip);
40}
41
42static int crc_pwm_enable(struct pwm_chip *c, struct pwm_device *pwm)
43{
44 struct crystalcove_pwm *crc_pwm = to_crc_pwm(c);
45
46 regmap_write(crc_pwm->regmap, BACKLIGHT_EN, 1);
47
48 return 0;
49}
50
51static void crc_pwm_disable(struct pwm_chip *c, struct pwm_device *pwm)
52{
53 struct crystalcove_pwm *crc_pwm = to_crc_pwm(c);
54
55 regmap_write(crc_pwm->regmap, BACKLIGHT_EN, 0);
56}
57
58static int crc_pwm_config(struct pwm_chip *c, struct pwm_device *pwm,
59 int duty_ns, int period_ns)
60{
61 struct crystalcove_pwm *crc_pwm = to_crc_pwm(c);
62 struct device *dev = crc_pwm->chip.dev;
63 int level;
64
65 if (period_ns > PWM_MAX_PERIOD_NS) {
66 dev_err(dev, "un-supported period_ns\n");
67 return -EINVAL;
68 }
69
70 if (pwm_get_period(pwm) != period_ns) {
71 int clk_div;
72
73 /* changing the clk divisor, need to disable fisrt */
74 crc_pwm_disable(c, pwm);
75 clk_div = PWM_BASE_CLK * period_ns / NSEC_PER_SEC;
76
77 regmap_write(crc_pwm->regmap, PWM0_CLK_DIV,
78 clk_div | PWM_OUTPUT_ENABLE);
79
80 /* enable back */
81 crc_pwm_enable(c, pwm);
82 }
83
84 /* change the pwm duty cycle */
85 level = duty_ns * PWM_MAX_LEVEL / period_ns;
86 regmap_write(crc_pwm->regmap, PWM0_DUTY_CYCLE, level);
87
88 return 0;
89}
90
91static const struct pwm_ops crc_pwm_ops = {
92 .config = crc_pwm_config,
93 .enable = crc_pwm_enable,
94 .disable = crc_pwm_disable,
95};
96
97static int crystalcove_pwm_probe(struct platform_device *pdev)
98{
99 struct crystalcove_pwm *pwm;
100 struct device *dev = pdev->dev.parent;
101 struct intel_soc_pmic *pmic = dev_get_drvdata(dev);
102
103 pwm = devm_kzalloc(&pdev->dev, sizeof(*pwm), GFP_KERNEL);
104 if (!pwm)
105 return -ENOMEM;
106
107 pwm->chip.dev = &pdev->dev;
108 pwm->chip.ops = &crc_pwm_ops;
109 pwm->chip.base = -1;
110 pwm->chip.npwm = 1;
111
112 /* get the PMIC regmap */
113 pwm->regmap = pmic->regmap;
114
115 platform_set_drvdata(pdev, pwm);
116
117 return pwmchip_add(&pwm->chip);
118}
119
120static int crystalcove_pwm_remove(struct platform_device *pdev)
121{
122 struct crystalcove_pwm *pwm = platform_get_drvdata(pdev);
123
124 return pwmchip_remove(&pwm->chip);
125}
126
127static struct platform_driver crystalcove_pwm_driver = {
128 .probe = crystalcove_pwm_probe,
129 .remove = crystalcove_pwm_remove,
130 .driver = {
131 .name = "crystal_cove_pwm",
132 },
133};
134
135builtin_platform_driver(crystalcove_pwm_driver);