GNU Linux-libre 4.9.328-gnu1
[releases.git] / drivers / pwm / pwm-crc.c
1 /*
2  * Copyright (C) 2015 Intel Corporation. All rights reserved.
3  *
4  * This program is free software; you can redistribute it and/or
5  * modify it under the terms of the GNU General Public License version
6  * 2 as published by the Free Software Foundation.
7  *
8  * This program is distributed in the hope that it will be useful,
9  * but WITHOUT ANY WARRANTY; without even the implied warranty of
10  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
11  * GNU General Public License for more details.
12  *
13  * Author: Shobhit Kumar <shobhit.kumar@intel.com>
14  */
15
16 #include <linux/platform_device.h>
17 #include <linux/regmap.h>
18 #include <linux/mfd/intel_soc_pmic.h>
19 #include <linux/pwm.h>
20
21 #define PWM0_CLK_DIV            0x4B
22 #define  PWM_OUTPUT_ENABLE      BIT(7)
23 #define  PWM_DIV_CLK_0          0x00 /* DIVIDECLK = BASECLK */
24 #define  PWM_DIV_CLK_100        0x63 /* DIVIDECLK = BASECLK/100 */
25 #define  PWM_DIV_CLK_128        0x7F /* DIVIDECLK = BASECLK/128 */
26
27 #define PWM0_DUTY_CYCLE         0x4E
28 #define BACKLIGHT_EN            0x51
29
30 #define PWM_MAX_LEVEL           0xFF
31
32 #define PWM_BASE_CLK            6000000  /* 6 MHz */
33 #define PWM_MAX_PERIOD_NS       21333    /* 46.875KHz */
34
35 /**
36  * struct crystalcove_pwm - Crystal Cove PWM controller
37  * @chip: the abstract pwm_chip structure.
38  * @regmap: the regmap from the parent device.
39  */
40 struct crystalcove_pwm {
41         struct pwm_chip chip;
42         struct regmap *regmap;
43 };
44
45 static inline struct crystalcove_pwm *to_crc_pwm(struct pwm_chip *pc)
46 {
47         return container_of(pc, struct crystalcove_pwm, chip);
48 }
49
50 static int crc_pwm_enable(struct pwm_chip *c, struct pwm_device *pwm)
51 {
52         struct crystalcove_pwm *crc_pwm = to_crc_pwm(c);
53
54         regmap_write(crc_pwm->regmap, BACKLIGHT_EN, 1);
55
56         return 0;
57 }
58
59 static void crc_pwm_disable(struct pwm_chip *c, struct pwm_device *pwm)
60 {
61         struct crystalcove_pwm *crc_pwm = to_crc_pwm(c);
62
63         regmap_write(crc_pwm->regmap, BACKLIGHT_EN, 0);
64 }
65
66 static int crc_pwm_config(struct pwm_chip *c, struct pwm_device *pwm,
67                           int duty_ns, int period_ns)
68 {
69         struct crystalcove_pwm *crc_pwm = to_crc_pwm(c);
70         struct device *dev = crc_pwm->chip.dev;
71         int level;
72
73         if (period_ns > PWM_MAX_PERIOD_NS) {
74                 dev_err(dev, "un-supported period_ns\n");
75                 return -EINVAL;
76         }
77
78         if (pwm_get_period(pwm) != period_ns) {
79                 int clk_div;
80
81                 /* changing the clk divisor, need to disable fisrt */
82                 crc_pwm_disable(c, pwm);
83                 clk_div = PWM_BASE_CLK * period_ns / NSEC_PER_SEC;
84
85                 regmap_write(crc_pwm->regmap, PWM0_CLK_DIV,
86                                         clk_div | PWM_OUTPUT_ENABLE);
87
88                 /* enable back */
89                 crc_pwm_enable(c, pwm);
90         }
91
92         /* change the pwm duty cycle */
93         level = duty_ns * PWM_MAX_LEVEL / period_ns;
94         regmap_write(crc_pwm->regmap, PWM0_DUTY_CYCLE, level);
95
96         return 0;
97 }
98
99 static const struct pwm_ops crc_pwm_ops = {
100         .config = crc_pwm_config,
101         .enable = crc_pwm_enable,
102         .disable = crc_pwm_disable,
103 };
104
105 static int crystalcove_pwm_probe(struct platform_device *pdev)
106 {
107         struct crystalcove_pwm *pwm;
108         struct device *dev = pdev->dev.parent;
109         struct intel_soc_pmic *pmic = dev_get_drvdata(dev);
110
111         pwm = devm_kzalloc(&pdev->dev, sizeof(*pwm), GFP_KERNEL);
112         if (!pwm)
113                 return -ENOMEM;
114
115         pwm->chip.dev = &pdev->dev;
116         pwm->chip.ops = &crc_pwm_ops;
117         pwm->chip.base = -1;
118         pwm->chip.npwm = 1;
119
120         /* get the PMIC regmap */
121         pwm->regmap = pmic->regmap;
122
123         platform_set_drvdata(pdev, pwm);
124
125         return pwmchip_add(&pwm->chip);
126 }
127
128 static int crystalcove_pwm_remove(struct platform_device *pdev)
129 {
130         struct crystalcove_pwm *pwm = platform_get_drvdata(pdev);
131
132         return pwmchip_remove(&pwm->chip);
133 }
134
135 static struct platform_driver crystalcove_pwm_driver = {
136         .probe = crystalcove_pwm_probe,
137         .remove = crystalcove_pwm_remove,
138         .driver = {
139                 .name = "crystal_cove_pwm",
140         },
141 };
142
143 builtin_platform_driver(crystalcove_pwm_driver);