1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
|
// SPDX-License-Identifier: GPL-2.0-only
/*
* Copyright (C) 2015 Intel Corporation. All rights reserved.
*
* Author: Shobhit Kumar <shobhit.kumar@intel.com>
*/
#include <linux/platform_device.h>
#include <linux/regmap.h>
#include <linux/mfd/intel_soc_pmic.h>
#include <linux/pwm.h>
#define PWM0_CLK_DIV 0x4B
#define PWM_OUTPUT_ENABLE BIT(7)
#define PWM_DIV_CLK_0 0x00 /* DIVIDECLK = BASECLK */
#define PWM_DIV_CLK_100 0x63 /* DIVIDECLK = BASECLK/100 */
#define PWM_DIV_CLK_128 0x7F /* DIVIDECLK = BASECLK/128 */
#define PWM0_DUTY_CYCLE 0x4E
#define BACKLIGHT_EN 0x51
#define PWM_MAX_LEVEL 0xFF
#define PWM_BASE_CLK_MHZ 6 /* 6 MHz */
#define PWM_MAX_PERIOD_NS 5461334 /* 183 Hz */
/**
* struct crystalcove_pwm - Crystal Cove PWM controller
* @chip: the abstract pwm_chip structure.
* @regmap: the regmap from the parent device.
*/
struct crystalcove_pwm {
struct pwm_chip chip;
struct regmap *regmap;
};
static inline struct crystalcove_pwm *to_crc_pwm(struct pwm_chip *pc)
{
return container_of(pc, struct crystalcove_pwm, chip);
}
static int crc_pwm_calc_clk_div(int period_ns)
{
int clk_div;
clk_div = PWM_BASE_CLK_MHZ * period_ns / (256 * NSEC_PER_USEC);
/* clk_div 1 - 128, maps to register values 0-127 */
if (clk_div > 0)
clk_div--;
return clk_div;
}
static int crc_pwm_apply(struct pwm_chip *chip, struct pwm_device *pwm,
const struct pwm_state *state)
{
struct crystalcove_pwm *crc_pwm = to_crc_pwm(chip);
struct device *dev = crc_pwm->chip.dev;
int err;
if (state->period > PWM_MAX_PERIOD_NS) {
dev_err(dev, "un-supported period_ns\n");
return -EINVAL;
}
if (state->polarity != PWM_POLARITY_NORMAL)
return -EOPNOTSUPP;
if (pwm_is_enabled(pwm) && !state->enabled) {
err = regmap_write(crc_pwm->regmap, BACKLIGHT_EN, 0);
if (err) {
dev_err(dev, "Error writing BACKLIGHT_EN %d\n", err);
return err;
}
}
if (pwm_get_duty_cycle(pwm) != state->duty_cycle ||
pwm_get_period(pwm) != state->period) {
u64 level = state->duty_cycle * PWM_MAX_LEVEL;
do_div(level, state->period);
err = regmap_write(crc_pwm->regmap, PWM0_DUTY_CYCLE, level);
if (err) {
dev_err(dev, "Error writing PWM0_DUTY_CYCLE %d\n", err);
return err;
}
}
if (pwm_is_enabled(pwm) && state->enabled &&
pwm_get_period(pwm) != state->period) {
/* changing the clk divisor, clear PWM_OUTPUT_ENABLE first */
err = regmap_write(crc_pwm->regmap, PWM0_CLK_DIV, 0);
if (err) {
dev_err(dev, "Error writing PWM0_CLK_DIV %d\n", err);
return err;
}
}
if (pwm_get_period(pwm) != state->period ||
pwm_is_enabled(pwm) != state->enabled) {
int clk_div = crc_pwm_calc_clk_div(state->period);
int pwm_output_enable = state->enabled ? PWM_OUTPUT_ENABLE : 0;
err = regmap_write(crc_pwm->regmap, PWM0_CLK_DIV,
clk_div | pwm_output_enable);
if (err) {
dev_err(dev, "Error writing PWM0_CLK_DIV %d\n", err);
return err;
}
}
if (!pwm_is_enabled(pwm) && state->enabled) {
err = regmap_write(crc_pwm->regmap, BACKLIGHT_EN, 1);
if (err) {
dev_err(dev, "Error writing BACKLIGHT_EN %d\n", err);
return err;
}
}
return 0;
}
static void crc_pwm_get_state(struct pwm_chip *chip, struct pwm_device *pwm,
struct pwm_state *state)
{
struct crystalcove_pwm *crc_pwm = to_crc_pwm(chip);
struct device *dev = crc_pwm->chip.dev;
unsigned int clk_div, clk_div_reg, duty_cycle_reg;
int error;
error = regmap_read(crc_pwm->regmap, PWM0_CLK_DIV, &clk_div_reg);
if (error) {
dev_err(dev, "Error reading PWM0_CLK_DIV %d\n", error);
return;
}
error = regmap_read(crc_pwm->regmap, PWM0_DUTY_CYCLE, &duty_cycle_reg);
if (error) {
dev_err(dev, "Error reading PWM0_DUTY_CYCLE %d\n", error);
return;
}
clk_div = (clk_div_reg & ~PWM_OUTPUT_ENABLE) + 1;
state->period =
DIV_ROUND_UP(clk_div * NSEC_PER_USEC * 256, PWM_BASE_CLK_MHZ);
state->duty_cycle =
DIV_ROUND_UP_ULL(duty_cycle_reg * state->period, PWM_MAX_LEVEL);
state->polarity = PWM_POLARITY_NORMAL;
state->enabled = !!(clk_div_reg & PWM_OUTPUT_ENABLE);
}
static const struct pwm_ops crc_pwm_ops = {
.apply = crc_pwm_apply,
.get_state = crc_pwm_get_state,
};
static int crystalcove_pwm_probe(struct platform_device *pdev)
{
struct crystalcove_pwm *pwm;
struct device *dev = pdev->dev.parent;
struct intel_soc_pmic *pmic = dev_get_drvdata(dev);
pwm = devm_kzalloc(&pdev->dev, sizeof(*pwm), GFP_KERNEL);
if (!pwm)
return -ENOMEM;
pwm->chip.dev = &pdev->dev;
pwm->chip.ops = &crc_pwm_ops;
pwm->chip.base = -1;
pwm->chip.npwm = 1;
/* get the PMIC regmap */
pwm->regmap = pmic->regmap;
platform_set_drvdata(pdev, pwm);
return pwmchip_add(&pwm->chip);
}
static int crystalcove_pwm_remove(struct platform_device *pdev)
{
struct crystalcove_pwm *pwm = platform_get_drvdata(pdev);
return pwmchip_remove(&pwm->chip);
}
static struct platform_driver crystalcove_pwm_driver = {
.probe = crystalcove_pwm_probe,
.remove = crystalcove_pwm_remove,
.driver = {
.name = "crystal_cove_pwm",
},
};
builtin_platform_driver(crystalcove_pwm_driver);
|
