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
|
// SPDX-License-Identifier: GPL-2.0
/*
* DesignWare PWM Controller driver core
*
* Copyright (C) 2018-2020 Intel Corporation
*
* Author: Felipe Balbi (Intel)
* Author: Jarkko Nikula <jarkko.nikula@linux.intel.com>
* Author: Raymond Tan <raymond.tan@intel.com>
*/
#define DEFAULT_SYMBOL_NAMESPACE "dwc_pwm"
#include <linux/bitops.h>
#include <linux/export.h>
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/pci.h>
#include <linux/pm_runtime.h>
#include <linux/pwm.h>
#include "pwm-dwc.h"
static void __dwc_pwm_set_enable(struct dwc_pwm *dwc, int pwm, int enabled)
{
u32 reg;
reg = dwc_pwm_readl(dwc, DWC_TIM_CTRL(pwm));
if (enabled)
reg |= DWC_TIM_CTRL_EN;
else
reg &= ~DWC_TIM_CTRL_EN;
dwc_pwm_writel(dwc, reg, DWC_TIM_CTRL(pwm));
}
static int __dwc_pwm_configure_timer(struct dwc_pwm *dwc,
struct pwm_device *pwm,
const struct pwm_state *state)
{
u64 tmp;
u32 ctrl;
u32 high;
u32 low;
/*
* Calculate width of low and high period in terms of input clock
* periods and check are the result within HW limits between 1 and
* 2^32 periods.
*/
tmp = DIV_ROUND_CLOSEST_ULL(state->duty_cycle, dwc->clk_ns);
if (tmp < 1 || tmp > (1ULL << 32))
return -ERANGE;
low = tmp - 1;
tmp = DIV_ROUND_CLOSEST_ULL(state->period - state->duty_cycle,
dwc->clk_ns);
if (tmp < 1 || tmp > (1ULL << 32))
return -ERANGE;
high = tmp - 1;
/*
* Specification says timer usage flow is to disable timer, then
* program it followed by enable. It also says Load Count is loaded
* into timer after it is enabled - either after a disable or
* a reset. Based on measurements it happens also without disable
* whenever Load Count is updated. But follow the specification.
*/
__dwc_pwm_set_enable(dwc, pwm->hwpwm, false);
/*
* Write Load Count and Load Count 2 registers. Former defines the
* width of low period and latter the width of high period in terms
* multiple of input clock periods:
* Width = ((Count + 1) * input clock period).
*/
dwc_pwm_writel(dwc, low, DWC_TIM_LD_CNT(pwm->hwpwm));
dwc_pwm_writel(dwc, high, DWC_TIM_LD_CNT2(pwm->hwpwm));
/*
* Set user-defined mode, timer reloads from Load Count registers
* when it counts down to 0.
* Set PWM mode, it makes output to toggle and width of low and high
* periods are set by Load Count registers.
*/
ctrl = DWC_TIM_CTRL_MODE_USER | DWC_TIM_CTRL_PWM;
dwc_pwm_writel(dwc, ctrl, DWC_TIM_CTRL(pwm->hwpwm));
/*
* Enable timer. Output starts from low period.
*/
__dwc_pwm_set_enable(dwc, pwm->hwpwm, state->enabled);
return 0;
}
static int dwc_pwm_apply(struct pwm_chip *chip, struct pwm_device *pwm,
const struct pwm_state *state)
{
struct dwc_pwm *dwc = to_dwc_pwm(chip);
if (state->polarity != PWM_POLARITY_INVERSED)
return -EINVAL;
if (state->enabled) {
if (!pwm->state.enabled)
pm_runtime_get_sync(pwmchip_parent(chip));
return __dwc_pwm_configure_timer(dwc, pwm, state);
} else {
if (pwm->state.enabled) {
__dwc_pwm_set_enable(dwc, pwm->hwpwm, false);
pm_runtime_put_sync(pwmchip_parent(chip));
}
}
return 0;
}
static int dwc_pwm_get_state(struct pwm_chip *chip, struct pwm_device *pwm,
struct pwm_state *state)
{
struct dwc_pwm *dwc = to_dwc_pwm(chip);
u64 duty, period;
u32 ctrl, ld, ld2;
pm_runtime_get_sync(pwmchip_parent(chip));
ctrl = dwc_pwm_readl(dwc, DWC_TIM_CTRL(pwm->hwpwm));
ld = dwc_pwm_readl(dwc, DWC_TIM_LD_CNT(pwm->hwpwm));
ld2 = dwc_pwm_readl(dwc, DWC_TIM_LD_CNT2(pwm->hwpwm));
state->enabled = !!(ctrl & DWC_TIM_CTRL_EN);
/*
* If we're not in PWM, technically the output is a 50-50
* based on the timer load-count only.
*/
if (ctrl & DWC_TIM_CTRL_PWM) {
duty = (ld + 1) * dwc->clk_ns;
period = (ld2 + 1) * dwc->clk_ns;
period += duty;
} else {
duty = (ld + 1) * dwc->clk_ns;
period = duty * 2;
}
state->polarity = PWM_POLARITY_INVERSED;
state->period = period;
state->duty_cycle = duty;
pm_runtime_put_sync(pwmchip_parent(chip));
return 0;
}
static const struct pwm_ops dwc_pwm_ops = {
.apply = dwc_pwm_apply,
.get_state = dwc_pwm_get_state,
};
struct pwm_chip *dwc_pwm_alloc(struct device *dev)
{
struct pwm_chip *chip;
struct dwc_pwm *dwc;
chip = devm_pwmchip_alloc(dev, DWC_TIMERS_TOTAL, sizeof(*dwc));
if (IS_ERR(chip))
return chip;
dwc = to_dwc_pwm(chip);
dwc->clk_ns = 10;
chip->ops = &dwc_pwm_ops;
return chip;
}
EXPORT_SYMBOL_GPL(dwc_pwm_alloc);
MODULE_AUTHOR("Felipe Balbi (Intel)");
MODULE_AUTHOR("Jarkko Nikula <jarkko.nikula@linux.intel.com>");
MODULE_AUTHOR("Raymond Tan <raymond.tan@intel.com>");
MODULE_DESCRIPTION("DesignWare PWM Controller");
MODULE_LICENSE("GPL");
|
