summaryrefslogtreecommitdiffstats
path: root/drivers/pwm/pwm-mediatek.c
blob: 5c11bc708a3cafe148d5311320d3b6bb46a41667 (plain)
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
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
/*
 * Mediatek Pulse Width Modulator driver
 *
 * Copyright (C) 2015 John Crispin <blogic@openwrt.org>
 *
 * This file is licensed under the terms of the GNU General Public
 * License version 2. This program is licensed "as is" without any
 * warranty of any kind, whether express or implied.
 */

#include <linux/err.h>
#include <linux/io.h>
#include <linux/ioport.h>
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/clk.h>
#include <linux/of.h>
#include <linux/platform_device.h>
#include <linux/pwm.h>
#include <linux/slab.h>
#include <linux/types.h>

/* PWM registers and bits definitions */
#define PWMCON			0x00
#define PWMHDUR			0x04
#define PWMLDUR			0x08
#define PWMGDUR			0x0c
#define PWMWAVENUM		0x28
#define PWMDWIDTH		0x2c
#define PWMTHRES		0x30

enum {
	MTK_CLK_MAIN = 0,
	MTK_CLK_TOP,
	MTK_CLK_PWM1,
	MTK_CLK_PWM2,
	MTK_CLK_PWM3,
	MTK_CLK_PWM4,
	MTK_CLK_PWM5,
	MTK_CLK_MAX,
};

static const char * const mtk_pwm_clk_name[] = {
	"main", "top", "pwm1", "pwm2", "pwm3", "pwm4", "pwm5"
};

/**
 * struct mtk_pwm_chip - struct representing PWM chip
 * @chip: linux PWM chip representation
 * @regs: base address of PWM chip
 * @clks: list of clocks
 */
struct mtk_pwm_chip {
	struct pwm_chip chip;
	void __iomem *regs;
	struct clk *clks[MTK_CLK_MAX];
};

static inline struct mtk_pwm_chip *to_mtk_pwm_chip(struct pwm_chip *chip)
{
	return container_of(chip, struct mtk_pwm_chip, chip);
}

static inline u32 mtk_pwm_readl(struct mtk_pwm_chip *chip, unsigned int num,
				unsigned int offset)
{
	return readl(chip->regs + 0x10 + (num * 0x40) + offset);
}

static inline void mtk_pwm_writel(struct mtk_pwm_chip *chip,
				  unsigned int num, unsigned int offset,
				  u32 value)
{
	writel(value, chip->regs + 0x10 + (num * 0x40) + offset);
}

static int mtk_pwm_config(struct pwm_chip *chip, struct pwm_device *pwm,
			  int duty_ns, int period_ns)
{
	struct mtk_pwm_chip *pc = to_mtk_pwm_chip(chip);
	struct clk *clk = pc->clks[MTK_CLK_PWM1 + pwm->hwpwm];
	u32 resolution, clkdiv = 0;

	resolution = NSEC_PER_SEC / clk_get_rate(clk);

	while (period_ns / resolution > 8191) {
		resolution *= 2;
		clkdiv++;
	}

	if (clkdiv > 7)
		return -EINVAL;

	mtk_pwm_writel(pc, pwm->hwpwm, PWMCON, BIT(15) | BIT(3) | clkdiv);
	mtk_pwm_writel(pc, pwm->hwpwm, PWMDWIDTH, period_ns / resolution);
	mtk_pwm_writel(pc, pwm->hwpwm, PWMTHRES, duty_ns / resolution);

	return 0;
}

static int mtk_pwm_enable(struct pwm_chip *chip, struct pwm_device *pwm)
{
	struct mtk_pwm_chip *pc = to_mtk_pwm_chip(chip);
	u32 value;
	int ret;

	ret = clk_prepare(pc->clks[MTK_CLK_PWM1 + pwm->hwpwm]);
	if (ret < 0)
		return ret;

	value = readl(pc->regs);
	value |= BIT(pwm->hwpwm);
	writel(value, pc->regs);

	return 0;
}

static void mtk_pwm_disable(struct pwm_chip *chip, struct pwm_device *pwm)
{
	struct mtk_pwm_chip *pc = to_mtk_pwm_chip(chip);
	u32 value;

	value = readl(pc->regs);
	value &= ~BIT(pwm->hwpwm);
	writel(value, pc->regs);

	clk_unprepare(pc->clks[MTK_CLK_PWM1 + pwm->hwpwm]);
}

static const struct pwm_ops mtk_pwm_ops = {
	.config = mtk_pwm_config,
	.enable = mtk_pwm_enable,
	.disable = mtk_pwm_disable,
	.owner = THIS_MODULE,
};

static int mtk_pwm_probe(struct platform_device *pdev)
{
	struct mtk_pwm_chip *pc;
	struct resource *res;
	unsigned int i;
	int ret;

	pc = devm_kzalloc(&pdev->dev, sizeof(*pc), GFP_KERNEL);
	if (!pc)
		return -ENOMEM;

	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
	pc->regs = devm_ioremap_resource(&pdev->dev, res);
	if (IS_ERR(pc->regs))
		return PTR_ERR(pc->regs);

	for (i = 0; i < MTK_CLK_MAX; i++) {
		pc->clks[i] = devm_clk_get(&pdev->dev, mtk_pwm_clk_name[i]);
		if (IS_ERR(pc->clks[i]))
			return PTR_ERR(pc->clks[i]);
	}

	ret = clk_prepare(pc->clks[MTK_CLK_TOP]);
	if (ret < 0)
		return ret;

	ret = clk_prepare(pc->clks[MTK_CLK_MAIN]);
	if (ret < 0)
		goto disable_clk_top;

	platform_set_drvdata(pdev, pc);

	pc->chip.dev = &pdev->dev;
	pc->chip.ops = &mtk_pwm_ops;
	pc->chip.base = -1;
	pc->chip.npwm = 5;

	ret = pwmchip_add(&pc->chip);
	if (ret < 0) {
		dev_err(&pdev->dev, "pwmchip_add() failed: %d\n", ret);
		goto disable_clk_main;
	}

	return 0;

disable_clk_main:
	clk_unprepare(pc->clks[MTK_CLK_MAIN]);
disable_clk_top:
	clk_unprepare(pc->clks[MTK_CLK_TOP]);

	return ret;
}

static int mtk_pwm_remove(struct platform_device *pdev)
{
	struct mtk_pwm_chip *pc = platform_get_drvdata(pdev);
	unsigned int i;

	for (i = 0; i < pc->chip.npwm; i++)
		pwm_disable(&pc->chip.pwms[i]);

	return pwmchip_remove(&pc->chip);
}

static const struct of_device_id mtk_pwm_of_match[] = {
	{ .compatible = "mediatek,mt7623-pwm" },
	{ }
};
MODULE_DEVICE_TABLE(of, mtk_pwm_of_match);

static struct platform_driver mtk_pwm_driver = {
	.driver = {
		.name = "mtk-pwm",
		.of_match_table = mtk_pwm_of_match,
	},
	.probe = mtk_pwm_probe,
	.remove = mtk_pwm_remove,
};
module_platform_driver(mtk_pwm_driver);

MODULE_AUTHOR("John Crispin <blogic@openwrt.org>");
MODULE_ALIAS("platform:mtk-pwm");
MODULE_LICENSE("GPL");