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Alexandre Pereira da Silva2132fa82012-07-10 11:38:10 -03001/*
2 * Copyright 2012 Alexandre Pereira da Silva <aletes.xgr@gmail.com>
3 *
4 * This program is free software; you can redistribute it and/or modify
5 * it under the terms of the GNU General Public License as published by
6 * the Free Software Foundation; version 2.
7 *
8 */
9
10#include <linux/clk.h>
11#include <linux/err.h>
12#include <linux/io.h>
13#include <linux/kernel.h>
14#include <linux/module.h>
15#include <linux/of.h>
16#include <linux/of_address.h>
17#include <linux/platform_device.h>
18#include <linux/pwm.h>
19#include <linux/slab.h>
20
21struct lpc32xx_pwm_chip {
22 struct pwm_chip chip;
23 struct clk *clk;
24 void __iomem *base;
25};
26
27#define PWM_ENABLE (1 << 31)
28#define PWM_RELOADV(x) (((x) & 0xFF) << 8)
29#define PWM_DUTY(x) ((x) & 0xFF)
30
31#define to_lpc32xx_pwm_chip(_chip) \
32 container_of(_chip, struct lpc32xx_pwm_chip, chip)
33
34static int lpc32xx_pwm_config(struct pwm_chip *chip, struct pwm_device *pwm,
35 int duty_ns, int period_ns)
36{
37 struct lpc32xx_pwm_chip *lpc32xx = to_lpc32xx_pwm_chip(chip);
38 unsigned long long c;
39 int period_cycles, duty_cycles;
40
41 c = clk_get_rate(lpc32xx->clk) / 256;
42 c = c * period_ns;
43 do_div(c, NSEC_PER_SEC);
44
45 /* Handle high and low extremes */
46 if (c == 0)
47 c = 1;
48 if (c > 255)
49 c = 0; /* 0 set division by 256 */
50 period_cycles = c;
51
Alban Bedela9a18e02012-11-14 12:58:13 +010052 /* The duty-cycle value is as follows:
53 *
54 * DUTY-CYCLE HIGH LEVEL
55 * 1 99.9%
56 * 25 90.0%
57 * 128 50.0%
58 * 220 10.0%
59 * 255 0.1%
60 * 0 0.0%
61 *
62 * In other words, the register value is duty-cycle % 256 with
63 * duty-cycle in the range 1-256.
64 */
Alexandre Pereira da Silva2132fa82012-07-10 11:38:10 -030065 c = 256 * duty_ns;
66 do_div(c, period_ns);
Alban Bedela9a18e02012-11-14 12:58:13 +010067 if (c > 255)
68 c = 255;
69 duty_cycles = 256 - c;
Alexandre Pereira da Silva2132fa82012-07-10 11:38:10 -030070
71 writel(PWM_ENABLE | PWM_RELOADV(period_cycles) | PWM_DUTY(duty_cycles),
72 lpc32xx->base + (pwm->hwpwm << 2));
73
74 return 0;
75}
76
77static int lpc32xx_pwm_enable(struct pwm_chip *chip, struct pwm_device *pwm)
78{
79 struct lpc32xx_pwm_chip *lpc32xx = to_lpc32xx_pwm_chip(chip);
80
81 return clk_enable(lpc32xx->clk);
82}
83
84static void lpc32xx_pwm_disable(struct pwm_chip *chip, struct pwm_device *pwm)
85{
86 struct lpc32xx_pwm_chip *lpc32xx = to_lpc32xx_pwm_chip(chip);
87
88 writel(0, lpc32xx->base + (pwm->hwpwm << 2));
89 clk_disable(lpc32xx->clk);
90}
91
92static const struct pwm_ops lpc32xx_pwm_ops = {
93 .config = lpc32xx_pwm_config,
94 .enable = lpc32xx_pwm_enable,
95 .disable = lpc32xx_pwm_disable,
96 .owner = THIS_MODULE,
97};
98
99static int lpc32xx_pwm_probe(struct platform_device *pdev)
100{
101 struct lpc32xx_pwm_chip *lpc32xx;
102 struct resource *res;
103 int ret;
104
105 lpc32xx = devm_kzalloc(&pdev->dev, sizeof(*lpc32xx), GFP_KERNEL);
106 if (!lpc32xx)
107 return -ENOMEM;
108
109 res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
110 if (!res)
111 return -EINVAL;
112
Thierry Reding6d4294d2013-01-21 11:09:16 +0100113 lpc32xx->base = devm_ioremap_resource(&pdev->dev, res);
114 if (IS_ERR(lpc32xx->base))
115 return PTR_ERR(lpc32xx->base);
Alexandre Pereira da Silva2132fa82012-07-10 11:38:10 -0300116
117 lpc32xx->clk = devm_clk_get(&pdev->dev, NULL);
118 if (IS_ERR(lpc32xx->clk))
119 return PTR_ERR(lpc32xx->clk);
120
121 lpc32xx->chip.dev = &pdev->dev;
122 lpc32xx->chip.ops = &lpc32xx_pwm_ops;
123 lpc32xx->chip.npwm = 2;
Alban Bedel8fc6d092012-11-14 12:58:15 +0100124 lpc32xx->chip.base = -1;
Alexandre Pereira da Silva2132fa82012-07-10 11:38:10 -0300125
126 ret = pwmchip_add(&lpc32xx->chip);
127 if (ret < 0) {
128 dev_err(&pdev->dev, "failed to add PWM chip, error %d\n", ret);
129 return ret;
130 }
131
132 platform_set_drvdata(pdev, lpc32xx);
133
134 return 0;
135}
136
Bill Pemberton77f37912012-11-19 13:26:09 -0500137static int lpc32xx_pwm_remove(struct platform_device *pdev)
Alexandre Pereira da Silva2132fa82012-07-10 11:38:10 -0300138{
139 struct lpc32xx_pwm_chip *lpc32xx = platform_get_drvdata(pdev);
Alban Bedel54b2a992012-11-14 12:58:14 +0100140 unsigned int i;
Alexandre Pereira da Silva2132fa82012-07-10 11:38:10 -0300141
Alban Bedel54b2a992012-11-14 12:58:14 +0100142 for (i = 0; i < lpc32xx->chip.npwm; i++)
143 pwm_disable(&lpc32xx->chip.pwms[i]);
144
Alexandre Pereira da Silva2132fa82012-07-10 11:38:10 -0300145 return pwmchip_remove(&lpc32xx->chip);
146}
147
148static struct of_device_id lpc32xx_pwm_dt_ids[] = {
149 { .compatible = "nxp,lpc3220-pwm", },
150 { /* sentinel */ }
151};
152MODULE_DEVICE_TABLE(of, lpc32xx_pwm_dt_ids);
153
154static struct platform_driver lpc32xx_pwm_driver = {
155 .driver = {
156 .name = "lpc32xx-pwm",
157 .of_match_table = of_match_ptr(lpc32xx_pwm_dt_ids),
158 },
159 .probe = lpc32xx_pwm_probe,
Bill Pembertonfd109112012-11-19 13:21:28 -0500160 .remove = lpc32xx_pwm_remove,
Alexandre Pereira da Silva2132fa82012-07-10 11:38:10 -0300161};
162module_platform_driver(lpc32xx_pwm_driver);
163
164MODULE_ALIAS("platform:lpc32xx-pwm");
165MODULE_AUTHOR("Alexandre Pereira da Silva <aletes.xgr@gmail.com>");
166MODULE_DESCRIPTION("LPC32XX PWM Driver");
167MODULE_LICENSE("GPL v2");