blob: 015a82235620e648e3b5f49f974ea9f2f7c01ad7 [file] [log] [blame]
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
52 c = 256 * duty_ns;
53 do_div(c, period_ns);
54 duty_cycles = c;
55
56 writel(PWM_ENABLE | PWM_RELOADV(period_cycles) | PWM_DUTY(duty_cycles),
57 lpc32xx->base + (pwm->hwpwm << 2));
58
59 return 0;
60}
61
62static int lpc32xx_pwm_enable(struct pwm_chip *chip, struct pwm_device *pwm)
63{
64 struct lpc32xx_pwm_chip *lpc32xx = to_lpc32xx_pwm_chip(chip);
65
66 return clk_enable(lpc32xx->clk);
67}
68
69static void lpc32xx_pwm_disable(struct pwm_chip *chip, struct pwm_device *pwm)
70{
71 struct lpc32xx_pwm_chip *lpc32xx = to_lpc32xx_pwm_chip(chip);
72
73 writel(0, lpc32xx->base + (pwm->hwpwm << 2));
74 clk_disable(lpc32xx->clk);
75}
76
77static const struct pwm_ops lpc32xx_pwm_ops = {
78 .config = lpc32xx_pwm_config,
79 .enable = lpc32xx_pwm_enable,
80 .disable = lpc32xx_pwm_disable,
81 .owner = THIS_MODULE,
82};
83
84static int lpc32xx_pwm_probe(struct platform_device *pdev)
85{
86 struct lpc32xx_pwm_chip *lpc32xx;
87 struct resource *res;
88 int ret;
89
90 lpc32xx = devm_kzalloc(&pdev->dev, sizeof(*lpc32xx), GFP_KERNEL);
91 if (!lpc32xx)
92 return -ENOMEM;
93
94 res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
95 if (!res)
96 return -EINVAL;
97
98 lpc32xx->base = devm_request_and_ioremap(&pdev->dev, res);
99 if (!lpc32xx->base)
100 return -EADDRNOTAVAIL;
101
102 lpc32xx->clk = devm_clk_get(&pdev->dev, NULL);
103 if (IS_ERR(lpc32xx->clk))
104 return PTR_ERR(lpc32xx->clk);
105
106 lpc32xx->chip.dev = &pdev->dev;
107 lpc32xx->chip.ops = &lpc32xx_pwm_ops;
108 lpc32xx->chip.npwm = 2;
109
110 ret = pwmchip_add(&lpc32xx->chip);
111 if (ret < 0) {
112 dev_err(&pdev->dev, "failed to add PWM chip, error %d\n", ret);
113 return ret;
114 }
115
116 platform_set_drvdata(pdev, lpc32xx);
117
118 return 0;
119}
120
Bill Pemberton77f37912012-11-19 13:26:09 -0500121static int lpc32xx_pwm_remove(struct platform_device *pdev)
Alexandre Pereira da Silva2132fa82012-07-10 11:38:10 -0300122{
123 struct lpc32xx_pwm_chip *lpc32xx = platform_get_drvdata(pdev);
124
125 clk_disable(lpc32xx->clk);
126 return pwmchip_remove(&lpc32xx->chip);
127}
128
129static struct of_device_id lpc32xx_pwm_dt_ids[] = {
130 { .compatible = "nxp,lpc3220-pwm", },
131 { /* sentinel */ }
132};
133MODULE_DEVICE_TABLE(of, lpc32xx_pwm_dt_ids);
134
135static struct platform_driver lpc32xx_pwm_driver = {
136 .driver = {
137 .name = "lpc32xx-pwm",
138 .of_match_table = of_match_ptr(lpc32xx_pwm_dt_ids),
139 },
140 .probe = lpc32xx_pwm_probe,
Bill Pembertonfd109112012-11-19 13:21:28 -0500141 .remove = lpc32xx_pwm_remove,
Alexandre Pereira da Silva2132fa82012-07-10 11:38:10 -0300142};
143module_platform_driver(lpc32xx_pwm_driver);
144
145MODULE_ALIAS("platform:lpc32xx-pwm");
146MODULE_AUTHOR("Alexandre Pereira da Silva <aletes.xgr@gmail.com>");
147MODULE_DESCRIPTION("LPC32XX PWM Driver");
148MODULE_LICENSE("GPL v2");