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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
Vladimir Zapolskiy5a9fc9c2015-12-06 13:32:01 +020027#define PWM_ENABLE BIT(31)
Alexandre Pereira da Silva2132fa82012-07-10 11:38:10 -030028
29#define to_lpc32xx_pwm_chip(_chip) \
30 container_of(_chip, struct lpc32xx_pwm_chip, chip)
31
32static int lpc32xx_pwm_config(struct pwm_chip *chip, struct pwm_device *pwm,
33 int duty_ns, int period_ns)
34{
35 struct lpc32xx_pwm_chip *lpc32xx = to_lpc32xx_pwm_chip(chip);
36 unsigned long long c;
37 int period_cycles, duty_cycles;
Axel Linaffb9232013-04-23 14:02:49 +080038 u32 val;
Vladimir Zapolskiy5a9fc9c2015-12-06 13:32:01 +020039 c = clk_get_rate(lpc32xx->clk);
Alexandre Pereira da Silva2132fa82012-07-10 11:38:10 -030040
Vladimir Zapolskiy5a9fc9c2015-12-06 13:32:01 +020041 /* The highest acceptable divisor is 256, which is represented by 0 */
42 period_cycles = div64_u64(c * period_ns,
43 (unsigned long long)NSEC_PER_SEC * 256);
Vladimir Zapolskiyd6dbdf02015-12-06 13:32:02 +020044 if (!period_cycles || period_cycles > 256)
45 return -ERANGE;
46 if (period_cycles == 256)
Vladimir Zapolskiy5a9fc9c2015-12-06 13:32:01 +020047 period_cycles = 0;
Alexandre Pereira da Silva2132fa82012-07-10 11:38:10 -030048
Vladimir Zapolskiy5a9fc9c2015-12-06 13:32:01 +020049 /* Compute 256 x #duty/period value and care for corner cases */
50 duty_cycles = div64_u64((unsigned long long)(period_ns - duty_ns) * 256,
51 period_ns);
52 if (!duty_cycles)
53 duty_cycles = 1;
54 if (duty_cycles > 255)
55 duty_cycles = 255;
Alexandre Pereira da Silva2132fa82012-07-10 11:38:10 -030056
Axel Linaffb9232013-04-23 14:02:49 +080057 val = readl(lpc32xx->base + (pwm->hwpwm << 2));
58 val &= ~0xFFFF;
Vladimir Zapolskiy5a9fc9c2015-12-06 13:32:01 +020059 val |= (period_cycles << 8) | duty_cycles;
Axel Linaffb9232013-04-23 14:02:49 +080060 writel(val, lpc32xx->base + (pwm->hwpwm << 2));
Alexandre Pereira da Silva2132fa82012-07-10 11:38:10 -030061
62 return 0;
63}
64
65static int lpc32xx_pwm_enable(struct pwm_chip *chip, struct pwm_device *pwm)
66{
67 struct lpc32xx_pwm_chip *lpc32xx = to_lpc32xx_pwm_chip(chip);
Axel Lin08ee77b2013-04-23 14:01:31 +080068 u32 val;
69 int ret;
Alexandre Pereira da Silva2132fa82012-07-10 11:38:10 -030070
Vladimir Zapolskiy82aff042015-12-06 13:32:00 +020071 ret = clk_prepare_enable(lpc32xx->clk);
Axel Lin08ee77b2013-04-23 14:01:31 +080072 if (ret)
73 return ret;
74
75 val = readl(lpc32xx->base + (pwm->hwpwm << 2));
76 val |= PWM_ENABLE;
77 writel(val, lpc32xx->base + (pwm->hwpwm << 2));
78
79 return 0;
Alexandre Pereira da Silva2132fa82012-07-10 11:38:10 -030080}
81
82static void lpc32xx_pwm_disable(struct pwm_chip *chip, struct pwm_device *pwm)
83{
84 struct lpc32xx_pwm_chip *lpc32xx = to_lpc32xx_pwm_chip(chip);
Axel Lin08ee77b2013-04-23 14:01:31 +080085 u32 val;
Alexandre Pereira da Silva2132fa82012-07-10 11:38:10 -030086
Axel Lin08ee77b2013-04-23 14:01:31 +080087 val = readl(lpc32xx->base + (pwm->hwpwm << 2));
88 val &= ~PWM_ENABLE;
89 writel(val, lpc32xx->base + (pwm->hwpwm << 2));
90
Vladimir Zapolskiy82aff042015-12-06 13:32:00 +020091 clk_disable_unprepare(lpc32xx->clk);
Alexandre Pereira da Silva2132fa82012-07-10 11:38:10 -030092}
93
94static const struct pwm_ops lpc32xx_pwm_ops = {
95 .config = lpc32xx_pwm_config,
96 .enable = lpc32xx_pwm_enable,
97 .disable = lpc32xx_pwm_disable,
98 .owner = THIS_MODULE,
99};
100
101static int lpc32xx_pwm_probe(struct platform_device *pdev)
102{
103 struct lpc32xx_pwm_chip *lpc32xx;
104 struct resource *res;
105 int ret;
106
107 lpc32xx = devm_kzalloc(&pdev->dev, sizeof(*lpc32xx), GFP_KERNEL);
108 if (!lpc32xx)
109 return -ENOMEM;
110
111 res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
Thierry Reding6d4294d2013-01-21 11:09:16 +0100112 lpc32xx->base = devm_ioremap_resource(&pdev->dev, res);
113 if (IS_ERR(lpc32xx->base))
114 return PTR_ERR(lpc32xx->base);
Alexandre Pereira da Silva2132fa82012-07-10 11:38:10 -0300115
116 lpc32xx->clk = devm_clk_get(&pdev->dev, NULL);
117 if (IS_ERR(lpc32xx->clk))
118 return PTR_ERR(lpc32xx->clk);
119
120 lpc32xx->chip.dev = &pdev->dev;
121 lpc32xx->chip.ops = &lpc32xx_pwm_ops;
Vladimir Zapolskiyebe1fca2015-12-06 13:31:59 +0200122 lpc32xx->chip.npwm = 1;
Alban Bedel8fc6d092012-11-14 12:58:15 +0100123 lpc32xx->chip.base = -1;
Alexandre Pereira da Silva2132fa82012-07-10 11:38:10 -0300124
125 ret = pwmchip_add(&lpc32xx->chip);
126 if (ret < 0) {
127 dev_err(&pdev->dev, "failed to add PWM chip, error %d\n", ret);
128 return ret;
129 }
130
131 platform_set_drvdata(pdev, lpc32xx);
132
133 return 0;
134}
135
Bill Pemberton77f37912012-11-19 13:26:09 -0500136static int lpc32xx_pwm_remove(struct platform_device *pdev)
Alexandre Pereira da Silva2132fa82012-07-10 11:38:10 -0300137{
138 struct lpc32xx_pwm_chip *lpc32xx = platform_get_drvdata(pdev);
Alban Bedel54b2a992012-11-14 12:58:14 +0100139 unsigned int i;
Alexandre Pereira da Silva2132fa82012-07-10 11:38:10 -0300140
Alban Bedel54b2a992012-11-14 12:58:14 +0100141 for (i = 0; i < lpc32xx->chip.npwm; i++)
142 pwm_disable(&lpc32xx->chip.pwms[i]);
143
Alexandre Pereira da Silva2132fa82012-07-10 11:38:10 -0300144 return pwmchip_remove(&lpc32xx->chip);
145}
146
Thierry Redingf1a88702013-04-18 10:04:14 +0200147static const struct of_device_id lpc32xx_pwm_dt_ids[] = {
Alexandre Pereira da Silva2132fa82012-07-10 11:38:10 -0300148 { .compatible = "nxp,lpc3220-pwm", },
149 { /* sentinel */ }
150};
151MODULE_DEVICE_TABLE(of, lpc32xx_pwm_dt_ids);
152
153static struct platform_driver lpc32xx_pwm_driver = {
154 .driver = {
155 .name = "lpc32xx-pwm",
Sachin Kamat3cb3b2b2013-09-30 08:56:40 +0530156 .of_match_table = lpc32xx_pwm_dt_ids,
Alexandre Pereira da Silva2132fa82012-07-10 11:38:10 -0300157 },
158 .probe = lpc32xx_pwm_probe,
Bill Pembertonfd109112012-11-19 13:21:28 -0500159 .remove = lpc32xx_pwm_remove,
Alexandre Pereira da Silva2132fa82012-07-10 11:38:10 -0300160};
161module_platform_driver(lpc32xx_pwm_driver);
162
163MODULE_ALIAS("platform:lpc32xx-pwm");
164MODULE_AUTHOR("Alexandre Pereira da Silva <aletes.xgr@gmail.com>");
165MODULE_DESCRIPTION("LPC32XX PWM Driver");
166MODULE_LICENSE("GPL v2");