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/*
* Marvell Berlin PWM driver
*
* Copyright (C) 2015 Marvell Technology Group Ltd.
*
* Author: Antoine Tenart <antoine.tenart@free-electrons.com>
*
* 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/clk.h>
#include <linux/io.h>
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/platform_device.h>
#include <linux/pwm.h>
#define BERLIN_PWM_EN 0x0
#define BERLIN_PWM_ENABLE BIT(0)
#define BERLIN_PWM_CONTROL 0x4
#define BERLIN_PWM_PRESCALE_MASK 0x7
#define BERLIN_PWM_PRESCALE_MAX 4096
#define BERLIN_PWM_INVERT_POLARITY BIT(3)
#define BERLIN_PWM_DUTY 0x8
#define BERLIN_PWM_TCNT 0xc
#define BERLIN_PWM_MAX_TCNT 65535
struct berlin_pwm_chip {
struct pwm_chip chip;
struct clk *clk;
void __iomem *base;
};
static inline struct berlin_pwm_chip *to_berlin_pwm_chip(struct pwm_chip *chip)
{
return container_of(chip, struct berlin_pwm_chip, chip);
}
static const u32 prescaler_table[] = {
1, 4, 8, 16, 64, 256, 1024, 4096
};
static inline u32 berlin_pwm_readl(struct berlin_pwm_chip *chip,
unsigned int channel, unsigned long offset)
{
return readl_relaxed(chip->base + channel * 0x10 + offset);
}
static inline void berlin_pwm_writel(struct berlin_pwm_chip *chip,
unsigned int channel, u32 value,
unsigned long offset)
{
writel_relaxed(value, chip->base + channel * 0x10 + offset);
}
static int berlin_pwm_config(struct pwm_chip *chip, struct pwm_device *pwm_dev,
int duty_ns, int period_ns)
{
struct berlin_pwm_chip *pwm = to_berlin_pwm_chip(chip);
unsigned int prescale;
u32 value, duty, period;
u64 cycles, tmp;
cycles = clk_get_rate(pwm->clk);
cycles *= period_ns;
do_div(cycles, NSEC_PER_SEC);
for (prescale = 0; prescale < ARRAY_SIZE(prescaler_table); prescale++) {
tmp = cycles;
do_div(tmp, prescaler_table[prescale]);
if (tmp <= BERLIN_PWM_MAX_TCNT)
break;
}
if (tmp > BERLIN_PWM_MAX_TCNT)
return -ERANGE;
period = tmp;
cycles = tmp * duty_ns;
do_div(cycles, period_ns);
duty = cycles;
value = berlin_pwm_readl(pwm, pwm_dev->hwpwm, BERLIN_PWM_CONTROL);
value &= ~BERLIN_PWM_PRESCALE_MASK;
value |= prescale;
berlin_pwm_writel(pwm, pwm_dev->hwpwm, value, BERLIN_PWM_CONTROL);
berlin_pwm_writel(pwm, pwm_dev->hwpwm, duty, BERLIN_PWM_DUTY);
berlin_pwm_writel(pwm, pwm_dev->hwpwm, period, BERLIN_PWM_TCNT);
return 0;
}
static int berlin_pwm_set_polarity(struct pwm_chip *chip,
struct pwm_device *pwm_dev,
enum pwm_polarity polarity)
{
struct berlin_pwm_chip *pwm = to_berlin_pwm_chip(chip);
u32 value;
value = berlin_pwm_readl(pwm, pwm_dev->hwpwm, BERLIN_PWM_CONTROL);
if (polarity == PWM_POLARITY_NORMAL)
value &= ~BERLIN_PWM_INVERT_POLARITY;
else
value |= BERLIN_PWM_INVERT_POLARITY;
berlin_pwm_writel(pwm, pwm_dev->hwpwm, value, BERLIN_PWM_CONTROL);
return 0;
}
static int berlin_pwm_enable(struct pwm_chip *chip, struct pwm_device *pwm_dev)
{
struct berlin_pwm_chip *pwm = to_berlin_pwm_chip(chip);
u32 value;
value = berlin_pwm_readl(pwm, pwm_dev->hwpwm, BERLIN_PWM_EN);
value |= BERLIN_PWM_ENABLE;
berlin_pwm_writel(pwm, pwm_dev->hwpwm, value, BERLIN_PWM_EN);
return 0;
}
static void berlin_pwm_disable(struct pwm_chip *chip,
struct pwm_device *pwm_dev)
{
struct berlin_pwm_chip *pwm = to_berlin_pwm_chip(chip);
u32 value;
value = berlin_pwm_readl(pwm, pwm_dev->hwpwm, BERLIN_PWM_EN);
value &= ~BERLIN_PWM_ENABLE;
berlin_pwm_writel(pwm, pwm_dev->hwpwm, value, BERLIN_PWM_EN);
}
static const struct pwm_ops berlin_pwm_ops = {
.config = berlin_pwm_config,
.set_polarity = berlin_pwm_set_polarity,
.enable = berlin_pwm_enable,
.disable = berlin_pwm_disable,
.owner = THIS_MODULE,
};
static const struct of_device_id berlin_pwm_match[] = {
{ .compatible = "marvell,berlin-pwm" },
{ },
};
MODULE_DEVICE_TABLE(of, berlin_pwm_match);
static int berlin_pwm_probe(struct platform_device *pdev)
{
struct berlin_pwm_chip *pwm;
struct resource *res;
int ret;
pwm = devm_kzalloc(&pdev->dev, sizeof(*pwm), GFP_KERNEL);
if (!pwm)
return -ENOMEM;
res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
pwm->base = devm_ioremap_resource(&pdev->dev, res);
if (IS_ERR(pwm->base))
return PTR_ERR(pwm->base);
pwm->clk = devm_clk_get(&pdev->dev, NULL);
if (IS_ERR(pwm->clk))
return PTR_ERR(pwm->clk);
ret = clk_prepare_enable(pwm->clk);
if (ret)
return ret;
pwm->chip.dev = &pdev->dev;
pwm->chip.ops = &berlin_pwm_ops;
pwm->chip.base = -1;
pwm->chip.npwm = 4;
pwm->chip.can_sleep = true;
pwm->chip.of_xlate = of_pwm_xlate_with_flags;
pwm->chip.of_pwm_n_cells = 3;
ret = pwmchip_add(&pwm->chip);
if (ret < 0) {
dev_err(&pdev->dev, "failed to add PWM chip: %d\n", ret);
clk_disable_unprepare(pwm->clk);
return ret;
}
platform_set_drvdata(pdev, pwm);
return 0;
}
static int berlin_pwm_remove(struct platform_device *pdev)
{
struct berlin_pwm_chip *pwm = platform_get_drvdata(pdev);
int ret;
ret = pwmchip_remove(&pwm->chip);
clk_disable_unprepare(pwm->clk);
return ret;
}
static struct platform_driver berlin_pwm_driver = {
.probe = berlin_pwm_probe,
.remove = berlin_pwm_remove,
.driver = {
.name = "berlin-pwm",
.of_match_table = berlin_pwm_match,
},
};
module_platform_driver(berlin_pwm_driver);
MODULE_AUTHOR("Antoine Tenart <antoine.tenart@free-electrons.com>");
MODULE_DESCRIPTION("Marvell Berlin PWM driver");
MODULE_LICENSE("GPL v2");
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