/*
* PWM framework driver for Cirrus Logic EP93xx
*
* Copyright (c) 2009 Matthieu Crapet <mcrapet@gmail.com>
* Copyright (c) 2009, 2013 H Hartley Sweeten <hsweeten@visionengravers.com>
*
* EP9301/02 have only one channel:
* platform device ep93xx-pwm.1 - PWMOUT1 (EGPIO14)
*
* EP9307 has only one channel:
* platform device ep93xx-pwm.0 - PWMOUT
*
* EP9312/15 have two channels:
* platform device ep93xx-pwm.0 - PWMOUT
* platform device ep93xx-pwm.1 - PWMOUT1 (EGPIO14)
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License
* as published by the Free Software Foundation; either version
* 2 of the License, or (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*/
#include <linux/module.h>
#include <linux/platform_device.h>
#include <linux/slab.h>
#include <linux/clk.h>
#include <linux/err.h>
#include <linux/io.h>
#include <linux/pwm.h>
#include <asm/div64.h>
#include <mach/platform.h> /* for ep93xx_pwm_{acquire,release}_gpio() */
#define EP93XX_PWMx_TERM_COUNT 0x00
#define EP93XX_PWMx_DUTY_CYCLE 0x04
#define EP93XX_PWMx_ENABLE 0x08
#define EP93XX_PWMx_INVERT 0x0c
struct ep93xx_pwm {
void __iomem *base;
struct clk *clk;
struct pwm_chip chip;
};
static inline struct ep93xx_pwm *to_ep93xx_pwm(struct pwm_chip *chip)
{
return container_of(chip, struct ep93xx_pwm, chip);
}
static int ep93xx_pwm_request(struct pwm_chip *chip, struct pwm_device *pwm)
{
struct platform_device *pdev = to_platform_device(chip->dev);
return ep93xx_pwm_acquire_gpio(pdev);
}
static void ep93xx_pwm_free(struct pwm_chip *chip, struct pwm_device *pwm)
{
struct platform_device *pdev = to_platform_device(chip->dev);
ep93xx_pwm_release_gpio(pdev);
}
static int ep93xx_pwm_config(struct pwm_chip *chip, struct pwm_device *pwm,
int duty_ns, int period_ns)
{
struct ep93xx_pwm *ep93xx_pwm = to_ep93xx_pwm(chip);
void __iomem *base = ep93xx_pwm->base;
unsigned long long c;
unsigned long period_cycles;
unsigned long duty_cycles;
unsigned long term;
int ret = 0;
/*
* The clock needs to be enabled to access the PWM registers.
* Configuration can be changed at any time.
*/
if (!test_bit(PWMF_ENABLED, &pwm->flags)) {
ret = clk_enable(ep93xx_pwm->clk);
if (ret)
return ret;
}
c = clk_get_rate(ep93xx_pwm->clk);
c *= period_ns;
do_div(c, 1000000000);
period_cycles = c;
c = period_cycles;
c *= duty_ns;
do_div(c, period_ns);
duty_cycles = c;
if (period_cycles < 0x10000 && duty_cycles < 0x10000) {
term = readw(base + EP93XX_PWMx_TERM_COUNT);
/* Order is important if PWM is running */
if (period_cycles > term) {
writew(period_cycles, base + EP93XX_PWMx_TERM_COUNT);
writew(duty_cycles, base + EP93XX_PWMx_DUTY_CYCLE);
} else {
writew(duty_cycles, base + EP93XX_PWMx_DUTY_CYCLE);
writew(period_cycles, base + EP93XX_PWMx_TERM_COUNT);
}
} else {
ret = -EINVAL;
}
if (!test_bit(PWMF_ENABLED, &pwm->flags))
clk_disable(ep93xx_pwm->clk);
return ret;
}
static int ep93xx_pwm_polarity(struct pwm_chip *chip, struct pwm_device *pwm,
enum pwm_polarity polarity)
{
struct ep93xx_pwm *ep93xx_pwm = to_ep93xx_pwm(chip);
int ret;
/*
* The clock needs to be enabled to access the PWM registers.
* Polarity can only be changed when the PWM is disabled.
*/
ret = clk_enable(ep93xx_pwm->clk);
if (ret)
return ret;
if (polarity == PWM_POLARITY_INVERSED)
writew(0x1, ep93xx_pwm->base + EP93XX_PWMx_INVERT);
else
writew(0x0, ep93xx_pwm->base + EP93XX_PWMx_INVERT);
clk_disable(ep93xx_pwm->clk);
return 0;
}
static int ep93xx_pwm_enable(struct pwm_chip *chip, struct pwm_device *pwm)
{
struct ep93xx_pwm *ep93xx_pwm = to_ep93xx_pwm(chip);
int ret;
ret = clk_enable(ep93xx_pwm->clk);
if (ret)
return ret;
writew(0x1, ep93xx_pwm->base + EP93XX_PWMx_ENABLE);
return 0;
}
static void ep93xx_pwm_disable(struct pwm_chip *chip, struct pwm_device *pwm)
{
struct ep93xx_pwm *ep93xx_pwm = to_ep93xx_pwm(chip);
writew(0x0, ep93xx_pwm->base + EP93XX_PWMx_ENABLE);
clk_disable(ep93xx_pwm->clk);
}
static const struct pwm_ops ep93xx_pwm_ops = {
.request = ep93xx_pwm_request,
.free = ep93xx_pwm_free,
.config = ep93xx_pwm_config,
.set_polarity = ep93xx_pwm_polarity,
.enable = ep93xx_pwm_enable,
.disable = ep93xx_pwm_disable,
.owner = THIS_MODULE,
};
static int ep93xx_pwm_probe(struct platform_device *pdev)
{
struct ep93xx_pwm *ep93xx_pwm;
struct resource *res;
int ret;
ep93xx_pwm = devm_kzalloc(&pdev->dev, sizeof(*ep93xx_pwm), GFP_KERNEL);
if (!ep93xx_pwm)
return -ENOMEM;
res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
ep93xx_pwm->base = devm_ioremap_resource(&pdev->dev, res);
if (IS_ERR(ep93xx_pwm->base))
return PTR_ERR(ep93xx_pwm->base);
ep93xx_pwm->clk = devm_clk_get(&pdev->dev, "pwm_clk");
if (IS_ERR(ep93xx_pwm->clk))
return PTR_ERR(ep93xx_pwm->clk);
ep93xx_pwm->chip.dev = &pdev->dev;
ep93xx_pwm->chip.ops = &ep93xx_pwm_ops;
ep93xx_pwm->chip.base = -1;
ep93xx_pwm->chip.npwm = 1;
ret = pwmchip_add(&ep93xx_pwm->chip);
if (ret < 0)
return ret;
platform_set_drvdata(pdev, ep93xx_pwm);
return 0;
}
static int ep93xx_pwm_remove(struct platform_device *pdev)
{
struct ep93xx_pwm *ep93xx_pwm = platform_get_drvdata(pdev);
return pwmchip_remove(&ep93xx_pwm->chip);
}
static struct platform_driver ep93xx_pwm_driver = {
.driver = {
.name = "ep93xx-pwm",
},
.probe = ep93xx_pwm_probe,
.remove = ep93xx_pwm_remove,
};
module_platform_driver(ep93xx_pwm_driver);
MODULE_DESCRIPTION("Cirrus Logic EP93xx PWM driver");
MODULE_AUTHOR("Matthieu Crapet <mcrapet@gmail.com>");
MODULE_AUTHOR("H Hartley Sweeten <hsweeten@visionengravers.com>");
MODULE_ALIAS("platform:ep93xx-pwm");
MODULE_LICENSE("GPL");
