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// SPDX-License-Identifier: GPL-2.0-or-later
/*
* 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)
*/
#include <linux/module.h>
#include <linux/mod_devicetable.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>
#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;
};
static inline struct ep93xx_pwm *to_ep93xx_pwm(struct pwm_chip *chip)
{
return pwmchip_get_drvdata(chip);
}
static int ep93xx_pwm_apply(struct pwm_chip *chip, struct pwm_device *pwm,
const struct pwm_state *state)
{
int ret;
struct ep93xx_pwm *ep93xx_pwm = to_ep93xx_pwm(chip);
bool enabled = state->enabled;
void __iomem *base = ep93xx_pwm->base;
unsigned long long c;
unsigned long period_cycles;
unsigned long duty_cycles;
unsigned long term;
if (state->polarity != pwm->state.polarity) {
if (enabled) {
writew(0x0, ep93xx_pwm->base + EP93XX_PWMx_ENABLE);
clk_disable_unprepare(ep93xx_pwm->clk);
enabled = false;
}
/*
* The clock needs to be enabled to access the PWM registers.
* Polarity can only be changed when the PWM is disabled.
*/
ret = clk_prepare_enable(ep93xx_pwm->clk);
if (ret)
return ret;
if (state->polarity == PWM_POLARITY_INVERSED)
writew(0x1, ep93xx_pwm->base + EP93XX_PWMx_INVERT);
else
writew(0x0, ep93xx_pwm->base + EP93XX_PWMx_INVERT);
clk_disable_unprepare(ep93xx_pwm->clk);
}
if (!state->enabled) {
if (enabled) {
writew(0x0, ep93xx_pwm->base + EP93XX_PWMx_ENABLE);
clk_disable_unprepare(ep93xx_pwm->clk);
}
return 0;
}
/*
* The clock needs to be enabled to access the PWM registers.
* Configuration can be changed at any time.
*/
if (!pwm_is_enabled(pwm)) {
ret = clk_prepare_enable(ep93xx_pwm->clk);
if (ret)
return ret;
}
c = clk_get_rate(ep93xx_pwm->clk);
c *= state->period;
do_div(c, 1000000000);
period_cycles = c;
c = period_cycles;
c *= state->duty_cycle;
do_div(c, state->period);
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);
}
ret = 0;
} else {
ret = -EINVAL;
}
if (!pwm_is_enabled(pwm))
clk_disable_unprepare(ep93xx_pwm->clk);
if (ret)
return ret;
if (!enabled) {
ret = clk_prepare_enable(ep93xx_pwm->clk);
if (ret)
return ret;
writew(0x1, ep93xx_pwm->base + EP93XX_PWMx_ENABLE);
}
return 0;
}
static const struct pwm_ops ep93xx_pwm_ops = {
.apply = ep93xx_pwm_apply,
};
static int ep93xx_pwm_probe(struct platform_device *pdev)
{
struct pwm_chip *chip;
struct ep93xx_pwm *ep93xx_pwm;
int ret;
chip = devm_pwmchip_alloc(&pdev->dev, 1, sizeof(*ep93xx_pwm));
if (IS_ERR(chip))
return PTR_ERR(chip);
ep93xx_pwm = to_ep93xx_pwm(chip);
ep93xx_pwm->base = devm_platform_ioremap_resource(pdev, 0);
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);
chip->ops = &ep93xx_pwm_ops;
ret = devm_pwmchip_add(&pdev->dev, chip);
if (ret < 0)
return ret;
return 0;
}
static const struct of_device_id ep93xx_pwm_of_ids[] = {
{ .compatible = "cirrus,ep9301-pwm" },
{ /* sentinel */}
};
MODULE_DEVICE_TABLE(of, ep93xx_pwm_of_ids);
static struct platform_driver ep93xx_pwm_driver = {
.driver = {
.name = "ep93xx-pwm",
.of_match_table = ep93xx_pwm_of_ids,
},
.probe = ep93xx_pwm_probe,
};
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");
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