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/*
* drivers/pwm/pwm-pxa.c
*
* simple driver for PWM (Pulse Width Modulator) controller
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License version 2 as
* published by the Free Software Foundation.
*
* 2008-02-13 initial version
* eric miao <eric.miao@marvell.com>
*/
#include <linux/module.h>
#include <linux/kernel.h>
#include <linux/platform_device.h>
#include <linux/slab.h>
#include <linux/err.h>
#include <linux/clk.h>
#include <linux/io.h>
#include <linux/pwm.h>
#include <asm/div64.h>
#define HAS_SECONDARY_PWM 0x10
static const struct platform_device_id pwm_id_table[] = {
/* PWM has_secondary_pwm? */
{ "pxa25x-pwm", 0 },
{ "pxa27x-pwm", HAS_SECONDARY_PWM },
{ "pxa168-pwm", 0 },
{ "pxa910-pwm", 0 },
{ },
};
MODULE_DEVICE_TABLE(platform, pwm_id_table);
/* PWM registers and bits definitions */
#define PWMCR (0x00)
#define PWMDCR (0x04)
#define PWMPCR (0x08)
#define PWMCR_SD (1 << 6)
#define PWMDCR_FD (1 << 10)
struct pxa_pwm_chip {
struct pwm_chip chip;
struct device *dev;
struct clk *clk;
void __iomem *mmio_base;
};
static inline struct pxa_pwm_chip *to_pxa_pwm_chip(struct pwm_chip *chip)
{
return container_of(chip, struct pxa_pwm_chip, chip);
}
/*
* period_ns = 10^9 * (PRESCALE + 1) * (PV + 1) / PWM_CLK_RATE
* duty_ns = 10^9 * (PRESCALE + 1) * DC / PWM_CLK_RATE
*/
static int pxa_pwm_config(struct pwm_chip *chip, struct pwm_device *pwm,
int duty_ns, int period_ns)
{
struct pxa_pwm_chip *pc = to_pxa_pwm_chip(chip);
unsigned long long c;
unsigned long period_cycles, prescale, pv, dc;
unsigned long offset;
int rc;
offset = pwm->hwpwm ? 0x10 : 0;
c = clk_get_rate(pc->clk);
c = c * period_ns;
do_div(c, 1000000000);
period_cycles = c;
if (period_cycles < 1)
period_cycles = 1;
prescale = (period_cycles - 1) / 1024;
pv = period_cycles / (prescale + 1) - 1;
if (prescale > 63)
return -EINVAL;
if (duty_ns == period_ns)
dc = PWMDCR_FD;
else
dc = (pv + 1) * duty_ns / period_ns;
/* NOTE: the clock to PWM has to be enabled first
* before writing to the registers
*/
rc = clk_prepare_enable(pc->clk);
if (rc < 0)
return rc;
writel(prescale, pc->mmio_base + offset + PWMCR);
writel(dc, pc->mmio_base + offset + PWMDCR);
writel(pv, pc->mmio_base + offset + PWMPCR);
clk_disable_unprepare(pc->clk);
return 0;
}
static int pxa_pwm_enable(struct pwm_chip *chip, struct pwm_device *pwm)
{
struct pxa_pwm_chip *pc = to_pxa_pwm_chip(chip);
return clk_prepare_enable(pc->clk);
}
static void pxa_pwm_disable(struct pwm_chip *chip, struct pwm_device *pwm)
{
struct pxa_pwm_chip *pc = to_pxa_pwm_chip(chip);
clk_disable_unprepare(pc->clk);
}
static struct pwm_ops pxa_pwm_ops = {
.config = pxa_pwm_config,
.enable = pxa_pwm_enable,
.disable = pxa_pwm_disable,
.owner = THIS_MODULE,
};
static int pwm_probe(struct platform_device *pdev)
{
const struct platform_device_id *id = platform_get_device_id(pdev);
struct pxa_pwm_chip *pwm;
struct resource *r;
int ret = 0;
pwm = devm_kzalloc(&pdev->dev, sizeof(*pwm), GFP_KERNEL);
if (pwm == NULL) {
dev_err(&pdev->dev, "failed to allocate memory\n");
return -ENOMEM;
}
pwm->clk = devm_clk_get(&pdev->dev, NULL);
if (IS_ERR(pwm->clk))
return PTR_ERR(pwm->clk);
pwm->chip.dev = &pdev->dev;
pwm->chip.ops = &pxa_pwm_ops;
pwm->chip.base = -1;
pwm->chip.npwm = (id->driver_data & HAS_SECONDARY_PWM) ? 2 : 1;
r = platform_get_resource(pdev, IORESOURCE_MEM, 0);
pwm->mmio_base = devm_ioremap_resource(&pdev->dev, r);
if (IS_ERR(pwm->mmio_base))
return PTR_ERR(pwm->mmio_base);
ret = pwmchip_add(&pwm->chip);
if (ret < 0) {
dev_err(&pdev->dev, "pwmchip_add() failed: %d\n", ret);
return ret;
}
platform_set_drvdata(pdev, pwm);
return 0;
}
static int pwm_remove(struct platform_device *pdev)
{
struct pxa_pwm_chip *chip;
chip = platform_get_drvdata(pdev);
if (chip == NULL)
return -ENODEV;
return pwmchip_remove(&chip->chip);
}
static struct platform_driver pwm_driver = {
.driver = {
.name = "pxa25x-pwm",
.owner = THIS_MODULE,
},
.probe = pwm_probe,
.remove = pwm_remove,
.id_table = pwm_id_table,
};
static int __init pwm_init(void)
{
return platform_driver_register(&pwm_driver);
}
arch_initcall(pwm_init);
static void __exit pwm_exit(void)
{
platform_driver_unregister(&pwm_driver);
}
module_exit(pwm_exit);
MODULE_LICENSE("GPL v2");
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