155 lines
3.5 KiB
C
155 lines
3.5 KiB
C
/*
|
|
* linux/arch/unicore32/kernel/pwm.c
|
|
*
|
|
* Code specific to PKUnity SoC and UniCore ISA
|
|
*
|
|
* Maintained by GUAN Xue-tao <gxt@mprc.pku.edu.cn>
|
|
* Copyright (C) 2001-2010 Guan Xuetao
|
|
*
|
|
* 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.
|
|
*/
|
|
|
|
#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>
|
|
#include <mach/hardware.h>
|
|
|
|
struct puv3_pwm_chip {
|
|
struct pwm_chip chip;
|
|
void __iomem *base;
|
|
struct clk *clk;
|
|
};
|
|
|
|
static inline struct puv3_pwm_chip *to_puv3(struct pwm_chip *chip)
|
|
{
|
|
return container_of(chip, struct puv3_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 puv3_pwm_config(struct pwm_chip *chip, struct pwm_device *pwm,
|
|
int duty_ns, int period_ns)
|
|
{
|
|
unsigned long period_cycles, prescale, pv, dc;
|
|
struct puv3_pwm_chip *puv3 = to_puv3(chip);
|
|
unsigned long long c;
|
|
|
|
c = clk_get_rate(puv3->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 = OST_PWMDCCR_FDCYCLE;
|
|
else
|
|
dc = (pv + 1) * duty_ns / period_ns;
|
|
|
|
/*
|
|
* NOTE: the clock to PWM has to be enabled first
|
|
* before writing to the registers
|
|
*/
|
|
clk_prepare_enable(puv3->clk);
|
|
|
|
writel(prescale, puv3->base + OST_PWM_PWCR);
|
|
writel(pv - dc, puv3->base + OST_PWM_DCCR);
|
|
writel(pv, puv3->base + OST_PWM_PCR);
|
|
|
|
clk_disable_unprepare(puv3->clk);
|
|
|
|
return 0;
|
|
}
|
|
|
|
static int puv3_pwm_enable(struct pwm_chip *chip, struct pwm_device *pwm)
|
|
{
|
|
struct puv3_pwm_chip *puv3 = to_puv3(chip);
|
|
|
|
return clk_prepare_enable(puv3->clk);
|
|
}
|
|
|
|
static void puv3_pwm_disable(struct pwm_chip *chip, struct pwm_device *pwm)
|
|
{
|
|
struct puv3_pwm_chip *puv3 = to_puv3(chip);
|
|
|
|
clk_disable_unprepare(puv3->clk);
|
|
}
|
|
|
|
static const struct pwm_ops puv3_pwm_ops = {
|
|
.config = puv3_pwm_config,
|
|
.enable = puv3_pwm_enable,
|
|
.disable = puv3_pwm_disable,
|
|
.owner = THIS_MODULE,
|
|
};
|
|
|
|
static int pwm_probe(struct platform_device *pdev)
|
|
{
|
|
struct puv3_pwm_chip *puv3;
|
|
struct resource *r;
|
|
int ret;
|
|
|
|
puv3 = devm_kzalloc(&pdev->dev, sizeof(*puv3), GFP_KERNEL);
|
|
if (puv3 == NULL) {
|
|
dev_err(&pdev->dev, "failed to allocate memory\n");
|
|
return -ENOMEM;
|
|
}
|
|
|
|
puv3->clk = devm_clk_get(&pdev->dev, "OST_CLK");
|
|
if (IS_ERR(puv3->clk))
|
|
return PTR_ERR(puv3->clk);
|
|
|
|
r = platform_get_resource(pdev, IORESOURCE_MEM, 0);
|
|
puv3->base = devm_ioremap_resource(&pdev->dev, r);
|
|
if (IS_ERR(puv3->base))
|
|
return PTR_ERR(puv3->base);
|
|
|
|
puv3->chip.dev = &pdev->dev;
|
|
puv3->chip.ops = &puv3_pwm_ops;
|
|
puv3->chip.base = -1;
|
|
puv3->chip.npwm = 1;
|
|
|
|
ret = pwmchip_add(&puv3->chip);
|
|
if (ret < 0) {
|
|
dev_err(&pdev->dev, "pwmchip_add() failed: %d\n", ret);
|
|
return ret;
|
|
}
|
|
|
|
platform_set_drvdata(pdev, puv3);
|
|
return 0;
|
|
}
|
|
|
|
static int pwm_remove(struct platform_device *pdev)
|
|
{
|
|
struct puv3_pwm_chip *puv3 = platform_get_drvdata(pdev);
|
|
|
|
return pwmchip_remove(&puv3->chip);
|
|
}
|
|
|
|
static struct platform_driver puv3_pwm_driver = {
|
|
.driver = {
|
|
.name = "PKUnity-v3-PWM",
|
|
},
|
|
.probe = pwm_probe,
|
|
.remove = pwm_remove,
|
|
};
|
|
module_platform_driver(puv3_pwm_driver);
|
|
|
|
MODULE_LICENSE("GPL v2");
|