pwm-ab8500.c
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/*
* Copyright (C) ST-Ericsson SA 2010
*
* Author: Arun R Murthy <arun.murthy@stericsson.com>
* License terms: GNU General Public License (GPL) version 2
*/
#include <linux/err.h>
#include <linux/platform_device.h>
#include <linux/slab.h>
#include <linux/pwm.h>
#include <linux/mfd/abx500.h>
#include <linux/mfd/abx500/ab8500.h>
#include <linux/module.h>
/*
* PWM Out generators
* Bank: 0x10
*/
#define AB8500_PWM_OUT_CTRL1_REG 0x60
#define AB8500_PWM_OUT_CTRL2_REG 0x61
#define AB8500_PWM_OUT_CTRL7_REG 0x66
/* backlight driver constants */
#define ENABLE_PWM 1
#define DISABLE_PWM 0
struct ab8500_pwm_chip {
struct pwm_chip chip;
};
static int ab8500_pwm_config(struct pwm_chip *chip, struct pwm_device *pwm,
int duty_ns, int period_ns)
{
int ret = 0;
unsigned int higher_val, lower_val;
u8 reg;
/*
* get the first 8 bits that are be written to
* AB8500_PWM_OUT_CTRL1_REG[0:7]
*/
lower_val = duty_ns & 0x00FF;
/*
* get bits [9:10] that are to be written to
* AB8500_PWM_OUT_CTRL2_REG[0:1]
*/
higher_val = ((duty_ns & 0x0300) >> 8);
reg = AB8500_PWM_OUT_CTRL1_REG + ((chip->base - 1) * 2);
ret = abx500_set_register_interruptible(chip->dev, AB8500_MISC,
reg, (u8)lower_val);
if (ret < 0)
return ret;
ret = abx500_set_register_interruptible(chip->dev, AB8500_MISC,
(reg + 1), (u8)higher_val);
return ret;
}
static int ab8500_pwm_enable(struct pwm_chip *chip, struct pwm_device *pwm)
{
int ret;
ret = abx500_mask_and_set_register_interruptible(chip->dev,
AB8500_MISC, AB8500_PWM_OUT_CTRL7_REG,
1 << (chip->base - 1), ENABLE_PWM);
if (ret < 0)
dev_err(chip->dev, "%s: Failed to enable PWM, Error %d\n",
pwm->label, ret);
return ret;
}
static void ab8500_pwm_disable(struct pwm_chip *chip, struct pwm_device *pwm)
{
int ret;
ret = abx500_mask_and_set_register_interruptible(chip->dev,
AB8500_MISC, AB8500_PWM_OUT_CTRL7_REG,
1 << (chip->base - 1), DISABLE_PWM);
if (ret < 0)
dev_err(chip->dev, "%s: Failed to disable PWM, Error %d\n",
pwm->label, ret);
return;
}
static const struct pwm_ops ab8500_pwm_ops = {
.config = ab8500_pwm_config,
.enable = ab8500_pwm_enable,
.disable = ab8500_pwm_disable,
.owner = THIS_MODULE,
};
static int ab8500_pwm_probe(struct platform_device *pdev)
{
struct ab8500_pwm_chip *ab8500;
int err;
/*
* Nothing to be done in probe, this is required to get the
* device which is required for ab8500 read and write
*/
ab8500 = devm_kzalloc(&pdev->dev, sizeof(*ab8500), GFP_KERNEL);
if (ab8500 == NULL) {
dev_err(&pdev->dev, "failed to allocate memory\n");
return -ENOMEM;
}
ab8500->chip.dev = &pdev->dev;
ab8500->chip.ops = &ab8500_pwm_ops;
ab8500->chip.base = pdev->id;
ab8500->chip.npwm = 1;
err = pwmchip_add(&ab8500->chip);
if (err < 0)
return err;
dev_dbg(&pdev->dev, "pwm probe successful\n");
platform_set_drvdata(pdev, ab8500);
return 0;
}
static int ab8500_pwm_remove(struct platform_device *pdev)
{
struct ab8500_pwm_chip *ab8500 = platform_get_drvdata(pdev);
int err;
err = pwmchip_remove(&ab8500->chip);
if (err < 0)
return err;
dev_dbg(&pdev->dev, "pwm driver removed\n");
return 0;
}
static struct platform_driver ab8500_pwm_driver = {
.driver = {
.name = "ab8500-pwm",
.owner = THIS_MODULE,
},
.probe = ab8500_pwm_probe,
.remove = ab8500_pwm_remove,
};
module_platform_driver(ab8500_pwm_driver);
MODULE_AUTHOR("Arun MURTHY <arun.murthy@stericsson.com>");
MODULE_DESCRIPTION("AB8500 Pulse Width Modulation Driver");
MODULE_ALIAS("platform:ab8500-pwm");
MODULE_LICENSE("GPL v2");