lp3943.c
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/*
* TI/National Semiconductor LP3943 MFD Core Driver
*
* Copyright 2013 Texas Instruments
*
* Author: Milo Kim <milo.kim@ti.com>
*
* 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.
*
* Driver structure:
* LP3943 is an integrated device capable of driving 16 output channels.
* It can be used for a GPIO expander and PWM generators.
*
* LED control General usage for a device
* ___________ ____________________________
*
* LP3943 MFD ---- GPIO expander leds-gpio eg) HW enable pin
* |
* --- PWM generator leds-pwm eg) PWM input
*
* Internal two PWM channels are used for LED dimming effect.
* And each output pin can be used as a GPIO as well.
* The LED functionality can work with GPIOs or PWMs.
* LEDs can be controlled with legacy leds-gpio(static brightness) or
* leds-pwm drivers(dynamic brightness control).
* Alternatively, it can be used for generic GPIO and PWM controller.
* For example, a GPIO is HW enable pin of a device.
* A PWM is input pin of a backlight device.
*/
#include <linux/err.h>
#include <linux/gpio.h>
#include <linux/i2c.h>
#include <linux/mfd/core.h>
#include <linux/mfd/lp3943.h>
#include <linux/module.h>
#include <linux/of.h>
#include <linux/slab.h>
#define LP3943_MAX_REGISTERS 0x09
/* Register configuration for pin MUX */
static const struct lp3943_reg_cfg lp3943_mux_cfg[] = {
/* address, mask, shift */
{ LP3943_REG_MUX0, 0x03, 0 },
{ LP3943_REG_MUX0, 0x0C, 2 },
{ LP3943_REG_MUX0, 0x30, 4 },
{ LP3943_REG_MUX0, 0xC0, 6 },
{ LP3943_REG_MUX1, 0x03, 0 },
{ LP3943_REG_MUX1, 0x0C, 2 },
{ LP3943_REG_MUX1, 0x30, 4 },
{ LP3943_REG_MUX1, 0xC0, 6 },
{ LP3943_REG_MUX2, 0x03, 0 },
{ LP3943_REG_MUX2, 0x0C, 2 },
{ LP3943_REG_MUX2, 0x30, 4 },
{ LP3943_REG_MUX2, 0xC0, 6 },
{ LP3943_REG_MUX3, 0x03, 0 },
{ LP3943_REG_MUX3, 0x0C, 2 },
{ LP3943_REG_MUX3, 0x30, 4 },
{ LP3943_REG_MUX3, 0xC0, 6 },
};
static struct mfd_cell lp3943_devs[] = {
{
.name = "lp3943-pwm",
.of_compatible = "ti,lp3943-pwm",
},
{
.name = "lp3943-gpio",
.of_compatible = "ti,lp3943-gpio",
},
};
int lp3943_read_byte(struct lp3943 *lp3943, u8 reg, u8 *read)
{
int ret;
unsigned int val;
ret = regmap_read(lp3943->regmap, reg, &val);
if (ret < 0)
return ret;
*read = (u8)val;
return 0;
}
EXPORT_SYMBOL_GPL(lp3943_read_byte);
int lp3943_write_byte(struct lp3943 *lp3943, u8 reg, u8 data)
{
return regmap_write(lp3943->regmap, reg, data);
}
EXPORT_SYMBOL_GPL(lp3943_write_byte);
int lp3943_update_bits(struct lp3943 *lp3943, u8 reg, u8 mask, u8 data)
{
return regmap_update_bits(lp3943->regmap, reg, mask, data);
}
EXPORT_SYMBOL_GPL(lp3943_update_bits);
static const struct regmap_config lp3943_regmap_config = {
.reg_bits = 8,
.val_bits = 8,
.max_register = LP3943_MAX_REGISTERS,
};
static int lp3943_probe(struct i2c_client *cl, const struct i2c_device_id *id)
{
struct lp3943 *lp3943;
struct device *dev = &cl->dev;
lp3943 = devm_kzalloc(dev, sizeof(*lp3943), GFP_KERNEL);
if (!lp3943)
return -ENOMEM;
lp3943->regmap = devm_regmap_init_i2c(cl, &lp3943_regmap_config);
if (IS_ERR(lp3943->regmap))
return PTR_ERR(lp3943->regmap);
lp3943->pdata = dev_get_platdata(dev);
lp3943->dev = dev;
lp3943->mux_cfg = lp3943_mux_cfg;
i2c_set_clientdata(cl, lp3943);
return mfd_add_devices(dev, -1, lp3943_devs, ARRAY_SIZE(lp3943_devs),
NULL, 0, NULL);
}
static int lp3943_remove(struct i2c_client *cl)
{
struct lp3943 *lp3943 = i2c_get_clientdata(cl);
mfd_remove_devices(lp3943->dev);
return 0;
}
static const struct i2c_device_id lp3943_ids[] = {
{ "lp3943", 0 },
{ }
};
MODULE_DEVICE_TABLE(i2c, lp3943_ids);
#ifdef CONFIG_OF
static const struct of_device_id lp3943_of_match[] = {
{ .compatible = "ti,lp3943", },
{ }
};
MODULE_DEVICE_TABLE(of, lp3943_of_match);
#endif
static struct i2c_driver lp3943_driver = {
.probe = lp3943_probe,
.remove = lp3943_remove,
.driver = {
.name = "lp3943",
.owner = THIS_MODULE,
.of_match_table = of_match_ptr(lp3943_of_match),
},
.id_table = lp3943_ids,
};
module_i2c_driver(lp3943_driver);
MODULE_DESCRIPTION("LP3943 MFD Core Driver");
MODULE_AUTHOR("Milo Kim");
MODULE_LICENSE("GPL");