/*
* TI/National Semiconductor LP3943 PWM 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 as published by
* the Free Software Foundation; version 2.
*/
#include <linux/err.h>
#include <linux/i2c.h>
#include <linux/mfd/lp3943.h>
#include <linux/module.h>
#include <linux/platform_device.h>
#include <linux/pwm.h>
#include <linux/slab.h>
#define LP3943_MAX_DUTY 255
#define LP3943_MIN_PERIOD 6250
#define LP3943_MAX_PERIOD 1600000
struct lp3943_pwm {
struct pwm_chip chip;
struct lp3943 *lp3943;
struct lp3943_platform_data *pdata;
};
static inline struct lp3943_pwm *to_lp3943_pwm(struct pwm_chip *_chip)
{
return container_of(_chip, struct lp3943_pwm, chip);
}
static struct lp3943_pwm_map *
lp3943_pwm_request_map(struct lp3943_pwm *lp3943_pwm, int hwpwm)
{
struct lp3943_platform_data *pdata = lp3943_pwm->pdata;
struct lp3943 *lp3943 = lp3943_pwm->lp3943;
struct lp3943_pwm_map *pwm_map;
int i, offset;
pwm_map = kzalloc(sizeof(*pwm_map), GFP_KERNEL);
if (!pwm_map)
return ERR_PTR(-ENOMEM);
pwm_map->output = pdata->pwms[hwpwm]->output;
pwm_map->num_outputs = pdata->pwms[hwpwm]->num_outputs;
for (i = 0; i < pwm_map->num_outputs; i++) {
offset = pwm_map->output[i];
/* Return an error if the pin is already assigned */
if (test_and_set_bit(offset, &lp3943->pin_used)) {
kfree(pwm_map);
return ERR_PTR(-EBUSY);
}
}
return pwm_map;
}
static int lp3943_pwm_request(struct pwm_chip *chip, struct pwm_device *pwm)
{
struct lp3943_pwm *lp3943_pwm = to_lp3943_pwm(chip);
struct lp3943_pwm_map *pwm_map;
pwm_map = lp3943_pwm_request_map(lp3943_pwm, pwm->hwpwm);
if (IS_ERR(pwm_map))
return PTR_ERR(pwm_map);
return pwm_set_chip_data(pwm, pwm_map);
}
static void lp3943_pwm_free_map(struct lp3943_pwm *lp3943_pwm,
struct lp3943_pwm_map *pwm_map)
{
struct lp3943 *lp3943 = lp3943_pwm->lp3943;
int i, offset;
for (i = 0; i < pwm_map->num_outputs; i++) {
offset = pwm_map->output[i];
clear_bit(offset, &lp3943->pin_used);
}
kfree(pwm_map);
}
static void lp3943_pwm_free(struct pwm_chip *chip, struct pwm_device *pwm)
{
struct lp3943_pwm *lp3943_pwm = to_lp3943_pwm(chip);
struct lp3943_pwm_map *pwm_map = pwm_get_chip_data(pwm);
lp3943_pwm_free_map(lp3943_pwm, pwm_map);
}
static int lp3943_pwm_config(struct pwm_chip *chip, struct pwm_device *pwm,
int duty_ns, int period_ns)
{
struct lp3943_pwm *lp3943_pwm = to_lp3943_pwm(chip);
struct lp3943 *lp3943 = lp3943_pwm->lp3943;
u8 val, reg_duty, reg_prescale;
int err;
/*
* How to configure the LP3943 PWMs
*
* 1) Period = 6250 ~ 1600000
* 2) Prescale = period / 6250 -1
* 3) Duty = input duty
*
* Prescale and duty are register values
*/
if (pwm->hwpwm == 0) {
reg_prescale = LP3943_REG_PRESCALE0;
reg_duty = LP3943_REG_PWM0;
} else {
reg_prescale = LP3943_REG_PRESCALE1;
reg_duty = LP3943_REG_PWM1;
}
period_ns = clamp(period_ns, LP3943_MIN_PERIOD, LP3943_MAX_PERIOD);
val = (u8)(period_ns / LP3943_MIN_PERIOD - 1);
err = lp3943_write_byte(lp3943, reg_prescale, val);
if (err)
return err;
val = (u8)(duty_ns * LP3943_MAX_DUTY / period_ns);
return lp3943_write_byte(lp3943, reg_duty, val);
}
static int lp3943_pwm_set_mode(struct lp3943_pwm *lp3943_pwm,
struct lp3943_pwm_map *pwm_map,
u8 val)
{
struct lp3943 *lp3943 = lp3943_pwm->lp3943;
const struct lp3943_reg_cfg *mux = lp3943->mux_cfg;
int i, index, err;
for (i = 0; i < pwm_map->num_outputs; i++) {
index = pwm_map->output[i];
err = lp3943_update_bits(lp3943, mux[index].reg,
mux[index].mask,
val << mux[index].shift);
if (err)
return err;
}
return 0;
}
static int lp3943_pwm_enable(struct pwm_chip *chip, struct pwm_device *pwm)
{
struct lp3943_pwm *lp3943_pwm = to_lp3943_pwm(chip);
struct lp3943_pwm_map *pwm_map = pwm_get_chip_data(pwm);
u8 val;
if (pwm->hwpwm == 0)
val = LP3943_DIM_PWM0;
else
val = LP3943_DIM_PWM1;
/*
* Each PWM generator is set to control any of outputs of LP3943.
* To enable/disable the PWM, these output pins should be configured.
*/
return lp3943_pwm_set_mode(lp3943_pwm, pwm_map, val);
}
static void lp3943_pwm_disable(struct pwm_chip *chip, struct pwm_device *pwm)
{
struct lp3943_pwm *lp3943_pwm = to_lp3943_pwm(chip);
struct lp3943_pwm_map *pwm_map = pwm_get_chip_data(pwm);
/*
* LP3943 outputs are open-drain, so the pin should be configured
* when the PWM is disabled.
*/
lp3943_pwm_set_mode(lp3943_pwm, pwm_map, LP3943_GPIO_OUT_HIGH);
}
static const struct pwm_ops lp3943_pwm_ops = {
.request = lp3943_pwm_request,
.free = lp3943_pwm_free,
.config = lp3943_pwm_config,
.enable = lp3943_pwm_enable,
.disable = lp3943_pwm_disable,
.owner = THIS_MODULE,
};
static int lp3943_pwm_parse_dt(struct device *dev,
struct lp3943_pwm *lp3943_pwm)
{
static const char * const name[] = { "ti,pwm0", "ti,pwm1", };
struct device_node *node = dev->of_node;
struct lp3943_platform_data *pdata;
struct lp3943_pwm_map *pwm_map;
enum lp3943_pwm_output *output;
int i, err, proplen, count = 0;
u32 num_outputs;
if (!node)
return -EINVAL;
pdata = devm_kzalloc(dev, sizeof(*pdata), GFP_KERNEL);
if (!pdata)
return -ENOMEM;
/*
* Read the output map configuration from the device tree.
* Each of the two PWM generators can drive zero or more outputs.
*/
for (i = 0; i < LP3943_NUM_PWMS; i++) {
if (!of_get_property(node, name[i], &proplen))
continue;
num_outputs = proplen / sizeof(u32);
if (num_outputs == 0)
continue;
output = devm_kzalloc(dev, sizeof(*output) * num_outputs,
GFP_KERNEL);
if (!output)
return -ENOMEM;
err = of_property_read_u32_array(node, name[i], output,
num_outputs);
if (err)
return err;
pwm_map = devm_kzalloc(dev, sizeof(*pwm_map), GFP_KERNEL);
if (!pwm_map)
return -ENOMEM;
pwm_map->output = output;
pwm_map->num_outputs = num_outputs;
pdata->pwms[i] = pwm_map;
count++;
}
if (count == 0)
return -ENODATA;
lp3943_pwm->pdata = pdata;
return 0;
}
static int lp3943_pwm_probe(struct platform_device *pdev)
{
struct lp3943 *lp3943 = dev_get_drvdata(pdev->dev.parent);
struct lp3943_pwm *lp3943_pwm;
int ret;
lp3943_pwm = devm_kzalloc(&pdev->dev, sizeof(*lp3943_pwm), GFP_KERNEL);
if (!lp3943_pwm)
return -ENOMEM;
lp3943_pwm->pdata = lp3943->pdata;
if (!lp3943_pwm->pdata) {
if (IS_ENABLED(CONFIG_OF))
ret = lp3943_pwm_parse_dt(&pdev->dev, lp3943_pwm);
else
ret = -ENODEV;
if (ret)
return ret;
}
lp3943_pwm->lp3943 = lp3943;
lp3943_pwm->chip.dev = &pdev->dev;
lp3943_pwm->chip.ops = &lp3943_pwm_ops;
lp3943_pwm->chip.npwm = LP3943_NUM_PWMS;
lp3943_pwm->chip.can_sleep = true;
platform_set_drvdata(pdev, lp3943_pwm);
return pwmchip_add(&lp3943_pwm->chip);
}
static int lp3943_pwm_remove(struct platform_device *pdev)
{
struct lp3943_pwm *lp3943_pwm = platform_get_drvdata(pdev);
return pwmchip_remove(&lp3943_pwm->chip);
}
#ifdef CONFIG_OF
static const struct of_device_id lp3943_pwm_of_match[] = {
{ .compatible = "ti,lp3943-pwm", },
{ }
};
MODULE_DEVICE_TABLE(of, lp3943_pwm_of_match);
#endif
static struct platform_driver lp3943_pwm_driver = {
.probe = lp3943_pwm_probe,
.remove = lp3943_pwm_remove,
.driver = {
.name = "lp3943-pwm",
.of_match_table = of_match_ptr(lp3943_pwm_of_match),
},
};
module_platform_driver(lp3943_pwm_driver);
MODULE_DESCRIPTION("LP3943 PWM driver");
MODULE_ALIAS("platform:lp3943-pwm");
MODULE_AUTHOR("Milo Kim");
MODULE_LICENSE("GPL");
