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linux-sg2042/drivers/pwm/pwm-pca9685.c

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/*
* Driver for PCA9685 16-channel 12-bit PWM LED controller
*
* Copyright (C) 2013 Steffen Trumtrar <s.trumtrar@pengutronix.de>
* Copyright (C) 2015 Clemens Gruber <clemens.gruber@pqgruber.com>
*
* based on the pwm-twl-led.c driver
*
* 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.
*
* This program is distributed in the hope that it will be useful, but WITHOUT
* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
* FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
* more details.
*
* You should have received a copy of the GNU General Public License along with
* this program. If not, see <http://www.gnu.org/licenses/>.
*/
#include <linux/acpi.h>
#include <linux/i2c.h>
#include <linux/module.h>
#include <linux/platform_device.h>
#include <linux/property.h>
#include <linux/pwm.h>
#include <linux/regmap.h>
#include <linux/slab.h>
#include <linux/delay.h>
/*
* Because the PCA9685 has only one prescaler per chip, changing the period of
* one channel affects the period of all 16 PWM outputs!
* However, the ratio between each configured duty cycle and the chip-wide
* period remains constant, because the OFF time is set in proportion to the
* counter range.
*/
#define PCA9685_MODE1 0x00
#define PCA9685_MODE2 0x01
#define PCA9685_SUBADDR1 0x02
#define PCA9685_SUBADDR2 0x03
#define PCA9685_SUBADDR3 0x04
#define PCA9685_ALLCALLADDR 0x05
#define PCA9685_LEDX_ON_L 0x06
#define PCA9685_LEDX_ON_H 0x07
#define PCA9685_LEDX_OFF_L 0x08
#define PCA9685_LEDX_OFF_H 0x09
#define PCA9685_ALL_LED_ON_L 0xFA
#define PCA9685_ALL_LED_ON_H 0xFB
#define PCA9685_ALL_LED_OFF_L 0xFC
#define PCA9685_ALL_LED_OFF_H 0xFD
#define PCA9685_PRESCALE 0xFE
#define PCA9685_PRESCALE_MIN 0x03 /* => max. frequency of 1526 Hz */
#define PCA9685_PRESCALE_MAX 0xFF /* => min. frequency of 24 Hz */
#define PCA9685_COUNTER_RANGE 4096
#define PCA9685_DEFAULT_PERIOD 5000000 /* Default period_ns = 1/200 Hz */
#define PCA9685_OSC_CLOCK_MHZ 25 /* Internal oscillator with 25 MHz */
#define PCA9685_NUMREGS 0xFF
#define PCA9685_MAXCHAN 0x10
#define LED_FULL (1 << 4)
#define MODE1_RESTART (1 << 7)
#define MODE1_SLEEP (1 << 4)
#define MODE2_INVRT (1 << 4)
#define MODE2_OUTDRV (1 << 2)
#define LED_N_ON_H(N) (PCA9685_LEDX_ON_H + (4 * (N)))
#define LED_N_ON_L(N) (PCA9685_LEDX_ON_L + (4 * (N)))
#define LED_N_OFF_H(N) (PCA9685_LEDX_OFF_H + (4 * (N)))
#define LED_N_OFF_L(N) (PCA9685_LEDX_OFF_L + (4 * (N)))
struct pca9685 {
struct pwm_chip chip;
struct regmap *regmap;
int active_cnt;
int duty_ns;
int period_ns;
};
static inline struct pca9685 *to_pca(struct pwm_chip *chip)
{
return container_of(chip, struct pca9685, chip);
}
static int pca9685_pwm_config(struct pwm_chip *chip, struct pwm_device *pwm,
int duty_ns, int period_ns)
{
struct pca9685 *pca = to_pca(chip);
unsigned long long duty;
unsigned int reg;
int prescale;
if (period_ns != pca->period_ns) {
prescale = DIV_ROUND_CLOSEST(PCA9685_OSC_CLOCK_MHZ * period_ns,
PCA9685_COUNTER_RANGE * 1000) - 1;
if (prescale >= PCA9685_PRESCALE_MIN &&
prescale <= PCA9685_PRESCALE_MAX) {
/* Put chip into sleep mode */
regmap_update_bits(pca->regmap, PCA9685_MODE1,
MODE1_SLEEP, MODE1_SLEEP);
/* Change the chip-wide output frequency */
regmap_write(pca->regmap, PCA9685_PRESCALE, prescale);
/* Wake the chip up */
regmap_update_bits(pca->regmap, PCA9685_MODE1,
MODE1_SLEEP, 0x0);
/* Wait 500us for the oscillator to be back up */
udelay(500);
pca->period_ns = period_ns;
/*
* If the duty cycle did not change, restart PWM with
* the same duty cycle to period ratio and return.
*/
if (duty_ns == pca->duty_ns) {
regmap_update_bits(pca->regmap, PCA9685_MODE1,
MODE1_RESTART, 0x1);
return 0;
}
} else {
dev_err(chip->dev,
"prescaler not set: period out of bounds!\n");
return -EINVAL;
}
}
pca->duty_ns = duty_ns;
if (duty_ns < 1) {
if (pwm->hwpwm >= PCA9685_MAXCHAN)
reg = PCA9685_ALL_LED_OFF_H;
else
reg = LED_N_OFF_H(pwm->hwpwm);
regmap_write(pca->regmap, reg, LED_FULL);
return 0;
}
if (duty_ns == period_ns) {
/* Clear both OFF registers */
if (pwm->hwpwm >= PCA9685_MAXCHAN)
reg = PCA9685_ALL_LED_OFF_L;
else
reg = LED_N_OFF_L(pwm->hwpwm);
regmap_write(pca->regmap, reg, 0x0);
if (pwm->hwpwm >= PCA9685_MAXCHAN)
reg = PCA9685_ALL_LED_OFF_H;
else
reg = LED_N_OFF_H(pwm->hwpwm);
regmap_write(pca->regmap, reg, 0x0);
/* Set the full ON bit */
if (pwm->hwpwm >= PCA9685_MAXCHAN)
reg = PCA9685_ALL_LED_ON_H;
else
reg = LED_N_ON_H(pwm->hwpwm);
regmap_write(pca->regmap, reg, LED_FULL);
return 0;
}
duty = PCA9685_COUNTER_RANGE * (unsigned long long)duty_ns;
duty = DIV_ROUND_UP_ULL(duty, period_ns);
if (pwm->hwpwm >= PCA9685_MAXCHAN)
reg = PCA9685_ALL_LED_OFF_L;
else
reg = LED_N_OFF_L(pwm->hwpwm);
regmap_write(pca->regmap, reg, (int)duty & 0xff);
if (pwm->hwpwm >= PCA9685_MAXCHAN)
reg = PCA9685_ALL_LED_OFF_H;
else
reg = LED_N_OFF_H(pwm->hwpwm);
regmap_write(pca->regmap, reg, ((int)duty >> 8) & 0xf);
/* Clear the full ON bit, otherwise the set OFF time has no effect */
if (pwm->hwpwm >= PCA9685_MAXCHAN)
reg = PCA9685_ALL_LED_ON_H;
else
reg = LED_N_ON_H(pwm->hwpwm);
regmap_write(pca->regmap, reg, 0);
return 0;
}
static int pca9685_pwm_enable(struct pwm_chip *chip, struct pwm_device *pwm)
{
struct pca9685 *pca = to_pca(chip);
unsigned int reg;
/*
* The PWM subsystem does not support a pre-delay.
* So, set the ON-timeout to 0
*/
if (pwm->hwpwm >= PCA9685_MAXCHAN)
reg = PCA9685_ALL_LED_ON_L;
else
reg = LED_N_ON_L(pwm->hwpwm);
regmap_write(pca->regmap, reg, 0);
if (pwm->hwpwm >= PCA9685_MAXCHAN)
reg = PCA9685_ALL_LED_ON_H;
else
reg = LED_N_ON_H(pwm->hwpwm);
regmap_write(pca->regmap, reg, 0);
/*
* Clear the full-off bit.
* It has precedence over the others and must be off.
*/
if (pwm->hwpwm >= PCA9685_MAXCHAN)
reg = PCA9685_ALL_LED_OFF_H;
else
reg = LED_N_OFF_H(pwm->hwpwm);
regmap_update_bits(pca->regmap, reg, LED_FULL, 0x0);
return 0;
}
static void pca9685_pwm_disable(struct pwm_chip *chip, struct pwm_device *pwm)
{
struct pca9685 *pca = to_pca(chip);
unsigned int reg;
if (pwm->hwpwm >= PCA9685_MAXCHAN)
reg = PCA9685_ALL_LED_OFF_H;
else
reg = LED_N_OFF_H(pwm->hwpwm);
regmap_write(pca->regmap, reg, LED_FULL);
/* Clear the LED_OFF counter. */
if (pwm->hwpwm >= PCA9685_MAXCHAN)
reg = PCA9685_ALL_LED_OFF_L;
else
reg = LED_N_OFF_L(pwm->hwpwm);
regmap_write(pca->regmap, reg, 0x0);
}
static int pca9685_pwm_request(struct pwm_chip *chip, struct pwm_device *pwm)
{
struct pca9685 *pca = to_pca(chip);
if (pca->active_cnt++ == 0)
return regmap_update_bits(pca->regmap, PCA9685_MODE1,
MODE1_SLEEP, 0x0);
return 0;
}
static void pca9685_pwm_free(struct pwm_chip *chip, struct pwm_device *pwm)
{
struct pca9685 *pca = to_pca(chip);
if (--pca->active_cnt == 0)
regmap_update_bits(pca->regmap, PCA9685_MODE1, MODE1_SLEEP,
MODE1_SLEEP);
}
static const struct pwm_ops pca9685_pwm_ops = {
.enable = pca9685_pwm_enable,
.disable = pca9685_pwm_disable,
.config = pca9685_pwm_config,
.request = pca9685_pwm_request,
.free = pca9685_pwm_free,
.owner = THIS_MODULE,
};
static const struct regmap_config pca9685_regmap_i2c_config = {
.reg_bits = 8,
.val_bits = 8,
.max_register = PCA9685_NUMREGS,
.cache_type = REGCACHE_NONE,
};
static int pca9685_pwm_probe(struct i2c_client *client,
const struct i2c_device_id *id)
{
struct pca9685 *pca;
int ret;
int mode2;
pca = devm_kzalloc(&client->dev, sizeof(*pca), GFP_KERNEL);
if (!pca)
return -ENOMEM;
pca->regmap = devm_regmap_init_i2c(client, &pca9685_regmap_i2c_config);
if (IS_ERR(pca->regmap)) {
ret = PTR_ERR(pca->regmap);
dev_err(&client->dev, "Failed to initialize register map: %d\n",
ret);
return ret;
}
pca->duty_ns = 0;
pca->period_ns = PCA9685_DEFAULT_PERIOD;
i2c_set_clientdata(client, pca);
regmap_read(pca->regmap, PCA9685_MODE2, &mode2);
if (device_property_read_bool(&client->dev, "invert"))
mode2 |= MODE2_INVRT;
else
mode2 &= ~MODE2_INVRT;
if (device_property_read_bool(&client->dev, "open-drain"))
mode2 &= ~MODE2_OUTDRV;
else
mode2 |= MODE2_OUTDRV;
regmap_write(pca->regmap, PCA9685_MODE2, mode2);
/* clear all "full off" bits */
regmap_write(pca->regmap, PCA9685_ALL_LED_OFF_L, 0);
regmap_write(pca->regmap, PCA9685_ALL_LED_OFF_H, 0);
pca->chip.ops = &pca9685_pwm_ops;
/* add an extra channel for ALL_LED */
pca->chip.npwm = PCA9685_MAXCHAN + 1;
pca->chip.dev = &client->dev;
pca->chip.base = -1;
return pwmchip_add(&pca->chip);
}
static int pca9685_pwm_remove(struct i2c_client *client)
{
struct pca9685 *pca = i2c_get_clientdata(client);
regmap_update_bits(pca->regmap, PCA9685_MODE1, MODE1_SLEEP,
MODE1_SLEEP);
return pwmchip_remove(&pca->chip);
}
static const struct i2c_device_id pca9685_id[] = {
{ "pca9685", 0 },
{ /* sentinel */ },
};
MODULE_DEVICE_TABLE(i2c, pca9685_id);
#ifdef CONFIG_ACPI
static const struct acpi_device_id pca9685_acpi_ids[] = {
{ "INT3492", 0 },
{ /* sentinel */ },
};
MODULE_DEVICE_TABLE(acpi, pca9685_acpi_ids);
#endif
#ifdef CONFIG_OF
static const struct of_device_id pca9685_dt_ids[] = {
{ .compatible = "nxp,pca9685-pwm", },
{ /* sentinel */ }
};
MODULE_DEVICE_TABLE(of, pca9685_dt_ids);
#endif
static struct i2c_driver pca9685_i2c_driver = {
.driver = {
.name = "pca9685-pwm",
.acpi_match_table = ACPI_PTR(pca9685_acpi_ids),
.of_match_table = of_match_ptr(pca9685_dt_ids),
},
.probe = pca9685_pwm_probe,
.remove = pca9685_pwm_remove,
.id_table = pca9685_id,
};
module_i2c_driver(pca9685_i2c_driver);
MODULE_AUTHOR("Steffen Trumtrar <s.trumtrar@pengutronix.de>");
MODULE_DESCRIPTION("PWM driver for PCA9685");
MODULE_LICENSE("GPL");
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