linux-hardened/drivers/pwm/pwm-pca9685.c
Sven Van Asbroeck c40c461e19 pwm: pca9685: Fix GPIO-only operation
GPIO-only driver operation never clears the SLEEP bit, which can cause
the GPIOs to become unusable.

Example:
1. user requests first PWM  ->      driver clears SLEEP bit
2. user frees last PWM      ->      driver sets SLEEP bit
3. user requests GPIO
4. user switches GPIO on    ->      output does not turn on
                                    because SLEEP bit is set

Prevent this behaviour by letting the runtime PM framework control the
SLEEP bit. This will put the chip to SLEEP if no PWMs/GPIOs are exported
or in use.

Fixes: bccec89f0a ("Allow any of the 16 PWMs to be used as a GPIO")
Reported-by: Sven Van Asbroeck <TheSven73@googlemail.com>
Signed-off-by: Sven Van Asbroeck <TheSven73@googlemail.com>
Suggested-by: Mika Westerberg <mika.westerberg@linux.intel.com>
Reviewed-by: Mika Westerberg <mika.westerberg@linux.intel.com>
Signed-off-by: Thierry Reding <thierry.reding@gmail.com>
2017-04-13 17:35:01 +02:00

594 lines
14 KiB
C

/*
* 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/gpio/driver.h>
#include <linux/i2c.h>
#include <linux/module.h>
#include <linux/mutex.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>
#include <linux/pm_runtime.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_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 duty_ns;
int period_ns;
#if IS_ENABLED(CONFIG_GPIOLIB)
struct mutex lock;
struct gpio_chip gpio;
#endif
};
static inline struct pca9685 *to_pca(struct pwm_chip *chip)
{
return container_of(chip, struct pca9685, chip);
}
#if IS_ENABLED(CONFIG_GPIOLIB)
static int pca9685_pwm_gpio_request(struct gpio_chip *gpio, unsigned int offset)
{
struct pca9685 *pca = gpiochip_get_data(gpio);
struct pwm_device *pwm;
mutex_lock(&pca->lock);
pwm = &pca->chip.pwms[offset];
if (pwm->flags & (PWMF_REQUESTED | PWMF_EXPORTED)) {
mutex_unlock(&pca->lock);
return -EBUSY;
}
pwm_set_chip_data(pwm, (void *)1);
mutex_unlock(&pca->lock);
pm_runtime_get_sync(pca->chip.dev);
return 0;
}
static bool pca9685_pwm_is_gpio(struct pca9685 *pca, struct pwm_device *pwm)
{
bool is_gpio = false;
mutex_lock(&pca->lock);
if (pwm->hwpwm >= PCA9685_MAXCHAN) {
unsigned int i;
/*
* Check if any of the GPIOs are requested and in that case
* prevent using the "all LEDs" channel.
*/
for (i = 0; i < pca->gpio.ngpio; i++)
if (gpiochip_is_requested(&pca->gpio, i)) {
is_gpio = true;
break;
}
} else if (pwm_get_chip_data(pwm)) {
is_gpio = true;
}
mutex_unlock(&pca->lock);
return is_gpio;
}
static int pca9685_pwm_gpio_get(struct gpio_chip *gpio, unsigned int offset)
{
struct pca9685 *pca = gpiochip_get_data(gpio);
struct pwm_device *pwm = &pca->chip.pwms[offset];
unsigned int value;
regmap_read(pca->regmap, LED_N_ON_H(pwm->hwpwm), &value);
return value & LED_FULL;
}
static void pca9685_pwm_gpio_set(struct gpio_chip *gpio, unsigned int offset,
int value)
{
struct pca9685 *pca = gpiochip_get_data(gpio);
struct pwm_device *pwm = &pca->chip.pwms[offset];
unsigned int on = value ? LED_FULL : 0;
/* Clear both OFF registers */
regmap_write(pca->regmap, LED_N_OFF_L(pwm->hwpwm), 0);
regmap_write(pca->regmap, LED_N_OFF_H(pwm->hwpwm), 0);
/* Set the full ON bit */
regmap_write(pca->regmap, LED_N_ON_H(pwm->hwpwm), on);
}
static void pca9685_pwm_gpio_free(struct gpio_chip *gpio, unsigned int offset)
{
struct pca9685 *pca = gpiochip_get_data(gpio);
struct pwm_device *pwm;
pca9685_pwm_gpio_set(gpio, offset, 0);
pm_runtime_put(pca->chip.dev);
mutex_lock(&pca->lock);
pwm = &pca->chip.pwms[offset];
pwm_set_chip_data(pwm, NULL);
mutex_unlock(&pca->lock);
}
static int pca9685_pwm_gpio_get_direction(struct gpio_chip *chip,
unsigned int offset)
{
/* Always out */
return 0;
}
static int pca9685_pwm_gpio_direction_input(struct gpio_chip *gpio,
unsigned int offset)
{
return -EINVAL;
}
static int pca9685_pwm_gpio_direction_output(struct gpio_chip *gpio,
unsigned int offset, int value)
{
pca9685_pwm_gpio_set(gpio, offset, value);
return 0;
}
/*
* The PCA9685 has a bit for turning the PWM output full off or on. Some
* boards like Intel Galileo actually uses these as normal GPIOs so we
* expose a GPIO chip here which can exclusively take over the underlying
* PWM channel.
*/
static int pca9685_pwm_gpio_probe(struct pca9685 *pca)
{
struct device *dev = pca->chip.dev;
mutex_init(&pca->lock);
pca->gpio.label = dev_name(dev);
pca->gpio.parent = dev;
pca->gpio.request = pca9685_pwm_gpio_request;
pca->gpio.free = pca9685_pwm_gpio_free;
pca->gpio.get_direction = pca9685_pwm_gpio_get_direction;
pca->gpio.direction_input = pca9685_pwm_gpio_direction_input;
pca->gpio.direction_output = pca9685_pwm_gpio_direction_output;
pca->gpio.get = pca9685_pwm_gpio_get;
pca->gpio.set = pca9685_pwm_gpio_set;
pca->gpio.base = -1;
pca->gpio.ngpio = PCA9685_MAXCHAN;
pca->gpio.can_sleep = true;
return devm_gpiochip_add_data(dev, &pca->gpio, pca);
}
#else
static inline bool pca9685_pwm_is_gpio(struct pca9685 *pca,
struct pwm_device *pwm)
{
return false;
}
static inline int pca9685_pwm_gpio_probe(struct pca9685 *pca)
{
return 0;
}
#endif
static void pca9685_set_sleep_mode(struct pca9685 *pca, int sleep)
{
regmap_update_bits(pca->regmap, PCA9685_MODE1,
MODE1_SLEEP, sleep ? MODE1_SLEEP : 0);
if (!sleep) {
/* Wait 500us for the oscillator to be back up */
udelay(500);
}
}
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) {
/*
* putting the chip briefly into SLEEP mode
* at this point won't interfere with the
* pm_runtime framework, because the pm_runtime
* state is guaranteed active here.
*/
/* Put chip into sleep mode */
pca9685_set_sleep_mode(pca, 1);
/* Change the chip-wide output frequency */
regmap_write(pca->regmap, PCA9685_PRESCALE, prescale);
/* Wake the chip up */
pca9685_set_sleep_mode(pca, 0);
pca->period_ns = period_ns;
} 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 (pca9685_pwm_is_gpio(pca, pwm))
return -EBUSY;
pm_runtime_get_sync(chip->dev);
return 0;
}
static void pca9685_pwm_free(struct pwm_chip *chip, struct pwm_device *pwm)
{
pca9685_pwm_disable(chip, pwm);
pm_runtime_put(chip->dev);
}
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;
ret = pwmchip_add(&pca->chip);
if (ret < 0)
return ret;
ret = pca9685_pwm_gpio_probe(pca);
if (ret < 0) {
pwmchip_remove(&pca->chip);
return ret;
}
/* the chip comes out of power-up in the active state */
pm_runtime_set_active(&client->dev);
/*
* enable will put the chip into suspend, which is what we
* want as all outputs are disabled at this point
*/
pm_runtime_enable(&client->dev);
return 0;
}
static int pca9685_pwm_remove(struct i2c_client *client)
{
struct pca9685 *pca = i2c_get_clientdata(client);
int ret;
ret = pwmchip_remove(&pca->chip);
if (ret)
return ret;
pm_runtime_disable(&client->dev);
return 0;
}
#ifdef CONFIG_PM
static int pca9685_pwm_runtime_suspend(struct device *dev)
{
struct i2c_client *client = to_i2c_client(dev);
struct pca9685 *pca = i2c_get_clientdata(client);
pca9685_set_sleep_mode(pca, 1);
return 0;
}
static int pca9685_pwm_runtime_resume(struct device *dev)
{
struct i2c_client *client = to_i2c_client(dev);
struct pca9685 *pca = i2c_get_clientdata(client);
pca9685_set_sleep_mode(pca, 0);
return 0;
}
#endif
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 const struct dev_pm_ops pca9685_pwm_pm = {
SET_RUNTIME_PM_OPS(pca9685_pwm_runtime_suspend,
pca9685_pwm_runtime_resume, NULL)
};
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),
.pm = &pca9685_pwm_pm,
},
.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");