Commit 1591caf2 authored by Cédric Le Goater's avatar Cédric Le Goater Committed by Jacek Anaszewski
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leds: pca955x: check for I2C errors 



This should also allow probing to fail when a pca955x chip is not
found on a I2C bus.

Signed-off-by: default avatarCédric Le Goater <clg@kaod.org>
Signed-off-by: default avatarJacek Anaszewski <jacek.anaszewski@gmail.com>
parent f5808ac1

drivers/leds/leds-pca955x.c

+83 −31
Original line number Diff line number Diff line
@@ -165,13 +165,18 @@ static inline u8 pca955x_ledsel(u8 oldval, int led_num, int state) 
 * Write to frequency prescaler register, used to program the

 * period of the PWM output.  period = (PSCx + 1) / 38

 */

static void pca955x_write_psc(struct i2c_client *client, int n, u8 val)

static int pca955x_write_psc(struct i2c_client *client, int n, u8 val)

{

	struct pca955x *pca955x = i2c_get_clientdata(client);

	int ret;



	i2c_smbus_write_byte_data(client,

	ret = i2c_smbus_write_byte_data(client,

		pca95xx_num_input_regs(pca955x->chipdef->bits) + 2*n,

		val);

	if (ret < 0)

		dev_err(&client->dev, "%s: reg 0x%x, val 0x%x, err %d\n",

			__func__, n, val, ret);

	return ret;

}



/*
@@ -181,38 +186,56 @@ static void pca955x_write_psc(struct i2c_client *client, int n, u8 val) 
 *

 * Duty cycle is (256 - PWMx) / 256

 */

static void pca955x_write_pwm(struct i2c_client *client, int n, u8 val)

static int pca955x_write_pwm(struct i2c_client *client, int n, u8 val)

{

	struct pca955x *pca955x = i2c_get_clientdata(client);

	int ret;



	i2c_smbus_write_byte_data(client,

	ret = i2c_smbus_write_byte_data(client,

		pca95xx_num_input_regs(pca955x->chipdef->bits) + 1 + 2*n,

		val);

	if (ret < 0)

		dev_err(&client->dev, "%s: reg 0x%x, val 0x%x, err %d\n",

			__func__, n, val, ret);

	return ret;

}



/*

 * Write to LED selector register, which determines the source that

 * drives the LED output.

 */

static void pca955x_write_ls(struct i2c_client *client, int n, u8 val)

static int pca955x_write_ls(struct i2c_client *client, int n, u8 val)

{

	struct pca955x *pca955x = i2c_get_clientdata(client);

	int ret;



	i2c_smbus_write_byte_data(client,

	ret = i2c_smbus_write_byte_data(client,

		pca95xx_num_input_regs(pca955x->chipdef->bits) + 4 + n,

		val);

	if (ret < 0)

		dev_err(&client->dev, "%s: reg 0x%x, val 0x%x, err %d\n",

			__func__, n, val, ret);

	return ret;

}



/*

 * Read the LED selector register, which determines the source that

 * drives the LED output.

 */

static u8 pca955x_read_ls(struct i2c_client *client, int n)

static int pca955x_read_ls(struct i2c_client *client, int n, u8 *val)

{

	struct pca955x *pca955x = i2c_get_clientdata(client);

	int ret;



	return (u8) i2c_smbus_read_byte_data(client,

	ret = i2c_smbus_read_byte_data(client,

		pca95xx_num_input_regs(pca955x->chipdef->bits) + 4 + n);

	if (ret < 0) {

		dev_err(&client->dev, "%s: reg 0x%x, err %d\n",

			__func__, n, ret);

		return ret;

	}

	*val = (u8)ret;

	return 0;

}



static int pca955x_led_set(struct led_classdev *led_cdev,
@@ -223,6 +246,7 @@ static int pca955x_led_set(struct led_classdev *led_cdev, 
	u8 ls;

	int chip_ls;	/* which LSx to use (0-3 potentially) */

	int ls_led;	/* which set of bits within LSx to use (0-3) */

	int ret;



	pca955x_led = container_of(led_cdev, struct pca955x_led, led_cdev);

	pca955x = pca955x_led->pca955x;
@@ -232,7 +256,9 @@ static int pca955x_led_set(struct led_classdev *led_cdev, 


	mutex_lock(&pca955x->lock);



	ls = pca955x_read_ls(pca955x->client, chip_ls);

	ret = pca955x_read_ls(pca955x->client, chip_ls, &ls);

	if (ret)

		goto out;



	switch (value) {

	case LED_FULL:
@@ -252,26 +278,37 @@ static int pca955x_led_set(struct led_classdev *led_cdev, 
		 * OFF, HALF, or FULL.  But, this is probably better than

		 * just turning off for all other values.

		 */

		pca955x_write_pwm(pca955x->client, 1,

				255 - value);

		ret = pca955x_write_pwm(pca955x->client, 1, 255 - value);

		if (ret)

			goto out;

		ls = pca955x_ledsel(ls, ls_led, PCA955X_LS_BLINK1);

		break;

	}



	pca955x_write_ls(pca955x->client, chip_ls, ls);

	ret = pca955x_write_ls(pca955x->client, chip_ls, ls);



out:

	mutex_unlock(&pca955x->lock);



	return 0;

	return ret;

}



#ifdef CONFIG_LEDS_PCA955X_GPIO

/*

 * Read the INPUT register, which contains the state of LEDs.

 */

static u8 pca955x_read_input(struct i2c_client *client, int n)

static int pca955x_read_input(struct i2c_client *client, int n, u8 *val)

{

	return (u8)i2c_smbus_read_byte_data(client, n);

	int ret = i2c_smbus_read_byte_data(client, n);



	if (ret < 0) {

		dev_err(&client->dev, "%s: reg 0x%x, err %d\n",

			__func__, n, ret);

		return ret;

	}

	*val = (u8)ret;

	return 0;



}



static int pca955x_gpio_request_pin(struct gpio_chip *gc, unsigned int offset)
@@ -285,23 +322,32 @@ static int pca955x_gpio_request_pin(struct gpio_chip *gc, unsigned int offset) 
	return -EBUSY;

}



static void pca955x_gpio_set_value(struct gpio_chip *gc, unsigned int offset,

static int pca955x_set_value(struct gpio_chip *gc, unsigned int offset,

			     int val)

{

	struct pca955x *pca955x = gpiochip_get_data(gc);

	struct pca955x_led *led = &pca955x->leds[offset];



	if (val)

		pca955x_led_set(&led->led_cdev, LED_FULL);

		return pca955x_led_set(&led->led_cdev, LED_FULL);

	else

		pca955x_led_set(&led->led_cdev, LED_OFF);

		return pca955x_led_set(&led->led_cdev, LED_OFF);

}



static void pca955x_gpio_set_value(struct gpio_chip *gc, unsigned int offset,

				   int val)

{

	pca955x_set_value(gc, offset, val);

}



static int pca955x_gpio_get_value(struct gpio_chip *gc, unsigned int offset)

{

	struct pca955x *pca955x = gpiochip_get_data(gc);

	struct pca955x_led *led = &pca955x->leds[offset];

	u8 reg = pca955x_read_input(pca955x->client, led->led_num / 8);

	u8 reg = 0;



	/* There is nothing we can do about errors */

	pca955x_read_input(pca955x->client, led->led_num / 8, &reg);



	return !!(reg & (1 << (led->led_num % 8)));

}
@@ -310,17 +356,13 @@ static int pca955x_gpio_direction_input(struct gpio_chip *gc, 
					unsigned int offset)

{

	/* To use as input ensure pin is not driven */

	pca955x_gpio_set_value(gc, offset, 0);



	return 0;

	return pca955x_set_value(gc, offset, 0);

}



static int pca955x_gpio_direction_output(struct gpio_chip *gc,

					 unsigned int offset, int val)

{

	pca955x_gpio_set_value(gc, offset, val);



	return 0;

	return pca955x_set_value(gc, offset, val);

}

#endif /* CONFIG_LEDS_PCA955X_GPIO */
@@ -495,19 +537,29 @@ static int pca955x_probe(struct i2c_client *client, 
				return err;



			/* Turn off LED */

			pca955x_led_set(&pca955x_led->led_cdev, LED_OFF);

			err = pca955x_led_set(&pca955x_led->led_cdev, LED_OFF);

			if (err)

				return err;

		}

	}



	/* PWM0 is used for half brightness or 50% duty cycle */

	pca955x_write_pwm(client, 0, 255-LED_HALF);

	err = pca955x_write_pwm(client, 0, 255 - LED_HALF);

	if (err)

		return err;



	/* PWM1 is used for variable brightness, default to OFF */

	pca955x_write_pwm(client, 1, 0);

	err = pca955x_write_pwm(client, 1, 0);

	if (err)

		return err;



	/* Set to fast frequency so we do not see flashing */

	pca955x_write_psc(client, 0, 0);

	pca955x_write_psc(client, 1, 0);

	err = pca955x_write_psc(client, 0, 0);

	if (err)

		return err;

	err = pca955x_write_psc(client, 1, 0);

	if (err)

		return err;



#ifdef CONFIG_LEDS_PCA955X_GPIO

	if (ngpios) {