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Commit 561099a1 authored by Cédric Le Goater's avatar Cédric Le Goater Committed by Jacek Anaszewski
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leds: pca955x: add GPIO support 



The PCA955x family of chips are I2C LED blinkers whose pins not used
to control LEDs can be used as general purpose I/Os (GPIOs).

The following adds such a support by defining different operation
modes for the pins (See bindings documentation for more details). The
pca955x driver is then extended with a gpio_chip when some of pins are
operating as GPIOs. The default operating mode is to behave as a LED.

The GPIO support is conditioned by CONFIG_LEDS_PCA955X_GPIO.

Signed-off-by: default avatarCédric Le Goater <clg@kaod.org>
Acked-by: default avatarPavel Machek <pavel@ucw.cz>
Signed-off-by: default avatarJacek Anaszewski <jacek.anaszewski@gmail.com>
parent 91940bb4

drivers/leds/Kconfig

+11 −0
Original line number Diff line number Diff line
@@ -377,6 +377,17 @@ config LEDS_PCA955X 
	  LED driver chips accessed via the I2C bus.  Supported

	  devices include PCA9550, PCA9551, PCA9552, and PCA9553.



config LEDS_PCA955X_GPIO

	bool "Enable GPIO support for PCA955X"

	depends on LEDS_PCA955X

	depends on GPIOLIB

	help

	  Allow unused pins on PCA955X to be used as gpio.



	  To use a pin as gpio the pin type should be set to

	  PCA955X_TYPE_GPIO in the device tree.





config LEDS_PCA963X

	tristate "LED support for PCA963x I2C chip"

	depends on LEDS_CLASS

drivers/leds/leds-pca955x.c

+120 −17
Original line number Diff line number Diff line
@@ -53,6 +53,8 @@ 
#include <linux/slab.h>

#include <linux/string.h>



#include <dt-bindings/leds/leds-pca955x.h>



/* LED select registers determine the source that drives LED outputs */

#define PCA955X_LS_LED_ON	0x0	/* Output LOW */

#define PCA955X_LS_LED_OFF	0x1	/* Output HI-Z */
@@ -118,6 +120,9 @@ struct pca955x { 
	struct pca955x_led *leds;

	struct pca955x_chipdef	*chipdef;

	struct i2c_client	*client;

#ifdef CONFIG_LEDS_PCA955X_GPIO

	struct gpio_chip gpio;

#endif

};



struct pca955x_led {
@@ -125,6 +130,7 @@ struct pca955x_led { 
	struct led_classdev	led_cdev;

	int			led_num;	/* 0 .. 15 potentially */

	char			name[32];

	u32			type;

	const char		*default_trigger;

};
@@ -259,6 +265,65 @@ static int pca955x_led_set(struct led_classdev *led_cdev, 
	return 0;

}



#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)

{

	return (u8)i2c_smbus_read_byte_data(client, n);

}



static int pca955x_gpio_request_pin(struct gpio_chip *gc, unsigned int offset)

{

	struct pca955x *pca955x = gpiochip_get_data(gc);

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



	if (led->type == PCA955X_TYPE_GPIO)

		return 0;



	return -EBUSY;

}



static void pca955x_gpio_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);

	else

		pca955x_led_set(&led->led_cdev, LED_OFF);

}



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);



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

}



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;

}



static int pca955x_gpio_direction_output(struct gpio_chip *gc,

					 unsigned int offset, int val)

{

	pca955x_gpio_set_value(gc, offset, val);



	return 0;

}

#endif /* CONFIG_LEDS_PCA955X_GPIO */



#if IS_ENABLED(CONFIG_OF)

static struct pca955x_platform_data *

pca955x_pdata_of_init(struct i2c_client *client, struct pca955x_chipdef *chip)
@@ -297,6 +362,8 @@ pca955x_pdata_of_init(struct i2c_client *client, struct pca955x_chipdef *chip) 
		snprintf(pdata->leds[reg].name, sizeof(pdata->leds[reg].name),

			 "%s", name);



		pdata->leds[reg].type = PCA955X_TYPE_LED;

		of_property_read_u32(child, "type", &pdata->leds[reg].type);

		of_property_read_string(child, "linux,default-trigger",

					&pdata->leds[reg].default_trigger);

	}
@@ -332,6 +399,7 @@ static int pca955x_probe(struct i2c_client *client, 
	struct i2c_adapter *adapter;

	int i, err;

	struct pca955x_platform_data *pdata;

	int ngpios = 0;



	if (id) {

		chip = &pca955x_chipdefs[id->driver_data];
@@ -392,9 +460,19 @@ static int pca955x_probe(struct i2c_client *client, 
		pca955x_led = &pca955x->leds[i];

		pca955x_led->led_num = i;

		pca955x_led->pca955x = pca955x;

		pca955x_led->type = pdata->leds[i].type;



		/* Platform data can specify LED names and default triggers */

		if (pdata) {

		switch (pca955x_led->type) {

		case PCA955X_TYPE_NONE:

			break;

		case PCA955X_TYPE_GPIO:

			ngpios++;

			break;

		case PCA955X_TYPE_LED:

			/*

			 * Platform data can specify LED names and

			 * default triggers

			 */

			if (pdata->leds[i].name)

				snprintf(pca955x_led->name,

					sizeof(pca955x_led->name), "pca955x:%s",
@@ -402,23 +480,20 @@ static int pca955x_probe(struct i2c_client *client, 
			if (pdata->leds[i].default_trigger)

				pca955x_led->led_cdev.default_trigger =

					pdata->leds[i].default_trigger;

		} else {

			snprintf(pca955x_led->name, sizeof(pca955x_led->name),

				 "pca955x:%d", i);

		}



			pca955x_led->led_cdev.name = pca955x_led->name;

		pca955x_led->led_cdev.brightness_set_blocking = pca955x_led_set;

			pca955x_led->led_cdev.brightness_set_blocking =

				pca955x_led_set;



			err = devm_led_classdev_register(&client->dev,

							&pca955x_led->led_cdev);

			if (err)

				return err;

	}



	/* Turn off LEDs */

	for (i = 0; i < pca95xx_num_led_regs(chip->bits); i++)

		pca955x_write_ls(client, i, 0x55);

			/* Turn off LED */

			pca955x_led_set(&pca955x_led->led_cdev, LED_OFF);

		}

	}



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

	pca955x_write_pwm(client, 0, 255-LED_HALF);
@@ -430,6 +505,34 @@ static int pca955x_probe(struct i2c_client *client, 
	pca955x_write_psc(client, 0, 0);

	pca955x_write_psc(client, 1, 0);



#ifdef CONFIG_LEDS_PCA955X_GPIO

	if (ngpios) {

		pca955x->gpio.label = "gpio-pca955x";

		pca955x->gpio.direction_input = pca955x_gpio_direction_input;

		pca955x->gpio.direction_output = pca955x_gpio_direction_output;

		pca955x->gpio.set = pca955x_gpio_set_value;

		pca955x->gpio.get = pca955x_gpio_get_value;

		pca955x->gpio.request = pca955x_gpio_request_pin;

		pca955x->gpio.can_sleep = 1;

		pca955x->gpio.base = -1;

		pca955x->gpio.ngpio = ngpios;

		pca955x->gpio.parent = &client->dev;

		pca955x->gpio.owner = THIS_MODULE;



		err = devm_gpiochip_add_data(&client->dev, &pca955x->gpio,

					     pca955x);

		if (err) {

			/* Use data->gpio.dev as a flag for freeing gpiochip */

			pca955x->gpio.parent = NULL;

			dev_warn(&client->dev, "could not add gpiochip\n");

			return err;

		}

		dev_info(&client->dev, "gpios %i...%i\n",

			 pca955x->gpio.base, pca955x->gpio.base +

			 pca955x->gpio.ngpio - 1);

	}

#endif



	return 0;

}

include/dt-bindings/leds/leds-pca955x.h

0 → 100644
+16 −0
Original line number Diff line number Diff line 
/*

 * This header provides constants for pca955x LED bindings.

 *

 * This file is licensed under the terms of the GNU General Public

 * License version 2.  This program is licensed "as is" without any

 * warranty of any kind, whether express or implied.

 */



#ifndef _DT_BINDINGS_LEDS_PCA955X_H

#define _DT_BINDINGS_LEDS_PCA955X_H



#define PCA955X_TYPE_NONE         0

#define PCA955X_TYPE_LED          1

#define PCA955X_TYPE_GPIO         2



#endif /* _DT_BINDINGS_LEDS_PCA955X_H */