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Commit f46e9203 authored by Nate Case's avatar Nate Case Committed by Richard Purdie
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leds: Add support for Philips PCA955x I2C LED drivers 



This driver supports the PCA9550, PCA9551, PCA9552, and PCA9553
LED driver chips.

Signed-off-by: default avatarNate Case <ncase@xes-inc.com>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarRichard Purdie <rpurdie@rpsys.net>
parent dd1160dc

drivers/leds/Kconfig

+8 −0
Original line number Diff line number Diff line
@@ -155,6 +155,14 @@ config LEDS_CLEVO_MAIL 
	  To compile this driver as a module, choose M here: the

	  module will be called leds-clevo-mail.



config LEDS_PCA955X

	tristate "LED Support for PCA955x I2C chips"

	depends on LEDS_CLASS && I2C

	help

	  This option enables support for LEDs connected to PCA955x

	  LED driver chips accessed via the I2C bus.  Supported

	  devices include PCA9550, PCA9551, PCA9552, and PCA9553.



comment "LED Triggers"



config LEDS_TRIGGERS

drivers/leds/Makefile

+1 −0
Original line number Diff line number Diff line
@@ -22,6 +22,7 @@ obj-$(CONFIG_LEDS_CM_X270) += leds-cm-x270.o 
obj-$(CONFIG_LEDS_CLEVO_MAIL)		+= leds-clevo-mail.o

obj-$(CONFIG_LEDS_HP6XX)		+= leds-hp6xx.o

obj-$(CONFIG_LEDS_FSG)			+= leds-fsg.o

obj-$(CONFIG_LEDS_PCA955X)		+= leds-pca955x.o



# LED Triggers

obj-$(CONFIG_LEDS_TRIGGER_TIMER)	+= ledtrig-timer.o

drivers/leds/leds-pca955x.c

0 → 100644
+384 −0
Original line number Diff line number Diff line 
/*

 * Copyright 2007-2008 Extreme Engineering Solutions, Inc.

 *

 * Author: Nate Case <ncase@xes-inc.com>

 *

 * This file is subject to the terms and conditions of version 2 of

 * the GNU General Public License.  See the file COPYING in the main

 * directory of this archive for more details.

 *

 * LED driver for various PCA955x I2C LED drivers

 *

 * Supported devices:

 *

 *	Device		Description		7-bit slave address

 *	------		-----------		-------------------

 *	PCA9550		2-bit driver		0x60 .. 0x61

 *	PCA9551		8-bit driver		0x60 .. 0x67

 *	PCA9552		16-bit driver		0x60 .. 0x67

 *	PCA9553/01	4-bit driver		0x62

 *	PCA9553/02	4-bit driver		0x63

 *

 * Philips PCA955x LED driver chips follow a register map as shown below:

 *

 *	Control Register		Description

 *	----------------		-----------

 *	0x0				Input register 0

 *					..

 *	NUM_INPUT_REGS - 1		Last Input register X

 *

 *	NUM_INPUT_REGS			Frequency prescaler 0

 *	NUM_INPUT_REGS + 1		PWM register 0

 *	NUM_INPUT_REGS + 2		Frequency prescaler 1

 *	NUM_INPUT_REGS + 3		PWM register 1

 *

 *	NUM_INPUT_REGS + 4		LED selector 0

 *	NUM_INPUT_REGS + 4

 *	    + NUM_LED_REGS - 1		Last LED selector

 *

 *  where NUM_INPUT_REGS and NUM_LED_REGS vary depending on how many

 *  bits the chip supports.

 */



#include <linux/module.h>

#include <linux/delay.h>

#include <linux/string.h>

#include <linux/ctype.h>

#include <linux/leds.h>

#include <linux/err.h>

#include <linux/i2c.h>

#include <linux/workqueue.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 */

#define PCA955X_LS_BLINK0	0x2	/* Blink at PWM0 rate */

#define PCA955X_LS_BLINK1	0x3	/* Blink at PWM1 rate */



enum pca955x_type {

	pca9550,

	pca9551,

	pca9552,

	pca9553,

};



struct pca955x_chipdef {

	int			bits;

	u8			slv_addr;	/* 7-bit slave address mask */

	int			slv_addr_shift;	/* Number of bits to ignore */

};



static struct pca955x_chipdef pca955x_chipdefs[] = {

	[pca9550] = {

		.bits		= 2,

		.slv_addr	= /* 110000x */ 0x60,

		.slv_addr_shift	= 1,

	},

	[pca9551] = {

		.bits		= 8,

		.slv_addr	= /* 1100xxx */ 0x60,

		.slv_addr_shift	= 3,

	},

	[pca9552] = {

		.bits		= 16,

		.slv_addr	= /* 1100xxx */ 0x60,

		.slv_addr_shift	= 3,

	},

	[pca9553] = {

		.bits		= 4,

		.slv_addr	= /* 110001x */ 0x62,

		.slv_addr_shift	= 1,

	},

};



static const struct i2c_device_id pca955x_id[] = {

	{ "pca9550", pca9550 },

	{ "pca9551", pca9551 },

	{ "pca9552", pca9552 },

	{ "pca9553", pca9553 },

	{ }

};

MODULE_DEVICE_TABLE(i2c, pca955x_id);



struct pca955x_led {

	struct pca955x_chipdef	*chipdef;

	struct i2c_client	*client;

	struct work_struct	work;

	spinlock_t		lock;

	enum led_brightness	brightness;

	struct led_classdev	led_cdev;

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

	char			name[32];

};



/* 8 bits per input register */

static inline int pca95xx_num_input_regs(int bits)

{

	return (bits + 7) / 8;

}



/* 4 bits per LED selector register */

static inline int pca95xx_num_led_regs(int bits)

{

	return (bits + 3)  / 4;

}



/*

 * Return an LED selector register value based on an existing one, with

 * the appropriate 2-bit state value set for the given LED number (0-3).

 */

static inline u8 pca955x_ledsel(u8 oldval, int led_num, int state)

{

	return (oldval & (~(0x3 << (led_num << 1)))) |

		((state & 0x3) << (led_num << 1));

}



/*

 * 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)

{

	struct pca955x_led *pca955x = i2c_get_clientdata(client);



	i2c_smbus_write_byte_data(client,

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

		val);

}



/*

 * Write to PWM register, which determines the duty cycle of the

 * output.  LED is OFF when the count is less than the value of this

 * register, and ON when it is greater.  If PWMx == 0, LED is always OFF.

 *

 * Duty cycle is (256 - PWMx) / 256

 */

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

{

	struct pca955x_led *pca955x = i2c_get_clientdata(client);



	i2c_smbus_write_byte_data(client,

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

		val);

}



/*

 * 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)

{

	struct pca955x_led *pca955x = i2c_get_clientdata(client);



	i2c_smbus_write_byte_data(client,

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

		val);

}



/*

 * 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)

{

	struct pca955x_led *pca955x = i2c_get_clientdata(client);



	return (u8) i2c_smbus_read_byte_data(client,

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

}



static void pca955x_led_work(struct work_struct *work)

{

	struct pca955x_led *pca955x;

	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) */



	pca955x = container_of(work, struct pca955x_led, work);

	chip_ls = pca955x->led_num / 4;

	ls_led = pca955x->led_num % 4;



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



	switch (pca955x->brightness) {

	case LED_FULL:

		ls = pca955x_ledsel(ls, ls_led, PCA955X_LS_LED_ON);

		break;

	case LED_OFF:

		ls = pca955x_ledsel(ls, ls_led, PCA955X_LS_LED_OFF);

		break;

	case LED_HALF:

		ls = pca955x_ledsel(ls, ls_led, PCA955X_LS_BLINK0);

		break;

	default:

		/*

		 * Use PWM1 for all other values.  This has the unwanted

		 * side effect of making all LEDs on the chip share the

		 * same brightness level if set to a value other than

		 * OFF, HALF, or FULL.  But, this is probably better than

		 * just turning off for all other values.

		 */

		pca955x_write_pwm(pca955x->client, 1, 255-pca955x->brightness);

		ls = pca955x_ledsel(ls, ls_led, PCA955X_LS_BLINK1);

		break;

	}



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

}



void pca955x_led_set(struct led_classdev *led_cdev, enum led_brightness value)

{

	struct pca955x_led *pca955x;



	pca955x = container_of(led_cdev, struct pca955x_led, led_cdev);



	spin_lock(&pca955x->lock);

	pca955x->brightness = value;



	/*

	 * Must use workqueue for the actual I/O since I2C operations

	 * can sleep.

	 */

	schedule_work(&pca955x->work);



	spin_unlock(&pca955x->lock);

}



static int __devinit pca955x_probe(struct i2c_client *client,

					const struct i2c_device_id *id)

{

	struct pca955x_led *pca955x;

	int i;

	int err = -ENODEV;

	struct pca955x_chipdef *chip;

	struct i2c_adapter *adapter;

	struct led_platform_data *pdata;



	chip = &pca955x_chipdefs[id->driver_data];

	adapter = to_i2c_adapter(client->dev.parent);

	pdata = client->dev.platform_data;



	/* Make sure the slave address / chip type combo given is possible */

	if ((client->addr & ~((1 << chip->slv_addr_shift) - 1)) !=

	    chip->slv_addr) {

		dev_err(&client->dev, "invalid slave address %02x\n",

				client->addr);

		return -ENODEV;

	}



	printk(KERN_INFO "leds-pca955x: Using %s %d-bit LED driver at "

			"slave address 0x%02x\n",

			id->name, chip->bits, client->addr);



	if (!i2c_check_functionality(adapter, I2C_FUNC_I2C))

		return -EIO;



	if (pdata) {

		if (pdata->num_leds != chip->bits) {

			dev_err(&client->dev, "board info claims %d LEDs"

					" on a %d-bit chip\n",

					pdata->num_leds, chip->bits);

			return -ENODEV;

		}

	}



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

		pca955x = kzalloc(sizeof(struct pca955x_led), GFP_KERNEL);

		if (!pca955x) {

			err = -ENOMEM;

			goto exit;

		}



		pca955x->chipdef = chip;

		pca955x->client = client;

		pca955x->led_num = i;

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

		if (pdata) {

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

				snprintf(pca955x->name, 32, "pca955x:%s",

							pdata->leds[i].name);

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

				pca955x->led_cdev.default_trigger =

					pdata->leds[i].default_trigger;

		} else {

			snprintf(pca955x->name, 32, "pca955x:%d", i);

		}

		spin_lock_init(&pca955x->lock);



		pca955x->led_cdev.name = pca955x->name;

		pca955x->led_cdev.brightness_set =

				pca955x_led_set;



		/*

		 * Client data is a pointer to the _first_ pca955x_led

		 * struct

		 */

		if (i == 0)

			i2c_set_clientdata(client, pca955x);



		INIT_WORK(&(pca955x->work), pca955x_led_work);



		led_classdev_register(&client->dev, &(pca955x->led_cdev));

	}



	/* Turn off LEDs */

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

		pca955x_write_ls(client, i, 0x55);



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

	pca955x_write_pwm(client, 0, 255-LED_HALF);



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

	pca955x_write_pwm(client, 1, 0);



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

	pca955x_write_psc(client, 0, 0);

	pca955x_write_psc(client, 1, 0);



	return 0;

exit:

	return err;

}



static int __devexit pca955x_remove(struct i2c_client *client)

{

	struct pca955x_led *pca955x = i2c_get_clientdata(client);

	int leds = pca955x->chipdef->bits;

	int i;



	for (i = 0; i < leds; i++) {

		led_classdev_unregister(&(pca955x->led_cdev));

		cancel_work_sync(&(pca955x->work));

		kfree(pca955x);

		pca955x = pca955x + 1;

	}



	return 0;

}



static struct i2c_driver pca955x_driver = {

	.driver = {

		.name	= "leds-pca955x",

		.owner	= THIS_MODULE,

	},

	.probe	= pca955x_probe,

	.remove	= __devexit_p(pca955x_remove),

	.id_table = pca955x_id,

};



static int __init pca955x_leds_init(void)

{

	return i2c_add_driver(&pca955x_driver);

}



static void __exit pca955x_leds_exit(void)

{

	i2c_del_driver(&pca955x_driver);

}



module_init(pca955x_leds_init);

module_exit(pca955x_leds_exit);



MODULE_AUTHOR("Nate Case <ncase@xes-inc.com>");

MODULE_DESCRIPTION("PCA955x LED driver");

MODULE_LICENSE("GPL v2");

include/linux/leds.h

+14 −0
Original line number Diff line number Diff line
@@ -118,6 +118,20 @@ extern void ledtrig_ide_activity(void); 
#define ledtrig_ide_activity() do {} while(0)

#endif



/*

 * Generic LED platform data for describing LED names and default triggers.

 */

struct led_info {

	const char	*name;

	char		*default_trigger;

	int		flags;

};



struct led_platform_data {

	int		num_leds;

	struct led_info	*leds;

};



/* For the leds-gpio driver */

struct gpio_led {

	const char *name;