Commit 8465b018 authored by Mark A. Greer's avatar Mark A. Greer Committed by Bryan Wu
Browse files

leds: pca9633: Add hardware blink support 



Add hardware blinking support to the pca9633 driver.

NOTE: Hardware blinking violates the leds infrastructure
driver interface since the hardware only supports
blinking all LEDs with the same delay_on/delay_off
rates.  That is, only the LEDs that are set to blink
will actually blink but all LEDs that are set to blink
will blink in identical fashion.  The delay_on/delay_off
values of the last LED that is set to blink will be used
for all of the blinking LEDs.  If the hardware doesn't
support the requested blinking pattern, a default of
500ms on and off will be used.

Hardware blinking is disabled by default but can be enabled
by setting the 'blink_type' member in the platform_data
struct to 'PCA9633_HW_BLINK' or by adding the 'nxp,hw-blink'
property to the DTS.

(fengguang.wu@intel.com: Removes unneeded semicolon.)

Signed-off-by: default avatarMark A. Greer <mgreer@animalcreek.com>
Reported-by: default avatarFengguang Wu <fengguang.wu@intel.com>
Signed-off-by: default avatarBryan Wu <cooloney@gmail.com>
parent 33b3a561

Documentation/devicetree/bindings/leds/pca9633.txt

+1 −0
Original line number Diff line number Diff line
@@ -5,6 +5,7 @@ Required properties: 


Optional properties:

- nxp,totem-pole : use totem pole (push-pull) instead of default open-drain

- nxp,hw-blink : use hardware blinking instead of software blinking



Each led is represented as a sub-node of the nxp,pca9633 device.

drivers/leds/leds-pca9633.c

+132 −4
Original line number Diff line number Diff line
@@ -11,6 +11,15 @@ 
 *

 * LED driver for the PCA9633 I2C LED driver (7-bit slave address 0x62)

 *

 * Note that hardware blinking violates the leds infrastructure driver

 * interface since the hardware only supports blinking all LEDs with the

 * same delay_on/delay_off rates.  That is, only the LEDs that are set to

 * blink will actually blink but all LEDs that are set to blink will blink

 * in identical fashion.  The delay_on/delay_off values of the last LED

 * that is set to blink will be used for all of the blinking LEDs.

 * Hardware blinking is disabled by default but can be enabled by setting

 * the 'blink_type' member in the platform_data struct to 'PCA9633_HW_BLINK'

 * or by adding the 'nxp,hw-blink' property to the DTS.

 */



#include <linux/module.h>
@@ -31,30 +40,44 @@ 
#define PCA9633_LED_PWM		0x2	/* Controlled through PWM */

#define PCA9633_LED_GRP_PWM	0x3	/* Controlled through PWM/GRPPWM */



#define PCA9633_MODE2_DMBLNK	0x20	/* Enable blinking */



#define PCA9633_MODE1		0x00

#define PCA9633_MODE2		0x01

#define PCA9633_PWM_BASE	0x02

#define PCA9633_GRPPWM		0x06

#define PCA9633_GRPFREQ		0x07

#define PCA9633_LEDOUT		0x08



/* Total blink period in milliseconds */

#define PCA9632_BLINK_PERIOD_MIN	42

#define PCA9632_BLINK_PERIOD_MAX	10667



static const struct i2c_device_id pca9633_id[] = {

	{ "pca9633", 0 },

	{ }

};

MODULE_DEVICE_TABLE(i2c, pca9633_id);



enum pca9633_cmd {

	BRIGHTNESS_SET,

	BLINK_SET,

};



struct pca9633_led {

	struct i2c_client *client;

	struct work_struct work;

	enum led_brightness brightness;

	struct led_classdev led_cdev;

	int led_num; /* 0 .. 3 potentially */

	enum pca9633_cmd cmd;

	char name[32];

	u8 gdc;

	u8 gfrq;

};



static void pca9633_led_work(struct work_struct *work)

static void pca9633_brightness_work(struct pca9633_led *pca9633)

{

	struct pca9633_led *pca9633 = container_of(work,

		struct pca9633_led, work);

	u8 ledout = i2c_smbus_read_byte_data(pca9633->client, PCA9633_LEDOUT);

	int shift = 2 * pca9633->led_num;

	u8 mask = 0x3 << shift;
@@ -78,6 +101,43 @@ static void pca9633_led_work(struct work_struct *work) 
	}

}



static void pca9633_blink_work(struct pca9633_led *pca9633)

{

	u8 ledout = i2c_smbus_read_byte_data(pca9633->client, PCA9633_LEDOUT);

	u8 mode2 = i2c_smbus_read_byte_data(pca9633->client, PCA9633_MODE2);

	int shift = 2 * pca9633->led_num;

	u8 mask = 0x3 << shift;



	i2c_smbus_write_byte_data(pca9633->client, PCA9633_GRPPWM,

		pca9633->gdc);



	i2c_smbus_write_byte_data(pca9633->client, PCA9633_GRPFREQ,

		pca9633->gfrq);



	if (!(mode2 & PCA9633_MODE2_DMBLNK))

		i2c_smbus_write_byte_data(pca9633->client, PCA9633_MODE2,

			mode2 | PCA9633_MODE2_DMBLNK);



	if ((ledout & mask) != (PCA9633_LED_GRP_PWM << shift))

		i2c_smbus_write_byte_data(pca9633->client, PCA9633_LEDOUT,

			(ledout & ~mask) | (PCA9633_LED_GRP_PWM << shift));

}



static void pca9633_work(struct work_struct *work)

{

	struct pca9633_led *pca9633 = container_of(work,

		struct pca9633_led, work);



	switch (pca9633->cmd) {

	case BRIGHTNESS_SET:

		pca9633_brightness_work(pca9633);

		break;

	case BLINK_SET:

		pca9633_blink_work(pca9633);

		break;

	}

}



static void pca9633_led_set(struct led_classdev *led_cdev,

	enum led_brightness value)

{
@@ -85,6 +145,7 @@ static void pca9633_led_set(struct led_classdev *led_cdev, 


	pca9633 = container_of(led_cdev, struct pca9633_led, led_cdev);



	pca9633->cmd = BRIGHTNESS_SET;

	pca9633->brightness = value;



	/*
@@ -94,6 +155,64 @@ static void pca9633_led_set(struct led_classdev *led_cdev, 
	schedule_work(&pca9633->work);

}



static int pca9633_blink_set(struct led_classdev *led_cdev,

		unsigned long *delay_on, unsigned long *delay_off)

{

	struct pca9633_led *pca9633;

	unsigned long time_on, time_off, period;

	u8 gdc, gfrq;



	pca9633 = container_of(led_cdev, struct pca9633_led, led_cdev);



	time_on = *delay_on;

	time_off = *delay_off;



	/* If both zero, pick reasonable defaults of 500ms each */

	if (!time_on && !time_off) {

		time_on = 500;

		time_off = 500;

	}



	period = time_on + time_off;



	/* If period not supported by hardware, default to someting sane. */

	if ((period < PCA9632_BLINK_PERIOD_MIN) ||

	    (period > PCA9632_BLINK_PERIOD_MAX)) {

		time_on = 500;

		time_off = 500;

		period = time_on + time_off;

	}



	/*

	 * From manual: duty cycle = (GDC / 256) ->

	 *	(time_on / period) = (GDC / 256) ->

	 *		GDC = ((time_on * 256) / period)

	 */

	gdc = (time_on * 256) / period;



	/*

	 * From manual: period = ((GFRQ + 1) / 24) in seconds.

	 * So, period (in ms) = (((GFRQ + 1) / 24) * 1000) ->

	 *		GFRQ = ((period * 24 / 1000) - 1)

	 */

	gfrq = (period * 24 / 1000) - 1;



	pca9633->cmd = BLINK_SET;

	pca9633->gdc = gdc;

	pca9633->gfrq = gfrq;



	/*

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

	 * can sleep.

	 */

	schedule_work(&pca9633->work);



	*delay_on = time_on;

	*delay_off = time_off;



	return 0;

}



#if IS_ENABLED(CONFIG_OF)

static struct pca9633_platform_data *

pca9633_dt_init(struct i2c_client *client)
@@ -140,6 +259,12 @@ pca9633_dt_init(struct i2c_client *client) 
	else

		pdata->outdrv = PCA9633_OPEN_DRAIN;



	/* default to software blinking unless hardware blinking is specified */

	if (of_property_read_bool(np, "nxp,hw-blink"))

		pdata->blink_type = PCA9633_HW_BLINK;

	else

		pdata->blink_type = PCA9633_SW_BLINK;



	return pdata;

}
@@ -206,7 +331,10 @@ static int pca9633_probe(struct i2c_client *client, 
		pca9633[i].led_cdev.name = pca9633[i].name;

		pca9633[i].led_cdev.brightness_set = pca9633_led_set;



		INIT_WORK(&pca9633[i].work, pca9633_led_work);

		if (pdata && pdata->blink_type == PCA9633_HW_BLINK)

			pca9633[i].led_cdev.blink_set = pca9633_blink_set;



		INIT_WORK(&pca9633[i].work, pca9633_work);



		err = led_classdev_register(&client->dev, &pca9633[i].led_cdev);

		if (err < 0)

include/linux/platform_data/leds-pca9633.h

+6 −0
Original line number Diff line number Diff line
@@ -27,9 +27,15 @@ enum pca9633_outdrv { 
	PCA9633_TOTEM_POLE, /* aka push-pull */

};



enum pca9633_blink_type {

	PCA9633_SW_BLINK,

	PCA9633_HW_BLINK,

};



struct pca9633_platform_data {

	struct led_platform_data leds;

	enum pca9633_outdrv outdrv;

	enum pca9633_blink_type blink_type;

};



#endif /* __LINUX_PCA9633_H*/

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