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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: Mark A. Greer <mgreer@animalcreek.com>
Reported-by: Fengguang Wu <fengguang.wu@intel.com>
Signed-off-by: Bryan Wu <cooloney@gmail.com>
hifive-unleashed-5.1
Mark A. Greer 2013-07-25 10:16:41 -07:00 committed by Bryan Wu
parent 33b3a561f4
commit 8465b01827
3 changed files with 139 additions and 4 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

1
Documentation/devicetree/bindings/leds/pca9633.txt
View File

@ -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.

136
drivers/leds/leds-pca9633.c
View File

@ -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)

6
include/linux/platform_data/leds-pca9633.h
View File

@ -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*/