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>
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@ -5,6 +5,7 @@ Required properties:
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Optional properties:
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- nxp,totem-pole : use totem pole (push-pull) instead of default open-drain
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- nxp,hw-blink : use hardware blinking instead of software blinking
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Each led is represented as a sub-node of the nxp,pca9633 device.
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@ -11,6 +11,15 @@
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*
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* LED driver for the PCA9633 I2C LED driver (7-bit slave address 0x62)
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*
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* Note that hardware blinking violates the leds infrastructure driver
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* interface since the hardware only supports blinking all LEDs with the
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* same delay_on/delay_off rates. That is, only the LEDs that are set to
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* blink will actually blink but all LEDs that are set to blink will blink
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* in identical fashion. The delay_on/delay_off values of the last LED
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* that is set to blink will be used for all of the blinking LEDs.
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* Hardware blinking is disabled by default but can be enabled by setting
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* the 'blink_type' member in the platform_data struct to 'PCA9633_HW_BLINK'
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* or by adding the 'nxp,hw-blink' property to the DTS.
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*/
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#include <linux/module.h>
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@ -31,30 +40,44 @@
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#define PCA9633_LED_PWM 0x2 /* Controlled through PWM */
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#define PCA9633_LED_GRP_PWM 0x3 /* Controlled through PWM/GRPPWM */
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#define PCA9633_MODE2_DMBLNK 0x20 /* Enable blinking */
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#define PCA9633_MODE1 0x00
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#define PCA9633_MODE2 0x01
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#define PCA9633_PWM_BASE 0x02
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#define PCA9633_GRPPWM 0x06
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#define PCA9633_GRPFREQ 0x07
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#define PCA9633_LEDOUT 0x08
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/* Total blink period in milliseconds */
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#define PCA9632_BLINK_PERIOD_MIN 42
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#define PCA9632_BLINK_PERIOD_MAX 10667
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static const struct i2c_device_id pca9633_id[] = {
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{ "pca9633", 0 },
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{ }
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};
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MODULE_DEVICE_TABLE(i2c, pca9633_id);
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enum pca9633_cmd {
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BRIGHTNESS_SET,
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BLINK_SET,
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};
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struct pca9633_led {
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struct i2c_client *client;
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struct work_struct work;
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enum led_brightness brightness;
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struct led_classdev led_cdev;
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int led_num; /* 0 .. 3 potentially */
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enum pca9633_cmd cmd;
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char name[32];
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u8 gdc;
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u8 gfrq;
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};
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static void pca9633_led_work(struct work_struct *work)
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static void pca9633_brightness_work(struct pca9633_led *pca9633)
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{
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struct pca9633_led *pca9633 = container_of(work,
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struct pca9633_led, work);
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u8 ledout = i2c_smbus_read_byte_data(pca9633->client, PCA9633_LEDOUT);
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int shift = 2 * pca9633->led_num;
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u8 mask = 0x3 << shift;
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@ -78,6 +101,43 @@ static void pca9633_led_work(struct work_struct *work)
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}
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}
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static void pca9633_blink_work(struct pca9633_led *pca9633)
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{
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u8 ledout = i2c_smbus_read_byte_data(pca9633->client, PCA9633_LEDOUT);
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u8 mode2 = i2c_smbus_read_byte_data(pca9633->client, PCA9633_MODE2);
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int shift = 2 * pca9633->led_num;
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u8 mask = 0x3 << shift;
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i2c_smbus_write_byte_data(pca9633->client, PCA9633_GRPPWM,
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pca9633->gdc);
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i2c_smbus_write_byte_data(pca9633->client, PCA9633_GRPFREQ,
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pca9633->gfrq);
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if (!(mode2 & PCA9633_MODE2_DMBLNK))
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i2c_smbus_write_byte_data(pca9633->client, PCA9633_MODE2,
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mode2 | PCA9633_MODE2_DMBLNK);
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if ((ledout & mask) != (PCA9633_LED_GRP_PWM << shift))
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i2c_smbus_write_byte_data(pca9633->client, PCA9633_LEDOUT,
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(ledout & ~mask) | (PCA9633_LED_GRP_PWM << shift));
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}
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static void pca9633_work(struct work_struct *work)
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{
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struct pca9633_led *pca9633 = container_of(work,
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struct pca9633_led, work);
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switch (pca9633->cmd) {
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case BRIGHTNESS_SET:
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pca9633_brightness_work(pca9633);
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break;
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case BLINK_SET:
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pca9633_blink_work(pca9633);
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break;
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}
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}
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static void pca9633_led_set(struct led_classdev *led_cdev,
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enum led_brightness value)
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{
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@ -85,6 +145,7 @@ static void pca9633_led_set(struct led_classdev *led_cdev,
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pca9633 = container_of(led_cdev, struct pca9633_led, led_cdev);
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pca9633->cmd = BRIGHTNESS_SET;
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pca9633->brightness = value;
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/*
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@ -94,6 +155,64 @@ static void pca9633_led_set(struct led_classdev *led_cdev,
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schedule_work(&pca9633->work);
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}
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static int pca9633_blink_set(struct led_classdev *led_cdev,
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unsigned long *delay_on, unsigned long *delay_off)
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{
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struct pca9633_led *pca9633;
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unsigned long time_on, time_off, period;
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u8 gdc, gfrq;
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pca9633 = container_of(led_cdev, struct pca9633_led, led_cdev);
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time_on = *delay_on;
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time_off = *delay_off;
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/* If both zero, pick reasonable defaults of 500ms each */
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if (!time_on && !time_off) {
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time_on = 500;
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time_off = 500;
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}
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period = time_on + time_off;
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/* If period not supported by hardware, default to someting sane. */
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if ((period < PCA9632_BLINK_PERIOD_MIN) ||
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(period > PCA9632_BLINK_PERIOD_MAX)) {
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time_on = 500;
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time_off = 500;
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period = time_on + time_off;
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}
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/*
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* From manual: duty cycle = (GDC / 256) ->
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* (time_on / period) = (GDC / 256) ->
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* GDC = ((time_on * 256) / period)
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*/
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gdc = (time_on * 256) / period;
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/*
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* From manual: period = ((GFRQ + 1) / 24) in seconds.
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* So, period (in ms) = (((GFRQ + 1) / 24) * 1000) ->
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* GFRQ = ((period * 24 / 1000) - 1)
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*/
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gfrq = (period * 24 / 1000) - 1;
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pca9633->cmd = BLINK_SET;
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pca9633->gdc = gdc;
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pca9633->gfrq = gfrq;
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/*
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* Must use workqueue for the actual I/O since I2C operations
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* can sleep.
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*/
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schedule_work(&pca9633->work);
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*delay_on = time_on;
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*delay_off = time_off;
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return 0;
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}
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#if IS_ENABLED(CONFIG_OF)
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static struct pca9633_platform_data *
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pca9633_dt_init(struct i2c_client *client)
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@ -140,6 +259,12 @@ pca9633_dt_init(struct i2c_client *client)
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else
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pdata->outdrv = PCA9633_OPEN_DRAIN;
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/* default to software blinking unless hardware blinking is specified */
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if (of_property_read_bool(np, "nxp,hw-blink"))
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pdata->blink_type = PCA9633_HW_BLINK;
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else
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pdata->blink_type = PCA9633_SW_BLINK;
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return pdata;
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}
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@ -206,7 +331,10 @@ static int pca9633_probe(struct i2c_client *client,
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pca9633[i].led_cdev.name = pca9633[i].name;
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pca9633[i].led_cdev.brightness_set = pca9633_led_set;
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INIT_WORK(&pca9633[i].work, pca9633_led_work);
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if (pdata && pdata->blink_type == PCA9633_HW_BLINK)
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pca9633[i].led_cdev.blink_set = pca9633_blink_set;
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INIT_WORK(&pca9633[i].work, pca9633_work);
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err = led_classdev_register(&client->dev, &pca9633[i].led_cdev);
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if (err < 0)
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@ -27,9 +27,15 @@ enum pca9633_outdrv {
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PCA9633_TOTEM_POLE, /* aka push-pull */
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};
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enum pca9633_blink_type {
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PCA9633_SW_BLINK,
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PCA9633_HW_BLINK,
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};
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struct pca9633_platform_data {
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struct led_platform_data leds;
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enum pca9633_outdrv outdrv;
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enum pca9633_blink_type blink_type;
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};
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#endif /* __LINUX_PCA9633_H*/
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