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leds-pca9633: Add mutex to the ledout register
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To update an LED a register has to be read, updated and writen. If
another LED whas been updated at the same time, this could lead into
wrong updates.

This patch adds a common mutex to all the leds of the same chip to
protect the ledout register.

Signed-off-by: Ricardo Ribalda Delgado <ricardo.ribalda@gmail.com>
Signed-off-by: Bryan Wu <cooloney@gmail.com>
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Ricardo Ribalda Delgado authored and Bryan Wu committed Aug 27, 2013
1 parent a5cd98b commit a7d0e98
Showing 1 changed file with 55 additions and 31 deletions.
86 changes: 55 additions & 31 deletions drivers/leds/leds-pca9633.c
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Original file line number Diff line number Diff line change
Expand Up @@ -93,9 +93,17 @@ enum pca9633_cmd {
BLINK_SET,
};

struct pca9633_led {
struct i2c_client *client;
struct pca9633_led;

struct pca9633 {
struct pca9633_chipdef *chipdef;
struct mutex mutex;
struct i2c_client *client;
struct pca9633_led *leds;
};

struct pca9633_led {
struct pca9633 *chip;
struct work_struct work;
enum led_brightness brightness;
struct led_classdev led_cdev;
Expand All @@ -108,52 +116,60 @@ struct pca9633_led {

static void pca9633_brightness_work(struct pca9633_led *pca9633)
{
u8 ledout_addr = pca9633->chipdef->ledout_base + (pca9633->led_num / 4);
u8 ledout_addr = pca9633->chip->chipdef->ledout_base
+ (pca9633->led_num / 4);
u8 ledout;
int shift = 2 * (pca9633->led_num % 4);
u8 mask = 0x3 << shift;

ledout = i2c_smbus_read_byte_data(pca9633->client, ledout_addr);
mutex_lock(&pca9633->chip->mutex);
ledout = i2c_smbus_read_byte_data(pca9633->chip->client, ledout_addr);
switch (pca9633->brightness) {
case LED_FULL:
i2c_smbus_write_byte_data(pca9633->client, ledout_addr,
i2c_smbus_write_byte_data(pca9633->chip->client, ledout_addr,
(ledout & ~mask) | (PCA9633_LED_ON << shift));
break;
case LED_OFF:
i2c_smbus_write_byte_data(pca9633->client, ledout_addr,
i2c_smbus_write_byte_data(pca9633->chip->client, ledout_addr,
ledout & ~mask);
break;
default:
i2c_smbus_write_byte_data(pca9633->client,
i2c_smbus_write_byte_data(pca9633->chip->client,
PCA9633_PWM_BASE + pca9633->led_num,
pca9633->brightness);
i2c_smbus_write_byte_data(pca9633->client, ledout_addr,
i2c_smbus_write_byte_data(pca9633->chip->client, ledout_addr,
(ledout & ~mask) | (PCA9633_LED_PWM << shift));
break;
}
mutex_unlock(&pca9633->chip->mutex);
}

static void pca9633_blink_work(struct pca9633_led *pca9633)
{
u8 ledout_addr = pca9633->chipdef->ledout_base + (pca9633->led_num / 4);
u8 ledout = i2c_smbus_read_byte_data(pca9633->client, ledout_addr);
u8 mode2 = i2c_smbus_read_byte_data(pca9633->client, PCA9633_MODE2);
u8 ledout_addr = pca9633->chip->chipdef->ledout_base +
(pca9633->led_num / 4);
u8 ledout;
u8 mode2 = i2c_smbus_read_byte_data(pca9633->chip->client,
PCA9633_MODE2);
int shift = 2 * (pca9633->led_num % 4);
u8 mask = 0x3 << shift;

i2c_smbus_write_byte_data(pca9633->client, pca9633->chipdef->grppwm,
pca9633->gdc);
i2c_smbus_write_byte_data(pca9633->chip->client,
pca9633->chip->chipdef->grppwm, pca9633->gdc);

i2c_smbus_write_byte_data(pca9633->client, pca9633->chipdef->grpfreq,
pca9633->gfrq);
i2c_smbus_write_byte_data(pca9633->chip->client,
pca9633->chip->chipdef->grpfreq, pca9633->gfrq);

if (!(mode2 & PCA9633_MODE2_DMBLNK))
i2c_smbus_write_byte_data(pca9633->client, PCA9633_MODE2,
i2c_smbus_write_byte_data(pca9633->chip->client, PCA9633_MODE2,
mode2 | PCA9633_MODE2_DMBLNK);

mutex_lock(&pca9633->chip->mutex);
ledout = i2c_smbus_read_byte_data(pca9633->chip->client, ledout_addr);
if ((ledout & mask) != (PCA9633_LED_GRP_PWM << shift))
i2c_smbus_write_byte_data(pca9633->client, ledout_addr,
i2c_smbus_write_byte_data(pca9633->chip->client, ledout_addr,
(ledout & ~mask) | (PCA9633_LED_GRP_PWM << shift));
mutex_unlock(&pca9633->chip->mutex);
}

static void pca9633_work(struct work_struct *work)
Expand Down Expand Up @@ -318,6 +334,7 @@ pca9633_dt_init(struct i2c_client *client, struct pca9633_chipdef *chip)
static int pca9633_probe(struct i2c_client *client,
const struct i2c_device_id *id)
{
struct pca9633 *pca9633_chip;
struct pca9633_led *pca9633;
struct pca9633_platform_data *pdata;
struct pca9633_chipdef *chip;
Expand All @@ -341,17 +358,30 @@ static int pca9633_probe(struct i2c_client *client,
return -EINVAL;
}

pca9633_chip = devm_kzalloc(&client->dev, sizeof(*pca9633_chip),
GFP_KERNEL);
if (!pca9633_chip)
return -ENOMEM;
pca9633 = devm_kzalloc(&client->dev, chip->n_leds * sizeof(*pca9633),
GFP_KERNEL);
if (!pca9633)
return -ENOMEM;

i2c_set_clientdata(client, pca9633);
i2c_set_clientdata(client, pca9633_chip);

mutex_init(&pca9633_chip->mutex);
pca9633_chip->chipdef = chip;
pca9633_chip->client = client;
pca9633_chip->leds = pca9633;

/* Turn off LEDs by default*/
i2c_smbus_write_byte_data(client, chip->ledout_base, 0x00);
if (chip->n_leds > 4)
i2c_smbus_write_byte_data(client, chip->ledout_base + 1, 0x00);

for (i = 0; i < chip->n_leds; i++) {
pca9633[i].client = client;
pca9633[i].led_num = i;
pca9633[i].chipdef = chip;
pca9633[i].chip = pca9633_chip;

/* Platform data can specify LED names and default triggers */
if (pdata && i < pdata->leds.num_leds) {
Expand Down Expand Up @@ -389,11 +419,6 @@ static int pca9633_probe(struct i2c_client *client,
if (pdata && pdata->outdrv == PCA9633_OPEN_DRAIN)
i2c_smbus_write_byte_data(client, PCA9633_MODE2, 0x01);

/* Turn off LEDs */
i2c_smbus_write_byte_data(client, chip->ledout_base, 0x00);
if (chip->n_leds > 4)
i2c_smbus_write_byte_data(client, chip->ledout_base + 1, 0x00);

return 0;

exit:
Expand All @@ -407,14 +432,13 @@ static int pca9633_probe(struct i2c_client *client,

static int pca9633_remove(struct i2c_client *client)
{
struct pca9633_led *pca9633 = i2c_get_clientdata(client);
struct pca9633 *pca9633 = i2c_get_clientdata(client);
int i;

for (i = 0; i < pca9633->chipdef->n_leds; i++)
if (pca9633[i].client != NULL) {
led_classdev_unregister(&pca9633[i].led_cdev);
cancel_work_sync(&pca9633[i].work);
}
for (i = 0; i < pca9633->chipdef->n_leds; i++) {
led_classdev_unregister(&pca9633->leds[i].led_cdev);
cancel_work_sync(&pca9633->leds[i].work);
}

return 0;
}
Expand Down

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