[PATCH 4/5] leds: pca955x: Add brightness_get function

Eddie James
2021-04-29T20:50:27Z

Add a function to fetch the state of the hardware LED.

Signed-off-by: Eddie James <eajames@linux.ibm.com>
---
drivers/leds/leds-pca955x.c | 52 +++++++++++++++++++++++++++++++++++++
1 file changed, 52 insertions(+)

diff --git a/drivers/leds/leds-pca955x.c b/drivers/leds/leds-pca955x.c
index f0d841cb59fc..e47ba7c3b7c7 100644
--- a/drivers/leds/leds-pca955x.c
+++ b/drivers/leds/leds-pca955x.c
@@ -233,6 +233,57 @@ static int pca955x_read_ls(struct i2c_client *client, int n, u8 *val)
return 0;
}

+static int pca955x_read_pwm(struct i2c_client *client, int n, u8 *val)
+{
+ struct pca955x *pca955x = i2c_get_clientdata(client);
+ u8 cmd = pca95xx_num_input_regs(pca955x->chipdef->bits) + 1 + (2 * n);
+ int ret;
+
+ ret = i2c_smbus_read_byte_data(client, cmd);
+ if (ret < 0) {
+ dev_err(&client->dev, "%s: reg 0x%x, err %d\n",
+ __func__, n, ret);
+ return ret;
+ }
+ *val = (u8)ret;
+ return 0;
+}
+
+static enum led_brightness pca955x_led_get(struct led_classdev *led_cdev)
+{
+ struct pca955x_led *pca955x_led = container_of(led_cdev,
+ struct pca955x_led,
+ led_cdev);
+ struct pca955x *pca955x = pca955x_led->pca955x;
+ u8 ls, pwm;
+ int ret;
+
+ ret = pca955x_read_ls(pca955x->client, pca955x_led->led_num / 4, &ls);
+ if (ret)
+ return ret;
+
+ ls = (ls >> ((pca955x_led->led_num % 4) << 1)) & 0x3;
+ switch (ls) {
+ case PCA955X_LS_LED_ON:
+ ret = LED_FULL;
+ break;
+ case PCA955X_LS_LED_OFF:
+ ret = LED_OFF;
+ break;
+ case PCA955X_LS_BLINK0:
+ ret = LED_HALF;
+ break;
+ case PCA955X_LS_BLINK1:
+ ret = pca955x_read_pwm(pca955x->client, 1, &pwm);
+ if (ret)
+ return ret;
+ ret = 255 - pwm;
+ break;
+ }
+
+ return ret;
+}
+
static int pca955x_led_set(struct led_classdev *led_cdev,
enum led_brightness value)
{
@@ -512,6 +563,7 @@ static int pca955x_probe(struct i2c_client *client,

led->name = pca955x_led->name;
led->brightness_set_blocking = pca955x_led_set;
+ led->brightness_get = pca955x_led_get;

err = devm_led_classdev_register(&client->dev, led);
if (err)
--
2.27.0