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From: Eddie James <eajames@linux.ibm.com>
To: joel@jms.id.au
Cc: openbmc@lists.ozlabs.org
Subject: [PATCH linux dev-5.10 4/7] leds: pca955x: Add brightness_get function
Date: Thu, 16 Sep 2021 16:21:37 -0500	[thread overview]
Message-ID: <20210916212140.33915-5-eajames@linux.ibm.com> (raw)
In-Reply-To: <20210916212140.33915-1-eajames@linux.ibm.com>

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

Signed-off-by: Eddie James <eajames@linux.ibm.com>
Signed-off-by: Pavel Machek <pavel@ucw.cz>
---
 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


  parent reply	other threads:[~2021-09-16 21:23 UTC|newest]

Thread overview: 9+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-09-16 21:21 [PATCH linux dev-5.10 0/7] leds: Support retaining state for the PCA955x Eddie James
2021-09-16 21:21 ` [PATCH linux dev-5.10 1/7] dt-bindings: leds: Add retain-state-shutdown boolean Eddie James
2021-09-16 21:21 ` [PATCH linux dev-5.10 2/7] leds: leds-core: Implement the retain-state-shutdown property Eddie James
2021-09-16 21:21 ` [PATCH linux dev-5.10 3/7] leds: pca955x: Clean up code formatting Eddie James
2021-09-16 21:21 ` Eddie James [this message]
2021-09-16 21:21 ` [PATCH linux dev-5.10 5/7] leds: pca955x: Implement the default-state property Eddie James
2021-09-16 21:21 ` [PATCH linux dev-5.10 6/7] leds: pca955x: Let the core process the fwnode Eddie James
2021-09-16 21:21 ` [PATCH linux dev-5.10 7/7] leds: pca955x: Switch to i2c probe_new Eddie James
2021-09-22  2:21 ` [PATCH linux dev-5.10 0/7] leds: Support retaining state for the PCA955x Joel Stanley

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