linux-kernel - [PATCH v2] leds: cat9532: support cat9532 in pca955x

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [day] [month] [year] [list]

Message-Id: <20250224082815.1827487-1-delphine_cc_chiu@wiwynn.com>
Date: Mon, 24 Feb 2025 16:28:15 +0800
From: Delphine CC Chiu <delphine_cc_chiu@...ynn.com>
To: patrick@...cx.xyz,
	Lee Jones <lee@...nel.org>,
	Pavel Machek <pavel@...nel.org>
Cc: MarshallZhan-wiwynn <marshall_zhan@...ynn.com>,
	Delphine CC Chiu <delphine_cc_chiu@...ynn.com>,
	linux-leds@...r.kernel.org,
	linux-kernel@...r.kernel.org
Subject: [PATCH v2] leds: cat9532: support cat9532 in pca955x

From: MarshallZhan-wiwynn <marshall_zhan@...ynn.com>

The CAT9532 chips are almost 100% compatible with PCA9552, except that
the CAT9532 uses the opposite polarity in register that sets on/off.

Compare the state at INPUT with the state of LSn and dynamically
adjust how you program LSn

Signed-off-by: MarshallZhan <marshall_zhan@...ynn.com>
Signed-off-by: Delphine CC Chiu <delphine_cc_chiu@...ynn.com>
---
 drivers/leds/leds-pca955x.c | 41 +++++++++++++++++++++++++++++++------
 1 file changed, 35 insertions(+), 6 deletions(-)

diff --git a/drivers/leds/leds-pca955x.c b/drivers/leds/leds-pca955x.c
index 94a9f8a54b35..447da4a2d089 100644
--- a/drivers/leds/leds-pca955x.c
+++ b/drivers/leds/leds-pca955x.c
@@ -4,7 +4,7 @@
  *
  * Author: Nate Case <ncase@...-inc.com>
  *
- * LED driver for various PCA955x I2C LED drivers
+ * LED driver for various PCA955x and CAT9532 I2C LED drivers
  *
  * Supported devices:
  *
@@ -145,6 +145,11 @@ static inline u8 pca955x_ledsel(u8 oldval, int led_num, int state)
 		((state & 0x3) << (led_num << 1));
 }
 
+static inline int pca955x_ledstate(u8 ls, int led_num)
+{
+	return (ls >> (led_num << 1)) & 0x3;
+}
+
 /*
  * Write to frequency prescaler register, used to program the
  * period of the PWM output.  period = (PSCx + 1) / 38
@@ -235,6 +240,21 @@ static int pca955x_read_pwm(struct i2c_client *client, int n, u8 *val)
 	return 0;
 }
 
+static int pca955x_read_input_bit(struct pca955x *pca955x, int led_num)
+{
+	u8 cmd = led_num / 8;
+	int input_state;
+
+	input_state= i2c_smbus_read_byte_data(pca955x->client, cmd);
+	if (input_state < 0) {
+		dev_err(&pca955x->client->dev, "%s: reg 0x%x, err %d\n", 
+				__func__, led_num, input_state);
+		return input_state;
+	}
+	return (input_state >> (led_num % 8)) & 1;
+
+}
+
 static enum led_brightness pca955x_led_get(struct led_classdev *led_cdev)
 {
 	struct pca955x_led *pca955x_led = container_of(led_cdev,
@@ -251,10 +271,11 @@ static enum led_brightness pca955x_led_get(struct led_classdev *led_cdev)
 	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;
+		if (pca955x_read_input_bit(pca955x, pca955x_led->led_num))
+			ret = LED_FULL;
+		else
+			ret = LED_OFF;
 		break;
 	case PCA955X_LS_BLINK0:
 		ret = LED_HALF;
@@ -276,6 +297,8 @@ static int pca955x_led_set(struct led_classdev *led_cdev,
 	struct pca955x_led *pca955x_led;
 	struct pca955x *pca955x;
 	u8 ls;
+	u8 ls_last_state;
+	int input_bit;
 	int chip_ls;	/* which LSx to use (0-3 potentially) */
 	int ls_led;	/* which set of bits within LSx to use (0-3) */
 	int ret;
@@ -292,12 +315,18 @@ static int pca955x_led_set(struct led_classdev *led_cdev,
 	if (ret)
 		goto out;
 
+	ls_last_state = pca955x_ledstate(ls, ls_led);
+	input_bit = pca955x_read_input_bit(pca955x, pca955x_led->led_num);
 	switch (value) {
 	case LED_FULL:
-		ls = pca955x_ledsel(ls, ls_led, PCA955X_LS_LED_ON);
+		ls = pca955x_ledsel(ls, ls_led,
+				(ls_last_state == input_bit) ? 
+				PCA955X_LS_LED_ON : PCA955X_LS_LED_OFF);
 		break;
 	case LED_OFF:
-		ls = pca955x_ledsel(ls, ls_led, PCA955X_LS_LED_OFF);
+		ls = pca955x_ledsel(ls, ls_led,
+				(ls_last_state == input_bit) ? 
+				PCA955X_LS_LED_OFF : PCA955X_LS_LED_ON);
 		break;
 	case LED_HALF:
 		ls = pca955x_ledsel(ls, ls_led, PCA955X_LS_BLINK0);
-- 
2.25.1