From 1d238cba561b2cb180387b31d18850e9bdfdad8e Mon Sep 17 00:00:00 2001
From: Josh Martinez <8892161+joshermar@users.noreply.github.com>
Date: Sun, 20 Apr 2025 17:29:36 -0500
Subject: [PATCH] hwmon: aht10: Fix AHT20 initialization

The existing driver claims AHT20 support in i2c_device_id, but fails to:
1. Use the correct init command (0xBE for AHT20 vs 0xE1 for AHT10)
2. Omit AHT10_MODE_CYC which AHT20 doesn't support/require

Add proper initialization sequence and include "aosong,aht20" in the
device tree match table to fully support the AHT20.

Signed-off-by: Josh Martinez <8892161+joshermar@users.noreply.github.com>
---
 drivers/hwmon/aht10.c | 12 ++++++++++--
 1 file changed, 10 insertions(+), 2 deletions(-)

--- a/drivers/hwmon/aht10.c
+++ b/drivers/hwmon/aht10.c
@@ -37,6 +37,8 @@
 #define AHT10_CMD_MEAS	0b10101100
 #define AHT10_CMD_RST	0b10111010
 
+#define AHT20_CMD_INIT	0b10111110
+
 /*
  * Flags in the answer byte/command
  */
@@ -59,6 +61,7 @@ MODULE_DEVICE_TABLE(i2c, aht10_id);
 
 static const struct of_device_id aht10_of_id[] = {
 	{ .compatible = "aosong,aht10", },
+	{ .compatible = "aosong,aht20", },
 	{ }
 };
 MODULE_DEVICE_TABLE(of, aht10_of_id);
@@ -107,8 +110,13 @@ struct aht10_data {
  */
 static int aht10_init(struct aht10_data *data)
 {
-	const u8 cmd_init[] = {AHT10_CMD_INIT, AHT10_CAL_ENABLED | AHT10_MODE_CYC,
-			       0x00};
+	u8 cmd_init[] = {AHT10_CMD_INIT, AHT10_CAL_ENABLED | AHT10_MODE_CYC, 0x00};
+
+	if (data->crc8) { /* AHT20 */
+		cmd_init[0] = AHT20_CMD_INIT;
+		cmd_init[1] = AHT10_CAL_ENABLED;
+	}
+
 	int res;
 	u8 status;
 	struct i2c_client *client = data->client;