hwmon: (pmbus/tps53679) Add support for TPS53685

The TPS53685 is a fully AMD SVI3 compliant step down controller with
trans-inductor voltage regulator(TLVR) topology support, dual channels,
built-in non-volatile memory (NVM), PMBus interface, and full compatible
with TI NexFET smart power stages.

Add support for it to the tps53679 driver.

Signed-off-by: Chiang Brian <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Guenter Roeck <[email protected]>

Author: BrianChiang0425

Documentation/hwmon/tps53679.rst

@@ -43,6 +43,14 @@ Supported chips:
 
     Datasheet: https://www.ti.com/lit/gpn/TPS53681
 
+  * Texas Instruments TPS53685
+
+    Prefix: 'tps53685'
+
+    Addresses scanned: -
+
+    Datasheet: https://www.ti.com/lit/gpn/TPS53685
+
   * Texas Instruments TPS53688
 
     Prefix: 'tps53688'

drivers/hwmon/pmbus/tps53679.c

@@ -16,7 +16,7 @@
 #include "pmbus.h"
 
 enum chips {
-	tps53647, tps53667, tps53676, tps53679, tps53681, tps53688
+	tps53647, tps53667, tps53676, tps53679, tps53681, tps53685, tps53688
 };
 
 #define TPS53647_PAGE_NUM		1
@@ -31,7 +31,8 @@ enum chips {
 #define TPS53679_PROT_VR13_5MV		0x07 /* VR13.0 mode, 5-mV DAC */
 #define TPS53679_PAGE_NUM		2
 
-#define TPS53681_DEVICE_ID		0x81
+#define TPS53681_DEVICE_ID     "\x81"
+#define TPS53685_DEVICE_ID     "TIShP"
 
 #define TPS53681_PMBUS_REVISION		0x33
 
@@ -86,10 +87,12 @@ static int tps53679_identify_phases(struct i2c_client *client,
 }
 
 static int tps53679_identify_chip(struct i2c_client *client,
-				  u8 revision, u16 id)
+				  u8 revision, char *id)
 {
 	u8 buf[I2C_SMBUS_BLOCK_MAX];
 	int ret;
+	int buf_len;
+	int id_len;
 
 	ret = pmbus_read_byte_data(client, 0, PMBUS_REVISION);
 	if (ret < 0)
@@ -102,8 +105,14 @@ static int tps53679_identify_chip(struct i2c_client *client,
 	ret = i2c_smbus_read_block_data(client, PMBUS_IC_DEVICE_ID, buf);
 	if (ret < 0)
 		return ret;
-	if (ret != 1 || buf[0] != id) {
-		dev_err(&client->dev, "Unexpected device ID 0x%x\n", buf[0]);
+
+	/* Adjust length if null terminator if present */
+	buf_len = (buf[ret - 1] != '\x00' ? ret : ret - 1);
+
+	id_len = strlen(id);
+
+	if (buf_len != id_len || strncmp(id, buf, id_len)) {
+		dev_err(&client->dev, "Unexpected device ID: %*ph\n", ret, buf);
 		return -ENODEV;
 	}
 	return 0;
@@ -117,7 +126,7 @@ static int tps53679_identify_chip(struct i2c_client *client,
  */
 static int tps53679_identify_multiphase(struct i2c_client *client,
 					struct pmbus_driver_info *info,
-					int pmbus_rev, int device_id)
+					int pmbus_rev, char *device_id)
 {
 	int ret;
 
@@ -138,6 +147,16 @@ static int tps53679_identify(struct i2c_client *client,
 	return tps53679_identify_mode(client, info);
 }
 
+static int tps53685_identify(struct i2c_client *client,
+			     struct pmbus_driver_info *info)
+{
+	info->func[1] |= PMBUS_HAVE_VIN | PMBUS_HAVE_IIN | PMBUS_HAVE_PIN |
+			 PMBUS_HAVE_STATUS_INPUT;
+	info->format[PSC_VOLTAGE_OUT] = linear;
+	return tps53679_identify_chip(client, TPS53681_PMBUS_REVISION,
+					   TPS53685_DEVICE_ID);
+}
+
 static int tps53681_identify(struct i2c_client *client,
 			     struct pmbus_driver_info *info)
 {
@@ -263,6 +282,10 @@ static int tps53679_probe(struct i2c_client *client)
 		info->identify = tps53681_identify;
 		info->read_word_data = tps53681_read_word_data;
 		break;
+	case tps53685:
+		info->pages = TPS53679_PAGE_NUM;
+		info->identify = tps53685_identify;
+		break;
 	default:
 		return -ENODEV;
 	}
@@ -277,6 +300,7 @@ static const struct i2c_device_id tps53679_id[] = {
 	{"tps53676", tps53676},
 	{"tps53679", tps53679},
 	{"tps53681", tps53681},
+	{"tps53685", tps53685},
 	{"tps53688", tps53688},
 	{}
 };
@@ -289,6 +313,7 @@ static const struct of_device_id __maybe_unused tps53679_of_match[] = {
 	{.compatible = "ti,tps53676", .data = (void *)tps53676},
 	{.compatible = "ti,tps53679", .data = (void *)tps53679},
 	{.compatible = "ti,tps53681", .data = (void *)tps53681},
+	{.compatible = "ti,tps53685", .data = (void *)tps53685},
 	{.compatible = "ti,tps53688", .data = (void *)tps53688},
 	{}
 };