[PATCH 6/6] hwmon: (pmbus/max20830): add support for max20830c and max20840c
From: Alexis Czezar Torreno
Date: Mon Jun 29 2026 - 22:54:24 EST
Add support for MAX20830C and MAX20840 step-down DC-DC switching
regulator with PMBus interface. MAX20830C is a different packaging
for MAX20830, and MAX20840C supports 40A regulation compared to
MAX20830 that is only 30A.
Signed-off-by: Alexis Czezar Torreno <alexisczezar.torreno@xxxxxxxxxx>
---
Documentation/hwmon/max20830.rst | 27 +++++++++++++---
drivers/hwmon/pmbus/max20830.c | 68 ++++++++++++++++++++++++++++------------
2 files changed, 70 insertions(+), 25 deletions(-)
diff --git a/Documentation/hwmon/max20830.rst b/Documentation/hwmon/max20830.rst
index 936e409dcc5c0898dde27d782308d4a7e1357e73..b850f3b6e40d1f1d0cec944be40af02265aced59 100644
--- a/Documentation/hwmon/max20830.rst
+++ b/Documentation/hwmon/max20830.rst
@@ -13,6 +13,22 @@ Supported chips:
Datasheet: https://www.analog.com/media/en/technical-documentation/data-sheets/max20830.pdf
+ * Analog Devices MAX20830C
+
+ Prefix: 'max20830c'
+
+ Addresses scanned: -
+
+ Datasheet:
+
+ * Analog Devices MAX20840C
+
+ Prefix: 'max20840c'
+
+ Addresses scanned: -
+
+ Datasheet:
+
Author:
- Alexis Czezar Torreno <alexisczezar.torreno@xxxxxxxxxx>
@@ -21,12 +37,13 @@ Author:
Description
-----------
-This driver supports hardware monitoring for Analog Devices MAX20830
-Step-Down Switching Regulator with PMBus Interface.
+This driver supports hardware monitoring for Analog Devices MAX20830, MAX20830C
+and MAX20840C. These are Step-Down Switching Regulator with PMBus Interface.
-The MAX20830 is a 2.7V to 16V, 30A fully integrated step-down DC-DC switching
-regulator. Through the PMBus interface, the device can monitor input/output
-voltages, output current and temperature.
+MAX20830, and MAX20830C are 2.7V to 16V, 30A fully integrated step-down DC-DC
+switching regulators. MAX20840C is similar but can reach 40A. Through the PMBus
+interface, these devices can monitor input/output voltages, output current and
+temperature.
The driver is a client driver to the core PMBus driver. Please see
Documentation/hwmon/pmbus.rst for details on PMBus client drivers.
diff --git a/drivers/hwmon/pmbus/max20830.c b/drivers/hwmon/pmbus/max20830.c
index a3abd24437e8e7560264aad55fc4f456d30ae235..252c77beb243c5a2d90fcf96941605ff31439383 100644
--- a/drivers/hwmon/pmbus/max20830.c
+++ b/drivers/hwmon/pmbus/max20830.c
@@ -14,7 +14,30 @@
#include <linux/string.h>
#include "pmbus.h"
-#define MAX20830_IC_DEVICE_ID_LENGTH 9
+struct max20830_chip_info {
+ const char *id_str;
+ u8 id_length;
+};
+
+static const struct max20830_chip_info max20830_chip = {
+ /*
+ * MAX20830 IC_DEVICE_ID has a byte length of 9 despite being an 8
+ * character string, as it includes a null terminator. The other
+ * devices do not include null.
+ */
+ .id_str = "MAX20830\0",
+ .id_length = 9,
+};
+
+static const struct max20830_chip_info max20830c_chip = {
+ .id_str = "MAX20830C",
+ .id_length = 9,
+};
+
+static const struct max20830_chip_info max20840c_chip = {
+ .id_str = "MAX20840C",
+ .id_length = 9,
+};
struct max20830_data {
struct pmbus_driver_info info;
@@ -60,11 +83,14 @@ static struct pmbus_driver_info max20830_info = {
static int max20830_probe(struct i2c_client *client)
{
+ const struct max20830_chip_info *chip;
u8 buf[I2C_SMBUS_BLOCK_MAX + 1] = {};
struct max20830_data *data;
struct gpio_desc *enable_gpio;
int ret;
+ chip = i2c_get_match_data(client);
+
data = devm_kzalloc(&client->dev, sizeof(*data), GFP_KERNEL);
if (!data)
return -ENOMEM;
@@ -90,16 +116,14 @@ static int max20830_probe(struct i2c_client *client)
* which do not support SMBus block reads.
*/
if (i2c_check_functionality(client->adapter, I2C_FUNC_SMBUS_READ_BLOCK_DATA)) {
- /* Reads 9 Data bytes from MAX20830 */
ret = i2c_smbus_read_block_data(client, PMBUS_IC_DEVICE_ID, buf);
if (ret < 0)
return dev_err_probe(&client->dev, ret,
"Failed to read IC_DEVICE_ID\n");
} else {
- /* Reads 1 length byte + 9 Data bytes from MAX20830 */
+ /* Reads 1 length byte + data bytes */
ret = i2c_smbus_read_i2c_block_data(client, PMBUS_IC_DEVICE_ID,
- MAX20830_IC_DEVICE_ID_LENGTH + 1,
- buf);
+ chip->id_length + 1, buf);
if (ret < 0)
return dev_err_probe(&client->dev, ret,
"Failed to read IC_DEVICE_ID\n");
@@ -108,36 +132,40 @@ static int max20830_probe(struct i2c_client *client)
* match the format of i2c_smbus_read_block_data().
* Also adjust return value to reflect length byte removal.
*/
- memmove(buf, buf + 1, MAX20830_IC_DEVICE_ID_LENGTH);
+ memmove(buf, buf + 1, chip->id_length);
ret = ret - 1;
}
- /*
- * MAX20830 IC_DEVICE_ID sends string data "MAX20830\0".
- * Return value should at least be 9 bytes of data.
- */
- if (ret < MAX20830_IC_DEVICE_ID_LENGTH)
+ /* Verify we read the expected number of bytes */
+ if (ret < chip->id_length)
return dev_err_probe(&client->dev, -ENODEV,
- "IC_DEVICE_ID too short: expected at least 9 bytes, got %d\n",
- ret);
+ "IC_DEVICE_ID too short: expected %d bytes, got %d\n",
+ chip->id_length, ret);
+
+ /* Null-terminate the string */
+ buf[chip->id_length] = '\0';
- /* 9 bytes of data, buf[0]-buf[7] = "MAX20830", buf[8] = '\0' */
- buf[MAX20830_IC_DEVICE_ID_LENGTH - 1] = '\0';
- if (strncmp(buf, "MAX20830", MAX20830_IC_DEVICE_ID_LENGTH - 1))
+ /* Verify the device ID matches what we expect */
+ if (strncmp(buf, chip->id_str, chip->id_length))
return dev_err_probe(&client->dev, -ENODEV,
- "Unsupported device: '%s'\n", buf);
+ "Device mismatch: expected '%s', got '%s'\n",
+ chip->id_str, buf);
- return pmbus_do_probe(client, &max20830_info);
+ return pmbus_do_probe(client, &data->info);
}
static const struct i2c_device_id max20830_id[] = {
- {"max20830"},
+ { "max20830", (kernel_ulong_t)&max20830_chip },
+ { "max20830c", (kernel_ulong_t)&max20830c_chip },
+ { "max20840c", (kernel_ulong_t)&max20840c_chip },
{ }
};
MODULE_DEVICE_TABLE(i2c, max20830_id);
static const struct of_device_id max20830_of_match[] = {
- { .compatible = "adi,max20830" },
+ { .compatible = "adi,max20830", .data = &max20830_chip },
+ { .compatible = "adi,max20830c", .data = &max20830c_chip },
+ { .compatible = "adi,max20840c", .data = &max20840c_chip },
{ }
};
MODULE_DEVICE_TABLE(of, max20830_of_match);
--
2.34.1