Implement support for setting the VOUT_SCALE_LOOP PMBus register
based on an optional device tree property
"mps,vout-fb-divider-ratio-permille".
This allows the driver to provide the correct VOUT value depending
on the feedback voltage divider configuration for chips where the
bootloader does not configure the VOUT_SCALE_LOOP register.
Signed-off-by: Pawel Dembicki <paweldembicki@xxxxxxxxx>
---
v4:
- no changes done
v3:
- droped comments and indexed the table with enums instead
- use device_property_read_u32() instead of_property_read_u32()
v2:
- renamed property to mps,vout-fb-divider-ratio-permille
- added register value range checking
---
drivers/hwmon/pmbus/mpq8785.c | 18 ++++++++++++++++++
1 file changed, 18 insertions(+)
diff --git a/drivers/hwmon/pmbus/mpq8785.c b/drivers/hwmon/pmbus/mpq8785.c
index d0ac294b4bbc..2e7c0d0c3f81 100644
--- a/drivers/hwmon/pmbus/mpq8785.c
+++ b/drivers/hwmon/pmbus/mpq8785.c
@@ -5,11 +5,16 @@
#include <linux/i2c.h>
#include <linux/module.h>
+#include <linux/property.h>
#include <linux/of_device.h>
#include "pmbus.h"
enum chips { mpq8785 };
+static u16 voltage_scale_loop_max_val[] = {
+ [mpq8785] = GENMASK(10, 0),
+};
+
static int mpq8785_identify(struct i2c_client *client,
struct pmbus_driver_info *info)
{
@@ -74,6 +79,8 @@ static int mpq8785_probe(struct i2c_client *client)
struct device *dev = &client->dev;
struct pmbus_driver_info *info;
enum chips chip_id;
+ u32 voltage_scale;
+ int ret;
info = devm_kmemdup(dev, &mpq8785_info, sizeof(*info), GFP_KERNEL);
if (!info)
@@ -92,6 +99,17 @@ static int mpq8785_probe(struct i2c_client *client)
return -ENODEV;
}
+ if (!device_property_read_u32(dev, "mps,vout-fb-divider-ratio-permille",
+ &voltage_scale)) {
+ if (voltage_scale > voltage_scale_loop_max_val[chip_id])
+ return -EINVAL;
+
+ ret = i2c_smbus_write_word_data(client, PMBUS_VOUT_SCALE_LOOP,
+ voltage_scale);
+ if (ret)
+ return ret;
+ }
+
return pmbus_do_probe(client, info);
};
--
2.43.0
