[PATCH v3 2/2] hwmon: (pmbus/lm25066) add current limit configuration support

[Potin Lai]

Add support for the 'ti,current-range' devicetree property to configure
the current limit via the DEVICE_SETUP (0xD9) register, overriding the
physical CL pin setting.

This configuration is supported on all chips in this driver (LM25066,
LM5064, LM5066, LM5066i) except LM25056.

The property values "low" and "high" map to:
- LM25066: low = 25 mV, high = 46 mV
- LM5064, LM5066, LM5066i: low = 26 mV, high = 50 mV

The Bit 4 mapping to High/Low current limit is handled dynamically on
probe because it is swapped for LM25066 compared to the other supported
chips.

Signed-off-by: Potin Lai <potin.lai.pt@xxxxxxxxx>
---
 drivers/hwmon/pmbus/lm25066.c | 37 +++++++++++++++++++++++++++++++++++++
 1 file changed, 37 insertions(+)

diff --git a/drivers/hwmon/pmbus/lm25066.c b/drivers/hwmon/pmbus/lm25066.c
index dd7275a67a0a..53d274033d66 100644
--- a/drivers/hwmon/pmbus/lm25066.c
+++ b/drivers/hwmon/pmbus/lm25066.c
@@ -34,6 +34,7 @@ enum chips { lm25056, lm25066, lm5064, lm5066, lm5066i };
 #define LM25066_READ_AVG_PIN		0xdf
 
 #define LM25066_DEV_SETUP_CL		BIT(4)	/* Current limit */
+#define LM25066_DEV_SETUP_CL_CFG	BIT(2)	/* Current limit configuration */
 
 #define LM25066_SAMPLES_FOR_AVG_MAX	4096
 
@@ -484,6 +485,42 @@ static int lm25066_probe(struct i2c_client *client)
 
 	data->id = (enum chips)(unsigned long)i2c_get_match_data(client);
 
+	if (data->id != lm25056) {
+		int config_new = config;
+		const char *cl_setting;
+		int ret;
+
+		if (!of_property_read_string(client->dev.of_node,
+					     "ti,current-range", &cl_setting)) {
+			config_new |= LM25066_DEV_SETUP_CL_CFG;
+			if (strcmp(cl_setting, "high") == 0) {
+				if (data->id == lm25066)
+					config_new |= LM25066_DEV_SETUP_CL;
+				else
+					config_new &= ~LM25066_DEV_SETUP_CL;
+			} else if (strcmp(cl_setting, "low") == 0) {
+				if (data->id == lm25066)
+					config_new &= ~LM25066_DEV_SETUP_CL;
+				else
+					config_new |= LM25066_DEV_SETUP_CL;
+			} else {
+				dev_err(&client->dev,
+					"invalid current-range setting: %s\n",
+					cl_setting);
+				return -EINVAL;
+			}
+		}
+
+		if (config_new != config) {
+			ret = i2c_smbus_write_byte_data(client,
+							LM25066_DEVICE_SETUP,
+							config_new);
+			if (ret < 0)
+				return ret;
+			config = config_new;
+		}
+	}
+
 	info = &data->info;
 
 	info->pages = 1;

-- 
2.52.0