[PATCH v2 2/2] hwmon: (pmbus/lm25066) add current limit configuration support

[Potin Lai]

Add support for the 'ti,current-limit' devicetree property. When
present, this property overrides the hardware configuration pins via the
DEVICE_SETUP (0xD9) register to set the Current Limit Configuration bit
(bit 2) and Current Limit Setting bit (bit 4) to "high" or "low".

The Bit 4 mapping to High/Low current limit is handled dynamically on
probe because it is swapped for lm25066 compared to other supported
chips (lm5064, lm5066, and lm5066i).

LM25056 is excluded since it does not support configuring the current
limit via software (bit 2 of DEVICE_SETUP register is reserved).

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..c8e7aa7c3acd 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-limit", &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-limit 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