[PATCH v4 4/5] hwmon: (adt7475) Add attenuator bypass support

Chris Packham
2020-02-21T04:16:59Z

From: Logan Shaw <logan.shaw@alliedtelesis.co.nz>

Added support for reading DTS properties to set attenuators on
device probe for the ADT7473, ADT7475, ADT7476, and ADT7490.

Signed-off-by: Logan Shaw <logan.shaw@alliedtelesis.co.nz>
Signed-off-by: Chris Packham <chris.packham@alliedtelesis.co.nz>
---

Notes:
Changes in v4:
- use vendor prefix for new property

Changes in v3:
- move config2 to struct adt7475_data
- set_property_bit() new helper function to set/clear bit based on dt
property value.
- rename to use load_attenuators()

drivers/hwmon/adt7475.c | 61 +++++++++++++++++++++++++++++++++++++++--
1 file changed, 58 insertions(+), 3 deletions(-)

diff --git a/drivers/hwmon/adt7475.c b/drivers/hwmon/adt7475.c
index 01c2eeb02aa9..3649b18359dc 100644
--- a/drivers/hwmon/adt7475.c
+++ b/drivers/hwmon/adt7475.c
@@ -19,6 +19,7 @@
#include <linux/hwmon-vid.h>
#include <linux/err.h>
#include <linux/jiffies.h>
+#include <linux/of.h>
#include <linux/util_macros.h>

/* Indexes for the sysfs hooks */
@@ -193,6 +194,7 @@ struct adt7475_data {
unsigned long measure_updated;
bool valid;

+ u8 config2;
u8 config4;
u8 config5;
u8 has_voltage;
@@ -1458,6 +1460,55 @@ static int adt7475_update_limits(struct i2c_client *client)
return 0;
}

+static int set_property_bit(const struct i2c_client *client, char *property,
+ u8 *config, u8 bit_index)
+{
+ u32 prop_value = 0;
+ int ret = of_property_read_u32(client->dev.of_node, property,
+ &prop_value);
+
+ if (!ret) {
+ if (prop_value)
+ *config |= (1 << bit_index);
+ else
+ *config &= ~(1 << bit_index);
+ }
+
+ return ret;
+}
+
+static int load_attenuators(const struct i2c_client *client, int chip,
+ struct adt7475_data *data)
+{
+ int ret;
+
+ if (chip == adt7476 || chip == adt7490) {
+ set_property_bit(client, "adi,bypass-attenuator-in0",
+ &data->config4, 4);
+ set_property_bit(client, "adi,bypass-attenuator-in1",
+ &data->config4, 5);
+ set_property_bit(client, "adi,bypass-attenuator-in3",
+ &data->config4, 6);
+ set_property_bit(client, "adi,bypass-attenuator-in4",
+ &data->config4, 7);
+
+ ret = i2c_smbus_write_byte_data(client, REG_CONFIG4,
+ data->config4);
+ if (ret < 0)
+ return ret;
+ } else if (chip == adt7473 || chip == adt7475) {
+ set_property_bit(client, "adi,bypass-attenuator-in1",
+ &data->config2, 5);
+
+ ret = i2c_smbus_write_byte_data(client, REG_CONFIG2,
+ data->config2);
+ if (ret < 0)
+ return ret;
+ }
+
+ return 0;
+}
+
static int adt7475_probe(struct i2c_client *client,
const struct i2c_device_id *id)
{
@@ -1472,7 +1523,7 @@ static int adt7475_probe(struct i2c_client *client,
struct adt7475_data *data;
struct device *hwmon_dev;
int i, ret = 0, revision, group_num = 0;
- u8 config2, config3;
+ u8 config3;

data = devm_kzalloc(&client->dev, sizeof(*data), GFP_KERNEL);
if (data == NULL)
@@ -1546,8 +1597,12 @@ static int adt7475_probe(struct i2c_client *client,
}

/* Voltage attenuators can be bypassed, globally or individually */
- config2 = adt7475_read(REG_CONFIG2);
- if (config2 & CONFIG2_ATTN) {
+ data->config2 = adt7475_read(REG_CONFIG2);
+ ret = load_attenuators(client, chip, data);
+ if (ret)
+ dev_err(&client->dev, "Error configuring attenuator bypass\n");
+
+ if (data->config2 & CONFIG2_ATTN) {
data->bypass_attn = (0x3 << 3) | 0x3;
} else {
data->bypass_attn = ((data->config4 & CONFIG4_ATTN_IN10) >> 4) |
--
2.25.0