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Subject[PATCH v5 5/5] hwmon: (adt7475) Add support for inverting pwm output
Date
Add a "adi,pwm-active-state" device-tree property to allow hardware
designs to use inverted logic on the PWM output.

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

Notes:
Changes in v5:
- change to adi,pwm-active-state
- uint32 array

Changes in v4:
- use vendor prefix for new property

Changes in v3:
- New

drivers/hwmon/adt7475.c | 34 ++++++++++++++++++++++++++++++++++
1 file changed, 34 insertions(+)

diff --git a/drivers/hwmon/adt7475.c b/drivers/hwmon/adt7475.c
index 3649b18359dc..142a4fec688b 100644
--- a/drivers/hwmon/adt7475.c
+++ b/drivers/hwmon/adt7475.c
@@ -1509,6 +1509,36 @@ static int load_attenuators(const struct i2c_client *client, int chip,
return 0;
}

+static int adt7475_set_pwm_polarity(struct i2c_client *client)
+{
+ u32 states[ADT7475_PWM_COUNT];
+ int ret, i;
+ u8 val;
+
+ ret = of_property_read_u32_array(client->dev.of_node,
+ "adi,pwm-active-state", states,
+ ARRAY_SIZE(states));
+ if (ret)
+ return ret;
+
+ for (i = 0; i < ADT7475_PWM_COUNT; i++) {
+ ret = adt7475_read(PWM_CONFIG_REG(i));
+ if (ret < 0)
+ return ret;
+ val = ret;
+ if (states[i])
+ val &= ~BIT(4);
+ else
+ val |= BIT(4);
+
+ ret = i2c_smbus_write_byte_data(client, PWM_CONFIG_REG(i), val);
+ if (ret)
+ return ret;
+ }
+
+ return 0;
+}
+
static int adt7475_probe(struct i2c_client *client,
const struct i2c_device_id *id)
{
@@ -1617,6 +1647,10 @@ static int adt7475_probe(struct i2c_client *client,
for (i = 0; i < ADT7475_PWM_COUNT; i++)
adt7475_read_pwm(client, i);

+ ret = adt7475_set_pwm_polarity(client);
+ if (ret && ret != -EINVAL)
+ dev_err(&client->dev, "Error configuring pwm polarity\n");
+
/* Start monitoring */
switch (chip) {
case adt7475:
--
2.25.1
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