[PATCH v4 5/5] hwmon: (adt7475) Add support for inverting pwm output

Chris Packham
2020-02-21T04:16:52Z

Add a "invert-pwm" device-tree property to allow hardware designs to use
inverted logic on the PWM output. Preserve the invert PWM output bit if
the property is not found to allow for bootloaders/bios which may have
configured this earlier.

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

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

Changes in v3:
- New

drivers/hwmon/adt7475.c | 39 +++++++++++++++++++++++++++++++++++++++
1 file changed, 39 insertions(+)

diff --git a/drivers/hwmon/adt7475.c b/drivers/hwmon/adt7475.c
index 3649b18359dc..13267181dde6 100644
--- a/drivers/hwmon/adt7475.c
+++ b/drivers/hwmon/adt7475.c
@@ -1509,6 +1509,41 @@ static int load_attenuators(const struct i2c_client *client, int chip,
return 0;
}

+static int adt7475_set_pwm_polarity(struct i2c_client *client)
+{
+ char *prop;
+ int ret, i;
+ u8 val;
+
+ for (i = 0; i < ADT7475_PWM_COUNT; i++) {
+ ret = adt7475_read(PWM_CONFIG_REG(i));
+ if (ret < 0)
+ return ret;
+ val = ret;
+ switch (i) {
+ case 0:
+ prop = "adi,invert-pwm1";
+ break;
+ case 1:
+ prop = "adi,invert-pwm2";
+ break;
+ case 2:
+ prop = "adi,invert-pwm3";
+ break;
+ }
+
+ ret = set_property_bit(client, prop, &val, 4);
+ if (ret)
+ continue;
+
+ 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 +1652,10 @@ 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)
+ dev_err(&client->dev, "Error configuring pwm polarity");
+
/* Start monitoring */
switch (chip) {
case adt7475:
--
2.25.0