On Sun, Apr 15, 2018 at 12:31 PM, Jonathan Cameron <jic23@xxxxxxxxxx> wrote:
On Fri, 13 Apr 2018 13:36:46 -0300
HernÃn Gonzalez <hernan@xxxxxxxxxxxxxxxxxxxx> wrote:
This allows the driver to be probed and removed as a module powering itAs this is a one off operation, perhaps it would be better to factor
down on remove().
Signed-off-by: HernÃn Gonzalez <hernan@xxxxxxxxxxxxxxxxxxxx>
---
drivers/staging/iio/cdc/ad7746.c | 26 ++++++++++++++++++++++++++
1 file changed, 26 insertions(+)
diff --git a/drivers/staging/iio/cdc/ad7746.c b/drivers/staging/iio/cdc/ad7746.c
index c29a221..05506bf9 100644
--- a/drivers/staging/iio/cdc/ad7746.c
+++ b/drivers/staging/iio/cdc/ad7746.c
@@ -775,6 +775,31 @@ static int ad7746_probe(struct i2c_client *client,
return 0;
}
+static int ad7746_remove(struct i2c_client *client)
+{
+ struct iio_dev *indio_dev = i2c_get_clientdata(client);
+ struct ad7746_chip_info *chip = iio_priv(indio_dev);
+ unsigned char regval;
+ int ret;
+
+ mutex_lock(&chip->lock);
+
+ regval = chip->config | AD7746_CONF_MODE_PWRDN;
+ ret = i2c_smbus_write_byte_data(chip->client, AD7746_REG_CFG, regval);
it out to a utility function then use devm_add_action_or_reset in
the probe?
Also, I am nervous about this change as there doesn't seem to be
path in probe by which this is deliberately reversed?
It seems to be 'accidentally' handled by the read_raw write to the
CFG register.
The data sheet doesn't really mention much about this register
at all. It may have special requirements to exit from power down - I have
no idea, but if it is costless, why do we bother with idle mode?
Perhaps Michael can confirm if this is safe to do or not.
I guess it'll be better to just drop this until Michael answers. I've
been trying to get a hold of the hw but with no success (or I have to
pay 3 times its cost in shipping), will keep searching though.
+You can't safely do this against the devm_iio_device_register.
+ mutex_unlock(&chip->lock);
+
+ if (ret < 0) {
+ dev_warn(&client->dev, "Could NOT Power Down!\n");
+ goto out;
+ }
+
+ iio_device_unregister(indio_dev);
+
+out:
+ return ret;
+}
+
static const struct i2c_device_id ad7746_id[] = {
{ "ad7745", 7745 },
{ "ad7746", 7746 },
@@ -799,6 +824,7 @@ static struct i2c_driver ad7746_driver = {
.of_match_table = of_match_ptr(ad7746_of_match),
},
.probe = ad7746_probe,
+ .remove = ad7746_remove,
.id_table = ad7746_id,
};
module_i2c_driver(ad7746_driver);