Adding the actual author :-)
Regards,
Hans
On 12/07/2018 12:25 PM, Michael Nazzareno Trimarchi wrote:
> Hi
>
> On Fri, Dec 7, 2018 at 12:12 PM Hans Verkuil <hverkuil@xxxxxxxxx> wrote:
>>
>> Subject: [PATCH 4/5] si470x-i2c: Add optional reset-gpio support
>> Date: Wed, 5 Dec 2018 16:47:49 +0100
>> From: Paweł Chmiel <pawel.mikolaj.chmiel@xxxxxxxxx>
>> To: mchehab@xxxxxxxxxx, robh+dt@xxxxxxxxxx, mark.rutland@xxxxxxx
>> CC: hverkuil@xxxxxxxxx, fischerdouglasc@xxxxxxxxx, keescook@xxxxxxxxxxxx, linux-media@xxxxxxxxxxxxxxx, linux-kernel@xxxxxxxxxxxxxxx,
>> devicetree@xxxxxxxxxxxxxxx, Paweł Chmiel <pawel.mikolaj.chmiel@xxxxxxxxx>
>>
>> If reset-gpio is defined, use it to bring device out of reset.
>> Without this, it's not possible to access si470x registers.
>>
>> Signed-off-by: Paweł Chmiel <pawel.mikolaj.chmiel@xxxxxxxxx>
>> ---
>> For some reason this patch was not picked up by patchwork. Resending to see if
>> it is picked up now.
>> ---
>> drivers/media/radio/si470x/radio-si470x-i2c.c | 15 +++++++++++++++
>> drivers/media/radio/si470x/radio-si470x.h | 1 +
>> 2 files changed, 16 insertions(+)
>>
>> diff --git a/drivers/media/radio/si470x/radio-si470x-i2c.c b/drivers/media/radio/si470x/radio-si470x-i2c.c
>> index a7ac09c55188..15eea2b2c90f 100644
>> --- a/drivers/media/radio/si470x/radio-si470x-i2c.c
>> +++ b/drivers/media/radio/si470x/radio-si470x-i2c.c
>> @@ -28,6 +28,7 @@
>> #include <linux/i2c.h>
>> #include <linux/slab.h>
>> #include <linux/delay.h>
>> +#include <linux/gpio/consumer.h>
>> #include <linux/interrupt.h>
>> #include "radio-si470x.h"
>> @@ -392,6 +393,17 @@ static int si470x_i2c_probe(struct i2c_client *client,
>> radio->videodev.release = video_device_release_empty;
>> video_set_drvdata(&radio->videodev, radio);
>> + radio->gpio_reset = devm_gpiod_get_optional(&client->dev, "reset",
>> + GPIOD_OUT_LOW);
>> + if (IS_ERR(radio->gpio_reset)) {
>> + retval = PTR_ERR(radio->gpio_reset);
>> + dev_err(&client->dev, "Failed to request gpio: %d\n", retval);
>> + goto err_all;
>> + }
>> +
>> + if (radio->gpio_reset)
>> + gpiod_set_value(radio->gpio_reset, 1);
>> +
>> /* power up : need 110ms */
>> radio->registers[POWERCFG] = POWERCFG_ENABLE;
>> if (si470x_set_register(radio, POWERCFG) < 0) {
>> @@ -478,6 +490,9 @@ static int si470x_i2c_remove(struct i2c_client *client)
>> video_unregister_device(&radio->videodev);
>> + if (radio->gpio_reset)
>> + gpiod_set_value(radio->gpio_reset, 0);
>
> I have a question for you. If the gpio is the last of the bank
> acquired for this cpu, when you put to 0, then the gpio will
> be free on remove and the clock of the logic will be deactivated so I
> think that you don't have any
> garantee that the state will be 0
>
> Michael
>
>> +
>> return 0;
>> }
>> diff --git a/drivers/media/radio/si470x/radio-si470x.h b/drivers/media/radio/si470x/radio-si470x.h
>> index 35fa0f3bbdd2..6fd6a399cb77 100644
>> --- a/drivers/media/radio/si470x/radio-si470x.h
>> +++ b/drivers/media/radio/si470x/radio-si470x.h
>> @@ -189,6 +189,7 @@ struct si470x_device {
>> #if IS_ENABLED(CONFIG_I2C_SI470X)
>> struct i2c_client *client;
>> + struct gpio_desc *gpio_reset;
>> #endif
>> };
>> -- 2.17.1
>>
>
>
