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SubjectRe: [RFC PATCH 3/4] i2c: core: treat EPROBE_DEFER when acquiring SCL/SDA GPIOs
On Fri, Jun 19, 2020 at 05:19:03PM +0300, Codrin Ciubotariu wrote:
> Even if I2C bus GPIO recovery is optional, devm_gpiod_get() can return
> -EPROBE_DEFER, so we should at least treat that. This ends up with
> i2c_register_adapter() to be able to return -EPROBE_DEFER.
>
> Signed-off-by: Codrin Ciubotariu <codrin.ciubotariu@microchip.com>
> ---
> drivers/i2c/i2c-core-base.c | 22 ++++++++++++++++------
> 1 file changed, 16 insertions(+), 6 deletions(-)
>
> diff --git a/drivers/i2c/i2c-core-base.c b/drivers/i2c/i2c-core-base.c
> index 4ee29fec4e93..f8d9f2048ca8 100644
> --- a/drivers/i2c/i2c-core-base.c
> +++ b/drivers/i2c/i2c-core-base.c
> @@ -368,15 +368,16 @@ static int i2c_gpio_init_recovery(struct i2c_adapter *adap)
> return i2c_gpio_init_generic_recovery(adap);
> }
>
> -static void i2c_init_recovery(struct i2c_adapter *adap)
> +static int i2c_init_recovery(struct i2c_adapter *adap)
> {
> struct i2c_bus_recovery_info *bri = adap->bus_recovery_info;
> char *err_str;
>
> if (!bri)
> - return;
> + return 0;
>
> - i2c_gpio_init_recovery(adap);
> + if (i2c_gpio_init_recovery(adap) == -EPROBE_DEFER)
> + return -EPROBE_DEFER;
>
> if (!bri->recover_bus) {
> err_str = "no recover_bus() found";
> @@ -392,7 +393,7 @@ static void i2c_init_recovery(struct i2c_adapter *adap)
> if (gpiod_get_direction(bri->sda_gpiod) == 0)
> bri->set_sda = set_sda_gpio_value;
> }
> - return;
> + return 0;

This is correct but I think the code flow is/was confusing. Can you drop
this 'return' and use 'else if' for the next code block? I think this is
more readable.

> }
>
> if (bri->recover_bus == i2c_generic_scl_recovery) {
> @@ -407,10 +408,12 @@ static void i2c_init_recovery(struct i2c_adapter *adap)
> }
> }
>
> - return;
> + return 0;
> err:
> dev_err(&adap->dev, "Not using recovery: %s\n", err_str);
> adap->bus_recovery_info = NULL;
> +
> + return 0;

'return -EINVAL;' I'd suggest.

> }
>
> static int i2c_smbus_host_notify_to_irq(const struct i2c_client *client)
> @@ -1476,7 +1479,9 @@ static int i2c_register_adapter(struct i2c_adapter *adap)
> "Failed to create compatibility class link\n");
> #endif
>
> - i2c_init_recovery(adap);
> + res = i2c_init_recovery(adap);
> + if (res == -EPROBE_DEFER)
> + goto out_link;

Please move 'i2c_init_recovery' above the class-link creation. It
shouldn't make a difference but we can skip the extra label and the
ifdeffery.

>
> /* create pre-declared device nodes */
> of_i2c_register_devices(adap);
> @@ -1493,6 +1498,11 @@ static int i2c_register_adapter(struct i2c_adapter *adap)
>
> return 0;
>
> +out_link:
> +#ifdef CONFIG_I2C_COMPAT
> + class_compat_remove_link(i2c_adapter_compat_class, &adap->dev,
> + adap->dev.parent);
> +#endif
> out_reg:
> init_completion(&adap->dev_released);
> device_unregister(&adap->dev);
> --
> 2.25.1
>
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