[RESEND v4 12/15] iio: adc: aspeed: Add func to set sampling rate.

Jonathan Cameron
2021-08-30T09:52:13Z

On Mon, 30 Aug 2021 08:35:53 +0000
Billy Tsai <billy_tsai@aspeedtech.com> wrote:

> Hi Jonathan,
>
> On 2021/8/29, 11:33 PM, "Jonathan Cameron" <jic23@kernel.org> wrote:
>
> On Tue, 24 Aug 2021 17:12:40 +0800
> Billy Tsai <billy_tsai@aspeedtech.com> wrote:
>
> >> Add the function to set the sampling rate and keep the sampling period
> >> for a driver used to wait the lastest value.
> >>
> >> Signed-off-by: Billy Tsai <billy_tsai@aspeedtech.com>
>
> > Why move the code as well as factoring out the setter function?
> > I doubt it does any harm, but I'd like to understand why you did it.
>
> > Jonathan
>
> >> + ret = clk_prepare_enable(data->clk_scaler->clk);
> >> + if (ret)
> >> + return ret;
> >> +
> >> + ret = devm_add_action_or_reset(data->dev,
> >> + aspeed_adc_clk_disable_unprepare,
> >> + data->clk_scaler->clk);
> >> + if (ret)
> >> + return ret;
> >> +
> >> + ret = aspeed_adc_set_sampling_rate(indio_dev, ASPEED_ADC_DEF_SAMPLING_RATE);
> >> + if (ret)
> >> + return ret;
> >> +
> >> ret = aspeed_adc_vref_config(indio_dev);
> >> if (ret)
> >> return ret;
> >> @@ -413,16 +445,6 @@ static int aspeed_adc_probe(struct platform_device *pdev)
> >> }
> >>
> >> /* Start all channels in normal mode. */
>
> > Why move this code up?
>
> Because the ADC clock is required when initializing the ADC device.
> In our system, the clock is always on. Thus, the legacy driver won't encounter any issues.
> I move the clk_prepare_enable ahead of initializing phase for making the driver probe logically closer to the hardware.

Thanks. Please add something to the patch description to say this.

Jonathan

>
> >> - ret = clk_prepare_enable(data->clk_scaler->clk);
> >> - if (ret)
> >> - return ret;
> >> -
> >> - ret = devm_add_action_or_reset(data->dev,
> >> - aspeed_adc_clk_disable_unprepare,
> >> - data->clk_scaler->clk);
> >> - if (ret)
> >> - return ret;
> >> -
> >> adc_engine_control_reg_val =
> >> readl(data->base + ASPEED_REG_ENGINE_CONTROL);
> >> adc_engine_control_reg_val |=
>
>
> Best Regards,
> Billy Tsai
>