On Mon, 29 May 2017 11:28:19 +0200
Fabrice Gasnier <fabrice.gasnier@xxxxxx> wrote:
> STM32F4 requires one clock per ADC instance for register access. But,
> newer version of ADC hardware block have common bus clock for all
> instances (per instance driver isn't responsible for getting it).
> So, make it optional by default. Still, enforce it's required on STM32F4.
>
> Signed-off-by: Fabrice Gasnier <fabrice.gasnier@xxxxxx>
Applied.
> ---
> drivers/iio/adc/stm32-adc.c | 28 ++++++++++++++++++++--------
> 1 file changed, 20 insertions(+), 8 deletions(-)
>
> diff --git a/drivers/iio/adc/stm32-adc.c b/drivers/iio/adc/stm32-adc.c
> index 50b2538..2ba9ca9 100644
> --- a/drivers/iio/adc/stm32-adc.c
> +++ b/drivers/iio/adc/stm32-adc.c
> @@ -160,6 +160,7 @@ struct stm32_adc_regspec {
> * @regs: registers descriptions
> * @adc_info: per instance input channels definitions
> * @trigs: external trigger sources
> + * @clk_required: clock is required
> * @start_conv: routine to start conversions
> * @stop_conv: routine to stop conversions
> */
> @@ -167,6 +168,7 @@ struct stm32_adc_cfg {
> const struct stm32_adc_regspec *regs;
> const struct stm32_adc_info *adc_info;
> struct stm32_adc_trig_info *trigs;
> + bool clk_required;
> void (*start_conv)(struct stm32_adc *, bool dma);
> void (*stop_conv)(struct stm32_adc *);
> };
> @@ -1145,14 +1147,21 @@ static int stm32_adc_probe(struct platform_device *pdev)
>
> adc->clk = devm_clk_get(&pdev->dev, NULL);
> if (IS_ERR(adc->clk)) {
> - dev_err(&pdev->dev, "Can't get clock\n");
> - return PTR_ERR(adc->clk);
> + ret = PTR_ERR(adc->clk);
> + if (ret == -ENOENT && !adc->cfg->clk_required) {
> + adc->clk = NULL;
> + } else {
> + dev_err(&pdev->dev, "Can't get clock\n");
> + return ret;
> + }
> }
>
> - ret = clk_prepare_enable(adc->clk);
> - if (ret < 0) {
> - dev_err(&pdev->dev, "clk enable failed\n");
> - return ret;
> + if (adc->clk) {
> + ret = clk_prepare_enable(adc->clk);
> + if (ret < 0) {
> + dev_err(&pdev->dev, "clk enable failed\n");
> + return ret;
> + }
> }
>
> ret = stm32_adc_of_get_resolution(indio_dev);
> @@ -1196,7 +1205,8 @@ static int stm32_adc_probe(struct platform_device *pdev)
> dma_release_channel(adc->dma_chan);
> }
> err_clk_disable:
> - clk_disable_unprepare(adc->clk);
> + if (adc->clk)
> + clk_disable_unprepare(adc->clk);
>
> return ret;
> }
> @@ -1214,7 +1224,8 @@ static int stm32_adc_remove(struct platform_device *pdev)
> adc->rx_buf, adc->rx_dma_buf);
> dma_release_channel(adc->dma_chan);
> }
> - clk_disable_unprepare(adc->clk);
> + if (adc->clk)
> + clk_disable_unprepare(adc->clk);
>
> return 0;
> }
> @@ -1223,6 +1234,7 @@ static int stm32_adc_remove(struct platform_device *pdev)
> .regs = &stm32f4_adc_regspec,
> .adc_info = &stm32f4_adc_info,
> .trigs = stm32f4_adc_trigs,
> + .clk_required = true,
> .start_conv = stm32f4_adc_start_conv,
> .stop_conv = stm32f4_adc_stop_conv,
> };
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