Re: [PATCH 2/3] mmc: sdhci-esdhc-imx: obtain the 'per' clock rate after its enablement

[Ciprian Marian Costea]

On 7/10/2024 3:33 PM, Adrian Hunter wrote:
> On 8/07/24 15:10, Ciprian Costea wrote:
> > The I.MX SDHCI driver assumes that the frequency of the 'per' clock
> > can be obtained even on disabled clocks, which is not always the case.
> >
> > According to 'clk_get_rate' documentation, it is only valid
> > once the clock source has been enabled.
>
> The kerneldoc comment for clk_get_rate() says
>
> 	Can be called regardless of the clock enabledness
>
> which sounds like the opposite.  Please clarify.

Hello Adrian,

My observation was based on the following [1] 'clk_get_rate()' 
documentation.

[1] 
https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/tree/include/linux/clk.h#n720

Best Regards,
Ciprian

> > Signed-off-by: Ciprian Costea <ciprianmarian.costea@xxxxxxxxxxx>
> > ---
> >   drivers/mmc/host/sdhci-esdhc-imx.c | 8 +++++++-
> >   1 file changed, 7 insertions(+), 1 deletion(-)
> >
> > diff --git a/drivers/mmc/host/sdhci-esdhc-imx.c b/drivers/mmc/host/sdhci-esdhc-imx.c
> > index 21d984a77be8..8f0bc6dca2b0 100644
> > --- a/drivers/mmc/host/sdhci-esdhc-imx.c
> > +++ b/drivers/mmc/host/sdhci-esdhc-imx.c
> > @@ -1709,7 +1709,6 @@ static int sdhci_esdhc_imx_probe(struct platform_device *pdev)
> >   	}
> >   
> >   	pltfm_host->clk = imx_data->clk_per;
> > -	pltfm_host->clock = clk_get_rate(pltfm_host->clk);
> >   	err = clk_prepare_enable(imx_data->clk_per);
> >   	if (err)
> >   		goto free_sdhci;
> > @@ -1720,6 +1719,13 @@ static int sdhci_esdhc_imx_probe(struct platform_device *pdev)
> >   	if (err)
> >   		goto disable_ipg_clk;
> >   
> > +	pltfm_host->clock = clk_get_rate(pltfm_host->clk);
> > +	if (!pltfm_host->clock) {
> > +		dev_err(mmc_dev(host->mmc), "could not get clk rate\n");
> > +		err = -EINVAL;
> > +		goto disable_ahb_clk;
> > +	}
> > +
> >   	imx_data->pinctrl = devm_pinctrl_get(&pdev->dev);
> >   	if (IS_ERR(imx_data->pinctrl))
> >   		dev_warn(mmc_dev(host->mmc), "could not get pinctrl\n");