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

[Adrian Hunter <adrian.hunter@intel.com>]

On 10/07/24 15:50, Ciprian Marian Costea wrote:
> 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

Yes, that is clear.

Acked-by: Adrian Hunter <adrian.hunter@intel.com>

> 
>>>
>>> Signed-off-by: Ciprian Costea <ciprianmarian.costea@oss.nxp.com>
>>> ---
>>>   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");
>>
>