Re: [PATCH V4] mmc: sdhci-msm: Reset GCC_SDCC_BCR register for SDHC

[Sajida Bhanu (Temp)]

Hi,

Thanks for the review.

Please find the inline comments.

Thanks,

Sajida

On 4/21/2022 3:26 PM, Philipp Zabel wrote:
> On Do, 2022-04-21 at 10:32 +0530, Sajida Bhanu (Temp) wrote:
> > Hi,
> >
> > Thanks for the review.
> >
> > Please find the inline comments.
> >
> > Thanks,
> >
> > Sajida
> >
> > On 4/19/2022 12:52 PM, Philipp Zabel wrote:
> > > Hi Sajida,
> > >
> > > On Di, 2022-04-19 at 11:46 +0530, Sajida Bhanu (Temp) wrote:
> > > [...]
> > > > > > +static int sdhci_msm_gcc_reset(struct device *dev, struct sdhci_host *host)
> > > > > > +{
> > > > > > +	struct reset_control *reset;
> > > > > > +	int ret = 0;
> > > > > No need to initialize ret.
> > > > >
> > > > > > +
> > > > > > +	reset = reset_control_get_optional_exclusive(dev, NULL);
> > > > > > +	if (IS_ERR(reset))
> > > > > > +		return dev_err_probe(dev, PTR_ERR(reset),
> > > > > > +				"unable to acquire core_reset\n");
> > > > > > +
> > > > > > +	if (!reset)
> > > > > > +		return ret;
> > > > Here we are returning ret directly if reset is NULL , so ret
> > > > initialization is required.
> > > You are right. I would just "return 0;" here, but this is correct as
> > > is.
> > Ok
> > > > > > +
> > > > > > +	ret = reset_control_assert(reset);
> > > > > > +	if (ret)
> > > > > > +		return dev_err_probe(dev, ret, "core_reset assert failed\n");
> > > > > Missing reset_control_put(reset) in the error path.
> > > > Sure will add
> > > > > > +
> > > > > > +	/*
> > > > > > +	 * The hardware requirement for delay between assert/deassert
> > > > > > +	 * is at least 3-4 sleep clock (32.7KHz) cycles, which comes to
> > > > > > +	 * ~125us (4/32768). To be on the safe side add 200us delay.
> > > > > > +	 */
> > > > > > +	usleep_range(200, 210);
> > > > > > +
> > > > > > +	ret = reset_control_deassert(reset);
> > > > > > +	if (ret)
> > > > > > +		return dev_err_probe(dev, ret, "core_reset deassert failed\n");
> > > > > Same as above. Maybe make both ret = dev_err_probe() and goto ...
> > > > In both cases error message is different so I think goto not good idea here.
> > > You could goto after the error message. Either way is fine.
> > Sorry didn't get this ..can  you please help
> I meant you could either use goto after the error messages:
>
> +static int sdhci_msm_gcc_reset(struct device *dev, struct sdhci_host *host)
> +{
> [...]
> +	ret = reset_control_assert(reset);
> +	if (ret) {
> +		dev_err_probe(dev, ret, "core_reset assert failed\n");
> +		goto out_reset_put;
> +	}
> [...]
> +	ret = reset_control_deassert(reset);
> +	if (ret) {
> +		dev_err_probe(dev, ret, "core_reset deassert failed\n");
> +		goto out_reset_put;
> +	}
> +
> +	usleep_range(200, 210);
> +
> +out_reset_put:
> +	reset_control_put(reset);
> +
> +	return ret;
> +}
>
> Or not use goto and copy the reset_control_put() into each error path:
>
> +static int sdhci_msm_gcc_reset(struct device *dev, struct sdhci_host *host)
> +{
> [...]
> +	ret = reset_control_assert(reset);
> +	if (ret) {
> +		reset_control_put(reset);
> +		return dev_err_probe(dev, ret, "core_reset assert failed\n");
> +	}
> [...]
> +	ret = reset_control_deassert(reset);
> +	if (ret) {
> +		reset_control_put(reset);
> +		return dev_err_probe(dev, ret, "core_reset deassert failed\n");
> +	}
> +
> +	usleep_range(200, 210);
> +	reset_control_put(reset);
> +
> +	return 0;
> +}
>
> regards
> Philipp
Sure I will call reset_control_put() in each error path