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SubjectRe: [PATCH v2 1/2] scsi: ufs: Extract devfreq registration
Hi,

On 2018년 05월 05일 07:44, Bjorn Andersson wrote:
> Failing to register with devfreq leaves hba->devfreq assigned, which
> causes the error path to dereference the ERR_PTR(). Rather than bolting
> on more conditionals, move the call of devm_devfreq_add_device() into
> it's own function and only update hba->devfreq once it's successfully
> registered.
>
> The subsequent patch builds upon this to make UFS actually work again,
> as it's been broken since f1d981eaecf8 ("PM / devfreq: Use the available
> min/max frequency")
>
> Reviewed-by: Subhash Jadavani <subhashj@codeaurora.org>
> Signed-off-by: Bjorn Andersson <bjorn.andersson@linaro.org>
> ---
>
> Changes since v1:
> - None
>
> drivers/scsi/ufs/ufshcd.c | 31 ++++++++++++++++++++++---------
> 1 file changed, 22 insertions(+), 9 deletions(-)
>
> diff --git a/drivers/scsi/ufs/ufshcd.c b/drivers/scsi/ufs/ufshcd.c
> index 8f22a980b1a7..2253f24309ec 100644
> --- a/drivers/scsi/ufs/ufshcd.c
> +++ b/drivers/scsi/ufs/ufshcd.c
> @@ -1255,6 +1255,26 @@ static struct devfreq_dev_profile ufs_devfreq_profile = {
> .get_dev_status = ufshcd_devfreq_get_dev_status,
> };
>
> +static int ufshcd_devfreq_init(struct ufs_hba *hba)
> +{
> + struct devfreq *devfreq;
> + int ret;
> +
> + devfreq = devm_devfreq_add_device(hba->dev,
> + &ufs_devfreq_profile,
> + "simple_ondemand",

You better to use 'DEVFREQ_GOV_SIMPLE_ONDEMAND' definition
in include/linux/devfreq.h in order to prevent the some typo.
- aa7c352f9841 ("PM / devfreq: Define the constant governor name")


> + NULL);
> + if (IS_ERR(devfreq)) {
> + ret = PTR_ERR(devfreq);
> + dev_err(hba->dev, "Unable to register with devfreq %d\n", ret);
> + return ret;
> + }
> +
> + hba->devfreq = devfreq;
> +
> + return 0;
> +}
> +
> static void __ufshcd_suspend_clkscaling(struct ufs_hba *hba)
> {
> unsigned long flags;
> @@ -6399,16 +6419,9 @@ static int ufshcd_probe_hba(struct ufs_hba *hba)
> sizeof(struct ufs_pa_layer_attr));
> hba->clk_scaling.saved_pwr_info.is_valid = true;
> if (!hba->devfreq) {
> - hba->devfreq = devm_devfreq_add_device(hba->dev,
> - &ufs_devfreq_profile,
> - "simple_ondemand",
> - NULL);
> - if (IS_ERR(hba->devfreq)) {
> - ret = PTR_ERR(hba->devfreq);
> - dev_err(hba->dev, "Unable to register with devfreq %d\n",
> - ret);
> + ret = ufshcd_devfreq_init(hba);
> + if (ret)
> goto out;
> - }
> }
> hba->clk_scaling.is_allowed = true;
> }
>

Reviewed-by: Chanwoo Choi <cw00.choi@samsung.com>

--
Best Regards,
Chanwoo Choi
Samsung Electronics

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