Re: [PATCH V2 1/3] scsi: ufs: set the device reference clock setting
From: Rob Herring
Date: Tue Jun 12 2018 - 15:26:44 EST
On Fri, Jun 08, 2018 at 04:36:28PM +0530, Sayali Lokhande wrote:
> From: Subhash Jadavani <subhashj@xxxxxxxxxxxxxx>
> UFS host supplies the reference clock to UFS device and UFS device
> specification allows host to provide one of the 4 frequencies (19.2 MHz,
> 26 MHz, 38.4 MHz, 52 MHz) for reference clock. Host should set the
> device reference clock frequency setting in the device based on what
> frequency it is supplying to UFS device.
> Signed-off-by: Subhash Jadavani <subhashj@xxxxxxxxxxxxxx>
> Signed-off-by: Can Guo <cang@xxxxxxxxxxxxxx>
> Signed-off-by: Sayali Lokhande <sayalil@xxxxxxxxxxxxxx>
> .../devicetree/bindings/ufs/ufshcd-pltfrm.txt | 7 +++
> drivers/scsi/ufs/ufs.h | 9 ++++
> drivers/scsi/ufs/ufshcd-pltfrm.c | 24 ++++++++++
> drivers/scsi/ufs/ufshcd.c | 52 ++++++++++++++++++++++
> drivers/scsi/ufs/ufshcd.h | 1 +
> 5 files changed, 93 insertions(+)
> diff --git a/Documentation/devicetree/bindings/ufs/ufshcd-pltfrm.txt b/Documentation/devicetree/bindings/ufs/ufshcd-pltfrm.txt
> index c39dfef..4522434 100644
> --- a/Documentation/devicetree/bindings/ufs/ufshcd-pltfrm.txt
> +++ b/Documentation/devicetree/bindings/ufs/ufshcd-pltfrm.txt
> @@ -41,6 +41,12 @@ Optional properties:
> -lanes-per-direction : number of lanes available per direction - either 1 or 2.
> Note that it is assume same number of lanes is used both
> directions at once. If not specified, default is 2 lanes per direction.
> +- dev-ref-clk-freq : Specify the device reference clock frequency, must be one of the following:
> + 0: 19.2 MHz
> + 1: 26 MHz
> + 2: 38.4 MHz
> + 3: 52 MHz
> + Defaults to 26 MHz if not specified.
I must have misunderstood your last response. I thought you could handle
things without DT. If not, my question remains.