Hi Rob,

For UFS provisioning, all we need is ref_clk to be set to 19.2MHz before
actual descriptor write happens.
So I can actually avoid parsing it via DT and use REF_CLK_FREQ_19_2_MHZ from
enum ref_clk_freq (which is already added in my current implementation).

Thanks,
Sayali
-----Original Message-----
From: Rob Herring [mailto:robh@kernel.org] 
Sent: Thursday, May 24, 2018 12:19 AM
To: Sayali Lokhande <redacted>
Cc: subhashj@codeaurora.org; cang@codeaurora.org;
vivek.gautam@codeaurora.org; rnayak@codeaurora.org; vinholikatti@gmail.com;
jejb@linux.vnet.ibm.com; martin.petersen@oracle.com;
asutoshd@codeaurora.org; linux-scsi@vger.kernel.org; Mark Rutland
[off-list ref]; Mathieu Malaterre [off-list ref]; open list:OPEN
FIRMWARE AND FLATTENED DEVICE TREE BINDINGS [off-list ref];
open list [off-list ref]
Subject: Re: [PATCH RFC 1/3] scsi: ufs: set the device reference clock
setting

On Tue, May 22, 2018 at 09:51:38AM +0530, Sayali Lokhande wrote:

From: Subhash Jadavani <redacted>

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 <redacted>
[cang@codeaurora.org: Resolved trivial merge conflicts]
Signed-off-by: Can Guo <redacted>
Signed-off-by: Sayali Lokhande <redacted>
---
 .../devicetree/bindings/ufs/ufshcd-pltfrm.txt      |  8 +++
 drivers/scsi/ufs/ufs.h                             |  9 ++++
 drivers/scsi/ufs/ufshcd-pltfrm.c                   | 20 ++++++++
 drivers/scsi/ufs/ufshcd.c                          | 60

++++++++++++++++++++++

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.

You already have "ref_clk", can't you just read its frequency?

Rob