Re: [PATCH 06/11] Documentation: mmc: sdhci-of-arasan: Add ability to export card clock
From: Rob Herring <robh@kernel.org>
Date: 2016-06-10 13:10:58
Also in:
linux-mmc, linux-rockchip, lkml
From: Rob Herring <robh@kernel.org>
Date: 2016-06-10 13:10:58
Also in:
linux-mmc, linux-rockchip, lkml
On Wed, Jun 08, 2016 at 01:52:20PM -0700, Doug Anderson wrote:
Rob, On Wed, Jun 8, 2016 at 1:19 PM, Rob Herring [off-list ref] wrote:quoted
On Tue, Jun 07, 2016 at 03:44:39PM -0700, Douglas Anderson wrote:quoted
Some SD/eMMC PHYs (like the PHY from Arasan that is designed to work with arasan,sdhci-5.1) need to know the card clock in order to function properly. Let's expose this clock using a standard device tree mechanism so that the PHY can get access to and query the card clock.Need to know the clock freq or need the clock? The former doesn't need to be in DT.The PHY needs to know the card clock frequency. This clock clock frequency is known nowhere else in the system except the SDHCI driver since the SDHCI component takes its input clock and applies some dividers to get the card clock. In silicon, the SDHCI component and the PHY are separate and there is a physical clock signal going from the SDHCI component to the PHY component, so modeling this as a clock in in the device tree seems sane, doesn't it?
Yes, please just re-word it to make it clear there is a connection. With that, Acked-by: Rob Herring <robh@kernel.org>