mmc: dw_mmc: set the supported max/min frequency

Both f_max and f_min will be informed for core layer to request
valid clock rate. But current setting from 'host->bus_hz' may
not represent the max/min frequency properly. Even if host can
actually support high speed than bus_hz, core layer will not
request clock rate over bus_hz. Basically, f_max/f_min can be set
with the values according to spec. And then host will make its best
effort to meet the rate.

Signed-off-by: Seungwon Jeon <tgih.jun@samsung.com>
Tested-by: Alim Akhtar <alim.akhtar@samsung.com>
Signed-off-by: Chris Ball <cjb@laptop.org>
This commit is contained in:
Seungwon Jeon
2013-08-31 00:13:31 +09:00
committed by Chris Ball
parent 10b498419f
commit 1f44a2a557
2 changed files with 16 additions and 2 deletions

View File

@@ -52,6 +52,9 @@ Optional properties:
is specified and the ciu clock is specified then we'll try to set the ciu
clock to this at probe time.
* clock-freq-min-max: Minimum and Maximum clock frequency for card output
clock(cclk_out). If it's not specified, max is 200MHZ and min is 400KHz by default.
* num-slots: specifies the number of slots supported by the controller.
The number of physical slots actually used could be equal or less than the
value specified by num-slots. If this property is not specified, the value
@@ -97,6 +100,7 @@ board specific portions as listed below.
dwmmc0@12200000 {
clock-frequency = <400000000>;
clock-freq-min-max = <400000 200000000>;
num-slots = <1>;
supports-highspeed;
caps2-mmc-hs200-1_8v;