[U-Boot] [PATCH V5 02/10] EXYNOS5: FDT: Add DWMMC device node data
Amarendra Reddy
amar.lavanuru at gmail.com
Fri Feb 15 07:19:32 CET 2013
Hi Simon,
Please find my response below.
Thanks & Regards
Amarendra
On 8 February 2013 22:33, Simon Glass <sjg at chromium.org> wrote:
> Hi Amarendra,
>
> On Mon, Jan 28, 2013 at 1:20 AM, Amarendra Reddy
> <amar.lavanuru at gmail.com> wrote:
> > Hi Simon,
> >
> > You mean to add "removable" flag in device node ?
>
> Yes
>
> > Are you referring to the overhead involved during MMC boot, and a SD
> card is
> > not present on the board ?
> > Can you please elaborate on the above.
>
> From my investigation of the mmc code some months back I found that
> for the eMMC case we are probing for an SD card, and when that fails,
> trying eMMC. If we can specify which it is (which we can in the case
> of a soldered-down device) then we might save that wasted time.
>
> Regards,
> Simon
>
Ok, I will add the flag 'removable' to mmc device node.
> >
> > Thanks & Regards
> > Amarendra Reddy
> >
> > On 23 January 2013 05:39, Simon Glass <sjg at chromium.org> wrote:
> >>
> >> Hi Amar,
> >>
> >> On Mon, Jan 21, 2013 at 3:43 AM, Amar <amarendra.xt at samsung.com> wrote:
> >> > This patch adds DWMMC device node data for exynos5.
> >> > This patch also adds binding file for DWMMC device node.
> >> >
> >> > Signed-off-by: Vivek Gautam <gautam.vivek at samsung.com>
> >> > Signed-off-by: Amar <amarendra.xt at samsung.com>
> >>
> >> Acked-by: Simon Glass <sjg at chromium.org>
> >>
> >> Can I suggest in a later patch you add a removable flag, so we can
> >> mark devices which cannot be removed (and can be assumed to be
> >> present). I believe that there is some overhead involved in detecting
> >> an MMC (we have to try SD first, and fail).
> >>
> >> > ---
> >> > Changes since V1:
> >> > 1)Added binding file for DWMMC device node at the location
> >> > "doc/device-tree-bindings/exynos/dwmmc.txt".
> >> > 2)Removed the propname 'index' from device node.
> >> > 3)Prefixed the vendor name 'samsung' before propname in device
> >> > node.
> >> >
> >> > Changes since V2:
> >> > 1)Updation of commit message and resubmition of proper patch
> >> > set.
> >> >
> >> > Changes since V3:
> >> > No change.
> >> >
> >> > Changes since V4:
> >> > 1)Updated the doc/device-tree-bindings/exynos/dwmmc.txt with
> >> > more
> >> > information regarding the property 'samsung,timing'.
> >> > 2)Replaced the name 'dwmmc' with 'mmc'.
> >> >
> >> > arch/arm/dts/exynos5250.dtsi | 31 +++++++++++++++++++
> >> > board/samsung/dts/exynos5250-smdk5250.dts | 22 ++++++++++++++
> >> > doc/device-tree-bindings/exynos/dwmmc.txt | 49
> >> > +++++++++++++++++++++++++++++++
> >> > 3 files changed, 102 insertions(+)
> >> > create mode 100644 doc/device-tree-bindings/exynos/dwmmc.txt
> >> >
> >> > diff --git a/arch/arm/dts/exynos5250.dtsi
> b/arch/arm/dts/exynos5250.dtsi
> >> > index ed8c8dd..6c08eb7 100644
> >> > --- a/arch/arm/dts/exynos5250.dtsi
> >> > +++ b/arch/arm/dts/exynos5250.dtsi
> >> > @@ -151,4 +151,35 @@
> >> > };
> >> > };
> >> >
> >> > + mmc at 12200000 {
> >> > + #address-cells = <1>;
> >> > + #size-cells = <0>;
> >> > + compatible = "samsung,exynos5250-dwmmc";
> >> > + reg = <0x12200000 0x1000>;
> >> > + interrupts = <0 75 0>;
> >> > + };
> >> > +
> >> > + mmc at 12210000 {
> >> > + #address-cells = <1>;
> >> > + #size-cells = <0>;
> >> > + compatible = "samsung,exynos5250-dwmmc";
> >> > + reg = <0x12210000 0x1000>;
> >> > + interrupts = <0 76 0>;
> >> > + };
> >> > +
> >> > + mmc at 12220000 {
> >> > + #address-cells = <1>;
> >> > + #size-cells = <0>;
> >> > + compatible = "samsung,exynos5250-dwmmc";
> >> > + reg = <0x12220000 0x1000>;
> >> > + interrupts = <0 77 0>;
> >> > + };
> >> > +
> >> > + mmc at 12230000 {
> >> > + #address-cells = <1>;
> >> > + #size-cells = <0>;
> >> > + compatible = "samsung,exynos5250-dwmmc";
> >> > + reg = <0x12230000 0x1000>;
> >> > + interrupts = <0 78 0>;
> >> > + };
> >> > };
> >> > diff --git a/board/samsung/dts/exynos5250-smdk5250.dts
> >> > b/board/samsung/dts/exynos5250-smdk5250.dts
> >> > index cbfab6f..1d3e42b 100644
> >> > --- a/board/samsung/dts/exynos5250-smdk5250.dts
> >> > +++ b/board/samsung/dts/exynos5250-smdk5250.dts
> >> > @@ -30,6 +30,10 @@
> >> > spi2 = "/spi at 12d40000";
> >> > spi3 = "/spi at 131a0000";
> >> > spi4 = "/spi at 131b0000";
> >> > + mmc0 = "/mmc at 12200000";
> >> > + mmc1 = "/mmc at 12210000";
> >> > + mmc2 = "/mmc at 12220000";
> >> > + mmc3 = "/mmc at 12230000";
> >> > };
> >> >
> >> > sromc at 12250000 {
> >> > @@ -66,4 +70,22 @@
> >> > compatible = "maxim,max77686_pmic";
> >> > };
> >> > };
> >> > +
> >> > + mmc at 12200000 {
> >> > + samsung,bus-width = <8>;
> >> > + samsung,timing = <1 3 3>;
> >> > + };
> >> > +
> >> > + mmc at 12210000 {
> >> > + status = "disabled";
> >> > + };
> >> > +
> >> > + mmc at 12220000 {
> >> > + samsung,bus-width = <4>;
> >> > + samsung,timing = <1 2 3>;
> >> > + };
> >> > +
> >> > + mmc at 12230000 {
> >> > + status = "disabled";
> >> > + };
> >> > };
> >> > diff --git a/doc/device-tree-bindings/exynos/dwmmc.txt
> >> > b/doc/device-tree-bindings/exynos/dwmmc.txt
> >> > new file mode 100644
> >> > index 0000000..0054ace
> >> > --- /dev/null
> >> > +++ b/doc/device-tree-bindings/exynos/dwmmc.txt
> >> > @@ -0,0 +1,49 @@
> >> > +* Exynos 5250 DWC_mobile_storage
> >> > +
> >> > +The Exynos 5250 provides DWC_mobile_storage interface which supports
> >> > +. Embedded Multimedia Cards (EMMC-version 4.5)
> >> > +. Secure Digital memory (SD mem-version 2.0)
> >> > +. Secure Digital I/O (SDIO-version 3.0)
> >> > +. Consumer Electronics Advanced Transport Architecture
> (CE-ATA-version
> >> > 1.1)
> >> > +
> >> > +The Exynos 5250 DWC_mobile_storage provides four channels.
> >> > +SOC specific and Board specific properties are channel specific.
> >> > +
> >> > +Required SoC Specific Properties:
> >> > +
> >> > +- compatible: should be
> >> > + - samsung,exynos5250-dwmmc: for exynos5250 platforms
> >> > +
> >> > +- reg: physical base address of the controller and length of memory
> >> > mapped
> >> > + region.
> >> > +
> >> > +- interrupts: The interrupt number to the cpu.
> >> > +
> >> > +Required Board Specific Properties:
> >> > +
> >> > +- #address-cells: should be 1.
> >> > +- #size-cells: should be 0.
> >> > +- samsung,bus-width: The width of the bus used to interface the
> devices
> >> > + supported by DWC_mobile_storage (SD-MMC/EMMC/SDIO).
> >> > + . Typically the bus width is 4 or 8.
> >> > +- samsung,timing: The timing values to be written into the
> >> > + Drv/sample clock selection register of corresponding channel.
> >> > + . It is comprised of 3 values corresponding to the 3 fileds
> >> > + 'SelClk_sample', 'SelClk_drv' and 'DIVRATIO' of CLKSEL
> >> > register.
> >> > + . SelClk_sample: Select sample clock among 8 shifted clocks.
> >> > + . SelClk_drv: Select drv clock among 8 shifted clocks.
> >> > + . DIVRATIO: Clock Divide ratio select.
> >> > + . The above 3 values are used by the clock phase shifter.
> >> > +
> >> > +Example:
> >> > +
> >> > +mmc at 12200000 {
> >> > + samsung,bus-width = <8>;
> >> > + samsung,timing = <1 3 3>;
> >> > +}
> >> > +In the above example,
> >> > + . The bus width is 8
> >> > + . Timing is comprised of 3 values as explained below
> >> > + 1 - SelClk_sample
> >> > + 3 - SelClk_drv
> >> > + 3 - DIVRATIO
> >> > --
> >> > 1.8.0
> >> >
> >> _______________________________________________
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> >
> >
>
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