On 27.11.2015 15:42, Anand Moon wrote: > hi Krzysztof, > > On 22 October 2015 at 18:34, Anand Moon <linux.am...@gmail.com> wrote: >> hi Krzysztof, >> >> On 22 October 2015 at 06:31, Krzysztof Kozlowski >> <k.kozlow...@samsung.com> wrote: >>> On 20.10.2015 21:56, Anand Moon wrote: >>>> Changes need for host controller to detect UHS-I highspeed cards. >>>> Changes in VDDQ_MMC2 voltage range help scale >>>> the required voltage to detect and load the microSD cards. >>> >>> Thanks for updating description of commit. >>> >>>> >>>> Signed-off-by: Anand Moon <linux.am...@gmail.com> >>>> --- >>>> Changes based on >>>> git://git.kernel.org/pub/scm/linux/kernel/git/kgene/linux-samsung.git >>>> v4.4-next/dt-samsung branch >>>> >>>> Changes: >>>> Drop the ranp_delay for LDO9. >>>> >>>> Thanks to : Krzysztof, Doug Anderson, Jaehoon Chung for helping >>>> me out figure out the mmc core requirement. >>>> >>>> Also drop the previous changes: >>>> use cd-gpio method to detect sd-card. >>>> Added UHS-I bus speed support. >>>> >>>> [ 4.713553] random: nonblocking pool is initialized >>>> [ 4.718423] 14530000.hdmi supply hdmi-en not found, using dummy >>>> regulator >>>> [ 4.726206] exynos-drm exynos-drm: bound 14400000.fimd (ops >>>> fimd_component_ops) >>>> [ 4.732555] exynos-drm exynos-drm: bound 14450000.mixer (ops >>>> mixer_component_ops) >>>> [ 4.740180] exynos-drm exynos-drm: bound 14530000.hdmi (ops >>>> hdmi_component_ops) >>>> [ 4.746936] [drm] Supports vblank timestamp caching Rev 2 (21.10.2013). >>>> [ 4.753428] [drm] No driver support for vblank timestamp query. >>>> [ 4.940794] Console: switching to colour frame buffer device 274x77 >>>> [ 4.995344] exynos-drm exynos-drm: fb0: frame buffer device >>>> [ 5.024573] [drm] Initialized exynos 1.0.0 20110530 on minor 0 >>>> [ 5.031164] exynos-dwc3 usb@12000000: no suspend clk specified >>>> [ 5.054571] usb 2-1: new full-speed USB device number 2 using >>>> exynos-ohci >>>> [ 5.159527] dwmmc_exynos 12220000.mmc: Busy; trying anyway >>>> [ 5.163705] mmc_host mmc1: Timeout sending command (cmd 0x202000 arg >>>> 0x0 status 0x0) >>>> --- >>>> arch/arm/boot/dts/exynos5422-odroidxu3-common.dtsi | 7 ++++++- >>>> 1 file changed, 6 insertions(+), 1 deletion(-) >>>> >>>> diff --git a/arch/arm/boot/dts/exynos5422-odroidxu3-common.dtsi >>>> b/arch/arm/boot/dts/exynos5422-odroidxu3-common.dtsi >>>> index 1af5bdc..a4be3e0 100644 >>>> --- a/arch/arm/boot/dts/exynos5422-odroidxu3-common.dtsi >>>> +++ b/arch/arm/boot/dts/exynos5422-odroidxu3-common.dtsi >>>> @@ -182,9 +182,10 @@ >>>> >>>> ldo13_reg: LDO13 { >>>> regulator-name = "vdd_ldo13"; >>>> - regulator-min-microvolt = <2800000>; >>>> + regulator-min-microvolt = <1800000>; >>> >>> You did not convinced me in previous discussion about the change to >>> 1.8V. I said that: >>>> On the same diagram few lines below: >>>> VDDQ_MMC2: 2.8V 250mA >>> >>> You responded: >>>> You are correct. >>> >>> So I am confused. Are you sure that this SD card block can/should >>> operate on 1.8V? Have you actually tried this? >>> >> >> Look like I missed this point. Here is the link I would like to share. >> >> http://www.hjreggel.net/cardspeed/cs_sdxc.html >> Section: Summary of SD modes >> >> https://en.wikipedia.org/wiki/Secure_Digital >> Section: Power consumption >> >> Their different requirement for voltage requirement for UHS-I, the max >> value is around 3.3V > > Do you have any comment on this voltage selection for UHS-I card (1.8V).
I asked whether you tried this, whether setting real 1.8V works fine. You did not respond. As you can see on Odroid schematics, the VDDQ for MMC[01] operates under 1.8V. The VDDQ for MMC2 - under 2.8V. In commit description you mentioned that this voltage "helps scale the required voltage to detect and load the microSD cards". What does it mean "help"? I would expect that detecting and loading of microSD cards either works or does not work. I am not sure how does it help. Best regards, Krzysztof -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/