Hi Shawn,
On 08/16/2017 05:47 PM, Shawn Lin wrote:
On 2017/8/17 6:46, Zhoujie Wu wrote:
Hi ,
On 08/15/2017 05:32 PM, Shawn Lin wrote:
Hi
On 2017/8/16 6:40, Zhoujie Wu wrote:
Hi Shawn,
----------------------------------------------------------------------
Hi
On 2017/8/15 6:19, Zhoujie Wu wrote:
On some platforms, like armada3700, SD card need to
do hard reset by gpio toggling to make it work properly
after warm reset the board.
I don't get this that SD card need to do hard reset...
I assume what you talk about is either for eMMC or a power-cycle
for SD card.
The subject of the patch confused you. What I want is a power-cycle
for the SD card. The gpio is used to enable/disable the vdd power
supply for sd card.
Actually on a3700, when warm reset the board, their is no
power-cycle for SD card, which will lead sd card can't response
correct ocr and never set S18A unless a power-cycle.
This is the purpose I submit this patch.
Well, if that is the case, I suggest you to use regulator-gpio.
i.e:
vcc_sd: regulator {
compatible = "regulator-gpio";
regulator-name = "vcc_sd";
regulator-min-microvolt = <3300000>;
regulator-max-microvolt = <3300000>;
gpios = <&gpio1 23 GPIO_ACTIVE_HIGH>;
enable-active-high;
};
&sdhci {
vmmc-supply = <&vcc_sd>;
}
I tried to use the vmmc-supply regulator before I submit this patch,
I met a issue in this case.
sdhci_set_power_reg will be called instead, and I saw
mmc_regulator_set_ocr do enabled the regulator, after that SW will
set 0xf to power controller register, but the register is
self-cleared to 0 soon which lead to later cmd timeout all the time.
I don't parse it from the SDHCI spec that SD bus power bit is
self-cleared one. Is it sdhci-xenon specific?
If yes, you need to hook you set_power callback and avoid touching this
bit with some proper description for the reason.
Thanks for your great help. Today I debugged this issue and found that
if I used sdhci_set_poewr_noreg right after I enabled the vmmc
regulator, the whole thing worked well. I can just write power on bit in
pwr_ctrl_reg.
I think this might be the xenon limitation, even with external vmmc
power supply, the xenon sdh controller still need to program voltage
select bits. I will check with our design guys to get more information.
As you said, I have to add set_power callback in our driver to make it
work perfectly. And the regulator I defined as a fixed regulator, which
is always on to make sure the card detection can work without issue.
I abandon this patch and nice to have this talk. Really appreciate.
Have you ever met similar issue before?
Haven't.
Add gpio hard reset feature for this purpose.
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