[U-Boot] [PATCH v3 4/4] exynos: more debug and cleanup in do_sdhci_init()

[Jaehoon Chung]

Hi, Przemyslaw.

On 10/28/2015 08:33 PM, Przemyslaw Marczak wrote:
> Hello Jaehoon,
> 
> On 10/28/2015 07:33 AM, Jaehoon Chung wrote:
>> Hi, All.
>>
>> On 10/05/2015 08:47 PM, Tobias Jakobi wrote:
>>> Add more debug printfs in do_sdhci_init() for calls
>>> that can potentially fail.
>>>
>>> Acked-by: Przemyslaw Marczak <p.marczak at samsung.com>
>>> Signed-off-by: Tobias Jakobi <tjakobi at math.uni-bielefeld.de>
>>> ---
>>>   drivers/mmc/s5p_sdhci.c | 20 +++++++++++---------
>>>   1 file changed, 11 insertions(+), 9 deletions(-)
>>>
>>> diff --git a/drivers/mmc/s5p_sdhci.c b/drivers/mmc/s5p_sdhci.c
>>> index b203bee..15ecfee 100644
>>> --- a/drivers/mmc/s5p_sdhci.c
>>> +++ b/drivers/mmc/s5p_sdhci.c
>>> @@ -101,29 +101,31 @@ struct sdhci_host sdhci_host[SDHCI_MAX_HOSTS];
>>>
>>>   static int do_sdhci_init(struct sdhci_host *host)
>>>   {
>>> -    int dev_id, flag;
>>> -    int err = 0;
>>> +    int dev_id, flag, ret;
>>>
>>>       flag = host->bus_width == 8 ? PINMUX_FLAG_8BIT_MODE : PINMUX_FLAG_NONE;
>>>       dev_id = host->index + PERIPH_ID_SDMMC0;
>>>
>>>       if (dm_gpio_is_valid(&host->pwr_gpio)) {
>>>           dm_gpio_set_value(&host->pwr_gpio, 1);
>>> -        err = exynos_pinmux_config(dev_id, flag);
>>> -        if (err) {
>>> +        ret = exynos_pinmux_config(dev_id, flag);
>>> +        if (ret) {
>>>               debug("MMC not configured\n");
>>> -            return err;
>>> +            return ret;
>>>           }
>>>       }
>>>
>>>       if (dm_gpio_is_valid(&host->cd_gpio)) {
>>> -        if (dm_gpio_get_value(&host->cd_gpio))
>>> +        ret = dm_gpio_get_value(&host->cd_gpio);
>>> +        if (ret) {
>>> +            debug("no SD card detected (%d)\n", ret);
>>>               return -ENODEV;
>>> +        }
>>
>> This patch was already applied. But i didn't know why used "ret" at here.
>> If cd-gpio is active-high, this should be always returned "no SD card detected".
>> Even if commonly cd-gpio is active-low, we don't know whether cd-gpio is active-low or not.
>>
>> And dm_gpio_get_value() should be returned error for only one case.
>>
>> Best Regards,
>> Jaehoon Chung
>>
> 
> Could you precise, where is the problem exactly? The active low or high can be set in device tree, so the code can be still common.

How can active low or high be set in device tree? I can't find any information.

Anyway, I have tested on Odroid-x2 board. And i have tried to boot with SD-card.
In that case, host can't detect SD-card.

MMC:   process_nodes: failed to initialize dev 0 (-19)

After Enable debug message..

no SD card detected (1)
process_nodes: failed to initialize dev 0 (-19)

no SD card detected (1) -> 1 is just gpio value. it should be to 0.
Do you distinguish between 0 and 1? We don't know whether gpio is active-low or high.
I don't think that included information. 

It's just my thinking...other people should be helpful.

And I'm making some patches...and below is one of them for detecting SD-card.

Subject: [PATCH] mmc: s5p_sdhci: change the flags of cd-gpio to ACTIVE_LOW

In case of exynos, "cd-gpio" is commonly used the active-low.
So it changed the flags of gpio from GPIOD_IS_IN to GPIOD_ACTIVE_LOW.

Signed-off-by: Jaehoon Chung <jh80.chung at samsung.com>
---
 drivers/mmc/s5p_sdhci.c | 5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)

diff --git a/drivers/mmc/s5p_sdhci.c b/drivers/mmc/s5p_sdhci.c
index 15ecfee..26a8fe8 100644
--- a/drivers/mmc/s5p_sdhci.c
+++ b/drivers/mmc/s5p_sdhci.c
@@ -164,7 +164,7 @@ static int sdhci_get_config(const void *blob, int node, struct sdhci_host *host)
        gpio_request_by_name_nodev(blob, node, "pwr-gpios", 0, &host->pwr_gpio,
                                   GPIOD_IS_OUT);
        gpio_request_by_name_nodev(blob, node, "cd-gpios", 0, &host->cd_gpio,
-                                  GPIOD_IS_IN);
+                                  GPIOD_ACTIVE_LOW);

        return 0;
 }
@@ -187,7 +187,8 @@ static int process_nodes(const void *blob, int node_list[], int count)

                ret = sdhci_get_config(blob, node, host);
                if (ret) {
-                       printf("%s: failed to decode dev %d (%d)\n",    __func__, i, ret);
+                       printf("%s: failed to decode dev %d (%d)\n",
+                                       __func__, i, ret);
                        failed++;
                        continue;
                }
--

Best Regards,
Jaehoon Chung


> 
> And the ret value can inform, if card is not detected or the error is in GPIO subsystem(ret < 0). So where is the problem?
> 
>>>
>>> -        err = exynos_pinmux_config(dev_id, flag);
>>> -        if (err) {
>>> +        ret = exynos_pinmux_config(dev_id, flag);
>>> +        if (ret) {
>>>               printf("external SD not configured\n");
>>> -            return err;
>>> +            return ret;
>>>           }
>>>       }
>>>
>>>
>>
>>
> Best regards,