[PATCH 2/2] mtd: nand: raw: atmel: Add error handling when rb-gpios missing

[Eugen Hristev]

On 8/23/23 09:54, Michael Nazzareno Trimarchi wrote:
> Hi
> 
> On Wed, Aug 23, 2023 at 8:28 AM Eugen Hristev
> <eugen.hristev at collabora.com> wrote:
>>
>> Hi,
>>
>> On 8/8/23 18:03, Alexander Dahl wrote:
>>> Hello Michael,
>>>
>>> Am Tue, Aug 08, 2023 at 03:49:45PM +0200 schrieb Michael Nazzareno Trimarchi:
>>>> Hi
>>>>
>>>> On Tue, Aug 8, 2023 at 3:03 PM Alexander Dahl <ada at thorsis.com> wrote:
>>>>>
>>>>> Adapt behaviour to Linux kernel driver.
>>>>>
>>>>> The return value of gpio_request_by_name_nodev() was not checked before,
>>>>> and thus in case 'rb-gpios' was missing in DT, rb.type was set to
>>>>> ATMEL_NAND_GPIO_RB nevertheless, leading to output like this for
>>>>> example (on sam9x60-curiosity with the line removed from dts):
>>>>>
>>>>>       NAND:  Could not find valid ONFI parameter page; aborting
>>>>>       device found, Manufacturer ID: 0xc2, Chip ID: 0xdc
>>>>>       Macronix NAND 512MiB 3,3V 8-bit
>>>>>       512 MiB, SLC, erase size: 256 KiB, page size: 4096, OOB size: 64
>>>>>       atmel-nand-controller nand-controller: NAND scan failed: -22
>>>>>       Failed to probe nand driver (err = -22)
>>>>>       Failed to initialize NAND controller. (error -22)
>>>>>       0 MiB
>>>>>
>>>>> Note: not having that gpio assigned in dts is fine, the driver does not
>>>>> override nand_chip->dev_ready() then and a generic solution is used.
>>>>>
>>>>> Fixes: 6a8dfd57220d ("nand: atmel: Add DM based NAND driver")
>>>>> Signed-off-by: Alexander Dahl <ada at thorsis.com>
>>>>> ---
>>>>>    drivers/mtd/nand/raw/atmel/nand-controller.c | 11 +++++++----
>>>>>    1 file changed, 7 insertions(+), 4 deletions(-)
>>>>>
>>>>> diff --git a/drivers/mtd/nand/raw/atmel/nand-controller.c b/drivers/mtd/nand/raw/atmel/nand-controller.c
>>>>> index 2b29c8def6..8e745a5111 100644
>>>>> --- a/drivers/mtd/nand/raw/atmel/nand-controller.c
>>>>> +++ b/drivers/mtd/nand/raw/atmel/nand-controller.c
>>>>> @@ -1600,10 +1600,13 @@ static struct atmel_nand *atmel_nand_create(struct atmel_nand_controller *nc,
>>>>>                           nand->cs[i].rb.type = ATMEL_NAND_NATIVE_RB;
>>>>>                           nand->cs[i].rb.id = val;
>>>>>                   } else {
>>>>> -                       gpio_request_by_name_nodev(np, "rb-gpios", 0,
>>>>> -                                                  &nand->cs[i].rb.gpio,
>>>>> -                                                  GPIOD_IS_IN);
>>>>> -                       nand->cs[i].rb.type = ATMEL_NAND_GPIO_RB;
>>>>> +                       ret = gpio_request_by_name_nodev(np, "rb-gpios", 0,
>>>>> +                                                        &nand->cs[i].rb.gpio,
>>>>> +                                                        GPIOD_IS_IN);
>>>>> +                       if (ret)
>>>>> +                               dev_err(nc->dev, "Failed to get R/B gpio (err = %d)\n", ret);
>>>>
>>>> Should not then an error here
>>>
>>> Different log level or no message at all?
>>>
>>> Note: Linux prints the same message with error level in that case.
>>>
>>> Greets
>>> Alex
>>>
>>
>> Since the rb-gpios is optional, we can continue probing without it.
>> Throwing an error message is optional and pure informative. So I am fine
>> with it
>>
> 
> Yes ok, but I'm not sure linux give an error if the gpio is get as
> optional and condition
> is IS_ERR. Am I right?


			if (IS_ERR(gpio) && PTR_ERR(gpio) != -ENOENT) {
				dev_err(nc->dev,
					"Failed to get R/B gpio (err = %ld)\n",
					PTR_ERR(gpio));
				return ERR_CAST(gpio);
			}

So Linux throws the message if IS_ERR . If the property is missing 
(ENOENT) it moves on.

Can we replicate the same behavior or this behavior does not suit us in 
U-boot ?

Basically I think it should be :
		
		if (ret && ret != -ENOENT)
			dev_err(...)
		if (!ret)
			rb.type = ATMEL_NAND_GPIO_RB;

Is this what you had in mind Michael ?

Eugen

> 
> For the rest is fine
> 
> Michael
> 
>> What I wanted to ask is what happens with nand->cs[i].rb.type , is it 0
>> by default ?
>>
>> Other than that, I can apply this patch, Michael, do you have any more
>> comments on it ?
>>
>> Thanks,
>> Eugen
>>>>
>>>> Michael
>>>>
>>>>> +                       else
>>>>> +                               nand->cs[i].rb.type = ATMEL_NAND_GPIO_RB;
>>>>>                   }
>>>>>
>>>>>                   gpio_request_by_name_nodev(np, "cs-gpios", 0,
>>>>> --
>>>>> 2.30.2
>>>>>
>>>>
>>>>
>>>> --
>>>> Michael Nazzareno Trimarchi
>>>> Co-Founder & Chief Executive Officer
>>>> M. +39 347 913 2170
>>>> michael at amarulasolutions.com
>>>> __________________________________
>>>>
>>>> Amarula Solutions BV
>>>> Joop Geesinkweg 125, 1114 AB, Amsterdam, NL
>>>> T. +31 (0)85 111 9172
>>>> info at amarulasolutions.com
>>>> www.amarulasolutions.com
>>
> 
>