Re: Boot failure with 5.4-rc5, bisected to 0f0581b24bd0 ("spi: fsl: Convert to use CS GPIO descriptors")

[Christophe Leroy <christophe.leroy@c-s.fr>]

Le 27/11/2019 à 11:55, Linus Walleij a écrit :
> On Wed, Nov 27, 2019 at 11:39 AM Christophe Leroy
> <christophe.leroy@c-s.fr> wrote:
>> Le 27/11/2019 à 11:02, Linus Walleij a écrit :
>>> On Wed, Nov 27, 2019 at 10:34 AM Christophe Leroy
>>> <christophe.leroy@c-s.fr> wrote:
>>>
>>>> In the meantime, I have tried changing "gpios" by "cs-gpios" in the
>>>> device tree, and I get the following warning:
>>> (...)
>>>> [    3.156654] WARNING: CPU: 0 PID: 1 at drivers/spi/spi-fsl-spi.c:716
>>>> fsl_spi_cs_control+0x64/0x7c
>>>
>>> That should be this one:
>>>
>>> if (WARN_ON_ONCE(!pinfo->immr_spi_cs))
>>>      return;
>>>
>>> That happens when spi->cs_gpiod is NULL so the
>>> chipselect isn't found and assigned, and the code
>>> goes on to check the native CS and find that this isn't
>>> available either and issues the warning.
>>
>> That's in spi_add_device(), it is spi->cs_gpio and not spi->cs_gpiod
>> which is assigned, so spi->cs_gpiod remains NULL.
> 
> That's weird, because when ->use_gpio_descriptors is set
> (as for this driver) the core only attempts to look up
> spi->cs_gpiods and not spi->cs_gpios, and consequently
> can only assign spi->cd_gpiod and not spi->cs_gpio:

That's it. ->use_gpio_descriptors isn't set for the FSL driver:

[root@po16098vm linux-powerpc]# git grep use_gpio_descriptors drivers/spi/
drivers/spi/spi-ath79.c:	master->use_gpio_descriptors = true;
drivers/spi/spi-atmel.c:	master->use_gpio_descriptors = true;
drivers/spi/spi-bcm2835.c:	 * as the flag use_gpio_descriptors enforces 
SPI_CS_HIGH.
drivers/spi/spi-bcm2835.c:	ctlr->use_gpio_descriptors = true;
drivers/spi/spi-cadence.c:	master->use_gpio_descriptors = true;
drivers/spi/spi-clps711x.c:	master->use_gpio_descriptors = true;
drivers/spi/spi-davinci.c:	master->use_gpio_descriptors = true;
drivers/spi/spi-dw.c:	master->use_gpio_descriptors = true;
drivers/spi/spi-ep93xx.c:	master->use_gpio_descriptors = true;
drivers/spi/spi-gpio.c:	master->use_gpio_descriptors = true;
drivers/spi/spi-sh-msiof.c:	ctlr->use_gpio_descriptors = true;
drivers/spi/spi-tegra114.c:	master->use_gpio_descriptors = true;
drivers/spi/spi.c:	if (ctlr->use_gpio_descriptors)
drivers/spi/spi.c:		if (ctlr->use_gpio_descriptors) {

I have now added it, together with the DTS cs-gpios name change (without 
your counting patch with crashes), and I get something which is almost 
working: I get temperature back into sensors, but temperature is 0°C !!!

root@vgoip:~# sensors
lm74-spi-0-5
Adapter: SPI adapter
Temperature processeur:   +0.0 C

lm74-spi-0-1
Adapter: SPI adapter
Temperature MIAE:   +0.0 C


Looking into dmesg, I see:

[    3.153521] lm74@1 GPIO handle specifies active low - ignored
[    3.178093] lm74@5 GPIO handle specifies active low - ignored

Any link with the problem ?

Christophe

> 
> if (ctlr->use_gpio_descriptors) {
>      status = spi_get_gpio_descs(ctlr);
> (...)
> } else {
> (....)
>      status = of_spi_get_gpio_numbers(ctlr);
> }
> (...)
> /* Descriptors take precedence */
> if (ctlr->cs_gpiods)
>      spi->cs_gpiod = ctlr->cs_gpiods[spi->chip_select];
> else if (ctlr->cs_gpios)
>      spi->cs_gpio = ctlr->cs_gpios[spi->chip_select];
> 
> So I'm a bit confused...
> 
> Yours,
> Linus Walleij
>