Re: [PATCH] spi/acpi: fix incorrect ACPI parent check

[Jarkko Nikula <jarkko.nikula@linux.intel.com>]

On 6/19/19 1:16 PM, Mika Westerberg wrote:
> On Wed, Jun 19, 2019 at 11:52:54AM +0200, Ard Biesheuvel wrote:
>> The ACPI device object parsing code for SPI slaves enumerates the
>> entire ACPI namespace to look for devices that refer to the master
>> in question via the 'resource_source' field in the 'SPISerialBus'
>> resource. If that field does not refer to a valid ACPI device or
>> if it refers to the wrong SPI master, we should disregard the
>> device.
>>
>> Current, the valid device check is wrong, since it gets the
>> polarity of 'status' wrong. This could cause issues if the
>> 'resource_source' field is bogus but parent_handle happens to
>> refer to the correct master (which is not entirely imaginary
>> since this code runs in a loop)
>>
>> So test for ACPI_FAILURE() instead, to make the code more
>> self explanatory.
>>
>> Fixes: 4c3c59544f33 ("spi/acpi: enumerate all SPI slaves in the namespace")
>> Reported-by: kbuild test robot <lkp@intel.com>
>> Reported-by: Dan Carpenter <dan.carpenter@oracle.com>
>> Cc: Mika Westerberg <mika.westerberg@linux.intel.com>
> 
> Acked-by: Mika Westerberg <mika.westerberg@linux.intel.com>
> 
I hit yesterday a regression caused by 4c3c59544f33. I've a custom ACPI 
tables defining I2C gpio expanders (gpio-pca953x.c as INT3491) and a 
spidev test device (SPT0001).

Both stopped enumerating after 4c3c59544f33. With this fix spidev device 
enumerates but still get confused with I2C GPIO expanders (INT3491):

[    5.629874][    T1] pxa2xx-spi pxa2xx-spi.3: registered master spi3
[    5.644447][    T1] pxa2xx-spi pxa2xx-spi.5: registered master spi5
[    5.653930][    T1] spi spi-SPT0001:00: in setup: DMA burst size set to 8
[    5.661300][    T1] spi spi-SPT0001:00: setup mode 0, 8 bits/w, 
1000000 Hz max --> 0
[    5.671360][    T1] spidev spi-SPT0001:00: do not use this driver in 
production systems!
[    5.682325][    T1] pxa2xx-spi pxa2xx-spi.5: registered child 
spi-SPT0001:00
[    5.690240][    T1] spi spi-PRP0001:00: in setup: DMA burst size set to 8
[    5.697492][    T1] spi spi-PRP0001:00: setup mode 0, 8 bits/w, 
20000000 Hz max --> 0
[    5.706928][    T1] pxa2xx-spi pxa2xx-spi.5: registered child 
spi-PRP0001:00
[    5.715754][    T1] pxa2xx-spi pxa2xx-spi.5: cs104 >= max 4
[    5.721688][    T1] spi_master spi5: failed to add SPI device 
INT3491:00 from ACPI
[    5.730648][    T1] pxa2xx-spi pxa2xx-spi.5: cs104 >= max 4
[    5.736657][    T1] spi_master spi5: failed to add SPI device 
INT3491:01 from ACPI
[    5.745617][    T1] pxa2xx-spi pxa2xx-spi.5: cs104 >= max 4
[    5.751546][    T1] spi_master spi5: failed to add SPI device 
INT3491:02 from ACPI
[    5.760628][    T1] pxa2xx-spi pxa2xx-spi.5: cs104 >= max 4
[    5.766549][    T1] spi_master spi5: failed to add SPI device 
INT3491:03 from ACPI
[    5.777160][    T1] pxa2xx-spi pxa2xx-spi.5: cs104 >= max 4
[    5.783087][    T1] spi_master spi5: failed to add SPI device 
BCM2E95:00 from ACPI
[    5.797008][    T1] pxa2xx-spi pxa2xx-spi.6: registered master spi6

Ok log with commit 4c3c59544f33 reverted:

[    5.633116][    T1] pxa2xx-spi pxa2xx-spi.3: registered master spi3
[    5.647701][    T1] pxa2xx-spi pxa2xx-spi.5: registered master spi5
[    5.655668][    T1] spi spi-SPT0001:00: in setup: DMA burst size set to 8
[    5.663066][    T1] spi spi-SPT0001:00: setup mode 0, 8 bits/w, 
1000000 Hz max --> 0
[    5.672758][    T1] pxa2xx-spi pxa2xx-spi.5: registered child 
spi-SPT0001:00
[    5.680602][    T1] spi spi-PRP0001:00: in setup: DMA burst size set to 8
[    5.687820][    T1] spi spi-PRP0001:00: setup mode 0, 8 bits/w, 
20000000 Hz max --> 0
[    5.697366][    T1] pxa2xx-spi pxa2xx-spi.5: registered child 
spi-PRP0001:00
[    5.709064][    T1] pxa2xx-spi pxa2xx-spi.6: registered master spi6
[   11.021760][   T84] spidev spi-SPT0001:00: do not use this driver in 
production systems!

-- 
Jarkko