[PATCH v8 08/14] mfd: rk8xx: add rk806 support

[Neil Armstrong]

Hi,

On 15/11/2023 19:00, Sebastian Reichel wrote:
> Hi Neil,
> 
> On Wed, Nov 15, 2023 at 06:17:50PM +0100, Neil Armstrong wrote:
>> Hi Sebastian,
>>
>> On 04/05/2023 19:36, Sebastian Reichel wrote:
>>> Add support for SPI connected rk806, which is used by the RK3588
>>> evaluation boards. The PMIC is advertised to support I2C and SPI,
>>> but the evaluation boards all use SPI. Thus only SPI support is
>>> added here.
>>>
>>> Acked-for-MFD-by: Lee Jones <lee at kernel.org>
>>> Tested-by: Diederik de Haas <didi.debian at cknow.org> # Rock64, Quartz64 Model A + B
>>> Tested-by: Vincent Legoll <vincent.legoll at gmail.com> # Pine64 QuartzPro64
>>> Signed-off-by: Sebastian Reichel <sebastian.reichel at collabora.com>
>>> ---
>>>    drivers/mfd/Kconfig       |  14 ++
>>>    drivers/mfd/Makefile      |   1 +
>>>    drivers/mfd/rk8xx-core.c  |  69 ++++++-
>>>    drivers/mfd/rk8xx-spi.c   | 124 ++++++++++++
>>>    include/linux/mfd/rk808.h | 409 ++++++++++++++++++++++++++++++++++++++
>>>    5 files changed, 614 insertions(+), 3 deletions(-)
>>>    create mode 100644 drivers/mfd/rk8xx-spi.c
>>>
>>
>> <snip>
>>
>>> -	ret = devm_mfd_add_devices(dev, PLATFORM_DEVID_NONE,
>>> -			      cells, nr_cells, NULL, 0,
>>> +	ret = devm_mfd_add_devices(dev, 0, cells, nr_cells, NULL, 0,
>>>    			      regmap_irq_get_domain(rk808->irq_data));
>>
>> It seems you replaced PLATFORM_DEVID_NONE by 0, triggering again the bug preventing
>> having multiples RK pmics on the same system I fixed earlier at [1].
> 
> All cells have PLATFORM_DEVID_NONE specified and thus are registered
> without an ID. I changed this bit to avoid overriding the
> information, since I did not want to have PLATFORM_DEVID_NONE for
> rk806.
> 
>> This gives (again):
>> <4>[ 0.664107] sysfs: cannot create duplicate filename '/bus/platform/devices/rk808-clkout'
> 
> Which means, you do not want PLATFORM_DEVID_NONE (-1), but
> PLATFORM_DEVID_AUTO (-2). The above path is the expected path
> for PLATFORM_DEVID_NONE.
> 
>> <4>[ 0.664120] CPU: 3 PID: 97 Comm: kworker/u12:2 Not tainted 6.6.1 #1
>> <4>[ 0.664131] Hardware name: Hardkernel ODROID-GO-Ultra (DT)
>> <4>[ 0.664139] Workqueue: events_unbound deferred_probe_work_func
>> <4>[ 0.664160] Call trace:
>> <4>[ 0.664165] dump_backtrace+0x9c/0x11c
>> <4>[ 0.664181] show_stack+0x18/0x24
>> <4>[ 0.664193] dump_stack_lvl+0x78/0xc4
>> <4>[ 0.664205] dump_stack+0x18/0x24
>> <4>[ 0.664215] sysfs_warn_dup+0x64/0x80
>> <4>[ 0.664227] sysfs_do_create_link_sd+0xf0/0xf8
>> <4>[ 0.664239] sysfs_create_link+0x20/0x40
>> <4>[ 0.664250] bus_add_device+0x114/0x160
>> <4>[ 0.664259] device_add+0x3f0/0x7cc
>> <4>[ 0.664267] platform_device_add+0x180/0x270
>> <4>[ 0.664278] mfd_add_device+0x390/0x4a8
>> <4>[ 0.664290] devm_mfd_add_devices+0xb0/0x150
>> <4>[ 0.664301] rk8xx_probe+0x26c/0x410
>> <4>[ 0.664312] rk8xx_i2c_probe+0x64/0x98
>> <4>[ 0.664323] i2c_device_probe+0x104/0x2e8
>> <4>[ 0.664333] really_probe+0x184/0x3c8
>> <4>[ 0.664342] __driver_probe_device+0x7c/0x16c
>> <4>[ 0.664351] driver_probe_device+0x3c/0x10c
>> <4>[ 0.664360] __device_attach_driver+0xbc/0x158
>> <4>[ 0.664369] bus_for_each_drv+0x80/0xdc
>> <4>[ 0.664377] __device_attach+0x9c/0x1ac
>> <4>[ 0.664386] device_initial_probe+0x14/0x20
>> <4>[ 0.664395] bus_probe_device+0xac/0xb0
>> <4>[ 0.664403] deferred_probe_work_func+0xa0/0xf4
>> <4>[ 0.664412] process_one_work+0x1bc/0x378
>> <4>[ 0.664421] worker_thread+0x1dc/0x3d4
>> <4>[ 0.664429] kthread+0x104/0x118
>> <4>[ 0.664440] ret_from_fork+0x10/0x20
>> <3>[ 0.664494] rk8xx-i2c 0-001c: error -EEXIST: failed to add MFD devices
>> <4>[ 0.666769] rk8xx-i2c: probe of 0-001c failed with error -17
> 
> I didn't notice when working on rk806, but after analyzing it now:
> 
> Your patch effectively set the cells to PLATFORM_DEVID_AUTO, because
> you set all cells to PLATFORM_DEVID_NONE (-1) and additionally used
> PLATFORM_DEVID_NONE (-1) for the devm_mfd_add_devices() call. But
> that uses the sum of both IDs. Adding -1 to -1 is -2 and thus
> PLATFORM_DEVID_AUTO. This is of course very confusing and just
> worked by chance. There are two options:
> 
> 1. Modify all cells to use PLATFORM_DEVID_AUTO instead of
> PLATFORM_DEVID_NONE
> 2. Drop the .id from all cells and use PLATFORM_DEVID_AUTO in the
> call to devm_mfd_add_devices()
> 
> Note, that switching from PLATFORM_DEVID_NONE to PLATFORM_DEVID_AUTO
> modifies sysfs paths and thus might break people's scripts; that's why
> I tried not to modify any existing platform. I will let you deal
> with that, since I cannot even test any !rk806 platform supported by
> this driver :)

Yes it will modify sysfs path, but it's a regression since this before this patch
everything was registered with PLATFORM_DEVID_AUTO anyway,
so I'll provide a fix adding back PLATFORM_DEVID_NONE to devm_mfd_add_devices
in a first time...

> 
> Also mfd_add_device should probably get special handling for
> PLATFORM_DEVID_NONE, just like it already has special handling
> for PLATFORM_DEVID_AUTO.

... and yes thanks for the great analysis I'll provide a change cleaning the mess.

Thanks,
Neil

> 
> Greetings,
> 
> -- Sebastian