Re: [PATCH v7 0/9] misc: Support TI FPC202 dual-port controller

[Tomi Valkeinen <tomi.valkeinen@ideasonboard.com>]

Hi,

On 04/02/2025 11:29, Romain Gantois wrote:
> Hello everyone,
> 
> This is version seven of my series which adds support for the TI FPC202
> dual-port controller. This is an unusual kind of device which is used as a
> low-speed signal aggregator for various types of SFP-like hardware ports.
> 
> The FPC202 exposes an I2C, or SPI (not supported in this series) control
> interface, which can be used to access two downstream I2C busses, along
> with a set of low-speed GPIO signals for each port. It also has I2C address
> translation (ATR) features, which allow multiple I2C devices with the same
> address (e.g. SFP EEPROMs at address 0x50) to be accessed from the upstream
> control interface on different addresses.
> 
> I've chosen to add this driver to the misc subsystem, as it doesn't
> strictly belong in either the i2c or gpio sybsystem, and as far as I know
> it is the first device of its kind to be added to the kernel.
> 
> Along with the FPC202 driver itself, this series also adds support for
> dynamic address translation to the i2c-atr module. This allows I2C address
> translators to update their translation table on-the-fly when they receive
> transactions to unmapped clients. This feature is needed by the FPC202
> driver to access up to three logical I2C devices per-port, given that the
> FPC202 address translation table only has two address slots.
> 
> Best Regards,
> 
> Romain

I tested this series on my ds90ub960 setup (with plenty of patches on 
top of mainline to get full multi-streaming), and it works fine for me. So:

Tested-by: Tomi Valkeinen <tomi.valkeinen@ideasonboard.com>

This series does conflict with the ub960 changes I've sent resently. 
Nothing difficult, but just something to be aware of.

I'll try to do an actual review next week.

We also still have the GMSL i2c-atr questions to sort out. Cosmin 
recently sent out this series to add a few patches which help on GMSL:

https://lore.kernel.org/all/20250203121629.2027871-1-demonsingur%40gmail.com/

  Tomi

> 
> Signed-off-by: Romain Gantois <romain.gantois@bootlin.com>
> ---
> Changes in v7:
> - Removed a superfluous log message
> - Link to v6: https://lore.kernel.org/r/20250115-fpc202-v6-0-d47a34820753@bootlin.com
> 
> Changes in v6:
> - Replaced spaces with tabs in misc Makefile
> - Link to v5: https://lore.kernel.org/r/20250108-fpc202-v5-0-a439ab999d5a@bootlin.com
> 
> Changes in v5:
> - Used mutex guards in ub960 and fpc202 drivers
> - Changed wording of some i2c-atr logs
> - Link to v4: https://lore.kernel.org/r/20241230-fpc202-v4-0-761b297dc697@bootlin.com
> 
> Changes in v4:
> - Fixed unbalanced refcounting in FPC202 port probing path
> - Fixed KASAN bug by setting alias_pool "shared" flag properly
> - Dropped requirement for both FPC202 ports to be described in the DT
> - Enabled dynamic translation by default, dropped support for non dynamic translation
> - Used aliased_addrs list instead of insufficient bitmap in ub960 driver
> - Added i2c_atr_destroy_c2a() function matching i2c_atr_create_c2a()
> - Fixed list corruption bug in dynamic address translation
> - Indented Kconfig entry with tabs instead of spaces
> - Link to v3: https://lore.kernel.org/r/20241125-fpc202-v3-0-34e86bcb5b56@bootlin.com
> 
> Changes in v3:
> - Described the "reg" property of downstream ports in the FPC202 bindings
> - Link to v2: https://lore.kernel.org/r/20241118-fpc202-v2-0-744e4f192a2d@bootlin.com
> 
> Changes in v2:
> - Renamed port nodes to match i2c adapter bindings.
> - Declared atr ops struct as static const.
> - Free downstream ports during FPC202 removal.
> - Link to v1: https://lore.kernel.org/r/20241108-fpc202-v1-0-fe42c698bc92@bootlin.com
> 
> ---
> Romain Gantois (9):
>        dt-bindings: misc: Describe TI FPC202 dual port controller
>        media: i2c: ds90ub960: Replace aliased clients list with address list
>        media: i2c: ds90ub960: Protect alias_use_mask with a mutex
>        i2c: use client addresses directly in ATR interface
>        i2c: move ATR alias pool to a separate struct
>        i2c: rename field 'alias_list' of struct i2c_atr_chan to 'alias_pairs'
>        i2c: support per-channel ATR alias pools
>        i2c: Support dynamic address translation
>        misc: add FPC202 dual port controller driver
> 
>   .../devicetree/bindings/misc/ti,fpc202.yaml        |  94 ++++
>   MAINTAINERS                                        |   7 +
>   drivers/i2c/i2c-atr.c                              | 483 ++++++++++++++-------
>   drivers/media/i2c/ds90ub913.c                      |   9 +-
>   drivers/media/i2c/ds90ub953.c                      |   9 +-
>   drivers/media/i2c/ds90ub960.c                      |  49 ++-
>   drivers/misc/Kconfig                               |  11 +
>   drivers/misc/Makefile                              |   1 +
>   drivers/misc/ti_fpc202.c                           | 438 +++++++++++++++++++
>   include/linux/i2c-atr.h                            |  54 ++-
>   10 files changed, 964 insertions(+), 191 deletions(-)
> ---
> base-commit: 2014c95afecee3e76ca4a56956a936e23283f05b
> change-id: 20241017-fpc202-6f0b739c2078
> 
> Best regards,