[PATCH 3/5] i2c: rzg2l: Add I2C driver for RZ/G2L family

[Marek Vasut]

On 11/19/23 21:48, Paul Barker wrote:
> On Sun, Nov 19, 2023 at 09:15:36PM +0100, Marek Vasut wrote:
>> On 11/15/23 18:40, Paul Barker wrote:
>>> This driver supports the I2C module on the Renesas RZ/G2L (R9A07G044)
>>> SoC, also known as the RIIC module.
>>>
>>> This patch is based on both the u-boot driver in the Renesas RZ BSP
>>> 3.0.5 release [1] (commit 7fcc1fdc2534), and the Linux v6.6 driver
>>> (commit ffc253263a13).
>>>
>>> Support for deblocking the I2C bus is included as this may be needed
>>> after triggering a reset via the Power Management IC (PMIC) over I2C
>>> (the PMIC asserts the reset line before the SoC completes the I2C write
>>> transaction with obvious bus locking effects). If the SDA line is
>>> observed to be low during initialisation, we automatically attempt to
>>> deblock.
>>>
>>> [1]: https://github.com/renesas-rz/renesas-u-boot-cip
>>>
>>> Signed-off-by: Paul Barker <paul.barker.ct at bp.renesas.com>
>>
>> The driver seems very similar to drivers/i2c/rcar_iic.c , can there be some
>> code reuse ?
> 
> My initial idea was to extend the R-Car iic driver but I quickly saw
> that would be very messy. All the registers and bits are in different
> places, the calculations are different (particularly in regard to
> setting bus speed) and the read/write process has more edge cases for
> the RZ/G2L. The bus recovery mechanism we use also doesn't exist on
> previous R-Car SoCs.
> 
> The Linux drivers for these modules are also separate, see
> drivers/i2c/busses/i2c-sh_mobile.c (for R-Car and earlier SoCs) and
> drivers/i2c/busses/i2c-riic.c (for RZ/G2L) in the Linux kernel.

Ah, I thought some of the registers were the same, but indeed the RZG 
core is much more extensive.

You should either use devm_clk_*() in probe() or implement .remove 
callback. With that fixed:

Reviewed-by: Marek Vasut <marek.vasut+renesas at mailbox.org>

And sorry for the delayed reply.