[PATCH v2 1/7] soc: rockchip: add driver for rockchip io domains

[Ahmad Fatoum]

Hi,

On 22.09.22 09:03, Sascha Hauer wrote:
> On Wed, Sep 21, 2022 at 01:49:49PM +0200, Michael Riesch wrote:
>> Hi Sascha,
>>
>> On 9/21/22 11:46, Sascha Hauer wrote:
>>> On Mon, Sep 19, 2022 at 01:39:42PM +0200, Michael Riesch wrote:
>>>> The IO domains in Rockchip SoCs need to be configured to match the
>>>> corresponding bank voltage. In Linux this is achieved by means of a
>>>> platform driver that reads the voltage value of the supplies and
>>>> configures the bits in the general register file (GRF) accordingly.
>>>> Port this driver to barebox to provide support for the Rockchip
>>>> RK356x SoCs.
>>>>
>>>> Signed-off-by: Michael Riesch <michael.riesch at wolfvision.net>
>>>> ---
>>>>  drivers/soc/Kconfig              |   1 +
>>>>  drivers/soc/Makefile             |   1 +
>>>>  drivers/soc/rockchip/Kconfig     |  17 +++
>>>>  drivers/soc/rockchip/Makefile    |   6 +
>>>>  drivers/soc/rockchip/io-domain.c | 223 +++++++++++++++++++++++++++++++
>>>>  5 files changed, 248 insertions(+)
>>>>  create mode 100644 drivers/soc/rockchip/Kconfig
>>>>  create mode 100644 drivers/soc/rockchip/Makefile
>>>>  create mode 100644 drivers/soc/rockchip/io-domain.c
>>>
>>> There's nothing in this driver that makes sure it is probed before the
>>> users of the io domains. What happens when the users are probed before
>>> the io domain driver?
>>
>> Correct. Unfortunately, the situation is quite the same in the kernel.
>> Only recently there was a discussion as to how to resolve this issue
>> [0]. While the RFC in [0] was received well there is no mainline
>> solution to this problem. I would suggest that the mainline kernel
>> solution is adopted once there is one.
>>
>> In the mean time we could
>>  - accept that it just works for some reason (TM)
>>  - leave the magic bits in the low-level initialization to be on the
>>    safe side
> 
> Decided for this solution for now.
> 
> I added the following as a reminder that there's still something
> to do.

Why not do an of_device_ensure_probed for the I/O domain driver in
rk3568_init()?

> 
> Sascha
> 
> ---------------------------8<---------------------------
> 
> From 502c4e819b80a6ccaefbce4af4c55b830b7e2c73 Mon Sep 17 00:00:00 2001
> From: Sascha Hauer <s.hauer at pengutronix.de>
> Date: Thu, 22 Sep 2022 09:56:57 +0200
> Subject: [PATCH] ARM: Rockchip: Add FIXME comment to io domain setup
> 
> We have a io-domain driver for rockchip boards which correctly
> configures the io domain voltages, but currently there is no way
> to make sure the io-domain driver is probed before its consumers.
> 
> To be on the safe side keep the io domain setup in the lowlevel code
> for now, but add a comment that it should be removed once this issue
> is resolved.
> 
> To solve this issue we need a phandle from the consumers to the io
> domain node. We could add this in barebox locally, but decided to
> wait until the upstream dts files have them.
> 
> Signed-off-by: Sascha Hauer <s.hauer at pengutronix.de>
> ---
>  arch/arm/boards/radxa-rock3/lowlevel.c               | 4 ++++
>  arch/arm/boards/rockchip-rk3568-bpi-r2pro/lowlevel.c | 4 ++++
>  arch/arm/boards/rockchip-rk3568-evb/lowlevel.c       | 4 ++++
>  3 files changed, 12 insertions(+)
> 
> diff --git a/arch/arm/boards/radxa-rock3/lowlevel.c b/arch/arm/boards/radxa-rock3/lowlevel.c
> index 2a449c17ae..a62f60dff8 100644
> --- a/arch/arm/boards/radxa-rock3/lowlevel.c
> +++ b/arch/arm/boards/radxa-rock3/lowlevel.c
> @@ -17,6 +17,10 @@ static noinline void rk3568_start(void)
>  	/*
>  	 * Enable vccio4 1.8V and vccio6 1.8V
>  	 * Needed for GMAC to work.
> +	 * FIXME: This is done by the io-domain driver as well, but there
> +	 * currently is no mechanism to make sure the driver gets probed
> +	 * before its consumers. Remove this setup once this issue is
> +	 * resolved.
>  	 */
>  	writel(RK_SETBITS(0x50), 0xfdc20140);
>  
> diff --git a/arch/arm/boards/rockchip-rk3568-bpi-r2pro/lowlevel.c b/arch/arm/boards/rockchip-rk3568-bpi-r2pro/lowlevel.c
> index f79f975080..4336d99365 100644
> --- a/arch/arm/boards/rockchip-rk3568-bpi-r2pro/lowlevel.c
> +++ b/arch/arm/boards/rockchip-rk3568-bpi-r2pro/lowlevel.c
> @@ -18,6 +18,10 @@ static noinline void rk3568_start(void)
>  	/*
>  	 * set iodomain vccio6 to 1.8V needed for GMAC1 to work.
>  	 * vccio4 (gmac0/switch) needs to stay at 3v3 (default)
> +	 * FIXME: This is done by the io-domain driver as well, but there
> +	 * currently is no mechanism to make sure the driver gets probed
> +	 * before its consumers. Remove this setup once this issue is
> +	 * resolved.
>  	 */
>  	//set bit 6 in PMU_GRF_IO_VSEL0 for vccio6 1v8
>  	writel(RK_SETBITS(BIT(6)), PMU_GRF_IO_VSEL0);
> diff --git a/arch/arm/boards/rockchip-rk3568-evb/lowlevel.c b/arch/arm/boards/rockchip-rk3568-evb/lowlevel.c
> index 363639d21b..9ab436135c 100644
> --- a/arch/arm/boards/rockchip-rk3568-evb/lowlevel.c
> +++ b/arch/arm/boards/rockchip-rk3568-evb/lowlevel.c
> @@ -18,6 +18,10 @@ static noinline void rk3568_start(void)
>  	/*
>  	 * Enable vccio4 1.8V and vccio6 1.8V
>  	 * Needed for GMAC to work.
> +	 * FIXME: This is done by the io-domain driver as well, but there
> +	 * currently is no mechanism to make sure the driver gets probed
> +	 * before its consumers. Remove this setup once this issue is
> +	 * resolved.
>  	 */
>  	writel(RK_SETBITS(0x50), 0xfdc20140);
>  


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