linux-kernel - Re: [PATCH v10 2/3] PCI: rockchip: Simplify reset control handling by using reset_control

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Message-ID: <20241115055346.m2rhcb7z5hoydxsb@thinkpad>
Date: Fri, 15 Nov 2024 11:23:46 +0530
From: Manivannan Sadhasivam <manivannan.sadhasivam@...aro.org>
To: Anand Moon <linux.amoon@...il.com>
Cc: Shawn Lin <shawn.lin@...k-chips.com>,
	Lorenzo Pieralisi <lpieralisi@...nel.org>,
	Krzysztof Wilczyński <kw@...ux.com>,
	Rob Herring <robh@...nel.org>, Bjorn Helgaas <bhelgaas@...gle.com>,
	Heiko Stuebner <heiko@...ech.de>,
	Philipp Zabel <p.zabel@...gutronix.de>,
	"open list:PCIE DRIVER FOR ROCKCHIP" <linux-pci@...r.kernel.org>,
	"open list:PCIE DRIVER FOR ROCKCHIP" <linux-rockchip@...ts.infradead.org>,
	"moderated list:ARM/Rockchip SoC support" <linux-arm-kernel@...ts.infradead.org>,
	open list <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH v10 2/3] PCI: rockchip: Simplify reset control handling
 by using reset_control_bulk*() function

On Sat, Oct 19, 2024 at 11:31:34AM +0530, Anand Moon wrote:
> Currently, the driver acquires and asserts/deasserts the resets
> individually thereby making the driver complex to read. But this
> can be simplified by using the reset_control_bulk APIs.
> Use devm_reset_control_bulk_get_exclusive() API to acquire all
> the resets and use reset_control_bulk_{assert/deassert}() APIs to
> assert/deassert them in bulk.
> 
> Following the recommendations in 'Rockchip RK3399 TRM v1.3 Part2':
> 
> 1. Split the reset controls into two groups as per section '17.5.8.1.1 PCIe
> as Root Complex'.
> 
> 2. Deassert the 'Pipe, MGMT Sticky, MGMT, Core' resets in groups as per
> section '17.5.8.1.1 PCIe as Root Complex'. This is accomplished using the
> reset_control_bulk APIs.
> 
> Signed-off-by: Anand Moon <linux.amoon@...il.com>

Reviewed-by: Manivannan Sadhasivam <manivannan.sadhasivam@...aro.org>

One nitpick below. But don't need to respin as it can be fixed while applying.

> ---
> v10: Fix some typo
> v9: Improved the commit message and try to fix few review comments.
> v8: I tried to address reviews and comments from Mani.
>     Follow the sequence of De-assert as per the driver code.
>     Drop the comment in the driver.
>     Improve the commit message with the description of the TMP section.
>     Improve the reason for the core functional changes in the commit
>     description.
>     Improve the error handling messages of the code.
> v7: replace devm_reset_control_bulk_get_optional_exclusive()
>         with devm_reset_control_bulk_get_exclusive()
>     update the functional changes.
> V6: Add reason for the split of the RESET pins.
> v5: Fix the De-assert reset core as per the TRM
>     De-assert the PIPE_RESET_N/MGMT_STICKY_RESET_N/MGMT_RESET_N/RESET_N
>     simultaneously.
> v4: use dev_err_probe in error path.
> v3: Fix typo in commit message, dropped reported by.
> v2: Fix compilation error reported by Intel test robot
>     fixed checkpatch warning.
> ---
>  drivers/pci/controller/pcie-rockchip.c | 154 +++++--------------------
>  drivers/pci/controller/pcie-rockchip.h |  26 +++--
>  2 files changed, 48 insertions(+), 132 deletions(-)
> 
> diff --git a/drivers/pci/controller/pcie-rockchip.c b/drivers/pci/controller/pcie-rockchip.c
> index 2777ef0cb599..c17aa8ec80b9 100644
> --- a/drivers/pci/controller/pcie-rockchip.c
> +++ b/drivers/pci/controller/pcie-rockchip.c

[...]

> @@ -252,31 +177,10 @@ int rockchip_pcie_init_port(struct rockchip_pcie *rockchip)
>  		goto err_power_off_phy;
>  	}
>  
> -	/*
> -	 * Please don't reorder the deassert sequence of the following
> -	 * four reset pins.
> -	 */
> -	err = reset_control_deassert(rockchip->mgmt_sticky_rst);
> -	if (err) {
> -		dev_err(dev, "deassert mgmt_sticky_rst err %d\n", err);
> -		goto err_power_off_phy;
> -	}
> -
> -	err = reset_control_deassert(rockchip->core_rst);
> -	if (err) {
> -		dev_err(dev, "deassert core_rst err %d\n", err);
> -		goto err_power_off_phy;
> -	}
> -
> -	err = reset_control_deassert(rockchip->mgmt_rst);
> -	if (err) {
> -		dev_err(dev, "deassert mgmt_rst err %d\n", err);
> -		goto err_power_off_phy;
> -	}
> -
> -	err = reset_control_deassert(rockchip->pipe_rst);
> +	err = reset_control_bulk_deassert(ROCKCHIP_NUM_CORE_RSTS,
> +					  rockchip->core_rsts);
>  	if (err) {
> -		dev_err(dev, "deassert pipe_rst err %d\n", err);
> +		dev_err(dev, "Couldn't deassert Core %d\n", err);

"Couldn't deassert Core resets %d"

- Mani

-- 
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