Re: [PATCH] clk: en7523: reset PCIE HB on init for AN7581

[Brian Masney <bmasney@redhat.com>]

Hi Christian,

Thanks for the patch.

On Wed, Jul 08, 2026 at 10:40:44AM +0200, Christian Marangi wrote:
> It was reported that PCIE HB should be reset for AN7581 or some instability
> or link training issue will be present on warm boot scenario.
> 
> Reset PCIE HB on clk HW init to handle warm boot problem with PCIe.
> 
> Signed-off-by: Christian Marangi <ansuelsmth@gmail.com>
> ---
>  drivers/clk/clk-en7523.c | 7 +++++++
>  1 file changed, 7 insertions(+)
> 
> diff --git a/drivers/clk/clk-en7523.c b/drivers/clk/clk-en7523.c
> index 1ab0e2eca5d3..c450d89bfa96 100644
> --- a/drivers/clk/clk-en7523.c
> +++ b/drivers/clk/clk-en7523.c
> @@ -57,6 +57,7 @@
>  
>  #define REG_RST_CTRL2			0x830
>  #define REG_RST_CTRL1			0x834
> +#define   REG_PCIE_HB_RST		BIT(29)
>  #define EN751221_REG_RST_DMT		0x84
>  #define EN751221_REG_RST_USB		0xec
>  
> @@ -853,6 +854,12 @@ static int en7581_clk_hw_init(struct platform_device *pdev,
>  	val = readl(base + REG_NP_SCU_PCIC);
>  	writel(val | 3, base + REG_NP_SCU_PCIC);
>  
> +	val = readl(base + REG_RST_CTRL1);
> +	val |= REG_PCIE_HB_RST;
> +	writel(val, base + REG_RST_CTRL1);
> +	val &= ~REG_PCIE_HB_RST;
> +	writel(val, base + REG_RST_CTRL1);
> +

Sashiko has a question about whether or not a delay or a flush is needed
between the writel() calls?

https://sashiko.dev/#/patchset/20260708084045.8380-1-ansuelsmth%40gmail.com

Brian