[PATCH RESEND] clk: meson: pll: copy retry workaround from vendor driver

[Jerome Brunet]

On Sun 14 Aug 2022 at 23:25, Heiner Kallweit <hkallweit1 at gmail.com> wrote:

> On a S905X4-based system this call fails randomly.
> The vendor driver has a retry mechanism and on my system
> the second attempt is successful always.
>

This reason looks a bit weak to me.
I'd like AML team to comment on this PLL problem as I suspect it might
relate to other PLL we have been seeing

> Signed-off-by: Heiner Kallweit <hkallweit1 at gmail.com>
> ---
>  drivers/clk/meson/clk-pll.c | 12 ++++++++----
>  1 file changed, 8 insertions(+), 4 deletions(-)
>
> diff --git a/drivers/clk/meson/clk-pll.c b/drivers/clk/meson/clk-pll.c
> index 9e55617bc..daa025b6d 100644
> --- a/drivers/clk/meson/clk-pll.c
> +++ b/drivers/clk/meson/clk-pll.c
> @@ -320,12 +320,16 @@ static int meson_clk_pll_is_enabled(struct clk_hw *hw)
>  
>  static int meson_clk_pcie_pll_enable(struct clk_hw *hw)
>  {
> -	meson_clk_pll_init(hw);
> +	int retries = 10;
>  
> -	if (meson_clk_pll_wait_lock(hw))
> -		return -EIO;
> +	do {
> +		meson_clk_pll_init(hw);
> +		if (!meson_clk_pll_wait_lock(hw))
> +			return 0;
> +		pr_info("Retry enabling PCIe PLL clock\n");
> +	} while (--retries);
>  
> -	return 0;
> +	return -EIO;
>  }
>  
>  static int meson_clk_pll_enable(struct clk_hw *hw)