Re: [PATCH] net: stmmac: dwmac-meson8b: fix mask definition of the m250_sel mux

[Jerome Brunet]

On Sat 05 Dec 2020 at 22:32, Martin Blumenstingl <martin.blumenstingl@xxxxxxxxxxxxxx> wrote:

> The m250_sel mux clock uses bit 4 in the PRG_ETH0 register. Fix this by
> shifting the PRG_ETH0_CLK_M250_SEL_MASK accordingly as the "mask" in
> struct clk_mux expects the mask relative to the "shift" field in the
> same struct.
>
> While here, get rid of the PRG_ETH0_CLK_M250_SEL_SHIFT macro and use
> __ffs() to determine it from the existing PRG_ETH0_CLK_M250_SEL_MASK
> macro.
>
> Fixes: 566e8251625304 ("net: stmmac: add a glue driver for the Amlogic Meson 8b / GXBB DWMAC")
> Signed-off-by: Martin Blumenstingl <martin.blumenstingl@xxxxxxxxxxxxxx>

Reviewed-by: Jerome Brunet <jbrunet@xxxxxxxxxxxx>

> ---
>  drivers/net/ethernet/stmicro/stmmac/dwmac-meson8b.c | 6 +++---
>  1 file changed, 3 insertions(+), 3 deletions(-)
>
> diff --git a/drivers/net/ethernet/stmicro/stmmac/dwmac-meson8b.c b/drivers/net/ethernet/stmicro/stmmac/dwmac-meson8b.c
> index dc0b8b6d180d..459ae715b33d 100644
> --- a/drivers/net/ethernet/stmicro/stmmac/dwmac-meson8b.c
> +++ b/drivers/net/ethernet/stmicro/stmmac/dwmac-meson8b.c
> @@ -30,7 +30,6 @@
>  #define PRG_ETH0_EXT_RMII_MODE		4
>  
>  /* mux to choose between fclk_div2 (bit unset) and mpll2 (bit set) */
> -#define PRG_ETH0_CLK_M250_SEL_SHIFT	4
>  #define PRG_ETH0_CLK_M250_SEL_MASK	GENMASK(4, 4)
>  
>  /* TX clock delay in ns = "8ns / 4 * tx_dly_val" (where 8ns are exactly one
> @@ -155,8 +154,9 @@ static int meson8b_init_rgmii_tx_clk(struct meson8b_dwmac *dwmac)
>  		return -ENOMEM;
>  
>  	clk_configs->m250_mux.reg = dwmac->regs + PRG_ETH0;
> -	clk_configs->m250_mux.shift = PRG_ETH0_CLK_M250_SEL_SHIFT;
> -	clk_configs->m250_mux.mask = PRG_ETH0_CLK_M250_SEL_MASK;
> +	clk_configs->m250_mux.shift = __ffs(PRG_ETH0_CLK_M250_SEL_MASK);
> +	clk_configs->m250_mux.mask = PRG_ETH0_CLK_M250_SEL_MASK >>
> +				     clk_configs->m250_mux.shift;
>  	clk = meson8b_dwmac_register_clk(dwmac, "m250_sel", mux_parents,
>  					 ARRAY_SIZE(mux_parents), &clk_mux_ops,
>  					 &clk_configs->m250_mux.hw);