Re: [linux-sunxi] [PATCH v3 02/13] clk: sunxi: add ahb1 clock for A83T

[Julian Calaby]

Hi Vishnu,

On Sun, Mar 6, 2016 at 2:42 AM, Vishnu Patekar
<vishnupatekar0510@xxxxxxxxx> wrote:
> AHB1 on A83T is similar to ahb1 on A31, except parents are different.
> clock index 0b1x is PLL6.
>
> Signed-off-by: Vishnu Patekar <vishnupatekar0510@xxxxxxxxx>
> Acked-by: Chen-Yu Tsai <wens@xxxxxxxx>
> Acked-by: Rob Herring <robh@xxxxxxxxxx>
> ---
>  Documentation/devicetree/bindings/clock/sunxi.txt |  1 +
>  drivers/clk/sunxi/clk-sunxi.c                     | 76 +++++++++++++++++++++++
>  2 files changed, 77 insertions(+)
>
> diff --git a/Documentation/devicetree/bindings/clock/sunxi.txt b/Documentation/devicetree/bindings/clock/sunxi.txt
> index c09f59b..2ee7841 100644
> --- a/Documentation/devicetree/bindings/clock/sunxi.txt
> +++ b/Documentation/devicetree/bindings/clock/sunxi.txt
> @@ -29,6 +29,7 @@ Required properties:
>         "allwinner,sun6i-a31-ar100-clk" - for the AR100 on A31
>         "allwinner,sun9i-a80-cpus-clk" - for the CPUS on A80
>         "allwinner,sun6i-a31-ahb1-clk" - for the AHB1 clock on A31
> +       "allwinner,sun8i-a83t-ahb1-clk" - for the AHB1 clock on A83T
>         "allwinner,sun8i-h3-ahb2-clk" - for the AHB2 clock on H3
>         "allwinner,sun6i-a31-ahb1-gates-clk" - for the AHB1 gates on A31
>         "allwinner,sun8i-a23-ahb1-gates-clk" - for the AHB1 gates on A23
> diff --git a/drivers/clk/sunxi/clk-sunxi.c b/drivers/clk/sunxi/clk-sunxi.c
> index 99f60ef..0ae1f09 100644
> --- a/drivers/clk/sunxi/clk-sunxi.c
> +++ b/drivers/clk/sunxi/clk-sunxi.c
> @@ -344,6 +344,67 @@ static void sun6i_ahb1_recalc(struct factors_request *req)
>         req->rate >>= req->p;
>  }
>
> +#define SUN8I_A83T_AHB1_PARENT_PLL6    2
> +/**
> + * sun8i_a83t_get_ahb_factors() - calculates m, p factors for AHB
> + * AHB rate is calculated as follows
> + * rate = parent_rate >> p
> + *
> + * if parent is pll6, then
> + * parent_rate = pll6 rate / (m + 1)
> + */
> +
> +static void sun8i_a83t_get_ahb1_factors(struct factors_request *req)
> +{
> +       u8 div, calcp, calcm = 1;
> +
> +       /*
> +        * clock can only divide, so we will never be able to achieve
> +        * frequencies higher than the parent frequency
> +        */
> +       if (req->parent_rate && req->rate > req->parent_rate)
> +               req->rate = req->parent_rate;
> +
> +       div = DIV_ROUND_UP(req->parent_rate, req->rate);
> +
> +       /* calculate pre-divider if parent is pll6 */
> +       if (req->parent_index >= SUN8I_A83T_AHB1_PARENT_PLL6) {
> +               if (div < 4)
> +                       calcp = 0;
> +               else if (div / 2 < 4)
> +                       calcp = 1;
> +               else if (div / 4 < 4)
> +                       calcp = 2;
> +               else
> +                       calcp = 3;
> +
> +               calcm = DIV_ROUND_UP(div, 1 << calcp);
> +       } else {
> +               calcp = __roundup_pow_of_two(div);
> +               calcp = calcp > 3 ? 3 : calcp;
> +}

You could do with a tab here.

> +
> +       req->rate = (req->parent_rate / calcm) >> calcp;
> +       req->p = calcp;
> +       req->m = calcm - 1;
> +}
> +
> +/**
> +* sun8i_a83t_ahb1_recalc() - calculates AHB clock rate from m, p factors and
> +*                       parent index
> +*/
> +static void sun8i_a83t_ahb1_recalc(struct factors_request *req)
> +{
> +       req->rate = req->parent_rate;
> +
> +/* apply pre-divider first if parent is pll6 */
> +       if (req->parent_index >= SUN6I_AHB1_PARENT_PLL6)
> +               req->rate /= req->m + 1;
> +
> +       /* clk divider */
> +       req->rate >>= req->p;
> +}
> +
>  /**
>   * sun4i_get_apb1_factors() - calculates m, p factors for APB1
>   * APB1 rate is calculated as follows
> @@ -555,6 +616,14 @@ static const struct factors_data sun6i_ahb1_data __initconst = {
>         .recalc = sun6i_ahb1_recalc,
>  };
>
> +static const struct factors_data sun8i_a83t_ahb1_data __initconst = {
> +       .mux = 12,
> +       .muxmask = BIT(1) | BIT(0),
> +       .table = &sun6i_ahb1_config,
> +       .getter = sun8i_a83t_get_ahb1_factors,
> +       .recalc = sun8i_a83t_ahb1_recalc,
> +};
> +
>  static const struct factors_data sun4i_apb1_data __initconst = {
>         .mux = 24,
>         .muxmask = BIT(1) | BIT(0),
> @@ -627,6 +696,13 @@ static void __init sun6i_ahb1_clk_setup(struct device_node *node)
>  CLK_OF_DECLARE(sun6i_a31_ahb1, "allwinner,sun6i-a31-ahb1-clk",
>                sun6i_ahb1_clk_setup);
>
> +static void __init sun8i_a83t_ahb1_clk_setup(struct device_node *node)
> +{
> +       sunxi_factors_clk_setup(node, &sun8i_a83t_ahb1_data);
> +}
> +CLK_OF_DECLARE(sun8i_a83t_ahb1, "allwinner,sun8i-a83t-ahb1-clk",
> +              sun8i_a83t_ahb1_clk_setup);
> +
>  static void __init sun4i_apb1_clk_setup(struct device_node *node)
>  {
>         sunxi_factors_clk_setup(node, &sun4i_apb1_data);
> --
> 1.9.1
>
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-- 
Julian Calaby

Email: julian.calaby@xxxxxxxxx
Profile: http://www.google.com/profiles/julian.calaby/