[PATCH 1/4] clk: sunxi: Allwinner A20 output clock support

[mturquette@linaro.org (Mike Turquette)]

Quoting Chen-Yu Tsai (2013-12-24 05:26:17)
> This patch adds support for the external clock outputs on the
> Allwinner A20 SoC. The clock outputs are similar to "module 0"
> type clocks, with different offsets and widths for clock factors.
> 
> Signed-off-by: Chen-Yu Tsai <wens@csie.org>

Looks good to me.

Regards,
Mike

> ---
>  Documentation/devicetree/bindings/clock/sunxi.txt |  1 +
>  drivers/clk/sunxi/clk-sunxi.c                     | 57 +++++++++++++++++++++++
>  2 files changed, 58 insertions(+)
> 
> diff --git a/Documentation/devicetree/bindings/clock/sunxi.txt b/Documentation/devicetree/bindings/clock/sunxi.txt
> index 46d8433..c2cb762 100644
> --- a/Documentation/devicetree/bindings/clock/sunxi.txt
> +++ b/Documentation/devicetree/bindings/clock/sunxi.txt
> @@ -36,6 +36,7 @@ Required properties:
>         "allwinner,sun6i-a31-apb2-div-clk" - for the APB2 gates on A31
>         "allwinner,sun6i-a31-apb2-gates-clk" - for the APB2 gates on A31
>         "allwinner,sun4i-mod0-clk" - for the module 0 family of clocks
> +       "allwinner,sun7i-a20-out-clk" - for the external output clocks
>  
>  Required properties for all clocks:
>  - reg : shall be the control register address for the clock.
> diff --git a/drivers/clk/sunxi/clk-sunxi.c b/drivers/clk/sunxi/clk-sunxi.c
> index 25d99b6..19d9e9e 100644
> --- a/drivers/clk/sunxi/clk-sunxi.c
> +++ b/drivers/clk/sunxi/clk-sunxi.c
> @@ -330,6 +330,47 @@ static void sun4i_get_mod0_factors(u32 *freq, u32 parent_rate,
>  
>  
>  /**
> + * sun7i_a20_get_out_factors() - calculates m, p factors for CLK_OUT_A/B
> + * CLK_OUT rate is calculated as follows
> + * rate = (parent_rate >> p) / (m + 1);
> + */
> +
> +static void sun7i_a20_get_out_factors(u32 *freq, u32 parent_rate,
> +                                     u8 *n, u8 *k, u8 *m, u8 *p)
> +{
> +       u8 div, calcm, calcp;
> +
> +       /* These clocks can only divide, so we will never be able to achieve
> +        * frequencies higher than the parent frequency */
> +       if (*freq > parent_rate)
> +               *freq = parent_rate;
> +
> +       div = parent_rate / *freq;
> +
> +       if (div < 32)
> +               calcp = 0;
> +       else if (div / 2 < 32)
> +               calcp = 1;
> +       else if (div / 4 < 32)
> +               calcp = 2;
> +       else
> +               calcp = 3;
> +
> +       calcm = DIV_ROUND_UP(div, 1 << calcp);
> +
> +       *freq = (parent_rate >> calcp) / calcm;
> +
> +       /* we were called to round the frequency, we can now return */
> +       if (n == NULL)
> +               return;
> +
> +       *m = calcm - 1;
> +       *p = calcp;
> +}
> +
> +
> +
> +/**
>   * sunxi_factors_clk_setup() - Setup function for factor clocks
>   */
>  
> @@ -384,6 +425,14 @@ static struct clk_factors_config sun4i_mod0_config = {
>         .pwidth = 2,
>  };
>  
> +/* user manual says "n" but it's really "p" */
> +static struct clk_factors_config sun7i_a20_out_config = {
> +       .mshift = 8,
> +       .mwidth = 5,
> +       .pshift = 20,
> +       .pwidth = 2,
> +};
> +
>  static const struct factors_data sun4i_pll1_data __initconst = {
>         .enable = 31,
>         .table = &sun4i_pll1_config,
> @@ -414,6 +463,13 @@ static const struct factors_data sun4i_mod0_data __initconst = {
>         .getter = sun4i_get_mod0_factors,
>  };
>  
> +static const struct factors_data sun7i_a20_out_data __initconst = {
> +       .enable = 31,
> +       .mux = 24,
> +       .table = &sun7i_a20_out_config,
> +       .getter = sun7i_a20_get_out_factors,
> +};
> +
>  static struct clk * __init sunxi_factors_clk_setup(struct device_node *node,
>                                                 const struct factors_data *data)
>  {
> @@ -912,6 +968,7 @@ static const struct of_device_id clk_factors_match[] __initconst = {
>         {.compatible = "allwinner,sun6i-a31-pll1-clk", .data = &sun6i_a31_pll1_data,},
>         {.compatible = "allwinner,sun4i-apb1-clk", .data = &sun4i_apb1_data,},
>         {.compatible = "allwinner,sun4i-mod0-clk", .data = &sun4i_mod0_data,},
> +       {.compatible = "allwinner,sun7i-a20-out-clk", .data = &sun7i_a20_out_data,},
>         {}
>  };
>  
> -- 
> 1.8.5.2
>