Re: [PATCH v3 1/8] clk: sunxi: Add Allwinner A20/A31 GMAC clock unit

[Chen-Yu Tsai]

Hi,

On Tue, Feb 4, 2014 at 3:31 AM, Maxime Ripard
<maxime.ripard@xxxxxxxxxxxxxxxxxx> wrote:
> Hi,
>
> On Mon, Feb 03, 2014 at 11:32:19AM +0800, Chen-Yu Tsai wrote:
>> The Allwinner A20/A31 clock module controls the transmit clock source
>> and interface type of the GMAC ethernet controller. Model this as
>> a single clock for GMAC drivers to use.
>>
>> Signed-off-by: Chen-Yu Tsai <wens@xxxxxxxx>
>> ---
>>  Documentation/devicetree/bindings/clock/sunxi.txt | 26 +++++++
>>  drivers/clk/sunxi/clk-sunxi.c                     | 83 +++++++++++++++++++++++
>>  2 files changed, 109 insertions(+)
>>
>> diff --git a/Documentation/devicetree/bindings/clock/sunxi.txt b/Documentation/devicetree/bindings/clock/sunxi.txt
>> index 0cf679b..f43b4c0 100644
>> --- a/Documentation/devicetree/bindings/clock/sunxi.txt
>> +++ b/Documentation/devicetree/bindings/clock/sunxi.txt
>> @@ -37,6 +37,7 @@ Required properties:
>>       "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
>> +     "allwinner,sun7i-a20-gmac-clk" - for the GMAC clock module on A20/A31
>>
>>  Required properties for all clocks:
>>  - reg : shall be the control register address for the clock.
>> @@ -50,6 +51,9 @@ Required properties for all clocks:
>>       If the clock module only has one output, the name shall be the
>>       module name.
>>


>> +For "allwinner,sun7i-a20-gmac-clk", the parent clocks shall be fixed rate
>> +dummy clocks at 25 MHz and 125 MHz, respectively. See example.
>> +


>>  Clock consumers should specify the desired clocks they use with a
>>  "clocks" phandle cell. Consumers that are using a gated clock should
>>  provide an additional ID in their clock property. This ID is the
>> @@ -96,3 +100,25 @@ mmc0_clk: clk@01c20088 {
>>       clocks = <&osc24M>, <&pll6 1>, <&pll5 1>;
>>       clock-output-names = "mmc0";
>>  };
>> +
>> +mii_phy_tx_clk: clk@2 {
>> +     #clock-cells = <0>;
>> +     compatible = "fixed-clock";
>> +     clock-frequency = <25000000>;
>> +     clock-output-names = "mii_phy_tx";
>> +};
>> +
>> +gmac_int_tx_clk: clk@3 {
>> +     #clock-cells = <0>;
>> +     compatible = "fixed-clock";
>> +     clock-frequency = <125000000>;
>> +     clock-output-names = "gmac_int_tx";
>> +};
>> +
>> +gmac_clk: clk@01c20164 {
>> +     #clock-cells = <0>;
>> +     compatible = "allwinner,sun7i-a20-gmac-clk";
>> +     reg = <0x01c20164 0x4>;
>> +     clocks = <&mii_phy_tx_clk>, <&gmac_int_tx_clk>;
>
> You should also document in which order you expect the parents to
> be. Or it will probably be easier to just use clock-names here.

Is it not clear from the "Required properties" section above?

>
>> +     clock-output-names = "gmac";
>> +};
>> diff --git a/drivers/clk/sunxi/clk-sunxi.c b/drivers/clk/sunxi/clk-sunxi.c
>> index 736fb60..0b361d2 100644
>> --- a/drivers/clk/sunxi/clk-sunxi.c
>> +++ b/drivers/clk/sunxi/clk-sunxi.c
>> @@ -379,6 +379,89 @@ static void sun7i_a20_get_out_factors(u32 *freq, u32 parent_rate,
>>
>>
>>  /**
>> + * sun7i_a20_gmac_clk_setup - Setup function for A20/A31 GMAC clock module
>> + *
>> + * This clock looks something like this
>> + *                               ________________________
>> + *  MII TX clock from PHY >-----|___________    _________|----> to GMAC core
>> + *  GMAC Int. RGMII TX clk >----|___________\__/__gate---|----> to PHY
>> + *  Ext. 125MHz RGMII TX clk >--|__divider__/            |
>> + *                              |________________________|
>> + *
>> + * The external 125 MHz reference is optional, i.e. GMAC can use its
>> + * internal TX clock just fine. The A31 GMAC clock module does not have
>> + * the divider controls for the external reference.
>> + *
>> + * To keep it simple, let the GMAC use either the MII TX clock for MII mode,
>> + * and its internal TX clock for GMII and RGMII modes. The GMAC driver should
>> + * select the appropriate source and gate/ungate the output to the PHY.
>> + *
>> + * Only the GMAC should use this clock. Altering the clock so that it doesn't
>> + * match the GMAC's operation parameters will result in the GMAC not being
>> + * able to send traffic out. The GMAC driver should set the clock rate and
>> + * enable/disable this clock to configure the required state. The clock
>> + * driver then responds by auto-reparenting the clock.
>> + */
>> +
>> +#define SUN7I_A20_GMAC_GPIT  2
>> +#define SUN7I_A20_GMAC_MASK  0x3
>> +#define SUN7I_A20_GMAC_MAX_PARENTS   2
>> +
>> +static void __init sun7i_a20_gmac_clk_setup(struct device_node *node)
>> +{
>> +     struct clk *clk;
>> +     struct clk_mux *mux;
>> +     struct clk_gate *gate;
>> +     const char *clk_name = node->name;
>> +     const char *parents[SUN7I_A20_GMAC_MAX_PARENTS];
>> +     void *reg;
>> +     int i = 0;
>> +
>> +     /* allocate mux and gate clock structs */
>> +     mux = kzalloc(sizeof(struct clk_mux), GFP_KERNEL);
>> +     if (!mux)
>> +             return;
>
> Newline.
>
>> +     gate = kzalloc(sizeof(struct clk_gate), GFP_KERNEL);
>> +     if (!gate) {
>> +             kfree(mux);
>> +             return;
>> +     }
>> +
>> +     reg = of_iomap(node, 0);
>
> You should check for the return code here.
>
>> +     of_property_read_string(node, "clock-output-names", &clk_name);
>
> And here too, since you made the clock-output-names property mandatory
>
>> +     while (i < SUN7I_A20_GMAC_MAX_PARENTS &&
>> +                     (parents[i] = of_clk_get_parent_name(node, i)) != NULL)
>
> You should check for an error here too, but if you switch to using
> clock-names, that will probably be refactored anyway.
>
>> +             i++;
>> +
>> +     /* set up gate and fixed rate properties */
>> +     gate->reg = reg;
>> +     gate->bit_idx = SUN7I_A20_GMAC_GPIT;
>> +     gate->lock = &clk_lock;
>> +     mux->reg = reg;
>> +     mux->mask = SUN7I_A20_GMAC_MASK;
>> +     mux->flags = CLK_MUX_INDEX_BIT;
>> +     mux->lock = &clk_lock;
>> +
>> +     clk = clk_register_composite(NULL, clk_name,
>> +                     parents, i,
>> +                     &mux->hw, &clk_mux_ops,
>> +                     NULL, NULL,
>> +                     &gate->hw, &clk_gate_ops,
>> +                     0);
>> +
>> +     if (!IS_ERR(clk)) {
>> +             of_clk_add_provider(node, of_clk_src_simple_get, clk);
>> +             clk_register_clkdev(clk, clk_name, NULL);
>> +     }
>> +}
>> +CLK_OF_DECLARE(sun7i_a20_gmac, "allwinner,sun7i-a20-gmac-clk",
>> +             sun7i_a20_gmac_clk_setup);
>> +
>> +
>> +
>> +/**
>>   * sunxi_factors_clk_setup() - Setup function for factor clocks
>>   */
>>
>> --
>> 1.9.rc1
>>
>
> It looks fine otherwise.

I'll fix the rest.


Cheers
ChenYu
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