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Message-ID: <CAGb2v64+qiBqYtWyc23b6p4aWyWj7a9K1qveTsW7ZGh0ti8_Wg@mail.gmail.com>
Date: Tue, 4 Feb 2014 10:43:33 +0800
From: Chen-Yu Tsai <wens@...e.org>
To: Maxime Ripard <maxime.ripard@...e-electrons.com>
Cc: Emilio Lopez <emilio@...pez.com.ar>,
Mike Turquette <mturquette@...aro.org>,
linux-arm-kernel <linux-arm-kernel@...ts.infradead.org>,
linux-sunxi <linux-sunxi@...glegroups.com>,
devicetree <devicetree@...r.kernel.org>,
linux-kernel <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH v3 1/8] clk: sunxi: Add Allwinner A20/A31 GMAC clock unit
Hi,
On Tue, Feb 4, 2014 at 3:31 AM, Maxime Ripard
<maxime.ripard@...e-electrons.com> 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@...e.org>
>> ---
>> 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@...20088 {
>> 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@...20164 {
>> + #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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