diff options
Diffstat (limited to 'drivers/clk/sunxi/clk-sunxi.c')
-rw-r--r-- | drivers/clk/sunxi/clk-sunxi.c | 96 |
1 files changed, 96 insertions, 0 deletions
diff --git a/drivers/clk/sunxi/clk-sunxi.c b/drivers/clk/sunxi/clk-sunxi.c index d4cf297e8fac..335c98721218 100644 --- a/drivers/clk/sunxi/clk-sunxi.c +++ b/drivers/clk/sunxi/clk-sunxi.c @@ -411,6 +411,102 @@ 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_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_PARENTS]; + void *reg; + + if (of_property_read_string(node, "clock-output-names", &clk_name)) + return; + + /* allocate mux and gate clock structs */ + mux = kzalloc(sizeof(struct clk_mux), GFP_KERNEL); + if (!mux) + return; + + gate = kzalloc(sizeof(struct clk_gate), GFP_KERNEL); + if (!gate) + goto free_mux; + + /* gmac clock requires exactly 2 parents */ + parents[0] = of_clk_get_parent_name(node, 0); + parents[1] = of_clk_get_parent_name(node, 1); + if (!parents[0] || !parents[1]) + goto free_gate; + + reg = of_iomap(node, 0); + if (!reg) + goto free_gate; + + /* 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, SUN7I_A20_GMAC_PARENTS, + &mux->hw, &clk_mux_ops, + NULL, NULL, + &gate->hw, &clk_gate_ops, + 0); + + if (IS_ERR(clk)) + goto iounmap_reg; + + of_clk_add_provider(node, of_clk_src_simple_get, clk); + clk_register_clkdev(clk, clk_name, NULL); + + return; + +iounmap_reg: + iounmap(reg); +free_gate: + kfree(gate); +free_mux: + kfree(mux); +} +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 */ |