121 lines
3.5 KiB
C
121 lines
3.5 KiB
C
/*
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* Copyright 2013 Emilio López
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* Emilio López <emilio@elopez.com.ar>
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*
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* Copyright 2013 Chen-Yu Tsai
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* Chen-Yu Tsai <wens@csie.org>
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation; either version 2 of the License, or
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* (at your option) any later version.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*/
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#include <linux/clk-provider.h>
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#include <linux/of.h>
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#include <linux/of_address.h>
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#include <linux/slab.h>
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static DEFINE_SPINLOCK(gmac_lock);
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/**
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* sun7i_a20_gmac_clk_setup - Setup function for A20/A31 GMAC clock module
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*
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* This clock looks something like this
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* ________________________
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* MII TX clock from PHY >-----|___________ _________|----> to GMAC core
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* GMAC Int. RGMII TX clk >----|___________\__/__gate---|----> to PHY
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* Ext. 125MHz RGMII TX clk >--|__divider__/ |
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* |________________________|
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*
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* The external 125 MHz reference is optional, i.e. GMAC can use its
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* internal TX clock just fine. The A31 GMAC clock module does not have
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* the divider controls for the external reference.
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*
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* To keep it simple, let the GMAC use either the MII TX clock for MII mode,
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* and its internal TX clock for GMII and RGMII modes. The GMAC driver should
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* select the appropriate source and gate/ungate the output to the PHY.
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*
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* Only the GMAC should use this clock. Altering the clock so that it doesn't
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* match the GMAC's operation parameters will result in the GMAC not being
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* able to send traffic out. The GMAC driver should set the clock rate and
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* enable/disable this clock to configure the required state. The clock
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* driver then responds by auto-reparenting the clock.
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*/
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#define SUN7I_A20_GMAC_GPIT 2
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#define SUN7I_A20_GMAC_MASK 0x3
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#define SUN7I_A20_GMAC_PARENTS 2
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static u32 sun7i_a20_gmac_mux_table[SUN7I_A20_GMAC_PARENTS] = {
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0x00, /* Select mii_phy_tx_clk */
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0x02, /* Select gmac_int_tx_clk */
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};
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static void __init sun7i_a20_gmac_clk_setup(struct device_node *node)
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{
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struct clk *clk;
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struct clk_mux *mux;
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struct clk_gate *gate;
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const char *clk_name = node->name;
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const char *parents[SUN7I_A20_GMAC_PARENTS];
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void __iomem *reg;
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if (of_property_read_string(node, "clock-output-names", &clk_name))
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return;
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/* allocate mux and gate clock structs */
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mux = kzalloc(sizeof(struct clk_mux), GFP_KERNEL);
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if (!mux)
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return;
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gate = kzalloc(sizeof(struct clk_gate), GFP_KERNEL);
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if (!gate)
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goto free_mux;
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/* gmac clock requires exactly 2 parents */
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if (of_clk_parent_fill(node, parents, 2) != 2)
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goto free_gate;
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reg = of_iomap(node, 0);
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if (!reg)
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goto free_gate;
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/* set up gate and fixed rate properties */
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gate->reg = reg;
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gate->bit_idx = SUN7I_A20_GMAC_GPIT;
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gate->lock = &gmac_lock;
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mux->reg = reg;
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mux->mask = SUN7I_A20_GMAC_MASK;
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mux->table = sun7i_a20_gmac_mux_table;
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mux->lock = &gmac_lock;
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clk = clk_register_composite(NULL, clk_name,
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parents, SUN7I_A20_GMAC_PARENTS,
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&mux->hw, &clk_mux_ops,
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NULL, NULL,
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&gate->hw, &clk_gate_ops,
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0);
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if (IS_ERR(clk))
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goto iounmap_reg;
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of_clk_add_provider(node, of_clk_src_simple_get, clk);
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return;
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iounmap_reg:
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iounmap(reg);
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free_gate:
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kfree(gate);
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free_mux:
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kfree(mux);
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}
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CLK_OF_DECLARE(sun7i_a20_gmac, "allwinner,sun7i-a20-gmac-clk",
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sun7i_a20_gmac_clk_setup);
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