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/*
* Copyright 2013 Emilio López
* Emilio López <emilio@elopez.com.ar>
*
* Copyright 2013 Chen-Yu Tsai
* Chen-Yu Tsai <wens@csie.org>
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*/
#include <linux/clk-provider.h>
#include <linux/clkdev.h>
#include <linux/of.h>
#include <linux/of_address.h>
#include <linux/slab.h>
static DEFINE_SPINLOCK(gmac_lock);
/**
* 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 __iomem *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 = &gmac_lock;
mux->reg = reg;
mux->mask = SUN7I_A20_GMAC_MASK;
mux->flags = CLK_MUX_INDEX_BIT;
mux->lock = &gmac_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);
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