drivers/clk/rockchip/clk-rockchip.c

   1 /*
   2  * Copyright (c) 2013 MundoReader S.L.
   3  * Author: Heiko Stuebner <heiko@sntech.de>
   4  *
   5  * This program is free software; you can redistribute it and/or modify
   6  * it under the terms of the GNU General Public License as published by
   7  * the Free Software Foundation; either version 2 of the License, or
   8  * (at your option) any later version.
   9  *
  10  * This program is distributed in the hope that it will be useful,
  11  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  12  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  13  * GNU General Public License for more details.
  14  */
  15
  16 #include <linux/clk-provider.h>
  17 #include <linux/clkdev.h>
  18 #include <linux/of.h>
  19 #include <linux/of_address.h>
  20
  21 static DEFINE_SPINLOCK(clk_lock);
  22
  23 /*
  24  * Gate clocks
  25  */
  26
  27 static void __init rk2928_gate_clk_init(struct device_node *node)
  28 {
  29         struct clk_onecell_data *clk_data;
  30         const char *clk_parent;
  31         const char *clk_name;
  32         void __iomem *reg;
  33         void __iomem *reg_idx;
  34         int flags;
  35         int qty;
  36         int reg_bit;
  37         int clkflags = CLK_SET_RATE_PARENT;
  38         int i;
  39
  40         qty = of_property_count_strings(node, "clock-output-names");
  41         if (qty < 0) {
  42                 pr_err("%s: error in clock-output-names %d\n", __func__, qty);
  43                 return;
  44         }
  45
  46         if (qty == 0) {
  47                 pr_info("%s: nothing to do\n", __func__);
  48                 return;
  49         }
  50
  51         reg = of_iomap(node, 0);
  52
  53         clk_data = kzalloc(sizeof(struct clk_onecell_data), GFP_KERNEL);
  54         if (!clk_data)
  55                 return;
  56
  57         clk_data->clks = kzalloc(qty * sizeof(struct clk *), GFP_KERNEL);
  58         if (!clk_data->clks) {
  59                 kfree(clk_data);
  60                 return;
  61         }
  62
  63         flags = CLK_GATE_HIWORD_MASK | CLK_GATE_SET_TO_DISABLE;
  64
  65         for (i = 0; i < qty; i++) {
  66                 of_property_read_string_index(node, "clock-output-names",
  67                                               i, &clk_name);
  68
  69                 /* ignore empty slots */
  70                 if (!strcmp("reserved", clk_name))
  71                         continue;
  72
  73                 clk_parent = of_clk_get_parent_name(node, i);
  74
  75                 /* keep all gates untouched for now */
  76                 clkflags |= CLK_IGNORE_UNUSED;
  77
  78                 reg_idx = reg + (4 * (i / 16));
  79                 reg_bit = (i % 16);
  80
  81                 clk_data->clks[i] = clk_register_gate(NULL, clk_name,
  82                                                       clk_parent, clkflags,
  83                                                       reg_idx, reg_bit,
  84                                                       flags,
  85                                                       &clk_lock);
  86                 WARN_ON(IS_ERR(clk_data->clks[i]));
  87         }
  88
  89         clk_data->clk_num = qty;
  90
  91         of_clk_add_provider(node, of_clk_src_onecell_get, clk_data);
  92 }
  93 CLK_OF_DECLARE(rk2928_gate, "rockchip,rk2928-gate-clk", rk2928_gate_clk_init);