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                                          void *data)
  29 {
  30         struct clk_onecell_data *clk_data;
  31         const char *clk_parent;
  32         const char *clk_name;
  33         void __iomem *reg;
  34         void __iomem *reg_idx;
  35         int flags;
  36         int qty;
  37         int reg_bit;
  38         int clkflags = CLK_SET_RATE_PARENT;
  39         int i;
  40
  41         qty = of_property_count_strings(node, "clock-output-names");
  42         if (qty < 0) {
  43                 pr_err("%s: error in clock-output-names %d\n", __func__, qty);
  44                 return;
  45         }
  46
  47         if (qty == 0) {
  48                 pr_info("%s: nothing to do\n", __func__);
  49                 return;
  50         }
  51
  52         reg = of_iomap(node, 0);
  53
  54         clk_data = kzalloc(sizeof(struct clk_onecell_data), GFP_KERNEL);
  55         if (!clk_data)
  56                 return;
  57
  58         clk_data->clks = kzalloc(qty * sizeof(struct clk *), GFP_KERNEL);
  59         if (!clk_data->clks) {
  60                 kfree(clk_data);
  61                 return;
  62         }
  63
  64         flags = CLK_GATE_HIWORD_MASK | CLK_GATE_SET_TO_DISABLE;
  65
  66         for (i = 0; i < qty; i++) {
  67                 of_property_read_string_index(node, "clock-output-names",
  68                                               i, &clk_name);
  69
  70                 /* ignore empty slots */
  71                 if (!strcmp("reserved", clk_name))
  72                         continue;
  73
  74                 clk_parent = of_clk_get_parent_name(node, i);
  75
  76                 /* keep all gates untouched for now */
  77                 clkflags |= CLK_IGNORE_UNUSED;
  78
  79                 reg_idx = reg + (4 * (i / 16));
  80                 reg_bit = (i % 16);
  81
  82                 clk_data->clks[i] = clk_register_gate(NULL, clk_name,
  83                                                       clk_parent, clkflags,
  84                                                       reg_idx, reg_bit,
  85                                                       flags,
  86                                                       &clk_lock);
  87                 WARN_ON(IS_ERR(clk_data->clks[i]));
  88         }
  89
  90         clk_data->clk_num = qty;
  91
  92         of_clk_add_provider(node, of_clk_src_onecell_get, clk_data);
  93 }
  94 CLK_OF_DECLARE(rk2928_gate, "rockchip,rk2928-gate-clk", rk2928_gate_clk_init);