drivers/clk/tegra/clk-tegra-fixed.c

   1 /*
   2  * Copyright (c) 2012, 2013, NVIDIA CORPORATION.  All rights reserved.
   3  *
   4  * This program is free software; you can redistribute it and/or modify it
   5  * under the terms and conditions of the GNU General Public License,
   6  * version 2, as published by the Free Software Foundation.
   7  *
   8  * This program is distributed in the hope it will be useful, but WITHOUT
   9  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
  10  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
  11  * more details.
  12  *
  13  * You should have received a copy of the GNU General Public License
  14  * along with this program.  If not, see <http://www.gnu.org/licenses/>.
  15  */
  16
  17 #include <linux/io.h>
  18 #include <linux/clk.h>
  19 #include <linux/clk-provider.h>
  20 #include <linux/of.h>
  21 #include <linux/of_address.h>
  22 #include <linux/delay.h>
  23 #include <linux/export.h>
  24 #include <linux/clk/tegra.h>
  25
  26 #include "clk.h"
  27 #include "clk-id.h"
  28
  29 #define OSC_CTRL                        0x50
  30 #define OSC_CTRL_OSC_FREQ_SHIFT         28
  31 #define OSC_CTRL_PLL_REF_DIV_SHIFT      26
  32
  33 int __init tegra_osc_clk_init(void __iomem *clk_base,
  34                                 struct tegra_clk *tegra_clks,
  35                                 unsigned long *input_freqs, int num,
  36                                 unsigned long *osc_freq,
  37                                 unsigned long *pll_ref_freq)
  38 {
  39         struct clk *clk;
  40         struct clk **dt_clk;
  41         u32 val, pll_ref_div;
  42         unsigned osc_idx;
  43
  44         val = readl_relaxed(clk_base + OSC_CTRL);
  45         osc_idx = val >> OSC_CTRL_OSC_FREQ_SHIFT;
  46
  47         if (osc_idx < num)
  48                 *osc_freq = input_freqs[osc_idx];
  49         else
  50                 *osc_freq = 0;
  51
  52         if (!*osc_freq) {
  53                 WARN_ON(1);
  54                 return -EINVAL;
  55         }
  56
  57         dt_clk = tegra_lookup_dt_id(tegra_clk_clk_m, tegra_clks);
  58         if (!dt_clk)
  59                 return 0;
  60
  61         clk = clk_register_fixed_rate(NULL, "clk_m", NULL, CLK_IS_ROOT,
  62                                       *osc_freq);
  63         *dt_clk = clk;
  64
  65         /* pll_ref */
  66         val = (val >> OSC_CTRL_PLL_REF_DIV_SHIFT) & 3;
  67         pll_ref_div = 1 << val;
  68         dt_clk = tegra_lookup_dt_id(tegra_clk_pll_ref, tegra_clks);
  69         if (!dt_clk)
  70                 return 0;
  71
  72         clk = clk_register_fixed_factor(NULL, "pll_ref", "clk_m",
  73                                         0, 1, pll_ref_div);
  74         *dt_clk = clk;
  75
  76         if (pll_ref_freq)
  77                 *pll_ref_freq = *osc_freq / pll_ref_div;
  78
  79         return 0;
  80 }
  81
  82 void __init tegra_fixed_clk_init(struct tegra_clk *tegra_clks)
  83 {
  84         struct clk *clk;
  85         struct clk **dt_clk;
  86
  87         /* clk_32k */
  88         dt_clk = tegra_lookup_dt_id(tegra_clk_clk_32k, tegra_clks);
  89         if (dt_clk) {
  90                 clk = clk_register_fixed_rate(NULL, "clk_32k", NULL,
  91                                         CLK_IS_ROOT, 32768);
  92                 *dt_clk = clk;
  93         }
  94
  95         /* clk_m_div2 */
  96         dt_clk = tegra_lookup_dt_id(tegra_clk_clk_m_div2, tegra_clks);
  97         if (dt_clk) {
  98                 clk = clk_register_fixed_factor(NULL, "clk_m_div2", "clk_m",
  99                                         CLK_SET_RATE_PARENT, 1, 2);
 100                 *dt_clk = clk;
 101         }
 102
 103         /* clk_m_div4 */
 104         dt_clk = tegra_lookup_dt_id(tegra_clk_clk_m_div4, tegra_clks);
 105         if (dt_clk) {
 106                 clk = clk_register_fixed_factor(NULL, "clk_m_div4", "clk_m",
 107                                         CLK_SET_RATE_PARENT, 1, 4);
 108                 *dt_clk = clk;
 109         }
 110 }
 111