drivers/clk/socfpga/clk-periph-a10.c

   1 /*
   2  * Copyright (C) 2015 Altera Corporation. All rights reserved
   3  *
   4  * This program is free software; you can redistribute it and/or modify
   5  * it 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 along with
  14  * this program.  If not, see <http://www.gnu.org/licenses/>.
  15  */
  16 #include <linux/clk-provider.h>
  17 #include <linux/io.h>
  18 #include <linux/of.h>
  19
  20 #include "clk.h"
  21
  22 #define CLK_MGR_FREE_SHIFT              16
  23 #define CLK_MGR_FREE_MASK               0x7
  24
  25 #define SOCFPGA_MPU_FREE_CLK            "mpu_free_clk"
  26 #define SOCFPGA_NOC_FREE_CLK            "noc_free_clk"
  27 #define SOCFPGA_SDMMC_FREE_CLK          "sdmmc_free_clk"
  28 #define to_socfpga_periph_clk(p) container_of(p, struct socfpga_periph_clk, hw.hw)
  29
  30 static unsigned long clk_periclk_recalc_rate(struct clk_hw *hwclk,
  31                                              unsigned long parent_rate)
  32 {
  33         struct socfpga_periph_clk *socfpgaclk = to_socfpga_periph_clk(hwclk);
  34         u32 div;
  35
  36         if (socfpgaclk->fixed_div) {
  37                 div = socfpgaclk->fixed_div;
  38         } else if (socfpgaclk->div_reg) {
  39                 div = readl(socfpgaclk->div_reg) >> socfpgaclk->shift;
  40                 div &= div_mask(socfpgaclk->width);
  41                 div += 1;
  42         } else {
  43                 div = ((readl(socfpgaclk->hw.reg) & 0x7ff) + 1);
  44         }
  45
  46         return parent_rate / div;
  47 }
  48
  49 static u8 clk_periclk_get_parent(struct clk_hw *hwclk)
  50 {
  51         struct socfpga_periph_clk *socfpgaclk = to_socfpga_periph_clk(hwclk);
  52         u32 clk_src;
  53
  54         clk_src = readl(socfpgaclk->hw.reg);
  55         if (streq(hwclk->init->name, SOCFPGA_MPU_FREE_CLK) ||
  56             streq(hwclk->init->name, SOCFPGA_NOC_FREE_CLK) ||
  57             streq(hwclk->init->name, SOCFPGA_SDMMC_FREE_CLK))
  58                 return (clk_src >> CLK_MGR_FREE_SHIFT) &
  59                         CLK_MGR_FREE_MASK;
  60         else
  61                 return 0;
  62 }
  63
  64 static const struct clk_ops periclk_ops = {
  65         .recalc_rate = clk_periclk_recalc_rate,
  66         .get_parent = clk_periclk_get_parent,
  67 };
  68
  69 static __init void __socfpga_periph_init(struct device_node *node,
  70         const struct clk_ops *ops)
  71 {
  72         u32 reg;
  73         struct clk *clk;
  74         struct socfpga_periph_clk *periph_clk;
  75         const char *clk_name = node->name;
  76         const char *parent_name;
  77         struct clk_init_data init;
  78         int rc;
  79         u32 fixed_div;
  80         u32 div_reg[3];
  81
  82         of_property_read_u32(node, "reg", &reg);
  83
  84         periph_clk = kzalloc(sizeof(*periph_clk), GFP_KERNEL);
  85         if (WARN_ON(!periph_clk))
  86                 return;
  87
  88         periph_clk->hw.reg = clk_mgr_a10_base_addr + reg;
  89
  90         rc = of_property_read_u32_array(node, "div-reg", div_reg, 3);
  91         if (!rc) {
  92                 periph_clk->div_reg = clk_mgr_a10_base_addr + div_reg[0];
  93                 periph_clk->shift = div_reg[1];
  94                 periph_clk->width = div_reg[2];
  95         } else {
  96                 periph_clk->div_reg = NULL;
  97         }
  98
  99         rc = of_property_read_u32(node, "fixed-divider", &fixed_div);
 100         if (rc)
 101                 periph_clk->fixed_div = 0;
 102         else
 103                 periph_clk->fixed_div = fixed_div;
 104
 105         of_property_read_string(node, "clock-output-names", &clk_name);
 106
 107         init.name = clk_name;
 108         init.ops = ops;
 109         init.flags = 0;
 110
 111         parent_name = of_clk_get_parent_name(node, 0);
 112         init.num_parents = 1;
 113         init.parent_names = &parent_name;
 114
 115         periph_clk->hw.hw.init = &init;
 116
 117         clk = clk_register(NULL, &periph_clk->hw.hw);
 118         if (WARN_ON(IS_ERR(clk))) {
 119                 kfree(periph_clk);
 120                 return;
 121         }
 122         rc = of_clk_add_provider(node, of_clk_src_simple_get, clk);
 123         if (rc < 0) {
 124                 pr_err("Could not register clock provider for node:%s\n",
 125                        clk_name);
 126                 goto err_clk;
 127         }
 128
 129         return;
 130
 131 err_clk:
 132         clk_unregister(clk);
 133 }
 134
 135 void __init socfpga_a10_periph_init(struct device_node *node)
 136 {
 137         __socfpga_periph_init(node, &periclk_ops);
 138 }