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/slab.h>
  17 #include <linux/clk-provider.h>
  18 #include <linux/io.h>
  19 #include <linux/of.h>
  20
  21 #include "clk.h"
  22
  23 #define CLK_MGR_FREE_SHIFT              16
  24 #define CLK_MGR_FREE_MASK               0x7
  25
  26 #define SOCFPGA_MPU_FREE_CLK            "mpu_free_clk"
  27 #define SOCFPGA_NOC_FREE_CLK            "noc_free_clk"
  28 #define SOCFPGA_SDMMC_FREE_CLK          "sdmmc_free_clk"
  29 #define to_socfpga_periph_clk(p) container_of(p, struct socfpga_periph_clk, hw.hw)
  30
  31 static unsigned long clk_periclk_recalc_rate(struct clk_hw *hwclk,
  32                                              unsigned long parent_rate)
  33 {
  34         struct socfpga_periph_clk *socfpgaclk = to_socfpga_periph_clk(hwclk);
  35         u32 div;
  36
  37         if (socfpgaclk->fixed_div) {
  38                 div = socfpgaclk->fixed_div;
  39         } else if (socfpgaclk->div_reg) {
  40                 div = readl(socfpgaclk->div_reg) >> socfpgaclk->shift;
  41                 div &= GENMASK(socfpgaclk->width - 1, 0);
  42                 div += 1;
  43         } else {
  44                 div = ((readl(socfpgaclk->hw.reg) & 0x7ff) + 1);
  45         }
  46
  47         return parent_rate / div;
  48 }
  49
  50 static u8 clk_periclk_get_parent(struct clk_hw *hwclk)
  51 {
  52         struct socfpga_periph_clk *socfpgaclk = to_socfpga_periph_clk(hwclk);
  53         u32 clk_src;
  54
  55         clk_src = readl(socfpgaclk->hw.reg);
  56         if (streq(hwclk->init->name, SOCFPGA_MPU_FREE_CLK) ||
  57             streq(hwclk->init->name, SOCFPGA_NOC_FREE_CLK) ||
  58             streq(hwclk->init->name, SOCFPGA_SDMMC_FREE_CLK))
  59                 return (clk_src >> CLK_MGR_FREE_SHIFT) &
  60                         CLK_MGR_FREE_MASK;
  61         else
  62                 return 0;
  63 }
  64
  65 static const struct clk_ops periclk_ops = {
  66         .recalc_rate = clk_periclk_recalc_rate,
  67         .get_parent = clk_periclk_get_parent,
  68 };
  69
  70 static __init void __socfpga_periph_init(struct device_node *node,
  71         const struct clk_ops *ops)
  72 {
  73         u32 reg;
  74         struct clk *clk;
  75         struct socfpga_periph_clk *periph_clk;
  76         const char *clk_name = node->name;
  77         const char *parent_name;
  78         struct clk_init_data init;
  79         int rc;
  80         u32 fixed_div;
  81         u32 div_reg[3];
  82
  83         of_property_read_u32(node, "reg", &reg);
  84
  85         periph_clk = kzalloc(sizeof(*periph_clk), GFP_KERNEL);
  86         if (WARN_ON(!periph_clk))
  87                 return;
  88
  89         periph_clk->hw.reg = clk_mgr_a10_base_addr + reg;
  90
  91         rc = of_property_read_u32_array(node, "div-reg", div_reg, 3);
  92         if (!rc) {
  93                 periph_clk->div_reg = clk_mgr_a10_base_addr + div_reg[0];
  94                 periph_clk->shift = div_reg[1];
  95                 periph_clk->width = div_reg[2];
  96         } else {
  97                 periph_clk->div_reg = NULL;
  98         }
  99
 100         rc = of_property_read_u32(node, "fixed-divider", &fixed_div);
 101         if (rc)
 102                 periph_clk->fixed_div = 0;
 103         else
 104                 periph_clk->fixed_div = fixed_div;
 105
 106         of_property_read_string(node, "clock-output-names", &clk_name);
 107
 108         init.name = clk_name;
 109         init.ops = ops;
 110         init.flags = 0;
 111
 112         parent_name = of_clk_get_parent_name(node, 0);
 113         init.num_parents = 1;
 114         init.parent_names = &parent_name;
 115
 116         periph_clk->hw.hw.init = &init;
 117
 118         clk = clk_register(NULL, &periph_clk->hw.hw);
 119         if (WARN_ON(IS_ERR(clk))) {
 120                 kfree(periph_clk);
 121                 return;
 122         }
 123         rc = of_clk_add_provider(node, of_clk_src_simple_get, clk);
 124         if (rc < 0) {
 125                 pr_err("Could not register clock provider for node:%s\n",
 126                        clk_name);
 127                 goto err_clk;
 128         }
 129
 130         return;
 131
 132 err_clk:
 133         clk_unregister(clk);
 134 }
 135
 136 void __init socfpga_a10_periph_init(struct device_node *node)
 137 {
 138         __socfpga_periph_init(node, &periclk_ops);
 139 }