drivers/clk/st/clkgen-mux.c

   1 /*
   2  * clkgen-mux.c: ST GEN-MUX Clock driver
   3  *
   4  * Copyright (C) 2014 STMicroelectronics (R&D) Limited
   5  *
   6  * Authors: Stephen Gallimore <stephen.gallimore@st.com>
   7  *          Pankaj Dev <pankaj.dev@st.com>
   8  *
   9  * This program is free software; you can redistribute it and/or modify
  10  * it under the terms of the GNU General Public License as published by
  11  * the Free Software Foundation; either version 2 of the License, or
  12  * (at your option) any later version.
  13  *
  14  */
  15
  16 #include <linux/slab.h>
  17 #include <linux/of_address.h>
  18 #include <linux/clk.h>
  19 #include <linux/clk-provider.h>
  20 #include "clkgen.h"
  21
  22 static const char ** __init clkgen_mux_get_parents(struct device_node *np,
  23                                                        int *num_parents)
  24 {
  25         const char **parents;
  26         unsigned int nparents;
  27
  28         nparents = of_clk_get_parent_count(np);
  29         if (WARN_ON(!nparents))
  30                 return ERR_PTR(-EINVAL);
  31
  32         parents = kcalloc(nparents, sizeof(const char *), GFP_KERNEL);
  33         if (!parents)
  34                 return ERR_PTR(-ENOMEM);
  35
  36         *num_parents = of_clk_parent_fill(np, parents, nparents);
  37         return parents;
  38 }
  39
  40 struct clkgen_mux_data {
  41         u32 offset;
  42         u8 shift;
  43         u8 width;
  44         spinlock_t *lock;
  45         unsigned long clk_flags;
  46         u8 mux_flags;
  47 };
  48
  49 static struct clkgen_mux_data stih407_a9_mux_data = {
  50         .offset = 0x1a4,
  51         .shift = 0,
  52         .width = 2,
  53         .lock = &clkgen_a9_lock,
  54 };
  55
  56 static void __init st_of_clkgen_mux_setup(struct device_node *np,
  57                 struct clkgen_mux_data *data)
  58 {
  59         struct clk *clk;
  60         void __iomem *reg;
  61         const char **parents;
  62         int num_parents = 0;
  63
  64         reg = of_iomap(np, 0);
  65         if (!reg) {
  66                 pr_err("%s: Failed to get base address\n", __func__);
  67                 return;
  68         }
  69
  70         parents = clkgen_mux_get_parents(np, &num_parents);
  71         if (IS_ERR(parents)) {
  72                 pr_err("%s: Failed to get parents (%ld)\n",
  73                                 __func__, PTR_ERR(parents));
  74                 goto err_parents;
  75         }
  76
  77         clk = clk_register_mux(NULL, np->name, parents, num_parents,
  78                                 data->clk_flags | CLK_SET_RATE_PARENT,
  79                                 reg + data->offset,
  80                                 data->shift, data->width, data->mux_flags,
  81                                 data->lock);
  82         if (IS_ERR(clk))
  83                 goto err;
  84
  85         pr_debug("%s: parent %s rate %u\n",
  86                         __clk_get_name(clk),
  87                         __clk_get_name(clk_get_parent(clk)),
  88                         (unsigned int)clk_get_rate(clk));
  89
  90         kfree(parents);
  91         of_clk_add_provider(np, of_clk_src_simple_get, clk);
  92         return;
  93
  94 err:
  95         kfree(parents);
  96 err_parents:
  97         iounmap(reg);
  98 }
  99
 100 static void __init st_of_clkgen_a9_mux_setup(struct device_node *np)
 101 {
 102         st_of_clkgen_mux_setup(np, &stih407_a9_mux_data);
 103 }
 104 CLK_OF_DECLARE(clkgen_a9mux, "st,stih407-clkgen-a9-mux",
 105                 st_of_clkgen_a9_mux_setup);