drivers/clk/versatile/clk-vexpress-osc.c

   1 /*
   2  * This program is free software; you can redistribute it and/or modify
   3  * it under the terms of the GNU General Public License version 2 as
   4  * published by the Free Software Foundation.
   5  *
   6  * This program is distributed in the hope that it will be useful,
   7  * but WITHOUT ANY WARRANTY; without even the implied warranty of
   8  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
   9  * GNU General Public License for more details.
  10  *
  11  * Copyright (C) 2012 ARM Limited
  12  */
  13
  14 #define pr_fmt(fmt) "vexpress-osc: " fmt
  15
  16 #include <linux/clkdev.h>
  17 #include <linux/clk-provider.h>
  18 #include <linux/err.h>
  19 #include <linux/of.h>
  20 #include <linux/platform_device.h>
  21 #include <linux/slab.h>
  22 #include <linux/vexpress.h>
  23
  24 struct vexpress_osc {
  25         struct vexpress_config_func *func;
  26         struct clk_hw hw;
  27         unsigned long rate_min;
  28         unsigned long rate_max;
  29 };
  30
  31 #define to_vexpress_osc(osc) container_of(osc, struct vexpress_osc, hw)
  32
  33 static unsigned long vexpress_osc_recalc_rate(struct clk_hw *hw,
  34                 unsigned long parent_rate)
  35 {
  36         struct vexpress_osc *osc = to_vexpress_osc(hw);
  37         u32 rate;
  38
  39         vexpress_config_read(osc->func, 0, &rate);
  40
  41         return rate;
  42 }
  43
  44 static long vexpress_osc_round_rate(struct clk_hw *hw, unsigned long rate,
  45                 unsigned long *parent_rate)
  46 {
  47         struct vexpress_osc *osc = to_vexpress_osc(hw);
  48
  49         if (WARN_ON(osc->rate_min && rate < osc->rate_min))
  50                 rate = osc->rate_min;
  51
  52         if (WARN_ON(osc->rate_max && rate > osc->rate_max))
  53                 rate = osc->rate_max;
  54
  55         return rate;
  56 }
  57
  58 static int vexpress_osc_set_rate(struct clk_hw *hw, unsigned long rate,
  59                 unsigned long parent_rate)
  60 {
  61         struct vexpress_osc *osc = to_vexpress_osc(hw);
  62
  63         return vexpress_config_write(osc->func, 0, rate);
  64 }
  65
  66 static struct clk_ops vexpress_osc_ops = {
  67         .recalc_rate = vexpress_osc_recalc_rate,
  68         .round_rate = vexpress_osc_round_rate,
  69         .set_rate = vexpress_osc_set_rate,
  70 };
  71
  72
  73 struct clk * __init vexpress_osc_setup(struct device *dev)
  74 {
  75         struct clk_init_data init;
  76         struct vexpress_osc *osc = kzalloc(sizeof(*osc), GFP_KERNEL);
  77
  78         if (!osc)
  79                 return NULL;
  80
  81         osc->func = vexpress_config_func_get_by_dev(dev);
  82         if (!osc->func) {
  83                 kfree(osc);
  84                 return NULL;
  85         }
  86
  87         init.name = dev_name(dev);
  88         init.ops = &vexpress_osc_ops;
  89         init.flags = CLK_IS_ROOT;
  90         init.num_parents = 0;
  91         osc->hw.init = &init;
  92
  93         return clk_register(NULL, &osc->hw);
  94 }
  95
  96 void __init vexpress_osc_of_setup(struct device_node *node)
  97 {
  98         struct clk_init_data init;
  99         struct vexpress_osc *osc;
 100         struct clk *clk;
 101         u32 range[2];
 102
 103         vexpress_sysreg_of_early_init();
 104
 105         osc = kzalloc(sizeof(*osc), GFP_KERNEL);
 106         if (!osc)
 107                 return;
 108
 109         osc->func = vexpress_config_func_get_by_node(node);
 110         if (!osc->func) {
 111                 pr_err("Failed to obtain config func for node '%s'!\n",
 112                                 node->full_name);
 113                 goto error;
 114         }
 115
 116         if (of_property_read_u32_array(node, "freq-range", range,
 117                         ARRAY_SIZE(range)) == 0) {
 118                 osc->rate_min = range[0];
 119                 osc->rate_max = range[1];
 120         }
 121
 122         of_property_read_string(node, "clock-output-names", &init.name);
 123         if (!init.name)
 124                 init.name = node->full_name;
 125
 126         init.ops = &vexpress_osc_ops;
 127         init.flags = CLK_IS_ROOT;
 128         init.num_parents = 0;
 129
 130         osc->hw.init = &init;
 131
 132         clk = clk_register(NULL, &osc->hw);
 133         if (IS_ERR(clk)) {
 134                 pr_err("Failed to register clock '%s'!\n", init.name);
 135                 goto error;
 136         }
 137
 138         of_clk_add_provider(node, of_clk_src_simple_get, clk);
 139
 140         pr_debug("Registered clock '%s'\n", init.name);
 141
 142         return;
 143
 144 error:
 145         if (osc->func)
 146                 vexpress_config_func_put(osc->func);
 147         kfree(osc);
 148 }
 149 CLK_OF_DECLARE(vexpress_soc, "arm,vexpress-osc", vexpress_osc_of_setup);