drivers/clk/clk-hi655x.c

   1 /*
   2  * Clock driver for Hi655x
   3  *
   4  * Copyright (c) 2017, Linaro Ltd.
   5  *
   6  * Author: Daniel Lezcano <daniel.lezcano@linaro.org>
   7  *
   8  * This program is free software; you can redistribute it and/or modify it
   9  * under the terms and conditions of the GNU General Public License,
  10  * version 2, as published by the Free Software Foundation.
  11  *
  12  * This program is distributed in the hope it will be useful, but WITHOUT
  13  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
  14  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
  15  * more details.
  16  */
  17 #include <linux/clk-provider.h>
  18 #include <linux/module.h>
  19 #include <linux/platform_device.h>
  20 #include <linux/regmap.h>
  21 #include <linux/slab.h>
  22 #include <linux/mfd/core.h>
  23 #include <linux/mfd/hi655x-pmic.h>
  24
  25 #define HI655X_CLK_BASE HI655X_BUS_ADDR(0x1c)
  26 #define HI655X_CLK_SET  BIT(6)
  27
  28 struct hi655x_clk {
  29         struct hi655x_pmic *hi655x;
  30         struct clk_hw       clk_hw;
  31 };
  32
  33 static unsigned long hi655x_clk_recalc_rate(struct clk_hw *hw,
  34                                             unsigned long parent_rate)
  35 {
  36         return 32768;
  37 }
  38
  39 static int hi655x_clk_enable(struct clk_hw *hw, bool enable)
  40 {
  41         struct hi655x_clk *hi655x_clk =
  42                 container_of(hw, struct hi655x_clk, clk_hw);
  43
  44         struct hi655x_pmic *hi655x = hi655x_clk->hi655x;
  45
  46         return regmap_update_bits(hi655x->regmap, HI655X_CLK_BASE,
  47                                   HI655X_CLK_SET, enable ? HI655X_CLK_SET : 0);
  48 }
  49
  50 static int hi655x_clk_prepare(struct clk_hw *hw)
  51 {
  52         return hi655x_clk_enable(hw, true);
  53 }
  54
  55 static void hi655x_clk_unprepare(struct clk_hw *hw)
  56 {
  57         hi655x_clk_enable(hw, false);
  58 }
  59
  60 static int hi655x_clk_is_prepared(struct clk_hw *hw)
  61 {
  62         struct hi655x_clk *hi655x_clk =
  63                 container_of(hw, struct hi655x_clk, clk_hw);
  64         struct hi655x_pmic *hi655x = hi655x_clk->hi655x;
  65         int ret;
  66         uint32_t val;
  67
  68         ret = regmap_read(hi655x->regmap, HI655X_CLK_BASE, &val);
  69         if (ret < 0)
  70                 return ret;
  71
  72         return val & HI655X_CLK_BASE;
  73 }
  74
  75 static const struct clk_ops hi655x_clk_ops = {
  76         .prepare     = hi655x_clk_prepare,
  77         .unprepare   = hi655x_clk_unprepare,
  78         .is_prepared = hi655x_clk_is_prepared,
  79         .recalc_rate = hi655x_clk_recalc_rate,
  80 };
  81
  82 static int hi655x_clk_probe(struct platform_device *pdev)
  83 {
  84         struct device *parent = pdev->dev.parent;
  85         struct hi655x_pmic *hi655x = dev_get_drvdata(parent);
  86         struct hi655x_clk *hi655x_clk;
  87         const char *clk_name = "hi655x-clk";
  88         struct clk_init_data init = {
  89                 .name = clk_name,
  90                 .ops = &hi655x_clk_ops
  91         };
  92         int ret;
  93
  94         hi655x_clk = devm_kzalloc(&pdev->dev, sizeof(*hi655x_clk), GFP_KERNEL);
  95         if (!hi655x_clk)
  96                 return -ENOMEM;
  97
  98         of_property_read_string_index(parent->of_node, "clock-output-names",
  99                                       0, &clk_name);
 100
 101         hi655x_clk->clk_hw.init = &init;
 102         hi655x_clk->hi655x      = hi655x;
 103
 104         platform_set_drvdata(pdev, hi655x_clk);
 105
 106         ret = devm_clk_hw_register(&pdev->dev, &hi655x_clk->clk_hw);
 107         if (ret)
 108                 return ret;
 109
 110         return of_clk_add_hw_provider(parent->of_node, of_clk_hw_simple_get,
 111                                      &hi655x_clk->clk_hw);
 112 }
 113
 114 static struct platform_driver hi655x_clk_driver = {
 115         .probe =  hi655x_clk_probe,
 116         .driver         = {
 117                 .name   = "hi655x-clk",
 118         },
 119 };
 120
 121 module_platform_driver(hi655x_clk_driver);
 122
 123 MODULE_DESCRIPTION("Clk driver for the hi655x series PMICs");
 124 MODULE_AUTHOR("Daniel Lezcano <daniel.lezcano@linaro.org>");
 125 MODULE_LICENSE("GPL");
 126 MODULE_ALIAS("platform:hi655x-clk");