drivers/clk/clk-bd718x7.c

   1 // SPDX-License-Identifier: GPL-2.0
   2 // Copyright (C) 2018 ROHM Semiconductors
   3
   4 #include <linux/kernel.h>
   5 #include <linux/module.h>
   6 #include <linux/init.h>
   7 #include <linux/err.h>
   8 #include <linux/platform_device.h>
   9 #include <linux/slab.h>
  10 #include <linux/mfd/rohm-generic.h>
  11 #include <linux/clk-provider.h>
  12 #include <linux/clkdev.h>
  13 #include <linux/regmap.h>
  14
  15 /* clk control registers */
  16 /* BD70528 */
  17 #define BD70528_REG_OUT32K      0x2c
  18 /* BD71828 */
  19 #define BD71828_REG_OUT32K      0x4B
  20 /* BD71837 and BD71847 */
  21 #define BD718XX_REG_OUT32K      0x2E
  22
  23 /*
  24  * BD71837, BD71847, BD70528 and BD71828 all use bit [0] to clk output control
  25  */
  26 #define CLK_OUT_EN_MASK         BIT(0)
  27
  28
  29 struct bd718xx_clk {
  30         struct clk_hw hw;
  31         u8 reg;
  32         u8 mask;
  33         struct platform_device *pdev;
  34         struct regmap *regmap;
  35 };
  36
  37 static int bd71837_clk_set(struct bd718xx_clk *c, unsigned int status)
  38 {
  39         return regmap_update_bits(c->regmap, c->reg, c->mask, status);
  40 }
  41
  42 static void bd71837_clk_disable(struct clk_hw *hw)
  43 {
  44         int rv;
  45         struct bd718xx_clk *c = container_of(hw, struct bd718xx_clk, hw);
  46
  47         rv = bd71837_clk_set(c, 0);
  48         if (rv)
  49                 dev_dbg(&c->pdev->dev, "Failed to disable 32K clk (%d)\n", rv);
  50 }
  51
  52 static int bd71837_clk_enable(struct clk_hw *hw)
  53 {
  54         struct bd718xx_clk *c = container_of(hw, struct bd718xx_clk, hw);
  55
  56         return bd71837_clk_set(c, 0xffffffff);
  57 }
  58
  59 static int bd71837_clk_is_enabled(struct clk_hw *hw)
  60 {
  61         int enabled;
  62         int rval;
  63         struct bd718xx_clk *c = container_of(hw, struct bd718xx_clk, hw);
  64
  65         rval = regmap_read(c->regmap, c->reg, &enabled);
  66
  67         if (rval)
  68                 return rval;
  69
  70         return enabled & c->mask;
  71 }
  72
  73 static const struct clk_ops bd71837_clk_ops = {
  74         .prepare = &bd71837_clk_enable,
  75         .unprepare = &bd71837_clk_disable,
  76         .is_prepared = &bd71837_clk_is_enabled,
  77 };
  78
  79 static int bd71837_clk_probe(struct platform_device *pdev)
  80 {
  81         struct bd718xx_clk *c;
  82         int rval = -ENOMEM;
  83         const char *parent_clk;
  84         struct device *parent = pdev->dev.parent;
  85         struct clk_init_data init = {
  86                 .name = "bd718xx-32k-out",
  87                 .ops = &bd71837_clk_ops,
  88         };
  89         enum rohm_chip_type chip = platform_get_device_id(pdev)->driver_data;
  90
  91         c = devm_kzalloc(&pdev->dev, sizeof(*c), GFP_KERNEL);
  92         if (!c)
  93                 return -ENOMEM;
  94
  95         c->regmap = dev_get_regmap(pdev->dev.parent, NULL);
  96         if (!c->regmap)
  97                 return -ENODEV;
  98
  99         init.num_parents = 1;
 100         parent_clk = of_clk_get_parent_name(parent->of_node, 0);
 101
 102         init.parent_names = &parent_clk;
 103         if (!parent_clk) {
 104                 dev_err(&pdev->dev, "No parent clk found\n");
 105                 return -EINVAL;
 106         }
 107         switch (chip) {
 108         case ROHM_CHIP_TYPE_BD71837:
 109         case ROHM_CHIP_TYPE_BD71847:
 110                 c->reg = BD718XX_REG_OUT32K;
 111                 c->mask = CLK_OUT_EN_MASK;
 112                 break;
 113         case ROHM_CHIP_TYPE_BD71828:
 114                 c->reg = BD71828_REG_OUT32K;
 115                 c->mask = CLK_OUT_EN_MASK;
 116                 break;
 117         case ROHM_CHIP_TYPE_BD70528:
 118                 c->reg = BD70528_REG_OUT32K;
 119                 c->mask = CLK_OUT_EN_MASK;
 120                 break;
 121         default:
 122                 dev_err(&pdev->dev, "Unknown clk chip\n");
 123                 return -EINVAL;
 124         }
 125         c->pdev = pdev;
 126         c->hw.init = &init;
 127
 128         of_property_read_string_index(parent->of_node,
 129                                       "clock-output-names", 0, &init.name);
 130
 131         rval = devm_clk_hw_register(&pdev->dev, &c->hw);
 132         if (rval) {
 133                 dev_err(&pdev->dev, "failed to register 32K clk");
 134                 return rval;
 135         }
 136         rval = devm_of_clk_add_hw_provider(&pdev->dev, of_clk_hw_simple_get,
 137                                            &c->hw);
 138         if (rval)
 139                 dev_err(&pdev->dev, "adding clk provider failed\n");
 140
 141         return rval;
 142 }
 143
 144 static const struct platform_device_id bd718x7_clk_id[] = {
 145         { "bd71837-clk", ROHM_CHIP_TYPE_BD71837 },
 146         { "bd71847-clk", ROHM_CHIP_TYPE_BD71847 },
 147         { "bd70528-clk", ROHM_CHIP_TYPE_BD70528 },
 148         { "bd71828-clk", ROHM_CHIP_TYPE_BD71828 },
 149         { },
 150 };
 151 MODULE_DEVICE_TABLE(platform, bd718x7_clk_id);
 152
 153 static struct platform_driver bd71837_clk = {
 154         .driver = {
 155                 .name = "bd718xx-clk",
 156         },
 157         .probe = bd71837_clk_probe,
 158         .id_table = bd718x7_clk_id,
 159 };
 160
 161 module_platform_driver(bd71837_clk);
 162
 163 MODULE_AUTHOR("Matti Vaittinen <matti.vaittinen@fi.rohmeurope.com>");
 164 MODULE_DESCRIPTION("BD71837/BD71847/BD70528 chip clk driver");
 165 MODULE_LICENSE("GPL");
 166 MODULE_ALIAS("platform:bd718xx-clk");