linux/drivers/clk/clk-bd718x7.c
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   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/* BD71815 */
  17#define BD71815_REG_OUT32K      0x1d
  18/* BD71828 */
  19#define BD71828_REG_OUT32K      0x4B
  20/* BD71837 and BD71847 */
  21#define BD718XX_REG_OUT32K      0x2E
  22
  23/*
  24 * BD71837, BD71847, and BD71828 all use bit [0] to clk output control
  25 */
  26#define CLK_OUT_EN_MASK         BIT(0)
  27
  28
  29struct bd718xx_clk {
  30        struct clk_hw hw;
  31        u8 reg;
  32        u8 mask;
  33        struct platform_device *pdev;
  34        struct regmap *regmap;
  35};
  36
  37static 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
  42static 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
  52static 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
  59static 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
  73static 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
  79static 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_BD71815:
 118                c->reg = BD71815_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
 144static const struct platform_device_id bd718x7_clk_id[] = {
 145        { "bd71837-clk", ROHM_CHIP_TYPE_BD71837 },
 146        { "bd71847-clk", ROHM_CHIP_TYPE_BD71847 },
 147        { "bd71828-clk", ROHM_CHIP_TYPE_BD71828 },
 148        { "bd71815-clk", ROHM_CHIP_TYPE_BD71815 },
 149        { },
 150};
 151MODULE_DEVICE_TABLE(platform, bd718x7_clk_id);
 152
 153static 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
 161module_platform_driver(bd71837_clk);
 162
 163MODULE_AUTHOR("Matti Vaittinen <matti.vaittinen@fi.rohmeurope.com>");
 164MODULE_DESCRIPTION("BD718(15/18/28/37/47/50) and chip clk driver");
 165MODULE_LICENSE("GPL");
 166MODULE_ALIAS("platform:bd718xx-clk");
 167