linux/drivers/clk/clk-palmas.c
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   1/*
   2 * Clock driver for Palmas device.
   3 *
   4 * Copyright (c) 2013, NVIDIA Corporation.
   5 * Copyright (c) 2013-2014 Texas Instruments, Inc.
   6 *
   7 * Author:      Laxman Dewangan <ldewangan@nvidia.com>
   8 *              Peter Ujfalusi <peter.ujfalusi@ti.com>
   9 *
  10 * This program is free software; you can redistribute it and/or
  11 * modify it under the terms of the GNU General Public License as
  12 * published by the Free Software Foundation version 2.
  13 *
  14 * This program is distributed "as is" WITHOUT ANY WARRANTY of any kind,
  15 * whether express or implied; without even the implied warranty of
  16 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
  17 * General Public License for more details.
  18 */
  19
  20#include <linux/clk.h>
  21#include <linux/clk-provider.h>
  22#include <linux/mfd/palmas.h>
  23#include <linux/module.h>
  24#include <linux/of.h>
  25#include <linux/of_device.h>
  26#include <linux/platform_device.h>
  27#include <linux/slab.h>
  28
  29#define PALMAS_CLOCK_DT_EXT_CONTROL_ENABLE1     1
  30#define PALMAS_CLOCK_DT_EXT_CONTROL_ENABLE2     2
  31#define PALMAS_CLOCK_DT_EXT_CONTROL_NSLEEP      3
  32
  33struct palmas_clk32k_desc {
  34        const char *clk_name;
  35        unsigned int control_reg;
  36        unsigned int enable_mask;
  37        unsigned int sleep_mask;
  38        unsigned int sleep_reqstr_id;
  39        int delay;
  40};
  41
  42struct palmas_clock_info {
  43        struct device *dev;
  44        struct clk_hw hw;
  45        struct palmas *palmas;
  46        const struct palmas_clk32k_desc *clk_desc;
  47        int ext_control_pin;
  48};
  49
  50static inline struct palmas_clock_info *to_palmas_clks_info(struct clk_hw *hw)
  51{
  52        return container_of(hw, struct palmas_clock_info, hw);
  53}
  54
  55static unsigned long palmas_clks_recalc_rate(struct clk_hw *hw,
  56                                             unsigned long parent_rate)
  57{
  58        return 32768;
  59}
  60
  61static int palmas_clks_prepare(struct clk_hw *hw)
  62{
  63        struct palmas_clock_info *cinfo = to_palmas_clks_info(hw);
  64        int ret;
  65
  66        ret = palmas_update_bits(cinfo->palmas, PALMAS_RESOURCE_BASE,
  67                                 cinfo->clk_desc->control_reg,
  68                                 cinfo->clk_desc->enable_mask,
  69                                 cinfo->clk_desc->enable_mask);
  70        if (ret < 0)
  71                dev_err(cinfo->dev, "Reg 0x%02x update failed, %d\n",
  72                        cinfo->clk_desc->control_reg, ret);
  73        else if (cinfo->clk_desc->delay)
  74                udelay(cinfo->clk_desc->delay);
  75
  76        return ret;
  77}
  78
  79static void palmas_clks_unprepare(struct clk_hw *hw)
  80{
  81        struct palmas_clock_info *cinfo = to_palmas_clks_info(hw);
  82        int ret;
  83
  84        /*
  85         * Clock can be disabled through external pin if it is externally
  86         * controlled.
  87         */
  88        if (cinfo->ext_control_pin)
  89                return;
  90
  91        ret = palmas_update_bits(cinfo->palmas, PALMAS_RESOURCE_BASE,
  92                                 cinfo->clk_desc->control_reg,
  93                                 cinfo->clk_desc->enable_mask, 0);
  94        if (ret < 0)
  95                dev_err(cinfo->dev, "Reg 0x%02x update failed, %d\n",
  96                        cinfo->clk_desc->control_reg, ret);
  97}
  98
  99static int palmas_clks_is_prepared(struct clk_hw *hw)
 100{
 101        struct palmas_clock_info *cinfo = to_palmas_clks_info(hw);
 102        int ret;
 103        u32 val;
 104
 105        if (cinfo->ext_control_pin)
 106                return 1;
 107
 108        ret = palmas_read(cinfo->palmas, PALMAS_RESOURCE_BASE,
 109                          cinfo->clk_desc->control_reg, &val);
 110        if (ret < 0) {
 111                dev_err(cinfo->dev, "Reg 0x%02x read failed, %d\n",
 112                        cinfo->clk_desc->control_reg, ret);
 113                return ret;
 114        }
 115        return !!(val & cinfo->clk_desc->enable_mask);
 116}
 117
 118static const struct clk_ops palmas_clks_ops = {
 119        .prepare        = palmas_clks_prepare,
 120        .unprepare      = palmas_clks_unprepare,
 121        .is_prepared    = palmas_clks_is_prepared,
 122        .recalc_rate    = palmas_clks_recalc_rate,
 123};
 124
 125struct palmas_clks_of_match_data {
 126        struct clk_init_data init;
 127        const struct palmas_clk32k_desc desc;
 128};
 129
 130static const struct palmas_clks_of_match_data palmas_of_clk32kg = {
 131        .init = {
 132                .name = "clk32kg",
 133                .ops = &palmas_clks_ops,
 134                .flags = CLK_IGNORE_UNUSED,
 135        },
 136        .desc = {
 137                .clk_name = "clk32kg",
 138                .control_reg = PALMAS_CLK32KG_CTRL,
 139                .enable_mask = PALMAS_CLK32KG_CTRL_MODE_ACTIVE,
 140                .sleep_mask = PALMAS_CLK32KG_CTRL_MODE_SLEEP,
 141                .sleep_reqstr_id = PALMAS_EXTERNAL_REQSTR_ID_CLK32KG,
 142                .delay = 200,
 143        },
 144};
 145
 146static const struct palmas_clks_of_match_data palmas_of_clk32kgaudio = {
 147        .init = {
 148                .name = "clk32kgaudio",
 149                .ops = &palmas_clks_ops,
 150                .flags = CLK_IGNORE_UNUSED,
 151        },
 152        .desc = {
 153                .clk_name = "clk32kgaudio",
 154                .control_reg = PALMAS_CLK32KGAUDIO_CTRL,
 155                .enable_mask = PALMAS_CLK32KG_CTRL_MODE_ACTIVE,
 156                .sleep_mask = PALMAS_CLK32KG_CTRL_MODE_SLEEP,
 157                .sleep_reqstr_id = PALMAS_EXTERNAL_REQSTR_ID_CLK32KGAUDIO,
 158                .delay = 200,
 159        },
 160};
 161
 162static const struct of_device_id palmas_clks_of_match[] = {
 163        {
 164                .compatible = "ti,palmas-clk32kg",
 165                .data = &palmas_of_clk32kg,
 166        },
 167        {
 168                .compatible = "ti,palmas-clk32kgaudio",
 169                .data = &palmas_of_clk32kgaudio,
 170        },
 171        { },
 172};
 173MODULE_DEVICE_TABLE(of, palmas_clks_of_match);
 174
 175static void palmas_clks_get_clk_data(struct platform_device *pdev,
 176                                     struct palmas_clock_info *cinfo)
 177{
 178        struct device_node *node = pdev->dev.of_node;
 179        unsigned int prop;
 180        int ret;
 181
 182        ret = of_property_read_u32(node, "ti,external-sleep-control",
 183                                   &prop);
 184        if (ret)
 185                return;
 186
 187        switch (prop) {
 188        case PALMAS_CLOCK_DT_EXT_CONTROL_ENABLE1:
 189                prop = PALMAS_EXT_CONTROL_ENABLE1;
 190                break;
 191        case PALMAS_CLOCK_DT_EXT_CONTROL_ENABLE2:
 192                prop = PALMAS_EXT_CONTROL_ENABLE2;
 193                break;
 194        case PALMAS_CLOCK_DT_EXT_CONTROL_NSLEEP:
 195                prop = PALMAS_EXT_CONTROL_NSLEEP;
 196                break;
 197        default:
 198                dev_warn(&pdev->dev, "%pOFn: Invalid ext control option: %u\n",
 199                         node, prop);
 200                prop = 0;
 201                break;
 202        }
 203        cinfo->ext_control_pin = prop;
 204}
 205
 206static int palmas_clks_init_configure(struct palmas_clock_info *cinfo)
 207{
 208        int ret;
 209
 210        ret = palmas_update_bits(cinfo->palmas, PALMAS_RESOURCE_BASE,
 211                                 cinfo->clk_desc->control_reg,
 212                                 cinfo->clk_desc->sleep_mask, 0);
 213        if (ret < 0) {
 214                dev_err(cinfo->dev, "Reg 0x%02x update failed, %d\n",
 215                        cinfo->clk_desc->control_reg, ret);
 216                return ret;
 217        }
 218
 219        if (cinfo->ext_control_pin) {
 220                ret = clk_prepare(cinfo->hw.clk);
 221                if (ret < 0) {
 222                        dev_err(cinfo->dev, "Clock prep failed, %d\n", ret);
 223                        return ret;
 224                }
 225
 226                ret = palmas_ext_control_req_config(cinfo->palmas,
 227                                        cinfo->clk_desc->sleep_reqstr_id,
 228                                        cinfo->ext_control_pin, true);
 229                if (ret < 0) {
 230                        dev_err(cinfo->dev, "Ext config for %s failed, %d\n",
 231                                cinfo->clk_desc->clk_name, ret);
 232                        clk_unprepare(cinfo->hw.clk);
 233                        return ret;
 234                }
 235        }
 236
 237        return ret;
 238}
 239static int palmas_clks_probe(struct platform_device *pdev)
 240{
 241        struct palmas *palmas = dev_get_drvdata(pdev->dev.parent);
 242        struct device_node *node = pdev->dev.of_node;
 243        const struct palmas_clks_of_match_data *match_data;
 244        struct palmas_clock_info *cinfo;
 245        int ret;
 246
 247        match_data = of_device_get_match_data(&pdev->dev);
 248        if (!match_data)
 249                return 1;
 250
 251        cinfo = devm_kzalloc(&pdev->dev, sizeof(*cinfo), GFP_KERNEL);
 252        if (!cinfo)
 253                return -ENOMEM;
 254
 255        palmas_clks_get_clk_data(pdev, cinfo);
 256        platform_set_drvdata(pdev, cinfo);
 257
 258        cinfo->dev = &pdev->dev;
 259        cinfo->palmas = palmas;
 260
 261        cinfo->clk_desc = &match_data->desc;
 262        cinfo->hw.init = &match_data->init;
 263        ret = devm_clk_hw_register(&pdev->dev, &cinfo->hw);
 264        if (ret) {
 265                dev_err(&pdev->dev, "Fail to register clock %s, %d\n",
 266                        match_data->desc.clk_name, ret);
 267                return ret;
 268        }
 269
 270        ret = palmas_clks_init_configure(cinfo);
 271        if (ret < 0) {
 272                dev_err(&pdev->dev, "Clock config failed, %d\n", ret);
 273                return ret;
 274        }
 275
 276        ret = of_clk_add_hw_provider(node, of_clk_hw_simple_get, &cinfo->hw);
 277        if (ret < 0)
 278                dev_err(&pdev->dev, "Fail to add clock driver, %d\n", ret);
 279        return ret;
 280}
 281
 282static int palmas_clks_remove(struct platform_device *pdev)
 283{
 284        of_clk_del_provider(pdev->dev.of_node);
 285        return 0;
 286}
 287
 288static struct platform_driver palmas_clks_driver = {
 289        .driver = {
 290                .name = "palmas-clk",
 291                .of_match_table = palmas_clks_of_match,
 292        },
 293        .probe = palmas_clks_probe,
 294        .remove = palmas_clks_remove,
 295};
 296
 297module_platform_driver(palmas_clks_driver);
 298
 299MODULE_DESCRIPTION("Clock driver for Palmas Series Devices");
 300MODULE_ALIAS("platform:palmas-clk");
 301MODULE_AUTHOR("Peter Ujfalusi <peter.ujfalusi@ti.com>");
 302MODULE_LICENSE("GPL v2");
 303