linux/drivers/iio/dac/vf610_dac.c
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   1/*
   2 * Freescale Vybrid vf610 DAC driver
   3 *
   4 * Copyright 2016 Toradex AG
   5 *
   6 * This program is free software; you can redistribute it and/or modify
   7 * it under the terms of the GNU General Public License as published by
   8 * the Free Software Foundation; either version 2 of the License, or
   9 * (at your option) any later version.
  10 *
  11 * This program is distributed in the hope that it will be useful,
  12 * but WITHOUT ANY WARRANTY; without even the implied warranty of
  13 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
  14 * GNU General Public License for more details.
  15 */
  16
  17#include <linux/clk.h>
  18#include <linux/err.h>
  19#include <linux/interrupt.h>
  20#include <linux/io.h>
  21#include <linux/kernel.h>
  22#include <linux/module.h>
  23#include <linux/platform_device.h>
  24#include <linux/regulator/consumer.h>
  25#include <linux/slab.h>
  26
  27#include <linux/iio/iio.h>
  28#include <linux/iio/sysfs.h>
  29
  30#define VF610_DACx_STATCTRL             0x20
  31
  32#define VF610_DAC_DACEN                 BIT(15)
  33#define VF610_DAC_DACRFS                BIT(14)
  34#define VF610_DAC_LPEN                  BIT(11)
  35
  36#define VF610_DAC_DAT0(x)               ((x) & 0xFFF)
  37
  38enum vf610_conversion_mode_sel {
  39        VF610_DAC_CONV_HIGH_POWER,
  40        VF610_DAC_CONV_LOW_POWER,
  41};
  42
  43struct vf610_dac {
  44        struct clk *clk;
  45        struct device *dev;
  46        enum vf610_conversion_mode_sel conv_mode;
  47        void __iomem *regs;
  48};
  49
  50static void vf610_dac_init(struct vf610_dac *info)
  51{
  52        int val;
  53
  54        info->conv_mode = VF610_DAC_CONV_LOW_POWER;
  55        val = VF610_DAC_DACEN | VF610_DAC_DACRFS |
  56                VF610_DAC_LPEN;
  57        writel(val, info->regs + VF610_DACx_STATCTRL);
  58}
  59
  60static void vf610_dac_exit(struct vf610_dac *info)
  61{
  62        int val;
  63
  64        val = readl(info->regs + VF610_DACx_STATCTRL);
  65        val &= ~VF610_DAC_DACEN;
  66        writel(val, info->regs + VF610_DACx_STATCTRL);
  67}
  68
  69static int vf610_set_conversion_mode(struct iio_dev *indio_dev,
  70                                const struct iio_chan_spec *chan,
  71                                unsigned int mode)
  72{
  73        struct vf610_dac *info = iio_priv(indio_dev);
  74        int val;
  75
  76        mutex_lock(&indio_dev->mlock);
  77        info->conv_mode = mode;
  78        val = readl(info->regs + VF610_DACx_STATCTRL);
  79        if (mode)
  80                val |= VF610_DAC_LPEN;
  81        else
  82                val &= ~VF610_DAC_LPEN;
  83        writel(val, info->regs + VF610_DACx_STATCTRL);
  84        mutex_unlock(&indio_dev->mlock);
  85
  86        return 0;
  87}
  88
  89static int vf610_get_conversion_mode(struct iio_dev *indio_dev,
  90                                const struct iio_chan_spec *chan)
  91{
  92        struct vf610_dac *info = iio_priv(indio_dev);
  93
  94        return info->conv_mode;
  95}
  96
  97static const char * const vf610_conv_modes[] = { "high-power", "low-power" };
  98
  99static const struct iio_enum vf610_conversion_mode = {
 100        .items = vf610_conv_modes,
 101        .num_items = ARRAY_SIZE(vf610_conv_modes),
 102        .get = vf610_get_conversion_mode,
 103        .set = vf610_set_conversion_mode,
 104};
 105
 106static const struct iio_chan_spec_ext_info vf610_ext_info[] = {
 107        IIO_ENUM("conversion_mode", IIO_SHARED_BY_DIR,
 108                &vf610_conversion_mode),
 109        {},
 110};
 111
 112#define VF610_DAC_CHAN(_chan_type) { \
 113        .type = (_chan_type), \
 114        .output = 1, \
 115        .info_mask_separate = BIT(IIO_CHAN_INFO_RAW), \
 116        .info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE), \
 117        .ext_info = vf610_ext_info, \
 118}
 119
 120static const struct iio_chan_spec vf610_dac_iio_channels[] = {
 121        VF610_DAC_CHAN(IIO_VOLTAGE),
 122};
 123
 124static int vf610_read_raw(struct iio_dev *indio_dev,
 125                        struct iio_chan_spec const *chan,
 126                        int *val, int *val2,
 127                        long mask)
 128{
 129        struct vf610_dac *info = iio_priv(indio_dev);
 130
 131        switch (mask) {
 132        case IIO_CHAN_INFO_RAW:
 133                *val = VF610_DAC_DAT0(readl(info->regs));
 134                return IIO_VAL_INT;
 135        case IIO_CHAN_INFO_SCALE:
 136                /*
 137                 * DACRFS is always 1 for valid reference and typical
 138                 * reference voltage as per Vybrid datasheet is 3.3V
 139                 * from section 9.1.2.1 of Vybrid datasheet
 140                 */
 141                *val = 3300 /* mV */;
 142                *val2 = 12;
 143                return IIO_VAL_FRACTIONAL_LOG2;
 144
 145        default:
 146                return -EINVAL;
 147        }
 148}
 149
 150static int vf610_write_raw(struct iio_dev *indio_dev,
 151                        struct iio_chan_spec const *chan,
 152                        int val, int val2,
 153                        long mask)
 154{
 155        struct vf610_dac *info = iio_priv(indio_dev);
 156
 157        switch (mask) {
 158        case IIO_CHAN_INFO_RAW:
 159                mutex_lock(&indio_dev->mlock);
 160                writel(VF610_DAC_DAT0(val), info->regs);
 161                mutex_unlock(&indio_dev->mlock);
 162                return 0;
 163
 164        default:
 165                return -EINVAL;
 166        }
 167}
 168
 169static const struct iio_info vf610_dac_iio_info = {
 170        .driver_module = THIS_MODULE,
 171        .read_raw = &vf610_read_raw,
 172        .write_raw = &vf610_write_raw,
 173};
 174
 175static const struct of_device_id vf610_dac_match[] = {
 176        { .compatible = "fsl,vf610-dac", },
 177        { /* sentinel */ }
 178};
 179MODULE_DEVICE_TABLE(of, vf610_dac_match);
 180
 181static int vf610_dac_probe(struct platform_device *pdev)
 182{
 183        struct iio_dev *indio_dev;
 184        struct vf610_dac *info;
 185        struct resource *mem;
 186        int ret;
 187
 188        indio_dev = devm_iio_device_alloc(&pdev->dev,
 189                                        sizeof(struct vf610_dac));
 190        if (!indio_dev) {
 191                dev_err(&pdev->dev, "Failed allocating iio device\n");
 192                return -ENOMEM;
 193        }
 194
 195        info = iio_priv(indio_dev);
 196        info->dev = &pdev->dev;
 197
 198        mem = platform_get_resource(pdev, IORESOURCE_MEM, 0);
 199        info->regs = devm_ioremap_resource(&pdev->dev, mem);
 200        if (IS_ERR(info->regs))
 201                return PTR_ERR(info->regs);
 202
 203        info->clk = devm_clk_get(&pdev->dev, "dac");
 204        if (IS_ERR(info->clk)) {
 205                dev_err(&pdev->dev, "Failed getting clock, err = %ld\n",
 206                        PTR_ERR(info->clk));
 207                return PTR_ERR(info->clk);
 208        }
 209
 210        platform_set_drvdata(pdev, indio_dev);
 211
 212        indio_dev->name = dev_name(&pdev->dev);
 213        indio_dev->dev.parent = &pdev->dev;
 214        indio_dev->dev.of_node = pdev->dev.of_node;
 215        indio_dev->info = &vf610_dac_iio_info;
 216        indio_dev->modes = INDIO_DIRECT_MODE;
 217        indio_dev->channels = vf610_dac_iio_channels;
 218        indio_dev->num_channels = ARRAY_SIZE(vf610_dac_iio_channels);
 219
 220        ret = clk_prepare_enable(info->clk);
 221        if (ret) {
 222                dev_err(&pdev->dev,
 223                        "Could not prepare or enable the clock\n");
 224                return ret;
 225        }
 226
 227        vf610_dac_init(info);
 228
 229        ret = iio_device_register(indio_dev);
 230        if (ret) {
 231                dev_err(&pdev->dev, "Couldn't register the device\n");
 232                goto error_iio_device_register;
 233        }
 234
 235        return 0;
 236
 237error_iio_device_register:
 238        clk_disable_unprepare(info->clk);
 239
 240        return ret;
 241}
 242
 243static int vf610_dac_remove(struct platform_device *pdev)
 244{
 245        struct iio_dev *indio_dev = platform_get_drvdata(pdev);
 246        struct vf610_dac *info = iio_priv(indio_dev);
 247
 248        iio_device_unregister(indio_dev);
 249        vf610_dac_exit(info);
 250        clk_disable_unprepare(info->clk);
 251
 252        return 0;
 253}
 254
 255#ifdef CONFIG_PM_SLEEP
 256static int vf610_dac_suspend(struct device *dev)
 257{
 258        struct iio_dev *indio_dev = dev_get_drvdata(dev);
 259        struct vf610_dac *info = iio_priv(indio_dev);
 260
 261        vf610_dac_exit(info);
 262        clk_disable_unprepare(info->clk);
 263
 264        return 0;
 265}
 266
 267static int vf610_dac_resume(struct device *dev)
 268{
 269        struct iio_dev *indio_dev = dev_get_drvdata(dev);
 270        struct vf610_dac *info = iio_priv(indio_dev);
 271        int ret;
 272
 273        ret = clk_prepare_enable(info->clk);
 274        if (ret)
 275                return ret;
 276
 277        vf610_dac_init(info);
 278
 279        return 0;
 280}
 281#endif
 282
 283static SIMPLE_DEV_PM_OPS(vf610_dac_pm_ops, vf610_dac_suspend, vf610_dac_resume);
 284
 285static struct platform_driver vf610_dac_driver = {
 286        .probe          = vf610_dac_probe,
 287        .remove         = vf610_dac_remove,
 288        .driver         = {
 289                .name   = "vf610-dac",
 290                .of_match_table = vf610_dac_match,
 291                .pm     = &vf610_dac_pm_ops,
 292        },
 293};
 294module_platform_driver(vf610_dac_driver);
 295
 296MODULE_AUTHOR("Sanchayan Maity <sanchayan.maity@toradex.com>");
 297MODULE_DESCRIPTION("Freescale VF610 DAC driver");
 298MODULE_LICENSE("GPL v2");
 299