drivers/iio/dac/vf610_dac.c

   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
  38 enum vf610_conversion_mode_sel {
  39         VF610_DAC_CONV_HIGH_POWER,
  40         VF610_DAC_CONV_LOW_POWER,
  41 };
  42
  43 struct vf610_dac {
  44         struct clk *clk;
  45         struct device *dev;
  46         enum vf610_conversion_mode_sel conv_mode;
  47         void __iomem *regs;
  48 };
  49
  50 static 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
  60 static 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
  69 static 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
  89 static 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
  97 static const char * const vf610_conv_modes[] = { "high-power", "low-power" };
  98
  99 static 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
 106 static 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
 120 static const struct iio_chan_spec vf610_dac_iio_channels[] = {
 121         VF610_DAC_CHAN(IIO_VOLTAGE),
 122 };
 123
 124 static 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
 150 static 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
 169 static 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
 175 static const struct of_device_id vf610_dac_match[] = {
 176         { .compatible = "fsl,vf610-dac", },
 177         { /* sentinel */ }
 178 };
 179 MODULE_DEVICE_TABLE(of, vf610_dac_match);
 180
 181 static 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
 237 error_iio_device_register:
 238         clk_disable_unprepare(info->clk);
 239
 240         return ret;
 241 }
 242
 243 static 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
 256 static 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
 267 static 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
 283 static SIMPLE_DEV_PM_OPS(vf610_dac_pm_ops, vf610_dac_suspend, vf610_dac_resume);
 284
 285 static 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 };
 294 module_platform_driver(vf610_dac_driver);
 295
 296 MODULE_AUTHOR("Sanchayan Maity <sanchayan.maity@toradex.com>");
 297 MODULE_DESCRIPTION("Freescale VF610 DAC driver");
 298 MODULE_LICENSE("GPL v2");