drivers/iio/adc/rn5t618-adc.c

   1 // SPDX-License-Identifier: GPL-2.0+
   2 /*
   3  * ADC driver for the RICOH RN5T618 power management chip family
   4  *
   5  * Copyright (C) 2019 Andreas Kemnade
   6  */
   7
   8 #include <linux/kernel.h>
   9 #include <linux/device.h>
  10 #include <linux/errno.h>
  11 #include <linux/interrupt.h>
  12 #include <linux/init.h>
  13 #include <linux/module.h>
  14 #include <linux/mfd/rn5t618.h>
  15 #include <linux/platform_device.h>
  16 #include <linux/completion.h>
  17 #include <linux/regmap.h>
  18 #include <linux/iio/iio.h>
  19 #include <linux/iio/driver.h>
  20 #include <linux/iio/machine.h>
  21 #include <linux/slab.h>
  22
  23 #define RN5T618_ADC_CONVERSION_TIMEOUT   (msecs_to_jiffies(500))
  24 #define RN5T618_REFERENCE_VOLT 2500
  25
  26 /* mask for selecting channels for single conversion */
  27 #define RN5T618_ADCCNT3_CHANNEL_MASK 0x7
  28 /* average 4-time conversion mode */
  29 #define RN5T618_ADCCNT3_AVG BIT(3)
  30 /* set for starting a single conversion, gets cleared by hw when done */
  31 #define RN5T618_ADCCNT3_GODONE BIT(4)
  32 /* automatic conversion, period is in ADCCNT2, selected channels are
  33  * in ADCCNT1
  34  */
  35 #define RN5T618_ADCCNT3_AUTO BIT(5)
  36 #define RN5T618_ADCEND_IRQ BIT(0)
  37
  38 struct rn5t618_adc_data {
  39         struct device *dev;
  40         struct rn5t618 *rn5t618;
  41         struct completion conv_completion;
  42         int irq;
  43 };
  44
  45 enum rn5t618_channels {
  46         LIMMON = 0,
  47         VBAT,
  48         VADP,
  49         VUSB,
  50         VSYS,
  51         VTHM,
  52         AIN1,
  53         AIN0
  54 };
  55
  56 static const struct u16_fract rn5t618_ratios[8] = {
  57         [LIMMON] = {50, 32}, /* measured across 20mOhm, amplified by 32 */
  58         [VBAT] = {2, 1},
  59         [VADP] = {3, 1},
  60         [VUSB] = {3, 1},
  61         [VSYS] = {3, 1},
  62         [VTHM] = {1, 1},
  63         [AIN1] = {1, 1},
  64         [AIN0] = {1, 1},
  65 };
  66
  67 static int rn5t618_read_adc_reg(struct rn5t618 *rn5t618, int reg, u16 *val)
  68 {
  69         u8 data[2];
  70         int ret;
  71
  72         ret = regmap_bulk_read(rn5t618->regmap, reg, data, sizeof(data));
  73         if (ret < 0)
  74                 return ret;
  75
  76         *val = (data[0] << 4) | (data[1] & 0xF);
  77
  78         return 0;
  79 }
  80
  81 static irqreturn_t rn5t618_adc_irq(int irq, void *data)
  82 {
  83         struct rn5t618_adc_data *adc = data;
  84         unsigned int r = 0;
  85         int ret;
  86
  87         /* clear low & high threshold irqs */
  88         regmap_write(adc->rn5t618->regmap, RN5T618_IR_ADC1, 0);
  89         regmap_write(adc->rn5t618->regmap, RN5T618_IR_ADC2, 0);
  90
  91         ret = regmap_read(adc->rn5t618->regmap, RN5T618_IR_ADC3, &r);
  92         if (ret < 0)
  93                 dev_err(adc->dev, "failed to read IRQ status: %d\n", ret);
  94
  95         regmap_write(adc->rn5t618->regmap, RN5T618_IR_ADC3, 0);
  96
  97         if (r & RN5T618_ADCEND_IRQ)
  98                 complete(&adc->conv_completion);
  99
 100         return IRQ_HANDLED;
 101 }
 102
 103 static int rn5t618_adc_read(struct iio_dev *iio_dev,
 104                             const struct iio_chan_spec *chan,
 105                             int *val, int *val2, long mask)
 106 {
 107         struct rn5t618_adc_data *adc = iio_priv(iio_dev);
 108         u16 raw;
 109         int ret;
 110
 111         if (mask == IIO_CHAN_INFO_SCALE) {
 112                 *val = RN5T618_REFERENCE_VOLT *
 113                        rn5t618_ratios[chan->channel].numerator;
 114                 *val2 = rn5t618_ratios[chan->channel].denominator * 4095;
 115
 116                 return IIO_VAL_FRACTIONAL;
 117         }
 118
 119         /* select channel */
 120         ret = regmap_update_bits(adc->rn5t618->regmap, RN5T618_ADCCNT3,
 121                                  RN5T618_ADCCNT3_CHANNEL_MASK,
 122                                  chan->channel);
 123         if (ret < 0)
 124                 return ret;
 125
 126         ret = regmap_write(adc->rn5t618->regmap, RN5T618_EN_ADCIR3,
 127                            RN5T618_ADCEND_IRQ);
 128         if (ret < 0)
 129                 return ret;
 130
 131         ret = regmap_update_bits(adc->rn5t618->regmap, RN5T618_ADCCNT3,
 132                                  RN5T618_ADCCNT3_AVG,
 133                                  mask == IIO_CHAN_INFO_AVERAGE_RAW ?
 134                                  RN5T618_ADCCNT3_AVG : 0);
 135         if (ret < 0)
 136                 return ret;
 137
 138         init_completion(&adc->conv_completion);
 139         /* single conversion */
 140         ret = regmap_update_bits(adc->rn5t618->regmap, RN5T618_ADCCNT3,
 141                                  RN5T618_ADCCNT3_GODONE,
 142                                  RN5T618_ADCCNT3_GODONE);
 143         if (ret < 0)
 144                 return ret;
 145
 146         ret = wait_for_completion_timeout(&adc->conv_completion,
 147                                           RN5T618_ADC_CONVERSION_TIMEOUT);
 148         if (ret == 0) {
 149                 dev_warn(adc->dev, "timeout waiting for adc result\n");
 150                 return -ETIMEDOUT;
 151         }
 152
 153         ret = rn5t618_read_adc_reg(adc->rn5t618,
 154                                    RN5T618_ILIMDATAH + 2 * chan->channel,
 155                                    &raw);
 156         if (ret < 0)
 157                 return ret;
 158
 159         *val = raw;
 160
 161         return IIO_VAL_INT;
 162 }
 163
 164 static const struct iio_info rn5t618_adc_iio_info = {
 165         .read_raw = &rn5t618_adc_read,
 166 };
 167
 168 #define RN5T618_ADC_CHANNEL(_channel, _type, _name) { \
 169         .type = _type, \
 170         .channel = _channel, \
 171         .info_mask_separate = BIT(IIO_CHAN_INFO_RAW) | \
 172                               BIT(IIO_CHAN_INFO_AVERAGE_RAW) | \
 173                               BIT(IIO_CHAN_INFO_SCALE), \
 174         .datasheet_name = _name, \
 175         .indexed = 1. \
 176 }
 177
 178 static const struct iio_chan_spec rn5t618_adc_iio_channels[] = {
 179         RN5T618_ADC_CHANNEL(LIMMON, IIO_CURRENT, "LIMMON"),
 180         RN5T618_ADC_CHANNEL(VBAT, IIO_VOLTAGE, "VBAT"),
 181         RN5T618_ADC_CHANNEL(VADP, IIO_VOLTAGE, "VADP"),
 182         RN5T618_ADC_CHANNEL(VUSB, IIO_VOLTAGE, "VUSB"),
 183         RN5T618_ADC_CHANNEL(VSYS, IIO_VOLTAGE, "VSYS"),
 184         RN5T618_ADC_CHANNEL(VTHM, IIO_VOLTAGE, "VTHM"),
 185         RN5T618_ADC_CHANNEL(AIN1, IIO_VOLTAGE, "AIN1"),
 186         RN5T618_ADC_CHANNEL(AIN0, IIO_VOLTAGE, "AIN0")
 187 };
 188
 189 static struct iio_map rn5t618_maps[] = {
 190         IIO_MAP("VADP", "rn5t618-power", "vadp"),
 191         IIO_MAP("VUSB", "rn5t618-power", "vusb"),
 192         { /* sentinel */ }
 193 };
 194
 195 static int rn5t618_adc_probe(struct platform_device *pdev)
 196 {
 197         int ret;
 198         struct iio_dev *iio_dev;
 199         struct rn5t618_adc_data *adc;
 200         struct rn5t618 *rn5t618 = dev_get_drvdata(pdev->dev.parent);
 201
 202         iio_dev = devm_iio_device_alloc(&pdev->dev, sizeof(*adc));
 203         if (!iio_dev) {
 204                 dev_err(&pdev->dev, "failed allocating iio device\n");
 205                 return -ENOMEM;
 206         }
 207
 208         adc = iio_priv(iio_dev);
 209         adc->dev = &pdev->dev;
 210         adc->rn5t618 = rn5t618;
 211
 212         if (rn5t618->irq_data)
 213                 adc->irq = regmap_irq_get_virq(rn5t618->irq_data,
 214                                                RN5T618_IRQ_ADC);
 215
 216         if (adc->irq <= 0) {
 217                 dev_err(&pdev->dev, "get virq failed\n");
 218                 return -EINVAL;
 219         }
 220
 221         init_completion(&adc->conv_completion);
 222
 223         iio_dev->name = dev_name(&pdev->dev);
 224         iio_dev->info = &rn5t618_adc_iio_info;
 225         iio_dev->modes = INDIO_DIRECT_MODE;
 226         iio_dev->channels = rn5t618_adc_iio_channels;
 227         iio_dev->num_channels = ARRAY_SIZE(rn5t618_adc_iio_channels);
 228
 229         /* stop any auto-conversion */
 230         ret = regmap_write(rn5t618->regmap, RN5T618_ADCCNT3, 0);
 231         if (ret < 0)
 232                 return ret;
 233
 234         platform_set_drvdata(pdev, iio_dev);
 235
 236         ret = devm_request_threaded_irq(adc->dev, adc->irq, NULL,
 237                                         rn5t618_adc_irq,
 238                                         IRQF_ONESHOT, dev_name(adc->dev),
 239                                         adc);
 240         if (ret < 0) {
 241                 dev_err(adc->dev, "request irq %d failed: %d\n", adc->irq, ret);
 242                 return ret;
 243         }
 244
 245         ret = devm_iio_map_array_register(adc->dev, iio_dev, rn5t618_maps);
 246         if (ret < 0)
 247                 return ret;
 248
 249         return devm_iio_device_register(adc->dev, iio_dev);
 250 }
 251
 252 static struct platform_driver rn5t618_adc_driver = {
 253         .driver = {
 254                 .name   = "rn5t618-adc",
 255         },
 256         .probe = rn5t618_adc_probe,
 257 };
 258
 259 module_platform_driver(rn5t618_adc_driver);
 260 MODULE_ALIAS("platform:rn5t618-adc");
 261 MODULE_DESCRIPTION("RICOH RN5T618 ADC driver");
 262 MODULE_LICENSE("GPL");