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 struct rn5t618_channel_ratios {
  46         u16 numerator;
  47         u16 denominator;
  48 };
  49
  50 enum rn5t618_channels {
  51         LIMMON = 0,
  52         VBAT,
  53         VADP,
  54         VUSB,
  55         VSYS,
  56         VTHM,
  57         AIN1,
  58         AIN0
  59 };
  60
  61 static const struct rn5t618_channel_ratios rn5t618_ratios[8] = {
  62         [LIMMON] = {50, 32}, /* measured across 20mOhm, amplified by 32 */
  63         [VBAT] = {2, 1},
  64         [VADP] = {3, 1},
  65         [VUSB] = {3, 1},
  66         [VSYS] = {3, 1},
  67         [VTHM] = {1, 1},
  68         [AIN1] = {1, 1},
  69         [AIN0] = {1, 1},
  70 };
  71
  72 static int rn5t618_read_adc_reg(struct rn5t618 *rn5t618, int reg, u16 *val)
  73 {
  74         u8 data[2];
  75         int ret;
  76
  77         ret = regmap_bulk_read(rn5t618->regmap, reg, data, sizeof(data));
  78         if (ret < 0)
  79                 return ret;
  80
  81         *val = (data[0] << 4) | (data[1] & 0xF);
  82
  83         return 0;
  84 }
  85
  86 static irqreturn_t rn5t618_adc_irq(int irq, void *data)
  87 {
  88         struct rn5t618_adc_data *adc = data;
  89         unsigned int r = 0;
  90         int ret;
  91
  92         /* clear low & high threshold irqs */
  93         regmap_write(adc->rn5t618->regmap, RN5T618_IR_ADC1, 0);
  94         regmap_write(adc->rn5t618->regmap, RN5T618_IR_ADC2, 0);
  95
  96         ret = regmap_read(adc->rn5t618->regmap, RN5T618_IR_ADC3, &r);
  97         if (ret < 0)
  98                 dev_err(adc->dev, "failed to read IRQ status: %d\n", ret);
  99
 100         regmap_write(adc->rn5t618->regmap, RN5T618_IR_ADC3, 0);
 101
 102         if (r & RN5T618_ADCEND_IRQ)
 103                 complete(&adc->conv_completion);
 104
 105         return IRQ_HANDLED;
 106 }
 107
 108 static int rn5t618_adc_read(struct iio_dev *iio_dev,
 109                             const struct iio_chan_spec *chan,
 110                             int *val, int *val2, long mask)
 111 {
 112         struct rn5t618_adc_data *adc = iio_priv(iio_dev);
 113         u16 raw;
 114         int ret;
 115
 116         if (mask == IIO_CHAN_INFO_SCALE) {
 117                 *val = RN5T618_REFERENCE_VOLT *
 118                        rn5t618_ratios[chan->channel].numerator;
 119                 *val2 = rn5t618_ratios[chan->channel].denominator * 4095;
 120
 121                 return IIO_VAL_FRACTIONAL;
 122         }
 123
 124         /* select channel */
 125         ret = regmap_update_bits(adc->rn5t618->regmap, RN5T618_ADCCNT3,
 126                                  RN5T618_ADCCNT3_CHANNEL_MASK,
 127                                  chan->channel);
 128         if (ret < 0)
 129                 return ret;
 130
 131         ret = regmap_write(adc->rn5t618->regmap, RN5T618_EN_ADCIR3,
 132                            RN5T618_ADCEND_IRQ);
 133         if (ret < 0)
 134                 return ret;
 135
 136         ret = regmap_update_bits(adc->rn5t618->regmap, RN5T618_ADCCNT3,
 137                                  RN5T618_ADCCNT3_AVG,
 138                                  mask == IIO_CHAN_INFO_AVERAGE_RAW ?
 139                                  RN5T618_ADCCNT3_AVG : 0);
 140         if (ret < 0)
 141                 return ret;
 142
 143         init_completion(&adc->conv_completion);
 144         /* single conversion */
 145         ret = regmap_update_bits(adc->rn5t618->regmap, RN5T618_ADCCNT3,
 146                                  RN5T618_ADCCNT3_GODONE,
 147                                  RN5T618_ADCCNT3_GODONE);
 148         if (ret < 0)
 149                 return ret;
 150
 151         ret = wait_for_completion_timeout(&adc->conv_completion,
 152                                           RN5T618_ADC_CONVERSION_TIMEOUT);
 153         if (ret == 0) {
 154                 dev_warn(adc->dev, "timeout waiting for adc result\n");
 155                 return -ETIMEDOUT;
 156         }
 157
 158         ret = rn5t618_read_adc_reg(adc->rn5t618,
 159                                    RN5T618_ILIMDATAH + 2 * chan->channel,
 160                                    &raw);
 161         if (ret < 0)
 162                 return ret;
 163
 164         *val = raw;
 165
 166         return IIO_VAL_INT;
 167 }
 168
 169 static const struct iio_info rn5t618_adc_iio_info = {
 170         .read_raw = &rn5t618_adc_read,
 171 };
 172
 173 #define RN5T618_ADC_CHANNEL(_channel, _type, _name) { \
 174         .type = _type, \
 175         .channel = _channel, \
 176         .info_mask_separate = BIT(IIO_CHAN_INFO_RAW) | \
 177                               BIT(IIO_CHAN_INFO_AVERAGE_RAW) | \
 178                               BIT(IIO_CHAN_INFO_SCALE), \
 179         .datasheet_name = _name, \
 180         .indexed = 1. \
 181 }
 182
 183 static const struct iio_chan_spec rn5t618_adc_iio_channels[] = {
 184         RN5T618_ADC_CHANNEL(LIMMON, IIO_CURRENT, "LIMMON"),
 185         RN5T618_ADC_CHANNEL(VBAT, IIO_VOLTAGE, "VBAT"),
 186         RN5T618_ADC_CHANNEL(VADP, IIO_VOLTAGE, "VADP"),
 187         RN5T618_ADC_CHANNEL(VUSB, IIO_VOLTAGE, "VUSB"),
 188         RN5T618_ADC_CHANNEL(VSYS, IIO_VOLTAGE, "VSYS"),
 189         RN5T618_ADC_CHANNEL(VTHM, IIO_VOLTAGE, "VTHM"),
 190         RN5T618_ADC_CHANNEL(AIN1, IIO_VOLTAGE, "AIN1"),
 191         RN5T618_ADC_CHANNEL(AIN0, IIO_VOLTAGE, "AIN0")
 192 };
 193
 194 static struct iio_map rn5t618_maps[] = {
 195         IIO_MAP("VADP", "rn5t618-power", "vadp"),
 196         IIO_MAP("VUSB", "rn5t618-power", "vusb"),
 197         { /* sentinel */ }
 198 };
 199
 200 static int rn5t618_adc_probe(struct platform_device *pdev)
 201 {
 202         int ret;
 203         struct iio_dev *iio_dev;
 204         struct rn5t618_adc_data *adc;
 205         struct rn5t618 *rn5t618 = dev_get_drvdata(pdev->dev.parent);
 206
 207         iio_dev = devm_iio_device_alloc(&pdev->dev, sizeof(*adc));
 208         if (!iio_dev) {
 209                 dev_err(&pdev->dev, "failed allocating iio device\n");
 210                 return -ENOMEM;
 211         }
 212
 213         adc = iio_priv(iio_dev);
 214         adc->dev = &pdev->dev;
 215         adc->rn5t618 = rn5t618;
 216
 217         if (rn5t618->irq_data)
 218                 adc->irq = regmap_irq_get_virq(rn5t618->irq_data,
 219                                                RN5T618_IRQ_ADC);
 220
 221         if (adc->irq <= 0) {
 222                 dev_err(&pdev->dev, "get virq failed\n");
 223                 return -EINVAL;
 224         }
 225
 226         init_completion(&adc->conv_completion);
 227
 228         iio_dev->name = dev_name(&pdev->dev);
 229         iio_dev->info = &rn5t618_adc_iio_info;
 230         iio_dev->modes = INDIO_DIRECT_MODE;
 231         iio_dev->channels = rn5t618_adc_iio_channels;
 232         iio_dev->num_channels = ARRAY_SIZE(rn5t618_adc_iio_channels);
 233
 234         /* stop any auto-conversion */
 235         ret = regmap_write(rn5t618->regmap, RN5T618_ADCCNT3, 0);
 236         if (ret < 0)
 237                 return ret;
 238
 239         platform_set_drvdata(pdev, iio_dev);
 240
 241         ret = devm_request_threaded_irq(adc->dev, adc->irq, NULL,
 242                                         rn5t618_adc_irq,
 243                                         IRQF_ONESHOT, dev_name(adc->dev),
 244                                         adc);
 245         if (ret < 0) {
 246                 dev_err(adc->dev, "request irq %d failed: %d\n", adc->irq, ret);
 247                 return ret;
 248         }
 249
 250         ret = devm_iio_map_array_register(adc->dev, iio_dev, rn5t618_maps);
 251         if (ret < 0)
 252                 return ret;
 253
 254         return devm_iio_device_register(adc->dev, iio_dev);
 255 }
 256
 257 static struct platform_driver rn5t618_adc_driver = {
 258         .driver = {
 259                 .name   = "rn5t618-adc",
 260         },
 261         .probe = rn5t618_adc_probe,
 262 };
 263
 264 module_platform_driver(rn5t618_adc_driver);
 265 MODULE_ALIAS("platform:rn5t618-adc");
 266 MODULE_DESCRIPTION("RICOH RN5T618 ADC driver");
 267 MODULE_LICENSE("GPL");