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/slab.h>
  20
  21 #define RN5T618_ADC_CONVERSION_TIMEOUT   (msecs_to_jiffies(500))
  22 #define RN5T618_REFERENCE_VOLT 2500
  23
  24 /* mask for selecting channels for single conversion */
  25 #define RN5T618_ADCCNT3_CHANNEL_MASK 0x7
  26 /* average 4-time conversion mode */
  27 #define RN5T618_ADCCNT3_AVG BIT(3)
  28 /* set for starting a single conversion, gets cleared by hw when done */
  29 #define RN5T618_ADCCNT3_GODONE BIT(4)
  30 /* automatic conversion, period is in ADCCNT2, selected channels are
  31  * in ADCCNT1
  32  */
  33 #define RN5T618_ADCCNT3_AUTO BIT(5)
  34 #define RN5T618_ADCEND_IRQ BIT(0)
  35
  36 struct rn5t618_adc_data {
  37         struct device *dev;
  38         struct rn5t618 *rn5t618;
  39         struct completion conv_completion;
  40         int irq;
  41 };
  42
  43 struct rn5t618_channel_ratios {
  44         u16 numerator;
  45         u16 denominator;
  46 };
  47
  48 enum rn5t618_channels {
  49         LIMMON = 0,
  50         VBAT,
  51         VADP,
  52         VUSB,
  53         VSYS,
  54         VTHM,
  55         AIN1,
  56         AIN0
  57 };
  58
  59 static const struct rn5t618_channel_ratios rn5t618_ratios[8] = {
  60         [LIMMON] = {50, 32}, /* measured across 20mOhm, amplified by 32 */
  61         [VBAT] = {2, 1},
  62         [VADP] = {3, 1},
  63         [VUSB] = {3, 1},
  64         [VSYS] = {3, 1},
  65         [VTHM] = {1, 1},
  66         [AIN1] = {1, 1},
  67         [AIN0] = {1, 1},
  68 };
  69
  70 static int rn5t618_read_adc_reg(struct rn5t618 *rn5t618, int reg, u16 *val)
  71 {
  72         u8 data[2];
  73         int ret;
  74
  75         ret = regmap_bulk_read(rn5t618->regmap, reg, data, sizeof(data));
  76         if (ret < 0)
  77                 return ret;
  78
  79         *val = (data[0] << 4) | (data[1] & 0xF);
  80
  81         return 0;
  82 }
  83
  84 static irqreturn_t rn5t618_adc_irq(int irq, void *data)
  85 {
  86         struct rn5t618_adc_data *adc = data;
  87         unsigned int r = 0;
  88         int ret;
  89
  90         /* clear low & high threshold irqs */
  91         regmap_write(adc->rn5t618->regmap, RN5T618_IR_ADC1, 0);
  92         regmap_write(adc->rn5t618->regmap, RN5T618_IR_ADC2, 0);
  93
  94         ret = regmap_read(adc->rn5t618->regmap, RN5T618_IR_ADC3, &r);
  95         if (ret < 0)
  96                 dev_err(adc->dev, "failed to read IRQ status: %d\n", ret);
  97
  98         regmap_write(adc->rn5t618->regmap, RN5T618_IR_ADC3, 0);
  99
 100         if (r & RN5T618_ADCEND_IRQ)
 101                 complete(&adc->conv_completion);
 102
 103         return IRQ_HANDLED;
 104 }
 105
 106 static int rn5t618_adc_read(struct iio_dev *iio_dev,
 107                             const struct iio_chan_spec *chan,
 108                             int *val, int *val2, long mask)
 109 {
 110         struct rn5t618_adc_data *adc = iio_priv(iio_dev);
 111         u16 raw;
 112         int ret;
 113
 114         if (mask == IIO_CHAN_INFO_SCALE) {
 115                 *val = RN5T618_REFERENCE_VOLT *
 116                        rn5t618_ratios[chan->channel].numerator;
 117                 *val2 = rn5t618_ratios[chan->channel].denominator * 4095;
 118
 119                 return IIO_VAL_FRACTIONAL;
 120         }
 121
 122         /* select channel */
 123         ret = regmap_update_bits(adc->rn5t618->regmap, RN5T618_ADCCNT3,
 124                                  RN5T618_ADCCNT3_CHANNEL_MASK,
 125                                  chan->channel);
 126         if (ret < 0)
 127                 return ret;
 128
 129         ret = regmap_write(adc->rn5t618->regmap, RN5T618_EN_ADCIR3,
 130                            RN5T618_ADCEND_IRQ);
 131         if (ret < 0)
 132                 return ret;
 133
 134         ret = regmap_update_bits(adc->rn5t618->regmap, RN5T618_ADCCNT3,
 135                                  RN5T618_ADCCNT3_AVG,
 136                                  mask == IIO_CHAN_INFO_AVERAGE_RAW ?
 137                                  RN5T618_ADCCNT3_AVG : 0);
 138         if (ret < 0)
 139                 return ret;
 140
 141         init_completion(&adc->conv_completion);
 142         /* single conversion */
 143         ret = regmap_update_bits(adc->rn5t618->regmap, RN5T618_ADCCNT3,
 144                                  RN5T618_ADCCNT3_GODONE,
 145                                  RN5T618_ADCCNT3_GODONE);
 146         if (ret < 0)
 147                 return ret;
 148
 149         ret = wait_for_completion_timeout(&adc->conv_completion,
 150                                           RN5T618_ADC_CONVERSION_TIMEOUT);
 151         if (ret == 0) {
 152                 dev_warn(adc->dev, "timeout waiting for adc result\n");
 153                 return -ETIMEDOUT;
 154         }
 155
 156         ret = rn5t618_read_adc_reg(adc->rn5t618,
 157                                    RN5T618_ILIMDATAH + 2 * chan->channel,
 158                                    &raw);
 159         if (ret < 0)
 160                 return ret;
 161
 162         *val = raw;
 163
 164         return IIO_VAL_INT;
 165 }
 166
 167 static const struct iio_info rn5t618_adc_iio_info = {
 168         .read_raw = &rn5t618_adc_read,
 169 };
 170
 171 #define RN5T618_ADC_CHANNEL(_channel, _type, _name) { \
 172         .type = _type, \
 173         .channel = _channel, \
 174         .info_mask_separate = BIT(IIO_CHAN_INFO_RAW) | \
 175                               BIT(IIO_CHAN_INFO_AVERAGE_RAW) | \
 176                               BIT(IIO_CHAN_INFO_SCALE), \
 177         .datasheet_name = _name, \
 178         .indexed = 1. \
 179 }
 180
 181 static const struct iio_chan_spec rn5t618_adc_iio_channels[] = {
 182         RN5T618_ADC_CHANNEL(LIMMON, IIO_CURRENT, "LIMMON"),
 183         RN5T618_ADC_CHANNEL(VBAT, IIO_VOLTAGE, "VBAT"),
 184         RN5T618_ADC_CHANNEL(VADP, IIO_VOLTAGE, "VADP"),
 185         RN5T618_ADC_CHANNEL(VUSB, IIO_VOLTAGE, "VUSB"),
 186         RN5T618_ADC_CHANNEL(VSYS, IIO_VOLTAGE, "VSYS"),
 187         RN5T618_ADC_CHANNEL(VTHM, IIO_VOLTAGE, "VTHM"),
 188         RN5T618_ADC_CHANNEL(AIN1, IIO_VOLTAGE, "AIN1"),
 189         RN5T618_ADC_CHANNEL(AIN0, IIO_VOLTAGE, "AIN0")
 190 };
 191
 192 static int rn5t618_adc_probe(struct platform_device *pdev)
 193 {
 194         int ret;
 195         struct iio_dev *iio_dev;
 196         struct rn5t618_adc_data *adc;
 197         struct rn5t618 *rn5t618 = dev_get_drvdata(pdev->dev.parent);
 198
 199         iio_dev = devm_iio_device_alloc(&pdev->dev, sizeof(*adc));
 200         if (!iio_dev) {
 201                 dev_err(&pdev->dev, "failed allocating iio device\n");
 202                 return -ENOMEM;
 203         }
 204
 205         adc = iio_priv(iio_dev);
 206         adc->dev = &pdev->dev;
 207         adc->rn5t618 = rn5t618;
 208
 209         if (rn5t618->irq_data)
 210                 adc->irq = regmap_irq_get_virq(rn5t618->irq_data,
 211                                                RN5T618_IRQ_ADC);
 212
 213         if (adc->irq <= 0) {
 214                 dev_err(&pdev->dev, "get virq failed\n");
 215                 return -EINVAL;
 216         }
 217
 218         init_completion(&adc->conv_completion);
 219
 220         iio_dev->name = dev_name(&pdev->dev);
 221         iio_dev->info = &rn5t618_adc_iio_info;
 222         iio_dev->modes = INDIO_DIRECT_MODE;
 223         iio_dev->channels = rn5t618_adc_iio_channels;
 224         iio_dev->num_channels = ARRAY_SIZE(rn5t618_adc_iio_channels);
 225
 226         /* stop any auto-conversion */
 227         ret = regmap_write(rn5t618->regmap, RN5T618_ADCCNT3, 0);
 228         if (ret < 0)
 229                 return ret;
 230
 231         platform_set_drvdata(pdev, iio_dev);
 232
 233         ret = devm_request_threaded_irq(adc->dev, adc->irq, NULL,
 234                                         rn5t618_adc_irq,
 235                                         IRQF_ONESHOT, dev_name(adc->dev),
 236                                         adc);
 237         if (ret < 0) {
 238                 dev_err(adc->dev, "request irq %d failed: %d\n", adc->irq, ret);
 239                 return ret;
 240         }
 241
 242         return devm_iio_device_register(adc->dev, iio_dev);
 243 }
 244
 245 static struct platform_driver rn5t618_adc_driver = {
 246         .driver = {
 247                 .name   = "rn5t618-adc",
 248         },
 249         .probe = rn5t618_adc_probe,
 250 };
 251
 252 module_platform_driver(rn5t618_adc_driver);
 253 MODULE_ALIAS("platform:rn5t618-adc");
 254 MODULE_DESCRIPTION("RICOH RN5T618 ADC driver");
 255 MODULE_LICENSE("GPL");