1*79e8a32dSPhil Reid // SPDX-License-Identifier: GPL-2.0+ 2*79e8a32dSPhil Reid /* 3*79e8a32dSPhil Reid * Analog Devices AD5272 digital potentiometer driver 4*79e8a32dSPhil Reid * Copyright (C) 2018 Phil Reid <preid@electromag.com.au> 5*79e8a32dSPhil Reid * 6*79e8a32dSPhil Reid * Datasheet: http://www.analog.com/media/en/technical-documentation/data-sheets/AD5272_5274.pdf 7*79e8a32dSPhil Reid * 8*79e8a32dSPhil Reid * DEVID #Wipers #Positions Resistor Opts (kOhm) i2c address 9*79e8a32dSPhil Reid * ad5272 1 1024 20, 50, 100 01011xx 10*79e8a32dSPhil Reid * ad5274 1 256 20, 100 01011xx 11*79e8a32dSPhil Reid */ 12*79e8a32dSPhil Reid 13*79e8a32dSPhil Reid #include <linux/delay.h> 14*79e8a32dSPhil Reid #include <linux/gpio/consumer.h> 15*79e8a32dSPhil Reid #include <linux/i2c.h> 16*79e8a32dSPhil Reid #include <linux/iio/iio.h> 17*79e8a32dSPhil Reid #include <linux/module.h> 18*79e8a32dSPhil Reid 19*79e8a32dSPhil Reid #define AD5272_RDAC_WR 1 20*79e8a32dSPhil Reid #define AD5272_RDAC_RD 2 21*79e8a32dSPhil Reid #define AD5272_RESET 4 22*79e8a32dSPhil Reid #define AD5272_CTL 7 23*79e8a32dSPhil Reid 24*79e8a32dSPhil Reid #define AD5272_RDAC_WR_EN BIT(1) 25*79e8a32dSPhil Reid 26*79e8a32dSPhil Reid struct ad5272_cfg { 27*79e8a32dSPhil Reid int max_pos; 28*79e8a32dSPhil Reid int kohms; 29*79e8a32dSPhil Reid int shift; 30*79e8a32dSPhil Reid }; 31*79e8a32dSPhil Reid 32*79e8a32dSPhil Reid enum ad5272_type { 33*79e8a32dSPhil Reid AD5272_020, 34*79e8a32dSPhil Reid AD5272_050, 35*79e8a32dSPhil Reid AD5272_100, 36*79e8a32dSPhil Reid AD5274_020, 37*79e8a32dSPhil Reid AD5274_100, 38*79e8a32dSPhil Reid }; 39*79e8a32dSPhil Reid 40*79e8a32dSPhil Reid static const struct ad5272_cfg ad5272_cfg[] = { 41*79e8a32dSPhil Reid [AD5272_020] = { .max_pos = 1024, .kohms = 20 }, 42*79e8a32dSPhil Reid [AD5272_050] = { .max_pos = 1024, .kohms = 50 }, 43*79e8a32dSPhil Reid [AD5272_100] = { .max_pos = 1024, .kohms = 100 }, 44*79e8a32dSPhil Reid [AD5274_020] = { .max_pos = 256, .kohms = 20, .shift = 2 }, 45*79e8a32dSPhil Reid [AD5274_100] = { .max_pos = 256, .kohms = 100, .shift = 2 }, 46*79e8a32dSPhil Reid }; 47*79e8a32dSPhil Reid 48*79e8a32dSPhil Reid struct ad5272_data { 49*79e8a32dSPhil Reid struct i2c_client *client; 50*79e8a32dSPhil Reid struct mutex lock; 51*79e8a32dSPhil Reid const struct ad5272_cfg *cfg; 52*79e8a32dSPhil Reid u8 buf[2] ____cacheline_aligned; 53*79e8a32dSPhil Reid }; 54*79e8a32dSPhil Reid 55*79e8a32dSPhil Reid static const struct iio_chan_spec ad5272_channel = { 56*79e8a32dSPhil Reid .type = IIO_RESISTANCE, 57*79e8a32dSPhil Reid .output = 1, 58*79e8a32dSPhil Reid .info_mask_separate = BIT(IIO_CHAN_INFO_RAW), 59*79e8a32dSPhil Reid .info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE), 60*79e8a32dSPhil Reid }; 61*79e8a32dSPhil Reid 62*79e8a32dSPhil Reid static int ad5272_write(struct ad5272_data *data, int reg, int val) 63*79e8a32dSPhil Reid { 64*79e8a32dSPhil Reid int ret; 65*79e8a32dSPhil Reid 66*79e8a32dSPhil Reid data->buf[0] = (reg << 2) | ((val >> 8) & 0x3); 67*79e8a32dSPhil Reid data->buf[1] = (u8)val; 68*79e8a32dSPhil Reid 69*79e8a32dSPhil Reid mutex_lock(&data->lock); 70*79e8a32dSPhil Reid ret = i2c_master_send(data->client, data->buf, sizeof(data->buf)); 71*79e8a32dSPhil Reid mutex_unlock(&data->lock); 72*79e8a32dSPhil Reid return ret < 0 ? ret : 0; 73*79e8a32dSPhil Reid } 74*79e8a32dSPhil Reid 75*79e8a32dSPhil Reid static int ad5272_read(struct ad5272_data *data, int reg, int *val) 76*79e8a32dSPhil Reid { 77*79e8a32dSPhil Reid int ret; 78*79e8a32dSPhil Reid 79*79e8a32dSPhil Reid data->buf[0] = reg << 2; 80*79e8a32dSPhil Reid data->buf[1] = 0; 81*79e8a32dSPhil Reid 82*79e8a32dSPhil Reid mutex_lock(&data->lock); 83*79e8a32dSPhil Reid ret = i2c_master_send(data->client, data->buf, sizeof(data->buf)); 84*79e8a32dSPhil Reid if (ret < 0) 85*79e8a32dSPhil Reid goto error; 86*79e8a32dSPhil Reid 87*79e8a32dSPhil Reid ret = i2c_master_recv(data->client, data->buf, sizeof(data->buf)); 88*79e8a32dSPhil Reid if (ret < 0) 89*79e8a32dSPhil Reid goto error; 90*79e8a32dSPhil Reid 91*79e8a32dSPhil Reid *val = ((data->buf[0] & 0x3) << 8) | data->buf[1]; 92*79e8a32dSPhil Reid ret = 0; 93*79e8a32dSPhil Reid error: 94*79e8a32dSPhil Reid mutex_unlock(&data->lock); 95*79e8a32dSPhil Reid return ret; 96*79e8a32dSPhil Reid } 97*79e8a32dSPhil Reid 98*79e8a32dSPhil Reid static int ad5272_read_raw(struct iio_dev *indio_dev, 99*79e8a32dSPhil Reid struct iio_chan_spec const *chan, 100*79e8a32dSPhil Reid int *val, int *val2, long mask) 101*79e8a32dSPhil Reid { 102*79e8a32dSPhil Reid struct ad5272_data *data = iio_priv(indio_dev); 103*79e8a32dSPhil Reid int ret; 104*79e8a32dSPhil Reid 105*79e8a32dSPhil Reid switch (mask) { 106*79e8a32dSPhil Reid case IIO_CHAN_INFO_RAW: { 107*79e8a32dSPhil Reid ret = ad5272_read(data, AD5272_RDAC_RD, val); 108*79e8a32dSPhil Reid *val = *val >> data->cfg->shift; 109*79e8a32dSPhil Reid return ret ? ret : IIO_VAL_INT; 110*79e8a32dSPhil Reid } 111*79e8a32dSPhil Reid case IIO_CHAN_INFO_SCALE: 112*79e8a32dSPhil Reid *val = 1000 * data->cfg->kohms; 113*79e8a32dSPhil Reid *val2 = data->cfg->max_pos; 114*79e8a32dSPhil Reid return IIO_VAL_FRACTIONAL; 115*79e8a32dSPhil Reid } 116*79e8a32dSPhil Reid 117*79e8a32dSPhil Reid return -EINVAL; 118*79e8a32dSPhil Reid } 119*79e8a32dSPhil Reid 120*79e8a32dSPhil Reid static int ad5272_write_raw(struct iio_dev *indio_dev, 121*79e8a32dSPhil Reid struct iio_chan_spec const *chan, 122*79e8a32dSPhil Reid int val, int val2, long mask) 123*79e8a32dSPhil Reid { 124*79e8a32dSPhil Reid struct ad5272_data *data = iio_priv(indio_dev); 125*79e8a32dSPhil Reid 126*79e8a32dSPhil Reid if (mask != IIO_CHAN_INFO_RAW) 127*79e8a32dSPhil Reid return -EINVAL; 128*79e8a32dSPhil Reid 129*79e8a32dSPhil Reid if (val >= data->cfg->max_pos || val < 0 || val2) 130*79e8a32dSPhil Reid return -EINVAL; 131*79e8a32dSPhil Reid 132*79e8a32dSPhil Reid return ad5272_write(data, AD5272_RDAC_WR, val << data->cfg->shift); 133*79e8a32dSPhil Reid } 134*79e8a32dSPhil Reid 135*79e8a32dSPhil Reid static const struct iio_info ad5272_info = { 136*79e8a32dSPhil Reid .read_raw = ad5272_read_raw, 137*79e8a32dSPhil Reid .write_raw = ad5272_write_raw, 138*79e8a32dSPhil Reid }; 139*79e8a32dSPhil Reid 140*79e8a32dSPhil Reid static int ad5272_reset(struct ad5272_data *data) 141*79e8a32dSPhil Reid { 142*79e8a32dSPhil Reid struct gpio_desc *reset_gpio; 143*79e8a32dSPhil Reid 144*79e8a32dSPhil Reid reset_gpio = devm_gpiod_get_optional(&data->client->dev, "reset", 145*79e8a32dSPhil Reid GPIOD_OUT_LOW); 146*79e8a32dSPhil Reid if (IS_ERR(reset_gpio)) 147*79e8a32dSPhil Reid return PTR_ERR(reset_gpio); 148*79e8a32dSPhil Reid 149*79e8a32dSPhil Reid if (reset_gpio) { 150*79e8a32dSPhil Reid udelay(1); 151*79e8a32dSPhil Reid gpiod_set_value(reset_gpio, 1); 152*79e8a32dSPhil Reid } else { 153*79e8a32dSPhil Reid ad5272_write(data, AD5272_RESET, 0); 154*79e8a32dSPhil Reid } 155*79e8a32dSPhil Reid usleep_range(1000, 2000); 156*79e8a32dSPhil Reid 157*79e8a32dSPhil Reid return 0; 158*79e8a32dSPhil Reid } 159*79e8a32dSPhil Reid 160*79e8a32dSPhil Reid static int ad5272_probe(struct i2c_client *client, 161*79e8a32dSPhil Reid const struct i2c_device_id *id) 162*79e8a32dSPhil Reid { 163*79e8a32dSPhil Reid struct device *dev = &client->dev; 164*79e8a32dSPhil Reid struct iio_dev *indio_dev; 165*79e8a32dSPhil Reid struct ad5272_data *data; 166*79e8a32dSPhil Reid int ret; 167*79e8a32dSPhil Reid 168*79e8a32dSPhil Reid indio_dev = devm_iio_device_alloc(dev, sizeof(*data)); 169*79e8a32dSPhil Reid if (!indio_dev) 170*79e8a32dSPhil Reid return -ENOMEM; 171*79e8a32dSPhil Reid 172*79e8a32dSPhil Reid i2c_set_clientdata(client, indio_dev); 173*79e8a32dSPhil Reid 174*79e8a32dSPhil Reid data = iio_priv(indio_dev); 175*79e8a32dSPhil Reid data->client = client; 176*79e8a32dSPhil Reid mutex_init(&data->lock); 177*79e8a32dSPhil Reid data->cfg = &ad5272_cfg[id->driver_data]; 178*79e8a32dSPhil Reid 179*79e8a32dSPhil Reid ret = ad5272_reset(data); 180*79e8a32dSPhil Reid if (ret) 181*79e8a32dSPhil Reid return ret; 182*79e8a32dSPhil Reid 183*79e8a32dSPhil Reid ret = ad5272_write(data, AD5272_CTL, AD5272_RDAC_WR_EN); 184*79e8a32dSPhil Reid if (ret < 0) 185*79e8a32dSPhil Reid return -ENODEV; 186*79e8a32dSPhil Reid 187*79e8a32dSPhil Reid indio_dev->dev.parent = dev; 188*79e8a32dSPhil Reid indio_dev->info = &ad5272_info; 189*79e8a32dSPhil Reid indio_dev->channels = &ad5272_channel; 190*79e8a32dSPhil Reid indio_dev->num_channels = 1; 191*79e8a32dSPhil Reid indio_dev->name = client->name; 192*79e8a32dSPhil Reid 193*79e8a32dSPhil Reid return devm_iio_device_register(dev, indio_dev); 194*79e8a32dSPhil Reid } 195*79e8a32dSPhil Reid 196*79e8a32dSPhil Reid #if defined(CONFIG_OF) 197*79e8a32dSPhil Reid static const struct of_device_id ad5272_dt_ids[] = { 198*79e8a32dSPhil Reid { .compatible = "adi,ad5272-020", .data = (void *)AD5272_020 }, 199*79e8a32dSPhil Reid { .compatible = "adi,ad5272-050", .data = (void *)AD5272_050 }, 200*79e8a32dSPhil Reid { .compatible = "adi,ad5272-100", .data = (void *)AD5272_100 }, 201*79e8a32dSPhil Reid { .compatible = "adi,ad5274-020", .data = (void *)AD5274_020 }, 202*79e8a32dSPhil Reid { .compatible = "adi,ad5274-100", .data = (void *)AD5274_100 }, 203*79e8a32dSPhil Reid {} 204*79e8a32dSPhil Reid }; 205*79e8a32dSPhil Reid MODULE_DEVICE_TABLE(of, ad5272_dt_ids); 206*79e8a32dSPhil Reid #endif /* CONFIG_OF */ 207*79e8a32dSPhil Reid 208*79e8a32dSPhil Reid static const struct i2c_device_id ad5272_id[] = { 209*79e8a32dSPhil Reid { "ad5272-020", AD5272_020 }, 210*79e8a32dSPhil Reid { "ad5272-050", AD5272_050 }, 211*79e8a32dSPhil Reid { "ad5272-100", AD5272_100 }, 212*79e8a32dSPhil Reid { "ad5274-020", AD5274_020 }, 213*79e8a32dSPhil Reid { "ad5274-100", AD5274_100 }, 214*79e8a32dSPhil Reid {} 215*79e8a32dSPhil Reid }; 216*79e8a32dSPhil Reid MODULE_DEVICE_TABLE(i2c, ad5272_id); 217*79e8a32dSPhil Reid 218*79e8a32dSPhil Reid static struct i2c_driver ad5272_driver = { 219*79e8a32dSPhil Reid .driver = { 220*79e8a32dSPhil Reid .name = "ad5272", 221*79e8a32dSPhil Reid .of_match_table = of_match_ptr(ad5272_dt_ids), 222*79e8a32dSPhil Reid }, 223*79e8a32dSPhil Reid .probe = ad5272_probe, 224*79e8a32dSPhil Reid .id_table = ad5272_id, 225*79e8a32dSPhil Reid }; 226*79e8a32dSPhil Reid 227*79e8a32dSPhil Reid module_i2c_driver(ad5272_driver); 228*79e8a32dSPhil Reid 229*79e8a32dSPhil Reid MODULE_AUTHOR("Phil Reid <preid@eletromag.com.au>"); 230*79e8a32dSPhil Reid MODULE_DESCRIPTION("AD5272 digital potentiometer"); 231*79e8a32dSPhil Reid MODULE_LICENSE("GPL v2"); 232