1 // SPDX-License-Identifier: GPL-2.0-only 2 /* 3 * ad2s1200.c simple support for the ADI Resolver to Digital Converters: 4 * AD2S1200/1205 5 * 6 * Copyright (c) 2018-2018 David Veenstra <davidjulianveenstra@gmail.com> 7 * Copyright (c) 2010-2010 Analog Devices Inc. 8 */ 9 10 #include <linux/bitops.h> 11 #include <linux/delay.h> 12 #include <linux/device.h> 13 #include <linux/gpio/consumer.h> 14 #include <linux/module.h> 15 #include <linux/mod_devicetable.h> 16 #include <linux/mutex.h> 17 #include <linux/spi/spi.h> 18 #include <linux/sysfs.h> 19 #include <linux/types.h> 20 21 #include <linux/iio/iio.h> 22 #include <linux/iio/sysfs.h> 23 24 #define DRV_NAME "ad2s1200" 25 26 /* input clock on serial interface */ 27 #define AD2S1200_HZ 8192000 28 /* clock period in nano second */ 29 #define AD2S1200_TSCLK (1000000000 / AD2S1200_HZ) 30 31 /** 32 * struct ad2s1200_state - driver instance specific data. 33 * @lock: protects both the GPIO pins and the rx buffer. 34 * @sdev: spi device. 35 * @sample: GPIO pin SAMPLE. 36 * @rdvel: GPIO pin RDVEL. 37 * @rx: buffer for spi transfers. 38 */ 39 struct ad2s1200_state { 40 struct mutex lock; 41 struct spi_device *sdev; 42 struct gpio_desc *sample; 43 struct gpio_desc *rdvel; 44 __be16 rx ____cacheline_aligned; 45 }; 46 47 static int ad2s1200_read_raw(struct iio_dev *indio_dev, 48 struct iio_chan_spec const *chan, 49 int *val, 50 int *val2, 51 long m) 52 { 53 struct ad2s1200_state *st = iio_priv(indio_dev); 54 int ret; 55 56 switch (m) { 57 case IIO_CHAN_INFO_SCALE: 58 switch (chan->type) { 59 case IIO_ANGL: 60 /* 2 * Pi / (2^12 - 1) ~= 0.001534355 */ 61 *val = 0; 62 *val2 = 1534355; 63 return IIO_VAL_INT_PLUS_NANO; 64 case IIO_ANGL_VEL: 65 /* 2 * Pi ~= 6.283185 */ 66 *val = 6; 67 *val2 = 283185; 68 return IIO_VAL_INT_PLUS_MICRO; 69 default: 70 return -EINVAL; 71 } 72 break; 73 case IIO_CHAN_INFO_RAW: 74 mutex_lock(&st->lock); 75 gpiod_set_value(st->sample, 0); 76 77 /* delay (6 * AD2S1200_TSCLK + 20) nano seconds */ 78 udelay(1); 79 gpiod_set_value(st->sample, 1); 80 gpiod_set_value(st->rdvel, !!(chan->type == IIO_ANGL)); 81 82 ret = spi_read(st->sdev, &st->rx, 2); 83 if (ret < 0) { 84 mutex_unlock(&st->lock); 85 return ret; 86 } 87 88 switch (chan->type) { 89 case IIO_ANGL: 90 *val = be16_to_cpup(&st->rx) >> 4; 91 break; 92 case IIO_ANGL_VEL: 93 *val = sign_extend32(be16_to_cpup(&st->rx) >> 4, 11); 94 break; 95 default: 96 mutex_unlock(&st->lock); 97 return -EINVAL; 98 } 99 100 /* delay (2 * AD2S1200_TSCLK + 20) ns for sample pulse */ 101 udelay(1); 102 mutex_unlock(&st->lock); 103 104 return IIO_VAL_INT; 105 default: 106 break; 107 } 108 109 return -EINVAL; 110 } 111 112 static const struct iio_chan_spec ad2s1200_channels[] = { 113 { 114 .type = IIO_ANGL, 115 .indexed = 1, 116 .channel = 0, 117 .info_mask_separate = BIT(IIO_CHAN_INFO_RAW), 118 .info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE), 119 }, { 120 .type = IIO_ANGL_VEL, 121 .indexed = 1, 122 .channel = 0, 123 .info_mask_separate = BIT(IIO_CHAN_INFO_RAW), 124 .info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE), 125 } 126 }; 127 128 static const struct iio_info ad2s1200_info = { 129 .read_raw = ad2s1200_read_raw, 130 }; 131 132 static int ad2s1200_probe(struct spi_device *spi) 133 { 134 struct ad2s1200_state *st; 135 struct iio_dev *indio_dev; 136 int ret; 137 138 indio_dev = devm_iio_device_alloc(&spi->dev, sizeof(*st)); 139 if (!indio_dev) 140 return -ENOMEM; 141 142 spi_set_drvdata(spi, indio_dev); 143 st = iio_priv(indio_dev); 144 mutex_init(&st->lock); 145 st->sdev = spi; 146 147 st->sample = devm_gpiod_get(&spi->dev, "adi,sample", GPIOD_OUT_LOW); 148 if (IS_ERR(st->sample)) { 149 dev_err(&spi->dev, "Failed to claim SAMPLE gpio: err=%ld\n", 150 PTR_ERR(st->sample)); 151 return PTR_ERR(st->sample); 152 } 153 154 st->rdvel = devm_gpiod_get(&spi->dev, "adi,rdvel", GPIOD_OUT_LOW); 155 if (IS_ERR(st->rdvel)) { 156 dev_err(&spi->dev, "Failed to claim RDVEL gpio: err=%ld\n", 157 PTR_ERR(st->rdvel)); 158 return PTR_ERR(st->rdvel); 159 } 160 161 indio_dev->info = &ad2s1200_info; 162 indio_dev->modes = INDIO_DIRECT_MODE; 163 indio_dev->channels = ad2s1200_channels; 164 indio_dev->num_channels = ARRAY_SIZE(ad2s1200_channels); 165 indio_dev->name = spi_get_device_id(spi)->name; 166 167 spi->max_speed_hz = AD2S1200_HZ; 168 spi->mode = SPI_MODE_3; 169 ret = spi_setup(spi); 170 171 if (ret < 0) { 172 dev_err(&spi->dev, "spi_setup failed!\n"); 173 return ret; 174 } 175 176 return devm_iio_device_register(&spi->dev, indio_dev); 177 } 178 179 static const struct of_device_id ad2s1200_of_match[] = { 180 { .compatible = "adi,ad2s1200", }, 181 { .compatible = "adi,ad2s1205", }, 182 { } 183 }; 184 MODULE_DEVICE_TABLE(of, ad2s1200_of_match); 185 186 static const struct spi_device_id ad2s1200_id[] = { 187 { "ad2s1200" }, 188 { "ad2s1205" }, 189 {} 190 }; 191 MODULE_DEVICE_TABLE(spi, ad2s1200_id); 192 193 static struct spi_driver ad2s1200_driver = { 194 .driver = { 195 .name = DRV_NAME, 196 .of_match_table = ad2s1200_of_match, 197 }, 198 .probe = ad2s1200_probe, 199 .id_table = ad2s1200_id, 200 }; 201 module_spi_driver(ad2s1200_driver); 202 203 MODULE_AUTHOR("David Veenstra <davidjulianveenstra@gmail.com>"); 204 MODULE_AUTHOR("Graff Yang <graff.yang@gmail.com>"); 205 MODULE_DESCRIPTION("Analog Devices AD2S1200/1205 Resolver to Digital SPI driver"); 206 MODULE_LICENSE("GPL v2"); 207