Michael Hennerich | e71d42e | 2012-05-11 11:36:54 +0200 | [diff] [blame] | 1 | /* |
| 2 | * AD8366 SPI Dual-Digital Variable Gain Amplifier (VGA) |
| 3 | * |
| 4 | * Copyright 2012 Analog Devices Inc. |
| 5 | * |
| 6 | * Licensed under the GPL-2. |
| 7 | */ |
| 8 | |
| 9 | #include <linux/device.h> |
| 10 | #include <linux/kernel.h> |
| 11 | #include <linux/slab.h> |
| 12 | #include <linux/sysfs.h> |
| 13 | #include <linux/spi/spi.h> |
| 14 | #include <linux/regulator/consumer.h> |
| 15 | #include <linux/err.h> |
| 16 | #include <linux/module.h> |
| 17 | #include <linux/bitrev.h> |
| 18 | |
| 19 | #include <linux/iio/iio.h> |
| 20 | #include <linux/iio/sysfs.h> |
| 21 | |
| 22 | struct ad8366_state { |
| 23 | struct spi_device *spi; |
| 24 | struct regulator *reg; |
| 25 | unsigned char ch[2]; |
| 26 | /* |
| 27 | * DMA (thus cache coherency maintenance) requires the |
| 28 | * transfer buffers to live in their own cache lines. |
| 29 | */ |
| 30 | unsigned char data[2] ____cacheline_aligned; |
| 31 | }; |
| 32 | |
| 33 | static int ad8366_write(struct iio_dev *indio_dev, |
| 34 | unsigned char ch_a, char unsigned ch_b) |
| 35 | { |
| 36 | struct ad8366_state *st = iio_priv(indio_dev); |
| 37 | int ret; |
| 38 | |
| 39 | ch_a = bitrev8(ch_a & 0x3F); |
| 40 | ch_b = bitrev8(ch_b & 0x3F); |
| 41 | |
| 42 | st->data[0] = ch_b >> 4; |
| 43 | st->data[1] = (ch_b << 4) | (ch_a >> 2); |
| 44 | |
| 45 | ret = spi_write(st->spi, st->data, ARRAY_SIZE(st->data)); |
| 46 | if (ret < 0) |
| 47 | dev_err(&indio_dev->dev, "write failed (%d)", ret); |
| 48 | |
| 49 | return ret; |
| 50 | } |
| 51 | |
| 52 | static int ad8366_read_raw(struct iio_dev *indio_dev, |
| 53 | struct iio_chan_spec const *chan, |
| 54 | int *val, |
| 55 | int *val2, |
| 56 | long m) |
| 57 | { |
| 58 | struct ad8366_state *st = iio_priv(indio_dev); |
| 59 | int ret; |
| 60 | unsigned code; |
| 61 | |
| 62 | mutex_lock(&indio_dev->mlock); |
| 63 | switch (m) { |
| 64 | case IIO_CHAN_INFO_HARDWAREGAIN: |
| 65 | code = st->ch[chan->channel]; |
| 66 | |
| 67 | /* Values in dB */ |
| 68 | code = code * 253 + 4500; |
| 69 | *val = code / 1000; |
| 70 | *val2 = (code % 1000) * 1000; |
| 71 | |
| 72 | ret = IIO_VAL_INT_PLUS_MICRO_DB; |
| 73 | break; |
| 74 | default: |
| 75 | ret = -EINVAL; |
| 76 | } |
| 77 | mutex_unlock(&indio_dev->mlock); |
| 78 | |
| 79 | return ret; |
| 80 | }; |
| 81 | |
| 82 | static int ad8366_write_raw(struct iio_dev *indio_dev, |
| 83 | struct iio_chan_spec const *chan, |
| 84 | int val, |
| 85 | int val2, |
| 86 | long mask) |
| 87 | { |
| 88 | struct ad8366_state *st = iio_priv(indio_dev); |
| 89 | unsigned code; |
| 90 | int ret; |
| 91 | |
| 92 | if (val < 0 || val2 < 0) |
| 93 | return -EINVAL; |
| 94 | |
| 95 | /* Values in dB */ |
| 96 | code = (((u8)val * 1000) + ((u32)val2 / 1000)); |
| 97 | |
| 98 | if (code > 20500 || code < 4500) |
| 99 | return -EINVAL; |
| 100 | |
| 101 | code = (code - 4500) / 253; |
| 102 | |
| 103 | mutex_lock(&indio_dev->mlock); |
| 104 | switch (mask) { |
| 105 | case IIO_CHAN_INFO_HARDWAREGAIN: |
| 106 | st->ch[chan->channel] = code; |
| 107 | ret = ad8366_write(indio_dev, st->ch[0], st->ch[1]); |
| 108 | break; |
| 109 | default: |
| 110 | ret = -EINVAL; |
| 111 | } |
| 112 | mutex_unlock(&indio_dev->mlock); |
| 113 | |
| 114 | return ret; |
| 115 | } |
| 116 | |
| 117 | static const struct iio_info ad8366_info = { |
| 118 | .read_raw = &ad8366_read_raw, |
| 119 | .write_raw = &ad8366_write_raw, |
| 120 | .driver_module = THIS_MODULE, |
| 121 | }; |
| 122 | |
| 123 | #define AD8366_CHAN(_channel) { \ |
| 124 | .type = IIO_VOLTAGE, \ |
| 125 | .output = 1, \ |
| 126 | .indexed = 1, \ |
| 127 | .channel = _channel, \ |
| 128 | .info_mask = IIO_CHAN_INFO_HARDWAREGAIN_SEPARATE_BIT,\ |
| 129 | } |
| 130 | |
| 131 | static const struct iio_chan_spec ad8366_channels[] = { |
| 132 | AD8366_CHAN(0), |
| 133 | AD8366_CHAN(1), |
| 134 | }; |
| 135 | |
| 136 | static int __devinit ad8366_probe(struct spi_device *spi) |
| 137 | { |
| 138 | struct iio_dev *indio_dev; |
| 139 | struct ad8366_state *st; |
| 140 | int ret; |
| 141 | |
| 142 | indio_dev = iio_device_alloc(sizeof(*st)); |
| 143 | if (indio_dev == NULL) |
| 144 | return -ENOMEM; |
| 145 | |
| 146 | st = iio_priv(indio_dev); |
| 147 | |
| 148 | st->reg = regulator_get(&spi->dev, "vcc"); |
| 149 | if (!IS_ERR(st->reg)) { |
| 150 | ret = regulator_enable(st->reg); |
| 151 | if (ret) |
| 152 | goto error_put_reg; |
| 153 | } |
| 154 | |
| 155 | spi_set_drvdata(spi, indio_dev); |
| 156 | st->spi = spi; |
| 157 | |
| 158 | indio_dev->dev.parent = &spi->dev; |
| 159 | indio_dev->name = spi_get_device_id(spi)->name; |
| 160 | indio_dev->info = &ad8366_info; |
| 161 | indio_dev->modes = INDIO_DIRECT_MODE; |
| 162 | indio_dev->channels = ad8366_channels; |
| 163 | indio_dev->num_channels = ARRAY_SIZE(ad8366_channels); |
| 164 | |
| 165 | ret = iio_device_register(indio_dev); |
| 166 | if (ret) |
| 167 | goto error_disable_reg; |
| 168 | |
| 169 | ad8366_write(indio_dev, 0 , 0); |
| 170 | |
| 171 | return 0; |
| 172 | |
| 173 | error_disable_reg: |
| 174 | if (!IS_ERR(st->reg)) |
| 175 | regulator_disable(st->reg); |
| 176 | error_put_reg: |
| 177 | if (!IS_ERR(st->reg)) |
| 178 | regulator_put(st->reg); |
| 179 | |
| 180 | iio_device_free(indio_dev); |
| 181 | |
| 182 | return ret; |
| 183 | } |
| 184 | |
| 185 | static int __devexit ad8366_remove(struct spi_device *spi) |
| 186 | { |
| 187 | struct iio_dev *indio_dev = spi_get_drvdata(spi); |
| 188 | struct ad8366_state *st = iio_priv(indio_dev); |
| 189 | struct regulator *reg = st->reg; |
| 190 | |
| 191 | iio_device_unregister(indio_dev); |
| 192 | |
| 193 | if (!IS_ERR(reg)) { |
| 194 | regulator_disable(reg); |
| 195 | regulator_put(reg); |
| 196 | } |
| 197 | |
| 198 | iio_device_free(indio_dev); |
| 199 | |
| 200 | return 0; |
| 201 | } |
| 202 | |
| 203 | static const struct spi_device_id ad8366_id[] = { |
| 204 | {"ad8366", 0}, |
| 205 | {} |
| 206 | }; |
| 207 | |
| 208 | static struct spi_driver ad8366_driver = { |
| 209 | .driver = { |
| 210 | .name = KBUILD_MODNAME, |
| 211 | .owner = THIS_MODULE, |
| 212 | }, |
| 213 | .probe = ad8366_probe, |
| 214 | .remove = __devexit_p(ad8366_remove), |
| 215 | .id_table = ad8366_id, |
| 216 | }; |
| 217 | |
| 218 | module_spi_driver(ad8366_driver); |
| 219 | |
| 220 | MODULE_AUTHOR("Michael Hennerich <hennerich@blackfin.uclinux.org>"); |
| 221 | MODULE_DESCRIPTION("Analog Devices AD8366 VGA"); |
| 222 | MODULE_LICENSE("GPL v2"); |