diff options
Diffstat (limited to 'drivers/iio/adc/ad7949.c')
| -rw-r--r-- | drivers/iio/adc/ad7949.c | 254 |
1 files changed, 180 insertions, 74 deletions
diff --git a/drivers/iio/adc/ad7949.c b/drivers/iio/adc/ad7949.c index 1b4b3203e428..44bb5fde83de 100644 --- a/drivers/iio/adc/ad7949.c +++ b/drivers/iio/adc/ad7949.c @@ -11,12 +11,41 @@ #include <linux/module.h> #include <linux/regulator/consumer.h> #include <linux/spi/spi.h> +#include <linux/bitfield.h> -#define AD7949_MASK_CHANNEL_SEL GENMASK(9, 7) -#define AD7949_MASK_TOTAL GENMASK(13, 0) -#define AD7949_OFFSET_CHANNEL_SEL 7 -#define AD7949_CFG_READ_BACK 0x1 -#define AD7949_CFG_REG_SIZE_BITS 14 +#define AD7949_CFG_MASK_TOTAL GENMASK(13, 0) + +/* CFG: Configuration Update */ +#define AD7949_CFG_MASK_OVERWRITE BIT(13) + +/* INCC: Input Channel Configuration */ +#define AD7949_CFG_MASK_INCC GENMASK(12, 10) +#define AD7949_CFG_VAL_INCC_UNIPOLAR_GND 7 +#define AD7949_CFG_VAL_INCC_UNIPOLAR_COMM 6 +#define AD7949_CFG_VAL_INCC_UNIPOLAR_DIFF 4 +#define AD7949_CFG_VAL_INCC_TEMP 3 +#define AD7949_CFG_VAL_INCC_BIPOLAR 2 +#define AD7949_CFG_VAL_INCC_BIPOLAR_DIFF 0 + +/* INX: Input channel Selection in a binary fashion */ +#define AD7949_CFG_MASK_INX GENMASK(9, 7) + +/* BW: select bandwidth for low-pass filter. Full or Quarter */ +#define AD7949_CFG_MASK_BW_FULL BIT(6) + +/* REF: reference/buffer selection */ +#define AD7949_CFG_MASK_REF GENMASK(5, 3) +#define AD7949_CFG_VAL_REF_EXT_TEMP_BUF 3 +#define AD7949_CFG_VAL_REF_EXT_TEMP 2 +#define AD7949_CFG_VAL_REF_INT_4096 1 +#define AD7949_CFG_VAL_REF_INT_2500 0 +#define AD7949_CFG_VAL_REF_EXTERNAL BIT(1) + +/* SEQ: channel sequencer. Allows for scanning channels */ +#define AD7949_CFG_MASK_SEQ GENMASK(2, 1) + +/* RB: Read back the CFG register */ +#define AD7949_CFG_MASK_RBN BIT(0) enum { ID_AD7949 = 0, @@ -41,41 +70,51 @@ static const struct ad7949_adc_spec ad7949_adc_spec[] = { * @vref: regulator generating Vref * @indio_dev: reference to iio structure * @spi: reference to spi structure + * @refsel: reference selection * @resolution: resolution of the chip * @cfg: copy of the configuration register * @current_channel: current channel in use * @buffer: buffer to send / receive data to / from device + * @buf8b: be16 buffer to exchange data with the device in 8-bit transfers */ struct ad7949_adc_chip { struct mutex lock; struct regulator *vref; struct iio_dev *indio_dev; struct spi_device *spi; + u32 refsel; u8 resolution; u16 cfg; unsigned int current_channel; u16 buffer ____cacheline_aligned; + __be16 buf8b; }; static int ad7949_spi_write_cfg(struct ad7949_adc_chip *ad7949_adc, u16 val, u16 mask) { int ret; - int bits_per_word = ad7949_adc->resolution; - int shift = bits_per_word - AD7949_CFG_REG_SIZE_BITS; - struct spi_message msg; - struct spi_transfer tx[] = { - { - .tx_buf = &ad7949_adc->buffer, - .len = 2, - .bits_per_word = bits_per_word, - }, - }; ad7949_adc->cfg = (val & mask) | (ad7949_adc->cfg & ~mask); - ad7949_adc->buffer = ad7949_adc->cfg << shift; - spi_message_init_with_transfers(&msg, tx, 1); - ret = spi_sync(ad7949_adc->spi, &msg); + + switch (ad7949_adc->spi->bits_per_word) { + case 16: + ad7949_adc->buffer = ad7949_adc->cfg << 2; + ret = spi_write(ad7949_adc->spi, &ad7949_adc->buffer, 2); + break; + case 14: + ad7949_adc->buffer = ad7949_adc->cfg; + ret = spi_write(ad7949_adc->spi, &ad7949_adc->buffer, 2); + break; + case 8: + /* Here, type is big endian as it must be sent in two transfers */ + ad7949_adc->buf8b = cpu_to_be16(ad7949_adc->cfg << 2); + ret = spi_write(ad7949_adc->spi, &ad7949_adc->buf8b, 2); + break; + default: + dev_err(&ad7949_adc->indio_dev->dev, "unsupported BPW\n"); + return -EINVAL; + } /* * This delay is to avoid a new request before the required time to @@ -90,16 +129,6 @@ static int ad7949_spi_read_channel(struct ad7949_adc_chip *ad7949_adc, int *val, { int ret; int i; - int bits_per_word = ad7949_adc->resolution; - int mask = GENMASK(ad7949_adc->resolution - 1, 0); - struct spi_message msg; - struct spi_transfer tx[] = { - { - .rx_buf = &ad7949_adc->buffer, - .len = 2, - .bits_per_word = bits_per_word, - }, - }; /* * 1: write CFG for sample N and read old data (sample N-2) @@ -109,8 +138,8 @@ static int ad7949_spi_read_channel(struct ad7949_adc_chip *ad7949_adc, int *val, */ for (i = 0; i < 2; i++) { ret = ad7949_spi_write_cfg(ad7949_adc, - channel << AD7949_OFFSET_CHANNEL_SEL, - AD7949_MASK_CHANNEL_SEL); + FIELD_PREP(AD7949_CFG_MASK_INX, channel), + AD7949_CFG_MASK_INX); if (ret) return ret; if (channel == ad7949_adc->current_channel) @@ -118,9 +147,11 @@ static int ad7949_spi_read_channel(struct ad7949_adc_chip *ad7949_adc, int *val, } /* 3: write something and read actual data */ - ad7949_adc->buffer = 0; - spi_message_init_with_transfers(&msg, tx, 1); - ret = spi_sync(ad7949_adc->spi, &msg); + if (ad7949_adc->spi->bits_per_word == 8) + ret = spi_read(ad7949_adc->spi, &ad7949_adc->buf8b, 2); + else + ret = spi_read(ad7949_adc->spi, &ad7949_adc->buffer, 2); + if (ret) return ret; @@ -132,7 +163,25 @@ static int ad7949_spi_read_channel(struct ad7949_adc_chip *ad7949_adc, int *val, ad7949_adc->current_channel = channel; - *val = ad7949_adc->buffer & mask; + switch (ad7949_adc->spi->bits_per_word) { + case 16: + *val = ad7949_adc->buffer; + /* Shift-out padding bits */ + *val >>= 16 - ad7949_adc->resolution; + break; + case 14: + *val = ad7949_adc->buffer & GENMASK(13, 0); + break; + case 8: + /* Here, type is big endian as data was sent in two transfers */ + *val = be16_to_cpu(ad7949_adc->buf8b); + /* Shift-out padding bits */ + *val >>= 16 - ad7949_adc->resolution; + break; + default: + dev_err(&ad7949_adc->indio_dev->dev, "unsupported BPW\n"); + return -EINVAL; + } return 0; } @@ -178,12 +227,26 @@ static int ad7949_spi_read_raw(struct iio_dev *indio_dev, return IIO_VAL_INT; case IIO_CHAN_INFO_SCALE: - ret = regulator_get_voltage(ad7949_adc->vref); - if (ret < 0) - return ret; + switch (ad7949_adc->refsel) { + case AD7949_CFG_VAL_REF_INT_2500: + *val = 2500; + break; + case AD7949_CFG_VAL_REF_INT_4096: + *val = 4096; + break; + case AD7949_CFG_VAL_REF_EXT_TEMP: + case AD7949_CFG_VAL_REF_EXT_TEMP_BUF: + ret = regulator_get_voltage(ad7949_adc->vref); + if (ret < 0) + return ret; + + /* convert value back to mV */ + *val = ret / 1000; + break; + } - *val = ret / 5000; - return IIO_VAL_INT; + *val2 = (1 << ad7949_adc->resolution) - 1; + return IIO_VAL_FRACTIONAL; } return -EINVAL; @@ -199,8 +262,8 @@ static int ad7949_spi_reg_access(struct iio_dev *indio_dev, if (readval) *readval = ad7949_adc->cfg; else - ret = ad7949_spi_write_cfg(ad7949_adc, - writeval & AD7949_MASK_TOTAL, AD7949_MASK_TOTAL); + ret = ad7949_spi_write_cfg(ad7949_adc, writeval, + AD7949_CFG_MASK_TOTAL); return ret; } @@ -214,10 +277,19 @@ static int ad7949_spi_init(struct ad7949_adc_chip *ad7949_adc) { int ret; int val; + u16 cfg; - /* Sequencer disabled, CFG readback disabled, IN0 as default channel */ ad7949_adc->current_channel = 0; - ret = ad7949_spi_write_cfg(ad7949_adc, 0x3C79, AD7949_MASK_TOTAL); + + cfg = FIELD_PREP(AD7949_CFG_MASK_OVERWRITE, 1) | + FIELD_PREP(AD7949_CFG_MASK_INCC, AD7949_CFG_VAL_INCC_UNIPOLAR_GND) | + FIELD_PREP(AD7949_CFG_MASK_INX, ad7949_adc->current_channel) | + FIELD_PREP(AD7949_CFG_MASK_BW_FULL, 1) | + FIELD_PREP(AD7949_CFG_MASK_REF, ad7949_adc->refsel) | + FIELD_PREP(AD7949_CFG_MASK_SEQ, 0x0) | + FIELD_PREP(AD7949_CFG_MASK_RBN, 1); + + ret = ad7949_spi_write_cfg(ad7949_adc, cfg, AD7949_CFG_MASK_TOTAL); /* * Do two dummy conversions to apply the first configuration setting. @@ -229,12 +301,19 @@ static int ad7949_spi_init(struct ad7949_adc_chip *ad7949_adc) return ret; } +static void ad7949_disable_reg(void *reg) +{ + regulator_disable(reg); +} + static int ad7949_spi_probe(struct spi_device *spi) { + u32 spi_ctrl_mask = spi->controller->bits_per_word_mask; struct device *dev = &spi->dev; const struct ad7949_adc_spec *spec; struct ad7949_adc_chip *ad7949_adc; struct iio_dev *indio_dev; + u32 tmp; int ret; indio_dev = devm_iio_device_alloc(dev, sizeof(*ad7949_adc)); @@ -257,16 +336,64 @@ static int ad7949_spi_probe(struct spi_device *spi) indio_dev->num_channels = spec->num_channels; ad7949_adc->resolution = spec->resolution; - ad7949_adc->vref = devm_regulator_get(dev, "vref"); + /* Set SPI bits per word */ + if (spi_ctrl_mask & SPI_BPW_MASK(ad7949_adc->resolution)) { + spi->bits_per_word = ad7949_adc->resolution; + } else if (spi_ctrl_mask == SPI_BPW_MASK(16)) { + spi->bits_per_word = 16; + } else if (spi_ctrl_mask == SPI_BPW_MASK(8)) { + spi->bits_per_word = 8; + } else { + dev_err(dev, "unable to find common BPW with spi controller\n"); + return -EINVAL; + } + + /* Setup internal voltage reference */ + tmp = 4096000; + device_property_read_u32(dev, "adi,internal-ref-microvolt", &tmp); + + switch (tmp) { + case 2500000: + ad7949_adc->refsel = AD7949_CFG_VAL_REF_INT_2500; + break; + case 4096000: + ad7949_adc->refsel = AD7949_CFG_VAL_REF_INT_4096; + break; + default: + dev_err(dev, "unsupported internal voltage reference\n"); + return -EINVAL; + } + + /* Setup external voltage reference, buffered? */ + ad7949_adc->vref = devm_regulator_get_optional(dev, "vrefin"); if (IS_ERR(ad7949_adc->vref)) { - dev_err(dev, "fail to request regulator\n"); - return PTR_ERR(ad7949_adc->vref); + ret = PTR_ERR(ad7949_adc->vref); + if (ret != -ENODEV) + return ret; + /* unbuffered? */ + ad7949_adc->vref = devm_regulator_get_optional(dev, "vref"); + if (IS_ERR(ad7949_adc->vref)) { + ret = PTR_ERR(ad7949_adc->vref); + if (ret != -ENODEV) + return ret; + } else { + ad7949_adc->refsel = AD7949_CFG_VAL_REF_EXT_TEMP; + } + } else { + ad7949_adc->refsel = AD7949_CFG_VAL_REF_EXT_TEMP_BUF; } - ret = regulator_enable(ad7949_adc->vref); - if (ret < 0) { - dev_err(dev, "fail to enable regulator\n"); - return ret; + if (ad7949_adc->refsel & AD7949_CFG_VAL_REF_EXTERNAL) { + ret = regulator_enable(ad7949_adc->vref); + if (ret < 0) { + dev_err(dev, "fail to enable regulator\n"); + return ret; + } + + ret = devm_add_action_or_reset(dev, ad7949_disable_reg, + ad7949_adc->vref); + if (ret) + return ret; } mutex_init(&ad7949_adc->lock); @@ -274,36 +401,16 @@ static int ad7949_spi_probe(struct spi_device *spi) ret = ad7949_spi_init(ad7949_adc); if (ret) { dev_err(dev, "enable to init this device: %d\n", ret); - goto err; + return ret; } - ret = iio_device_register(indio_dev); - if (ret) { + ret = devm_iio_device_register(dev, indio_dev); + if (ret) dev_err(dev, "fail to register iio device: %d\n", ret); - goto err; - } - - return 0; - -err: - mutex_destroy(&ad7949_adc->lock); - regulator_disable(ad7949_adc->vref); return ret; } -static int ad7949_spi_remove(struct spi_device *spi) -{ - struct iio_dev *indio_dev = spi_get_drvdata(spi); - struct ad7949_adc_chip *ad7949_adc = iio_priv(indio_dev); - - iio_device_unregister(indio_dev); - mutex_destroy(&ad7949_adc->lock); - regulator_disable(ad7949_adc->vref); - - return 0; -} - static const struct of_device_id ad7949_spi_of_id[] = { { .compatible = "adi,ad7949" }, { .compatible = "adi,ad7682" }, @@ -326,7 +433,6 @@ static struct spi_driver ad7949_spi_driver = { .of_match_table = ad7949_spi_of_id, }, .probe = ad7949_spi_probe, - .remove = ad7949_spi_remove, .id_table = ad7949_spi_id, }; module_spi_driver(ad7949_spi_driver); |