diff options
Diffstat (limited to 'drivers/iio/adc/mcp3911.c')
| -rw-r--r-- | drivers/iio/adc/mcp3911.c | 257 |
1 files changed, 216 insertions, 41 deletions
diff --git a/drivers/iio/adc/mcp3911.c b/drivers/iio/adc/mcp3911.c index 890af7dca62d..b35fd2c9c3c0 100644 --- a/drivers/iio/adc/mcp3911.c +++ b/drivers/iio/adc/mcp3911.c @@ -5,16 +5,25 @@ * Copyright (C) 2018 Marcus Folkesson <marcus.folkesson@gmail.com> * Copyright (C) 2018 Kent Gustavsson <kent@minoris.se> */ +#include <linux/bitfield.h> +#include <linux/bits.h> #include <linux/clk.h> #include <linux/delay.h> #include <linux/err.h> -#include <linux/iio/iio.h> #include <linux/module.h> #include <linux/mod_devicetable.h> #include <linux/property.h> #include <linux/regulator/consumer.h> #include <linux/spi/spi.h> +#include <linux/iio/iio.h> +#include <linux/iio/buffer.h> +#include <linux/iio/triggered_buffer.h> +#include <linux/iio/trigger_consumer.h> +#include <linux/iio/trigger.h> + +#include <asm/unaligned.h> + #define MCP3911_REG_CHANNEL0 0x00 #define MCP3911_REG_CHANNEL1 0x03 #define MCP3911_REG_MOD 0x06 @@ -22,6 +31,8 @@ #define MCP3911_REG_GAIN 0x09 #define MCP3911_REG_STATUSCOM 0x0a +#define MCP3911_STATUSCOM_DRHIZ BIT(12) +#define MCP3911_STATUSCOM_READ GENMASK(7, 6) #define MCP3911_STATUSCOM_CH1_24WIDTH BIT(4) #define MCP3911_STATUSCOM_CH0_24WIDTH BIT(3) #define MCP3911_STATUSCOM_EN_OFFCAL BIT(2) @@ -30,6 +41,7 @@ #define MCP3911_REG_CONFIG 0x0c #define MCP3911_CONFIG_CLKEXT BIT(1) #define MCP3911_CONFIG_VREFEXT BIT(2) +#define MCP3911_CONFIG_OSR GENMASK(13, 11) #define MCP3911_REG_OFFCAL_CH0 0x0e #define MCP3911_REG_GAINCAL_CH0 0x11 @@ -48,12 +60,22 @@ #define MCP3911_NUM_CHANNELS 2 +static const int mcp3911_osr_table[] = { 32, 64, 128, 256, 512, 1024, 2048, 4096 }; + struct mcp3911 { struct spi_device *spi; struct mutex lock; struct regulator *vref; struct clk *clki; u32 dev_addr; + struct iio_trigger *trig; + struct { + u32 channels[MCP3911_NUM_CHANNELS]; + s64 ts __aligned(8); + } scan; + + u8 tx_buf __aligned(IIO_DMA_MINALIGN); + u8 rx_buf[MCP3911_NUM_CHANNELS * 3]; }; static int mcp3911_read(struct mcp3911 *adc, u8 reg, u32 *val, u8 len) @@ -98,6 +120,36 @@ static int mcp3911_update(struct mcp3911 *adc, u8 reg, u32 mask, return mcp3911_write(adc, reg, val, len); } +static int mcp3911_write_raw_get_fmt(struct iio_dev *indio_dev, + struct iio_chan_spec const *chan, + long mask) +{ + switch (mask) { + case IIO_CHAN_INFO_SCALE: + return IIO_VAL_INT_PLUS_NANO; + case IIO_CHAN_INFO_OVERSAMPLING_RATIO: + return IIO_VAL_INT; + default: + return IIO_VAL_INT_PLUS_NANO; + } +} + +static int mcp3911_read_avail(struct iio_dev *indio_dev, + struct iio_chan_spec const *chan, + const int **vals, int *type, int *length, + long info) +{ + switch (info) { + case IIO_CHAN_INFO_OVERSAMPLING_RATIO: + *type = IIO_VAL_INT; + *vals = mcp3911_osr_table; + *length = ARRAY_SIZE(mcp3911_osr_table); + return IIO_AVAIL_LIST; + default: + return -EINVAL; + } +} + static int mcp3911_read_raw(struct iio_dev *indio_dev, struct iio_chan_spec const *channel, int *val, int *val2, long mask) @@ -126,6 +178,15 @@ static int mcp3911_read_raw(struct iio_dev *indio_dev, ret = IIO_VAL_INT; break; + case IIO_CHAN_INFO_OVERSAMPLING_RATIO: + ret = mcp3911_read(adc, MCP3911_REG_CONFIG, val, 2); + if (ret) + goto out; + + *val = FIELD_GET(MCP3911_CONFIG_OSR, *val); + *val = 32 << *val; + ret = IIO_VAL_INT; + break; case IIO_CHAN_INFO_SCALE: if (adc->vref) { @@ -185,6 +246,17 @@ static int mcp3911_write_raw(struct iio_dev *indio_dev, MCP3911_STATUSCOM_EN_OFFCAL, MCP3911_STATUSCOM_EN_OFFCAL, 2); break; + + case IIO_CHAN_INFO_OVERSAMPLING_RATIO: + for (int i = 0; i < sizeof(mcp3911_osr_table); i++) { + if (val == mcp3911_osr_table[i]) { + val = FIELD_PREP(MCP3911_CONFIG_OSR, i); + ret = mcp3911_update(adc, MCP3911_REG_CONFIG, MCP3911_CONFIG_OSR, + val, 2); + break; + } + } + break; } out: @@ -196,25 +268,80 @@ out: .type = IIO_VOLTAGE, \ .indexed = 1, \ .channel = idx, \ + .scan_index = idx, \ + .info_mask_shared_by_type = BIT(IIO_CHAN_INFO_OVERSAMPLING_RATIO), \ .info_mask_separate = BIT(IIO_CHAN_INFO_RAW) | \ BIT(IIO_CHAN_INFO_OFFSET) | \ BIT(IIO_CHAN_INFO_SCALE), \ + .info_mask_shared_by_type_available = \ + BIT(IIO_CHAN_INFO_OVERSAMPLING_RATIO), \ + .scan_type = { \ + .sign = 's', \ + .realbits = 24, \ + .storagebits = 32, \ + .endianness = IIO_BE, \ + }, \ } static const struct iio_chan_spec mcp3911_channels[] = { MCP3911_CHAN(0), MCP3911_CHAN(1), + IIO_CHAN_SOFT_TIMESTAMP(2), }; +static irqreturn_t mcp3911_trigger_handler(int irq, void *p) +{ + struct iio_poll_func *pf = p; + struct iio_dev *indio_dev = pf->indio_dev; + struct mcp3911 *adc = iio_priv(indio_dev); + struct spi_transfer xfer[] = { + { + .tx_buf = &adc->tx_buf, + .len = 1, + }, { + .rx_buf = adc->rx_buf, + .len = sizeof(adc->rx_buf), + }, + }; + int scan_index; + int i = 0; + int ret; + + mutex_lock(&adc->lock); + adc->tx_buf = MCP3911_REG_READ(MCP3911_CHANNEL(0), adc->dev_addr); + ret = spi_sync_transfer(adc->spi, xfer, ARRAY_SIZE(xfer)); + if (ret < 0) { + dev_warn(&adc->spi->dev, + "failed to get conversion data\n"); + goto out; + } + + for_each_set_bit(scan_index, indio_dev->active_scan_mask, indio_dev->masklength) { + const struct iio_chan_spec *scan_chan = &indio_dev->channels[scan_index]; + + adc->scan.channels[i] = get_unaligned_be24(&adc->rx_buf[scan_chan->channel * 3]); + i++; + } + iio_push_to_buffers_with_timestamp(indio_dev, &adc->scan, + iio_get_time_ns(indio_dev)); +out: + mutex_unlock(&adc->lock); + iio_trigger_notify_done(indio_dev->trig); + + return IRQ_HANDLED; +} + static const struct iio_info mcp3911_info = { .read_raw = mcp3911_read_raw, .write_raw = mcp3911_write_raw, + .read_avail = mcp3911_read_avail, + .write_raw_get_fmt = mcp3911_write_raw_get_fmt, }; static int mcp3911_config(struct mcp3911 *adc) { struct device *dev = &adc->spi->dev; - u32 configreg; + u32 regval; int ret; ret = device_property_read_u32(dev, "microchip,device-addr", &adc->dev_addr); @@ -233,31 +360,67 @@ static int mcp3911_config(struct mcp3911 *adc) } dev_dbg(&adc->spi->dev, "use device address %i\n", adc->dev_addr); - ret = mcp3911_read(adc, MCP3911_REG_CONFIG, &configreg, 2); + ret = mcp3911_read(adc, MCP3911_REG_CONFIG, ®val, 2); if (ret) return ret; + regval &= ~MCP3911_CONFIG_VREFEXT; if (adc->vref) { dev_dbg(&adc->spi->dev, "use external voltage reference\n"); - configreg |= MCP3911_CONFIG_VREFEXT; + regval |= FIELD_PREP(MCP3911_CONFIG_VREFEXT, 1); } else { dev_dbg(&adc->spi->dev, "use internal voltage reference (1.2V)\n"); - configreg &= ~MCP3911_CONFIG_VREFEXT; + regval |= FIELD_PREP(MCP3911_CONFIG_VREFEXT, 0); } + regval &= ~MCP3911_CONFIG_CLKEXT; if (adc->clki) { dev_dbg(&adc->spi->dev, "use external clock as clocksource\n"); - configreg |= MCP3911_CONFIG_CLKEXT; + regval |= FIELD_PREP(MCP3911_CONFIG_CLKEXT, 1); } else { dev_dbg(&adc->spi->dev, "use crystal oscillator as clocksource\n"); - configreg &= ~MCP3911_CONFIG_CLKEXT; + regval |= FIELD_PREP(MCP3911_CONFIG_CLKEXT, 0); } - return mcp3911_write(adc, MCP3911_REG_CONFIG, configreg, 2); + ret = mcp3911_write(adc, MCP3911_REG_CONFIG, regval, 2); + if (ret) + return ret; + + ret = mcp3911_read(adc, MCP3911_REG_STATUSCOM, ®val, 2); + if (ret) + return ret; + + /* Address counter incremented, cycle through register types */ + regval &= ~MCP3911_STATUSCOM_READ; + regval |= FIELD_PREP(MCP3911_STATUSCOM_READ, 0x02); + + return mcp3911_write(adc, MCP3911_REG_STATUSCOM, regval, 2); } +static void mcp3911_cleanup_regulator(void *vref) +{ + regulator_disable(vref); +} + +static int mcp3911_set_trigger_state(struct iio_trigger *trig, bool enable) +{ + struct mcp3911 *adc = iio_trigger_get_drvdata(trig); + + if (enable) + enable_irq(adc->spi->irq); + else + disable_irq(adc->spi->irq); + + return 0; +} + +static const struct iio_trigger_ops mcp3911_trigger_ops = { + .validate_device = iio_trigger_validate_own_device, + .set_trigger_state = mcp3911_set_trigger_state, +}; + static int mcp3911_probe(struct spi_device *spi) { struct iio_dev *indio_dev; @@ -286,9 +449,14 @@ static int mcp3911_probe(struct spi_device *spi) ret = regulator_enable(adc->vref); if (ret) return ret; + + ret = devm_add_action_or_reset(&spi->dev, + mcp3911_cleanup_regulator, adc->vref); + if (ret) + return ret; } - adc->clki = devm_clk_get(&adc->spi->dev, NULL); + adc->clki = devm_clk_get_enabled(&adc->spi->dev, NULL); if (IS_ERR(adc->clki)) { if (PTR_ERR(adc->clki) == -ENOENT) { adc->clki = NULL; @@ -296,21 +464,22 @@ static int mcp3911_probe(struct spi_device *spi) dev_err(&adc->spi->dev, "failed to get adc clk (%ld)\n", PTR_ERR(adc->clki)); - ret = PTR_ERR(adc->clki); - goto reg_disable; - } - } else { - ret = clk_prepare_enable(adc->clki); - if (ret < 0) { - dev_err(&adc->spi->dev, - "Failed to enable clki: %d\n", ret); - goto reg_disable; + return PTR_ERR(adc->clki); } } ret = mcp3911_config(adc); if (ret) - goto clk_disable; + return ret; + + if (device_property_read_bool(&adc->spi->dev, "microchip,data-ready-hiz")) + ret = mcp3911_update(adc, MCP3911_REG_STATUSCOM, MCP3911_STATUSCOM_DRHIZ, + 0, 2); + else + ret = mcp3911_update(adc, MCP3911_REG_STATUSCOM, MCP3911_STATUSCOM_DRHIZ, + MCP3911_STATUSCOM_DRHIZ, 2); + if (ret) + return ret; indio_dev->name = spi_get_device_id(spi)->name; indio_dev->modes = INDIO_DIRECT_MODE; @@ -322,31 +491,38 @@ static int mcp3911_probe(struct spi_device *spi) mutex_init(&adc->lock); - ret = iio_device_register(indio_dev); - if (ret) - goto clk_disable; - - return ret; - -clk_disable: - clk_disable_unprepare(adc->clki); -reg_disable: - if (adc->vref) - regulator_disable(adc->vref); + if (spi->irq > 0) { + adc->trig = devm_iio_trigger_alloc(&spi->dev, "%s-dev%d", + indio_dev->name, + iio_device_id(indio_dev)); + if (!adc->trig) + return PTR_ERR(adc->trig); - return ret; -} + adc->trig->ops = &mcp3911_trigger_ops; + iio_trigger_set_drvdata(adc->trig, adc); + ret = devm_iio_trigger_register(&spi->dev, adc->trig); + if (ret) + return ret; -static void mcp3911_remove(struct spi_device *spi) -{ - struct iio_dev *indio_dev = spi_get_drvdata(spi); - struct mcp3911 *adc = iio_priv(indio_dev); + /* + * The device generates interrupts as long as it is powered up. + * Some platforms might not allow the option to power it down so + * don't enable the interrupt to avoid extra load on the system. + */ + ret = devm_request_irq(&spi->dev, spi->irq, + &iio_trigger_generic_data_rdy_poll, IRQF_NO_AUTOEN | IRQF_ONESHOT, + indio_dev->name, adc->trig); + if (ret) + return ret; + } - iio_device_unregister(indio_dev); + ret = devm_iio_triggered_buffer_setup(&spi->dev, indio_dev, + NULL, + mcp3911_trigger_handler, NULL); + if (ret) + return ret; - clk_disable_unprepare(adc->clki); - if (adc->vref) - regulator_disable(adc->vref); + return devm_iio_device_register(&adc->spi->dev, indio_dev); } static const struct of_device_id mcp3911_dt_ids[] = { @@ -367,7 +543,6 @@ static struct spi_driver mcp3911_driver = { .of_match_table = mcp3911_dt_ids, }, .probe = mcp3911_probe, - .remove = mcp3911_remove, .id_table = mcp3911_id, }; module_spi_driver(mcp3911_driver); |