diff options
Diffstat (limited to 'drivers/iio/adc/mcp3911.c')
| -rw-r--r-- | drivers/iio/adc/mcp3911.c | 127 |
1 files changed, 74 insertions, 53 deletions
diff --git a/drivers/iio/adc/mcp3911.c b/drivers/iio/adc/mcp3911.c index 7a32e7a1be9d..a6f21791c685 100644 --- a/drivers/iio/adc/mcp3911.c +++ b/drivers/iio/adc/mcp3911.c @@ -6,11 +6,13 @@ * Copyright (C) 2018 Kent Gustavsson <kent@minoris.se> */ #include <linux/bitfield.h> -#include <linux/bits.h> +#include <linux/bitops.h> #include <linux/cleanup.h> #include <linux/clk.h> #include <linux/delay.h> +#include <linux/dev_printk.h> #include <linux/err.h> +#include <linux/gpio/consumer.h> #include <linux/module.h> #include <linux/mod_devicetable.h> #include <linux/property.h> @@ -23,7 +25,7 @@ #include <linux/iio/trigger_consumer.h> #include <linux/iio/trigger.h> -#include <asm/unaligned.h> +#include <linux/unaligned.h> #define MCP3911_REG_CHANNEL0 0x00 #define MCP3911_REG_CHANNEL1 0x03 @@ -79,6 +81,8 @@ #define MCP3910_CONFIG1_CLKEXT BIT(6) #define MCP3910_CONFIG1_VREFEXT BIT(7) +#define MCP3910_CHANNEL(ch) (MCP3911_REG_CHANNEL0 + (ch)) + #define MCP3910_REG_OFFCAL_CH0 0x0f #define MCP3910_OFFCAL(ch) (MCP3910_REG_OFFCAL_CH0 + (ch) * 6) @@ -103,19 +107,19 @@ struct mcp3911_chip_info { const struct iio_chan_spec *channels; unsigned int num_channels; - int (*config)(struct mcp3911 *adc); + int (*config)(struct mcp3911 *adc, bool external_vref); int (*get_osr)(struct mcp3911 *adc, u32 *val); int (*set_osr)(struct mcp3911 *adc, u32 val); int (*enable_offset)(struct mcp3911 *adc, bool enable); int (*get_offset)(struct mcp3911 *adc, int channel, int *val); int (*set_offset)(struct mcp3911 *adc, int channel, int val); int (*set_scale)(struct mcp3911 *adc, int channel, u32 val); + int (*get_raw)(struct mcp3911 *adc, int channel, int *val); }; struct mcp3911 { struct spi_device *spi; struct mutex lock; - struct regulator *vref; struct clk *clki; u32 dev_addr; struct iio_trigger *trig; @@ -123,7 +127,7 @@ struct mcp3911 { const struct mcp3911_chip_info *chip; struct { u32 channels[MCP39XX_MAX_NUM_CHANNELS]; - s64 ts __aligned(8); + aligned_s64 ts; } scan; u8 tx_buf __aligned(IIO_DMA_MINALIGN); @@ -171,6 +175,18 @@ static int mcp3911_update(struct mcp3911 *adc, u8 reg, u32 mask, u32 val, u8 len return mcp3911_write(adc, reg, val, len); } +static int mcp3911_read_s24(struct mcp3911 *const adc, u8 const reg, s32 *const val) +{ + u32 uval; + int const ret = mcp3911_read(adc, reg, &uval, 3); + + if (ret) + return ret; + + *val = sign_extend32(uval, 23); + return ret; +} + static int mcp3910_enable_offset(struct mcp3911 *adc, bool enable) { unsigned int mask = MCP3910_CONFIG0_EN_OFFCAL; @@ -195,6 +211,11 @@ static int mcp3910_set_offset(struct mcp3911 *adc, int channel, int val) return adc->chip->enable_offset(adc, 1); } +static int mcp3910_get_raw(struct mcp3911 *adc, int channel, s32 *val) +{ + return mcp3911_read_s24(adc, MCP3910_CHANNEL(channel), val); +} + static int mcp3911_enable_offset(struct mcp3911 *adc, bool enable) { unsigned int mask = MCP3911_STATUSCOM_EN_OFFCAL; @@ -219,6 +240,11 @@ static int mcp3911_set_offset(struct mcp3911 *adc, int channel, int val) return adc->chip->enable_offset(adc, 1); } +static int mcp3911_get_raw(struct mcp3911 *adc, int channel, s32 *val) +{ + return mcp3911_read_s24(adc, MCP3911_CHANNEL(channel), val); +} + static int mcp3910_get_osr(struct mcp3911 *adc, u32 *val) { int ret; @@ -322,12 +348,9 @@ static int mcp3911_read_raw(struct iio_dev *indio_dev, guard(mutex)(&adc->lock); switch (mask) { case IIO_CHAN_INFO_RAW: - ret = mcp3911_read(adc, - MCP3911_CHANNEL(channel->channel), val, 3); + ret = adc->chip->get_raw(adc, channel->channel, val); if (ret) return ret; - - *val = sign_extend32(*val, 23); return IIO_VAL_INT; case IIO_CHAN_INFO_OFFSET: ret = adc->chip->get_offset(adc, channel->channel, val); @@ -385,23 +408,11 @@ static int mcp3911_write_raw(struct iio_dev *indio_dev, } } -static int mcp3911_calc_scale_table(struct mcp3911 *adc) +static int mcp3911_calc_scale_table(u32 vref_mv) { - struct device *dev = &adc->spi->dev; - u32 ref = MCP3911_INT_VREF_MV; u32 div; - int ret; u64 tmp; - if (adc->vref) { - ret = regulator_get_voltage(adc->vref); - if (ret < 0) { - return dev_err_probe(dev, ret, "failed to get vref voltage\n"); - } - - ref = ret / 1000; - } - /* * For 24-bit Conversion * Raw = ((Voltage)/(Vref) * 2^23 * Gain * 1.5 @@ -412,7 +423,7 @@ static int mcp3911_calc_scale_table(struct mcp3911 *adc) */ for (int i = 0; i < MCP3911_NUM_SCALES; i++) { div = 12582912 * BIT(i); - tmp = div_s64((s64)ref * 1000000000LL, div); + tmp = div_s64((s64)vref_mv * 1000000000LL, div); mcp3911_scale_table[i][0] = 0; mcp3911_scale_table[i][1] = tmp; @@ -523,14 +534,14 @@ static irqreturn_t mcp3911_trigger_handler(int irq, void *p) goto out; } - for_each_set_bit(scan_index, indio_dev->active_scan_mask, indio_dev->masklength) { + iio_for_each_active_channel(indio_dev, scan_index) { 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)); + iio_push_to_buffers_with_ts(indio_dev, &adc->scan, sizeof(adc->scan), + iio_get_time_ns(indio_dev)); out: iio_trigger_notify_done(indio_dev->trig); @@ -544,7 +555,7 @@ static const struct iio_info mcp3911_info = { .write_raw_get_fmt = mcp3911_write_raw_get_fmt, }; -static int mcp3911_config(struct mcp3911 *adc) +static int mcp3911_config(struct mcp3911 *adc, bool external_vref) { struct device *dev = &adc->spi->dev; u32 regval; @@ -555,7 +566,7 @@ static int mcp3911_config(struct mcp3911 *adc) return ret; regval &= ~MCP3911_CONFIG_VREFEXT; - if (adc->vref) { + if (external_vref) { dev_dbg(dev, "use external voltage reference\n"); regval |= FIELD_PREP(MCP3911_CONFIG_VREFEXT, 1); } else { @@ -610,7 +621,7 @@ static int mcp3911_config(struct mcp3911 *adc) return mcp3911_write(adc, MCP3911_REG_GAIN, regval, 1); } -static int mcp3910_config(struct mcp3911 *adc) +static int mcp3910_config(struct mcp3911 *adc, bool external_vref) { struct device *dev = &adc->spi->dev; u32 regval; @@ -621,7 +632,7 @@ static int mcp3910_config(struct mcp3911 *adc) return ret; regval &= ~MCP3910_CONFIG1_VREFEXT; - if (adc->vref) { + if (external_vref) { dev_dbg(dev, "use external voltage reference\n"); regval |= FIELD_PREP(MCP3910_CONFIG1_VREFEXT, 1); } else { @@ -677,11 +688,6 @@ static int mcp3910_config(struct mcp3911 *adc) return adc->chip->enable_offset(adc, 0); } -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); @@ -702,8 +708,11 @@ static const struct iio_trigger_ops mcp3911_trigger_ops = { static int mcp3911_probe(struct spi_device *spi) { struct device *dev = &spi->dev; + struct gpio_desc *gpio_reset; struct iio_dev *indio_dev; struct mcp3911 *adc; + bool external_vref; + u32 vref_mv; int ret; indio_dev = devm_iio_device_alloc(dev, sizeof(*adc)); @@ -714,23 +723,12 @@ static int mcp3911_probe(struct spi_device *spi) adc->spi = spi; adc->chip = spi_get_device_match_data(spi); - adc->vref = devm_regulator_get_optional(dev, "vref"); - if (IS_ERR(adc->vref)) { - if (PTR_ERR(adc->vref) == -ENODEV) { - adc->vref = NULL; - } else { - return dev_err_probe(dev, PTR_ERR(adc->vref), "failed to get regulator\n"); - } - - } else { - ret = regulator_enable(adc->vref); - if (ret) - return ret; + ret = devm_regulator_get_enable_read_voltage(dev, "vref"); + if (ret < 0 && ret != -ENODEV) + return dev_err_probe(dev, ret, "failed to get vref voltage\n"); - ret = devm_add_action_or_reset(dev, mcp3911_cleanup_regulator, adc->vref); - if (ret) - return ret; - } + external_vref = ret != -ENODEV; + vref_mv = external_vref ? ret / 1000 : MCP3911_INT_VREF_MV; adc->clki = devm_clk_get_enabled(dev, NULL); if (IS_ERR(adc->clki)) { @@ -755,11 +753,27 @@ static int mcp3911_probe(struct spi_device *spi) } dev_dbg(dev, "use device address %i\n", adc->dev_addr); - ret = adc->chip->config(adc); + gpio_reset = devm_gpiod_get_optional(&spi->dev, "reset", GPIOD_OUT_HIGH); + if (IS_ERR(gpio_reset)) + return dev_err_probe(dev, PTR_ERR(gpio_reset), + "Cannot get reset GPIO\n"); + + if (gpio_reset) { + gpiod_set_value_cansleep(gpio_reset, 0); + + /* + * Settling time after Hard Reset Mode (determined experimentally): + * 330 micro-seconds are too few; 470 micro-seconds are sufficient. + * Just in case, we add some safety factor... + */ + fsleep(600); + } + + ret = adc->chip->config(adc, external_vref); if (ret) return ret; - ret = mcp3911_calc_scale_table(adc); + ret = mcp3911_calc_scale_table(vref_mv); if (ret) return ret; @@ -826,6 +840,7 @@ static const struct mcp3911_chip_info mcp3911_chip_info[] = { .get_offset = mcp3910_get_offset, .set_offset = mcp3910_set_offset, .set_scale = mcp3910_set_scale, + .get_raw = mcp3910_get_raw, }, [MCP3911] = { .channels = mcp3911_channels, @@ -837,6 +852,7 @@ static const struct mcp3911_chip_info mcp3911_chip_info[] = { .get_offset = mcp3911_get_offset, .set_offset = mcp3911_set_offset, .set_scale = mcp3911_set_scale, + .get_raw = mcp3911_get_raw, }, [MCP3912] = { .channels = mcp3912_channels, @@ -848,6 +864,7 @@ static const struct mcp3911_chip_info mcp3911_chip_info[] = { .get_offset = mcp3910_get_offset, .set_offset = mcp3910_set_offset, .set_scale = mcp3910_set_scale, + .get_raw = mcp3910_get_raw, }, [MCP3913] = { .channels = mcp3913_channels, @@ -859,6 +876,7 @@ static const struct mcp3911_chip_info mcp3911_chip_info[] = { .get_offset = mcp3910_get_offset, .set_offset = mcp3910_set_offset, .set_scale = mcp3910_set_scale, + .get_raw = mcp3910_get_raw, }, [MCP3914] = { .channels = mcp3914_channels, @@ -870,6 +888,7 @@ static const struct mcp3911_chip_info mcp3911_chip_info[] = { .get_offset = mcp3910_get_offset, .set_offset = mcp3910_set_offset, .set_scale = mcp3910_set_scale, + .get_raw = mcp3910_get_raw, }, [MCP3918] = { .channels = mcp3918_channels, @@ -881,6 +900,7 @@ static const struct mcp3911_chip_info mcp3911_chip_info[] = { .get_offset = mcp3910_get_offset, .set_offset = mcp3910_set_offset, .set_scale = mcp3910_set_scale, + .get_raw = mcp3910_get_raw, }, [MCP3919] = { .channels = mcp3919_channels, @@ -892,6 +912,7 @@ static const struct mcp3911_chip_info mcp3911_chip_info[] = { .get_offset = mcp3910_get_offset, .set_offset = mcp3910_set_offset, .set_scale = mcp3910_set_scale, + .get_raw = mcp3910_get_raw, }, }; static const struct of_device_id mcp3911_dt_ids[] = { |