// SPDX-License-Identifier: GPL-2.0 /* * Driver for Microchip MCP3911, Two-channel Analog Front End * * Copyright (C) 2018 Marcus Folkesson * Copyright (C) 2018 Kent Gustavsson */ #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #define MCP3911_REG_CHANNEL0 0x00 #define MCP3911_REG_CHANNEL1 0x03 #define MCP3911_REG_MOD 0x06 #define MCP3911_REG_PHASE 0x07 #define MCP3911_REG_GAIN 0x09 #define MCP3911_GAIN_MASK(ch) (GENMASK(2, 0) << 3 * ch) #define MCP3911_GAIN_VAL(ch, val) ((val << 3 * ch) & MCP3911_GAIN_MASK(ch)) #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) #define MCP3911_STATUSCOM_EN_GAINCAL BIT(1) #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 #define MCP3911_REG_OFFCAL_CH1 0x14 #define MCP3911_REG_GAINCAL_CH1 0x17 #define MCP3911_REG_VREFCAL 0x1a #define MCP3911_CHANNEL(x) (MCP3911_REG_CHANNEL0 + x * 3) #define MCP3911_OFFCAL(x) (MCP3911_REG_OFFCAL_CH0 + x * 6) /* Internal voltage reference in mV */ #define MCP3911_INT_VREF_MV 1200 #define MCP3911_REG_READ(reg, id) ((((reg) << 1) | ((id) << 6) | (1 << 0)) & 0xff) #define MCP3911_REG_WRITE(reg, id) ((((reg) << 1) | ((id) << 6) | (0 << 0)) & 0xff) #define MCP3911_REG_MASK GENMASK(4, 1) #define MCP3911_NUM_CHANNELS 2 #define MCP3911_NUM_SCALES 6 static const int mcp3911_osr_table[] = { 32, 64, 128, 256, 512, 1024, 2048, 4096 }; static u32 mcp3911_scale_table[MCP3911_NUM_SCALES][2]; struct mcp3911 { struct spi_device *spi; struct mutex lock; struct regulator *vref; struct clk *clki; u32 dev_addr; struct iio_trigger *trig; u32 gain[MCP3911_NUM_CHANNELS]; 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) { int ret; reg = MCP3911_REG_READ(reg, adc->dev_addr); ret = spi_write_then_read(adc->spi, ®, 1, val, len); if (ret < 0) return ret; be32_to_cpus(val); *val >>= ((4 - len) * 8); dev_dbg(&adc->spi->dev, "reading 0x%x from register 0x%lx\n", *val, FIELD_GET(MCP3911_REG_MASK, reg)); return ret; } static int mcp3911_write(struct mcp3911 *adc, u8 reg, u32 val, u8 len) { dev_dbg(&adc->spi->dev, "writing 0x%x to register 0x%x\n", val, reg); val <<= (3 - len) * 8; cpu_to_be32s(&val); val |= MCP3911_REG_WRITE(reg, adc->dev_addr); return spi_write(adc->spi, &val, len + 1); } static int mcp3911_update(struct mcp3911 *adc, u8 reg, u32 mask, u32 val, u8 len) { u32 tmp; int ret; ret = mcp3911_read(adc, reg, &tmp, len); if (ret) return ret; val &= mask; val |= tmp & ~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; case IIO_CHAN_INFO_SCALE: *type = IIO_VAL_INT_PLUS_NANO; *vals = (int *)mcp3911_scale_table; *length = ARRAY_SIZE(mcp3911_scale_table) * 2; 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) { struct mcp3911 *adc = iio_priv(indio_dev); int ret = -EINVAL; mutex_lock(&adc->lock); switch (mask) { case IIO_CHAN_INFO_RAW: ret = mcp3911_read(adc, MCP3911_CHANNEL(channel->channel), val, 3); if (ret) goto out; *val = sign_extend32(*val, 23); ret = IIO_VAL_INT; break; case IIO_CHAN_INFO_OFFSET: ret = mcp3911_read(adc, MCP3911_OFFCAL(channel->channel), val, 3); if (ret) goto out; 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: *val = mcp3911_scale_table[ilog2(adc->gain[channel->channel])][0]; *val2 = mcp3911_scale_table[ilog2(adc->gain[channel->channel])][1]; ret = IIO_VAL_INT_PLUS_NANO; break; } out: mutex_unlock(&adc->lock); return ret; } static int mcp3911_write_raw(struct iio_dev *indio_dev, struct iio_chan_spec const *channel, int val, int val2, long mask) { struct mcp3911 *adc = iio_priv(indio_dev); int ret = -EINVAL; mutex_lock(&adc->lock); switch (mask) { case IIO_CHAN_INFO_SCALE: for (int i = 0; i < MCP3911_NUM_SCALES; i++) { if (val == mcp3911_scale_table[i][0] && val2 == mcp3911_scale_table[i][1]) { adc->gain[channel->channel] = BIT(i); ret = mcp3911_update(adc, MCP3911_REG_GAIN, MCP3911_GAIN_MASK(channel->channel), MCP3911_GAIN_VAL(channel->channel, i), 1); } } break; case IIO_CHAN_INFO_OFFSET: if (val2 != 0) { ret = -EINVAL; goto out; } /* Write offset */ ret = mcp3911_write(adc, MCP3911_OFFCAL(channel->channel), val, 3); if (ret) goto out; /* Enable offset*/ ret = mcp3911_update(adc, MCP3911_REG_STATUSCOM, MCP3911_STATUSCOM_EN_OFFCAL, MCP3911_STATUSCOM_EN_OFFCAL, 2); break; case IIO_CHAN_INFO_OVERSAMPLING_RATIO: for (int i = 0; i < ARRAY_SIZE(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: mutex_unlock(&adc->lock); return ret; } static int mcp3911_calc_scale_table(struct mcp3911 *adc) { u32 ref = MCP3911_INT_VREF_MV; u32 div; int ret; u64 tmp; if (adc->vref) { ret = regulator_get_voltage(adc->vref); if (ret < 0) { dev_err(&adc->spi->dev, "failed to get vref voltage: %d\n", ret); return ret; } ref = ret / 1000; } /* * For 24-bit Conversion * Raw = ((Voltage)/(Vref) * 2^23 * Gain * 1.5 * Voltage = Raw * (Vref)/(2^23 * Gain * 1.5) * * ref = Reference voltage * div = (2^23 * 1.5 * gain) = 12582912 * gain */ for (int i = 0; i < MCP3911_NUM_SCALES; i++) { div = 12582912 * BIT(i); tmp = div_s64((s64)ref * 1000000000LL, div); mcp3911_scale_table[i][0] = 0; mcp3911_scale_table[i][1] = tmp; } return 0; } #define MCP3911_CHAN(idx) { \ .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), \ .info_mask_separate_available = \ BIT(IIO_CHAN_INFO_SCALE), \ .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 regval; int ret; ret = device_property_read_u32(dev, "microchip,device-addr", &adc->dev_addr); /* * Fallback to "device-addr" due to historical mismatch between * dt-bindings and implementation */ if (ret) device_property_read_u32(dev, "device-addr", &adc->dev_addr); if (adc->dev_addr > 3) { dev_err(&adc->spi->dev, "invalid device address (%i). Must be in range 0-3.\n", adc->dev_addr); return -EINVAL; } dev_dbg(&adc->spi->dev, "use device address %i\n", adc->dev_addr); 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"); regval |= FIELD_PREP(MCP3911_CONFIG_VREFEXT, 1); } else { dev_dbg(&adc->spi->dev, "use internal voltage reference (1.2V)\n"); 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"); regval |= FIELD_PREP(MCP3911_CONFIG_CLKEXT, 1); } else { dev_dbg(&adc->spi->dev, "use crystal oscillator as clocksource\n"); regval |= FIELD_PREP(MCP3911_CONFIG_CLKEXT, 0); } 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; struct mcp3911 *adc; int ret; indio_dev = devm_iio_device_alloc(&spi->dev, sizeof(*adc)); if (!indio_dev) return -ENOMEM; adc = iio_priv(indio_dev); adc->spi = spi; adc->vref = devm_regulator_get_optional(&adc->spi->dev, "vref"); if (IS_ERR(adc->vref)) { if (PTR_ERR(adc->vref) == -ENODEV) { adc->vref = NULL; } else { dev_err(&adc->spi->dev, "failed to get regulator (%ld)\n", PTR_ERR(adc->vref)); return PTR_ERR(adc->vref); } } else { 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_enabled(&adc->spi->dev, NULL); if (IS_ERR(adc->clki)) { if (PTR_ERR(adc->clki) == -ENOENT) { adc->clki = NULL; } else { dev_err(&adc->spi->dev, "failed to get adc clk (%ld)\n", PTR_ERR(adc->clki)); return PTR_ERR(adc->clki); } } ret = mcp3911_config(adc); if (ret) 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; ret = mcp3911_calc_scale_table(adc); if (ret) return ret; /* Set gain to 1 for all channels */ for (int i = 0; i < MCP3911_NUM_CHANNELS; i++) { adc->gain[i] = 1; ret = mcp3911_update(adc, MCP3911_REG_GAIN, MCP3911_GAIN_MASK(i), MCP3911_GAIN_VAL(i, 0), 1); if (ret) return ret; } indio_dev->name = spi_get_device_id(spi)->name; indio_dev->modes = INDIO_DIRECT_MODE; indio_dev->info = &mcp3911_info; spi_set_drvdata(spi, indio_dev); indio_dev->channels = mcp3911_channels; indio_dev->num_channels = ARRAY_SIZE(mcp3911_channels); mutex_init(&adc->lock); 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 -ENOMEM; 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; /* * 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; } ret = devm_iio_triggered_buffer_setup(&spi->dev, indio_dev, NULL, mcp3911_trigger_handler, NULL); if (ret) return ret; return devm_iio_device_register(&adc->spi->dev, indio_dev); } static const struct of_device_id mcp3911_dt_ids[] = { { .compatible = "microchip,mcp3911" }, { } }; MODULE_DEVICE_TABLE(of, mcp3911_dt_ids); static const struct spi_device_id mcp3911_id[] = { { "mcp3911", 0 }, { } }; MODULE_DEVICE_TABLE(spi, mcp3911_id); static struct spi_driver mcp3911_driver = { .driver = { .name = "mcp3911", .of_match_table = mcp3911_dt_ids, }, .probe = mcp3911_probe, .id_table = mcp3911_id, }; module_spi_driver(mcp3911_driver); MODULE_AUTHOR("Marcus Folkesson "); MODULE_AUTHOR("Kent Gustavsson "); MODULE_DESCRIPTION("Microchip Technology MCP3911"); MODULE_LICENSE("GPL v2");