| // SPDX-License-Identifier: GPL-2.0 |
| /* |
| * Driver for Microchip MCP3911, Two-channel Analog Front End |
| * |
| * Copyright (C) 2018 Marcus Folkesson <marcus.folkesson@gmail.com> |
| * Copyright (C) 2018 Kent Gustavsson <kent@minoris.se> |
| */ |
| #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> |
| |
| #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_REG_STATUSCOM 0x0a |
| #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_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) << 5) | (1 << 0)) & 0xff) |
| #define MCP3911_REG_WRITE(reg, id) ((((reg) << 1) | ((id) << 5) | (0 << 0)) & 0xff) |
| |
| #define MCP3911_NUM_CHANNELS 2 |
| |
| struct mcp3911 { |
| struct spi_device *spi; |
| struct mutex lock; |
| struct regulator *vref; |
| struct clk *clki; |
| u32 dev_addr; |
| }; |
| |
| 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%x\n", *val, |
| reg >> 1); |
| 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_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_SCALE: |
| if (adc->vref) { |
| ret = regulator_get_voltage(adc->vref); |
| if (ret < 0) { |
| dev_err(indio_dev->dev.parent, |
| "failed to get vref voltage: %d\n", |
| ret); |
| goto out; |
| } |
| |
| *val = ret / 1000; |
| } else { |
| *val = MCP3911_INT_VREF_MV; |
| } |
| |
| /* |
| * For 24bit Conversion |
| * Raw = ((Voltage)/(Vref) * 2^23 * Gain * 1.5 |
| * Voltage = Raw * (Vref)/(2^23 * Gain * 1.5) |
| */ |
| |
| /* val2 = (2^23 * 1.5) */ |
| *val2 = 12582912; |
| ret = IIO_VAL_FRACTIONAL; |
| 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_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; |
| } |
| |
| out: |
| mutex_unlock(&adc->lock); |
| return ret; |
| } |
| |
| #define MCP3911_CHAN(idx) { \ |
| .type = IIO_VOLTAGE, \ |
| .indexed = 1, \ |
| .channel = idx, \ |
| .info_mask_separate = BIT(IIO_CHAN_INFO_RAW) | \ |
| BIT(IIO_CHAN_INFO_OFFSET) | \ |
| BIT(IIO_CHAN_INFO_SCALE), \ |
| } |
| |
| static const struct iio_chan_spec mcp3911_channels[] = { |
| MCP3911_CHAN(0), |
| MCP3911_CHAN(1), |
| }; |
| |
| static const struct iio_info mcp3911_info = { |
| .read_raw = mcp3911_read_raw, |
| .write_raw = mcp3911_write_raw, |
| }; |
| |
| static int mcp3911_config(struct mcp3911 *adc) |
| { |
| struct device *dev = &adc->spi->dev; |
| u32 configreg; |
| 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, &configreg, 2); |
| if (ret) |
| return ret; |
| |
| if (adc->vref) { |
| dev_dbg(&adc->spi->dev, "use external voltage reference\n"); |
| configreg |= MCP3911_CONFIG_VREFEXT; |
| } else { |
| dev_dbg(&adc->spi->dev, |
| "use internal voltage reference (1.2V)\n"); |
| configreg &= ~MCP3911_CONFIG_VREFEXT; |
| } |
| |
| if (adc->clki) { |
| dev_dbg(&adc->spi->dev, "use external clock as clocksource\n"); |
| configreg |= MCP3911_CONFIG_CLKEXT; |
| } else { |
| dev_dbg(&adc->spi->dev, |
| "use crystal oscillator as clocksource\n"); |
| configreg &= ~MCP3911_CONFIG_CLKEXT; |
| } |
| |
| return mcp3911_write(adc, MCP3911_REG_CONFIG, configreg, 2); |
| } |
| |
| 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; |
| } |
| |
| adc->clki = devm_clk_get(&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)); |
| 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; |
| } |
| } |
| |
| ret = mcp3911_config(adc); |
| if (ret) |
| goto clk_disable; |
| |
| 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); |
| |
| 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); |
| |
| 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); |
| |
| iio_device_unregister(indio_dev); |
| |
| clk_disable_unprepare(adc->clki); |
| if (adc->vref) |
| regulator_disable(adc->vref); |
| } |
| |
| 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, |
| .remove = mcp3911_remove, |
| .id_table = mcp3911_id, |
| }; |
| module_spi_driver(mcp3911_driver); |
| |
| MODULE_AUTHOR("Marcus Folkesson <marcus.folkesson@gmail.com>"); |
| MODULE_AUTHOR("Kent Gustavsson <kent@minoris.se>"); |
| MODULE_DESCRIPTION("Microchip Technology MCP3911"); |
| MODULE_LICENSE("GPL v2"); |