The MAX14001 is configurable, isolated 10-bit ADCs for multi-range
binary inputs.
Signed-off-by: Kim Seer Paller <[email protected]>
---
V8 -> V9: Changed SPI buffer data types to __le16, removed force cast
and modified spi buffers bit sequence. Removed max14001_reg_update
function and directly handled its functionality within the caller.
Removed unused headers.
V7 -> V8: Added a bitwise OR operation to combine the bitfield element
with the reg_data value.
V6 -> V7: Swapped ADC external vref source and regulator_get_voltage
calls. Added forced cast and comment to addressed endian warning.
V5 -> V6: Replaced fixed length assignment with dynamic size
assignment in xfers struct initialization. Removed .channel
assignment in max14001_channels definition.
V4 -> V5: No changes.
V3 -> V4: Removed regmap setup, structures, and include.
MAINTAINERS | 1 +
drivers/iio/adc/Kconfig | 10 ++
drivers/iio/adc/Makefile | 1 +
drivers/iio/adc/max14001.c | 325 +++++++++++++++++++++++++++++++++++++
4 files changed, 337 insertions(+)
create mode 100644 drivers/iio/adc/max14001.c
diff --git a/MAINTAINERS b/MAINTAINERS
index 0253058c345b..bd4bbe4f1749 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -12797,6 +12797,7 @@ L: [email protected]
S: Supported
W: https://ez.analog.com/linux-software-drivers
F: Documentation/devicetree/bindings/iio/adc/adi,max14001.yaml
+F: drivers/iio/adc/max14001.c
MAXBOTIX ULTRASONIC RANGER IIO DRIVER
M: Andreas Klinger <[email protected]>
diff --git a/drivers/iio/adc/Kconfig b/drivers/iio/adc/Kconfig
index dc14bde31ac1..bdd5033b0733 100644
--- a/drivers/iio/adc/Kconfig
+++ b/drivers/iio/adc/Kconfig
@@ -706,6 +706,16 @@ config MAX11410
To compile this driver as a module, choose M here: the module will be
called max11410.
+config MAX14001
+ tristate "Analog Devices MAX14001 ADC driver"
+ depends on SPI
+ help
+ Say yes here to build support for Analog Devices MAX14001 Configurable,
+ Isolated 10-bit ADCs for Multi-Range Binary Inputs.
+
+ To compile this driver as a module, choose M here: the module will be
+ called max14001.
+
config MAX1241
tristate "Maxim max1241 ADC driver"
depends on SPI_MASTER
diff --git a/drivers/iio/adc/Makefile b/drivers/iio/adc/Makefile
index eb6e891790fb..5a825cf9066f 100644
--- a/drivers/iio/adc/Makefile
+++ b/drivers/iio/adc/Makefile
@@ -65,6 +65,7 @@ obj-$(CONFIG_MAX11100) += max11100.o
obj-$(CONFIG_MAX1118) += max1118.o
obj-$(CONFIG_MAX11205) += max11205.o
obj-$(CONFIG_MAX11410) += max11410.o
+obj-$(CONFIG_MAX14001) += max14001.o
obj-$(CONFIG_MAX1241) += max1241.o
obj-$(CONFIG_MAX1363) += max1363.o
obj-$(CONFIG_MAX77541_ADC) += max77541-adc.o
diff --git a/drivers/iio/adc/max14001.c b/drivers/iio/adc/max14001.c
new file mode 100644
index 000000000000..09686a9faa2e
--- /dev/null
+++ b/drivers/iio/adc/max14001.c
@@ -0,0 +1,325 @@
+// SPDX-License-Identifier: (GPL-2.0-only OR BSD-3-Clause)
+/*
+ * Analog Devices MAX14001 ADC driver
+ *
+ * Copyright 2023 Analog Devices Inc.
+ */
+
+#include <linux/bitfield.h>
+#include <linux/bitrev.h>
+#include <linux/device.h>
+#include <linux/iio/iio.h>
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/regulator/consumer.h>
+#include <linux/spi/spi.h>
+#include <linux/types.h>
+
+/* MAX14001 Registers Address */
+#define MAX14001_ADC 0x00
+#define MAX14001_FADC 0x01
+#define MAX14001_FLAGS 0x02
+#define MAX14001_FLTEN 0x03
+#define MAX14001_THL 0x04
+#define MAX14001_THU 0x05
+#define MAX14001_INRR 0x06
+#define MAX14001_INRT 0x07
+#define MAX14001_INRP 0x08
+#define MAX14001_CFG 0x09
+#define MAX14001_ENBL 0x0A
+#define MAX14001_ACT 0x0B
+#define MAX14001_WEN 0x0C
+
+#define MAX14001_VERIFICATION_REG(x) ((x) + 0x10)
+
+#define MAX14001_CFG_EXRF BIT(5)
+
+#define MAX14001_ADDR_MASK GENMASK(15, 11)
+#define MAX14001_DATA_MASK GENMASK(9, 0)
+#define MAX14001_FILTER_MASK GENMASK(3, 2)
+
+#define MAX14001_SET_WRITE_BIT BIT(10)
+#define MAX14001_WRITE_WEN 0x294
+
+struct max14001_state {
+ struct spi_device *spi;
+ /*
+ * lock protect against multiple concurrent accesses, RMW sequence, and
+ * SPI transfer
+ */
+ struct mutex lock;
+ int vref_mv;
+ /*
+ * DMA (thus cache coherency maintenance) requires the
+ * transfer buffers to live in their own cache lines.
+ */
+ __le16 spi_tx_buffer __aligned(IIO_DMA_MINALIGN);
+ __le16 spi_rx_buffer;
+};
+
+static int max14001_read(void *context, unsigned int reg_addr, unsigned int *data)
+{
+ struct max14001_state *st = context;
+ int ret;
+
+ struct spi_transfer xfers[] = {
+ {
+ .tx_buf = &st->spi_tx_buffer,
+ .len = sizeof(st->spi_tx_buffer),
+ .cs_change = 1,
+ }, {
+ .rx_buf = &st->spi_rx_buffer,
+ .len = sizeof(st->spi_rx_buffer),
+ },
+ };
+
+ /*
+ * Prepare SPI transmit buffer 16 bit-value to big-endian format and
+ * reverses bit order to align with the LSB-first input on SDI port.
+ */
+ st->spi_tx_buffer = bitrev16(cpu_to_be16(FIELD_PREP(MAX14001_ADDR_MASK,
+ reg_addr)));
+
+ ret = spi_sync_transfer(st->spi, xfers, ARRAY_SIZE(xfers));
+ if (ret)
+ return ret;
+
+ /*
+ * Convert received 16-bit value from big-endian to little-endian format
+ * and reverses bit order.
+ */
+ *data = bitrev16(be16_to_cpu(st->spi_rx_buffer));
+
+ return 0;
+}
+
+static int max14001_write(void *context, unsigned int reg_addr, unsigned int data)
+{
+ struct max14001_state *st = context;
+
+ /*
+ * Prepare SPI transmit buffer 16 bit-value to big-endian format and
+ * reverses bit order to align with the LSB-first input on SDI port.
+ */
+ st->spi_tx_buffer = bitrev16(cpu_to_be16(
+ FIELD_PREP(MAX14001_ADDR_MASK, reg_addr) |
+ FIELD_PREP(MAX14001_SET_WRITE_BIT, 1) |
+ FIELD_PREP(MAX14001_DATA_MASK, data)));
+
+ return spi_write(st->spi, &st->spi_tx_buffer, sizeof(st->spi_tx_buffer));
+}
+
+static int max14001_write_verification_reg(struct max14001_state *st,
+ unsigned int reg_addr)
+{
+ unsigned int reg_data;
+ int ret;
+
+ ret = max14001_read(st, reg_addr, ®_data);
+ if (ret)
+ return ret;
+
+ return max14001_write(st, MAX14001_VERIFICATION_REG(reg_addr), reg_data);
+}
+
+static int max14001_read_raw(struct iio_dev *indio_dev,
+ struct iio_chan_spec const *chan,
+ int *val, int *val2, long mask)
+{
+ struct max14001_state *st = iio_priv(indio_dev);
+ unsigned int data;
+ int ret;
+
+ switch (mask) {
+ case IIO_CHAN_INFO_RAW:
+ mutex_lock(&st->lock);
+ ret = max14001_read(st, MAX14001_ADC, &data);
+ mutex_unlock(&st->lock);
+ if (ret < 0)
+ return ret;
+
+ *val = data;
+
+ return IIO_VAL_INT;
+ case IIO_CHAN_INFO_SCALE:
+ *val = st->vref_mv;
+ *val2 = 10;
+
+ return IIO_VAL_FRACTIONAL_LOG2;
+ default:
+ return -EINVAL;
+ }
+}
+
+static const struct iio_info max14001_info = {
+ .read_raw = max14001_read_raw,
+};
+
+static const struct iio_chan_spec max14001_channels[] = {
+ {
+ .type = IIO_VOLTAGE,
+ .info_mask_separate = BIT(IIO_CHAN_INFO_RAW) |
+ BIT(IIO_CHAN_INFO_SCALE),
+ }
+};
+
+static void max14001_regulator_disable(void *data)
+{
+ struct regulator *reg = data;
+
+ regulator_disable(reg);
+}
+
+static int max14001_init(struct max14001_state *st)
+{
+ int ret;
+
+ /* Enable SPI Registers Write */
+ ret = max14001_write(st, MAX14001_WEN, MAX14001_WRITE_WEN);
+ if (ret)
+ return ret;
+
+ /*
+ * Reads all registers and writes the values back to their appropriate
+ * verification registers to clear the Memory Validation fault.
+ */
+ ret = max14001_write_verification_reg(st, MAX14001_FLTEN);
+ if (ret)
+ return ret;
+
+ ret = max14001_write_verification_reg(st, MAX14001_THL);
+ if (ret)
+ return ret;
+
+ ret = max14001_write_verification_reg(st, MAX14001_THU);
+ if (ret)
+ return ret;
+
+ ret = max14001_write_verification_reg(st, MAX14001_INRR);
+ if (ret)
+ return ret;
+
+ ret = max14001_write_verification_reg(st, MAX14001_INRT);
+ if (ret)
+ return ret;
+
+ ret = max14001_write_verification_reg(st, MAX14001_INRP);
+ if (ret)
+ return ret;
+
+ ret = max14001_write_verification_reg(st, MAX14001_CFG);
+ if (ret)
+ return ret;
+
+ ret = max14001_write_verification_reg(st, MAX14001_ENBL);
+ if (ret)
+ return ret;
+
+ /* Disable SPI Registers Write */
+ return max14001_write(st, MAX14001_WEN, 0);
+}
+
+static int max14001_probe(struct spi_device *spi)
+{
+ struct iio_dev *indio_dev;
+ struct max14001_state *st;
+ struct regulator *vref;
+ struct device *dev = &spi->dev;
+ unsigned int reg_data;
+ int ret;
+
+ indio_dev = devm_iio_device_alloc(dev, sizeof(*st));
+ if (!indio_dev)
+ return -ENOMEM;
+
+ st = iio_priv(indio_dev);
+ st->spi = spi;
+
+ indio_dev->name = "max14001";
+ indio_dev->info = &max14001_info;
+ indio_dev->channels = max14001_channels;
+ indio_dev->num_channels = ARRAY_SIZE(max14001_channels);
+ indio_dev->modes = INDIO_DIRECT_MODE;
+
+ ret = max14001_init(st);
+ if (ret)
+ return ret;
+
+ vref = devm_regulator_get_optional(dev, "vref");
+ if (IS_ERR(vref)) {
+ if (PTR_ERR(vref) != -ENODEV)
+ return dev_err_probe(dev, PTR_ERR(vref),
+ "Failed to get vref regulator");
+
+ /* internal reference */
+ st->vref_mv = 1250;
+ } else {
+ ret = regulator_enable(vref);
+ if (ret)
+ return dev_err_probe(dev, ret,
+ "Failed to enable vref regulators\n");
+
+ ret = devm_add_action_or_reset(dev, max14001_regulator_disable,
+ vref);
+ if (ret)
+ return ret;
+
+ ret = regulator_get_voltage(vref);
+ if (ret < 0)
+ return dev_err_probe(dev, ret,
+ "Failed to get vref\n");
+
+ st->vref_mv = ret / 1000;
+
+ /*
+ * Enable SPI registers write and select external voltage
+ * reference source for the ADC.
+ */
+ ret = max14001_write(st, MAX14001_WEN, MAX14001_WRITE_WEN);
+ if (ret)
+ return ret;
+
+ ret = max14001_read(st, MAX14001_CFG, ®_data);
+ if (ret)
+ return ret;
+
+ reg_data |= FIELD_PREP(MAX14001_CFG_EXRF, 1);
+
+ ret = max14001_write(st, MAX14001_CFG, reg_data);
+ if (ret)
+ return ret;
+
+ /* Write Verification Register */
+ ret = max14001_write_verification_reg(st, MAX14001_CFG);
+ if (ret)
+ return ret;
+
+ /* Disable SPI Registers Write */
+ ret = max14001_write(st, MAX14001_WEN, 0);
+ if (ret)
+ return ret;
+ }
+
+ mutex_init(&st->lock);
+
+ return devm_iio_device_register(dev, indio_dev);
+}
+
+static const struct of_device_id max14001_of_match[] = {
+ { .compatible = "adi,max14001" },
+ { }
+};
+MODULE_DEVICE_TABLE(of, max14001_of_match);
+
+static struct spi_driver max14001_driver = {
+ .driver = {
+ .name = "max14001",
+ .of_match_table = max14001_of_match,
+ },
+ .probe = max14001_probe,
+};
+module_spi_driver(max14001_driver);
+
+MODULE_AUTHOR("Kim Seer Paller");
+MODULE_DESCRIPTION("MAX14001 ADC driver");
+MODULE_LICENSE("GPL");
--
2.34.1
On Mon, Jul 10, 2023 at 10:36 AM Andy Shevchenko
<[email protected]> wrote:
> On Mon, Jul 10, 2023 at 7:27 AM Kim Seer Paller
> <[email protected]> wrote:
...
> > V8 -> V9: Changed SPI buffer data types to __le16,
>
> Why?
>
> ...
>
> > + __le16 spi_tx_buffer __aligned(IIO_DMA_MINALIGN);
> > + __le16 spi_rx_buffer;
>
> ...
>
> > + /*
> > + * Prepare SPI transmit buffer 16 bit-value to big-endian format and
> > + * reverses bit order to align with the LSB-first input on SDI port.
>
> reverse
>
> > + */
> > + st->spi_tx_buffer = bitrev16(cpu_to_be16(FIELD_PREP(MAX14001_ADDR_MASK,
> > + reg_addr)));
>
> ...
>
> > + /*
> > + * Convert received 16-bit value from big-endian to little-endian format
> > + * and reverses bit order.
>
> reverse
>
> > + */
> > + *data = bitrev16(be16_to_cpu(st->spi_rx_buffer));
On top of that, this left unfixed.
...
> > + /*
> > + * Prepare SPI transmit buffer 16 bit-value to big-endian format and
> > + * reverses bit order to align with the LSB-first input on SDI port.
>
> reverse
>
> > + */
> > + st->spi_tx_buffer = bitrev16(cpu_to_be16(
> > + FIELD_PREP(MAX14001_ADDR_MASK, reg_addr) |
> > + FIELD_PREP(MAX14001_SET_WRITE_BIT, 1) |
> > + FIELD_PREP(MAX14001_DATA_MASK, data)));
>
> Obviously it's incorrect now even more than before.
> The types are defined as __le, while ops are against __be.
--
With Best Regards,
Andy Shevchenko
On Mon, Jul 10, 2023 at 7:27 AM Kim Seer Paller
<[email protected]> wrote:
>
> The MAX14001 is configurable, isolated 10-bit ADCs for multi-range
> binary inputs.
...
> V8 -> V9: Changed SPI buffer data types to __le16,
Why?
...
> + __le16 spi_tx_buffer __aligned(IIO_DMA_MINALIGN);
> + __le16 spi_rx_buffer;
...
> + /*
> + * Prepare SPI transmit buffer 16 bit-value to big-endian format and
> + * reverses bit order to align with the LSB-first input on SDI port.
reverse
> + */
> + st->spi_tx_buffer = bitrev16(cpu_to_be16(FIELD_PREP(MAX14001_ADDR_MASK,
> + reg_addr)));
...
> + /*
> + * Convert received 16-bit value from big-endian to little-endian format
> + * and reverses bit order.
reverse
> + */
> + *data = bitrev16(be16_to_cpu(st->spi_rx_buffer));
...
> + /*
> + * Prepare SPI transmit buffer 16 bit-value to big-endian format and
> + * reverses bit order to align with the LSB-first input on SDI port.
reverse
> + */
> + st->spi_tx_buffer = bitrev16(cpu_to_be16(
> + FIELD_PREP(MAX14001_ADDR_MASK, reg_addr) |
> + FIELD_PREP(MAX14001_SET_WRITE_BIT, 1) |
> + FIELD_PREP(MAX14001_DATA_MASK, data)));
Obviously it's incorrect now even more than before.
The types are defined as __le, while ops are against __be.
--
With Best Regards,
Andy Shevchenko