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Subject[PATCH v7] iio: add support of the max1027
Date
This driver add partial support of the
maxim 1027/1029/1031. Differential mode is not
supported.

It was tested on armadeus apf27 board.

Signed-off-by: Philippe Reynes <tremyfr@yahoo.fr>
---
.../devicetree/bindings/iio/adc/max1027-adc.txt | 22 +
drivers/iio/adc/Kconfig | 9 +
drivers/iio/adc/Makefile | 1 +
drivers/iio/adc/max1027.c | 521 ++++++++++++++++++++
4 files changed, 553 insertions(+), 0 deletions(-)
create mode 100644 Documentation/devicetree/bindings/iio/adc/max1027-adc.txt
create mode 100644 drivers/iio/adc/max1027.c

Changelog:
v7: (thanks Hartmut Knaack and Jonathan Cameron for the feedback)
- use const with info in max1027_state
- use bitops.h (and BIT)
- separate operators with whitespace
- define a reg member in max1027_state

v6: (thanks Peter Meerwald for the feedback)
- dont use index with temperature
- use const on scan mask
- use __be16 * for buffer
- return -EBUSY if trigger is already running
- replace it by interrupt in comment
- dont finish case with ";"
- use iio_push_to_buffers
- remove useless initialization of st->buffer
- remove useless obvious comment

v5: (thanks Jonathan Cameron for the feedback)
- add validate_trigger
- add validate_device
- remove useless (void *) cast
- use allocated buffer for spi_write

v4: (thanks Jonathan Cameron for the feedback)
- use iio_trigger_generic_data_rdy_poll

v3: (thanks Hartmut Knaack, Lars-Peter Clausen and Jonathan Cameron for the feedback)
- move to drivers/iio/adc (was in staging)
- clean binding doc
- drop empty update_scan_mode callback
- add a lock around single channel read code
- remove useless wrappers around spi_write and spi_read
- fix available scan mask (a bit was missing)
- remove useless header
- some others little cleanp

v2: (thanks Hartmut Knaack and Jonathan Cameron for the feedback)
- really use devm_*
- use demux magic
- use spi_read and spi_write (instead of spi_sync)
- use define for register (instead of hardcoded value)

diff --git a/Documentation/devicetree/bindings/iio/adc/max1027-adc.txt b/Documentation/devicetree/bindings/iio/adc/max1027-adc.txt
new file mode 100644
index 0000000..a8770cc
--- /dev/null
+++ b/Documentation/devicetree/bindings/iio/adc/max1027-adc.txt
@@ -0,0 +1,22 @@
+* Maxim 1027/1029/1031 Analog to Digital Converter (ADC)
+
+Required properties:
+ - compatible: Should be "maxim,max1027" or "maxim,max1029" or "maxim,max1031"
+ - reg: SPI chip select number for the device
+ - interrupt-parent: phandle to the parent interrupt controller
+ see: Documentation/devicetree/bindings/interrupt-controller/interrupts.txt
+ - interrupts: IRQ line for the ADC
+ see: Documentation/devicetree/bindings/interrupt-controller/interrupts.txt
+
+Recommended properties:
+- spi-max-frequency: Definition as per
+ Documentation/devicetree/bindings/spi/spi-bus.txt
+
+Example:
+adc@0 {
+ compatible = "maxim,max1027";
+ reg = <0>;
+ interrupt-parent = <&gpio5>;
+ interrupts = <15 IRQ_TYPE_EDGE_RISING>;
+ spi-max-frequency = <1000000>;
+};
diff --git a/drivers/iio/adc/Kconfig b/drivers/iio/adc/Kconfig
index a80d236..20a7073 100644
--- a/drivers/iio/adc/Kconfig
+++ b/drivers/iio/adc/Kconfig
@@ -131,6 +131,15 @@ config LP8788_ADC
help
Say yes here to build support for TI LP8788 ADC.

+config MAX1027
+ tristate "Maxim max1027 ADC driver"
+ depends on SPI
+ select IIO_BUFFER
+ select IIO_TRIGGERED_BUFFER
+ help
+ Say yes here to build support for Maxim SPI ADC models
+ max1027, max1029 and max1031.
+
config MAX1363
tristate "Maxim max1363 ADC driver"
depends on I2C
diff --git a/drivers/iio/adc/Makefile b/drivers/iio/adc/Makefile
index 9d60f2d..38cf5c3 100644
--- a/drivers/iio/adc/Makefile
+++ b/drivers/iio/adc/Makefile
@@ -15,6 +15,7 @@ obj-$(CONFIG_AD799X) += ad799x.o
obj-$(CONFIG_AT91_ADC) += at91_adc.o
obj-$(CONFIG_EXYNOS_ADC) += exynos_adc.o
obj-$(CONFIG_LP8788_ADC) += lp8788_adc.o
+obj-$(CONFIG_MAX1027) += max1027.o
obj-$(CONFIG_MAX1363) += max1363.o
obj-$(CONFIG_MCP320X) += mcp320x.o
obj-$(CONFIG_MCP3422) += mcp3422.o
diff --git a/drivers/iio/adc/max1027.c b/drivers/iio/adc/max1027.c
new file mode 100644
index 0000000..87ee1c7
--- /dev/null
+++ b/drivers/iio/adc/max1027.c
@@ -0,0 +1,521 @@
+ /*
+ * iio/adc/max1027.c
+ * Copyright (C) 2014 Philippe Reynes
+ *
+ * based on linux/drivers/iio/ad7923.c
+ * Copyright 2011 Analog Devices Inc (from AD7923 Driver)
+ * Copyright 2012 CS Systemes d'Information
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ *
+ * max1027.c
+ *
+ * Partial support for max1027 and similar chips.
+ */
+
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/spi/spi.h>
+#include <linux/delay.h>
+
+#include <linux/iio/iio.h>
+#include <linux/iio/buffer.h>
+#include <linux/iio/trigger.h>
+#include <linux/iio/trigger_consumer.h>
+#include <linux/iio/triggered_buffer.h>
+
+#define MAX1027_CONV_REG BIT(7)
+#define MAX1027_SETUP_REG BIT(6)
+#define MAX1027_AVG_REG BIT(5)
+#define MAX1027_RST_REG BIT(4)
+
+/* conversion register */
+#define MAX1027_TEMP BIT(0)
+#define MAX1027_SCAN_0_N (0x00 << 1)
+#define MAX1027_SCAN_N_M (0x01 << 1)
+#define MAX1027_SCAN_N (0x02 << 1)
+#define MAX1027_NOSCAN (0x03 << 1)
+#define MAX1027_CHAN(n) ((n) << 3)
+
+/* setup register */
+#define MAX1027_UNIPOLAR 0x02
+#define MAX1027_BIPOLAR 0x03
+#define MAX1027_REF_MODE0 (0x00 << 2)
+#define MAX1027_REF_MODE1 (0x01 << 2)
+#define MAX1027_REF_MODE2 (0x02 << 2)
+#define MAX1027_REF_MODE3 (0x03 << 2)
+#define MAX1027_CKS_MODE0 (0x00 << 4)
+#define MAX1027_CKS_MODE1 (0x01 << 4)
+#define MAX1027_CKS_MODE2 (0x02 << 4)
+#define MAX1027_CKS_MODE3 (0x03 << 4)
+
+/* averaging register */
+#define MAX1027_NSCAN_4 0x00
+#define MAX1027_NSCAN_8 0x01
+#define MAX1027_NSCAN_12 0x02
+#define MAX1027_NSCAN_16 0x03
+#define MAX1027_NAVG_4 (0x00 << 2)
+#define MAX1027_NAVG_8 (0x01 << 2)
+#define MAX1027_NAVG_16 (0x02 << 2)
+#define MAX1027_NAVG_32 (0x03 << 2)
+#define MAX1027_AVG_EN BIT(4)
+
+enum max1027_id {
+ max1027,
+ max1029,
+ max1031,
+};
+
+static const struct spi_device_id max1027_id[] = {
+ {"max1027", max1027},
+ {"max1029", max1029},
+ {"max1031", max1031},
+ {}
+};
+MODULE_DEVICE_TABLE(spi, max1027_id);
+
+#ifdef CONFIG_OF
+static const struct of_device_id max1027_adc_dt_ids[] = {
+ { .compatible = "maxim,max1027" },
+ { .compatible = "maxim,max1029" },
+ { .compatible = "maxim,max1031" },
+ {},
+};
+MODULE_DEVICE_TABLE(of, max1027_adc_dt_ids);
+#endif
+
+#define MAX1027_V_CHAN(index) \
+ { \
+ .type = IIO_VOLTAGE, \
+ .indexed = 1, \
+ .channel = index, \
+ .info_mask_separate = BIT(IIO_CHAN_INFO_RAW), \
+ .info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE), \
+ .scan_index = index + 1, \
+ .scan_type = { \
+ .sign = 'u', \
+ .realbits = 10, \
+ .storagebits = 16, \
+ .shift = 2, \
+ .endianness = IIO_BE, \
+ }, \
+ }
+
+#define MAX1027_T_CHAN \
+ { \
+ .type = IIO_TEMP, \
+ .channel = 0, \
+ .info_mask_separate = BIT(IIO_CHAN_INFO_RAW), \
+ .info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE), \
+ .scan_index = 0, \
+ .scan_type = { \
+ .sign = 'u', \
+ .realbits = 12, \
+ .storagebits = 16, \
+ .endianness = IIO_BE, \
+ }, \
+ }
+
+static const struct iio_chan_spec max1027_channels[] = {
+ MAX1027_T_CHAN,
+ MAX1027_V_CHAN(0),
+ MAX1027_V_CHAN(1),
+ MAX1027_V_CHAN(2),
+ MAX1027_V_CHAN(3),
+ MAX1027_V_CHAN(4),
+ MAX1027_V_CHAN(5),
+ MAX1027_V_CHAN(6),
+ MAX1027_V_CHAN(7)
+};
+
+static const struct iio_chan_spec max1029_channels[] = {
+ MAX1027_T_CHAN,
+ MAX1027_V_CHAN(0),
+ MAX1027_V_CHAN(1),
+ MAX1027_V_CHAN(2),
+ MAX1027_V_CHAN(3),
+ MAX1027_V_CHAN(4),
+ MAX1027_V_CHAN(5),
+ MAX1027_V_CHAN(6),
+ MAX1027_V_CHAN(7),
+ MAX1027_V_CHAN(8),
+ MAX1027_V_CHAN(9),
+ MAX1027_V_CHAN(10),
+ MAX1027_V_CHAN(11)
+};
+
+static const struct iio_chan_spec max1031_channels[] = {
+ MAX1027_T_CHAN,
+ MAX1027_V_CHAN(0),
+ MAX1027_V_CHAN(1),
+ MAX1027_V_CHAN(2),
+ MAX1027_V_CHAN(3),
+ MAX1027_V_CHAN(4),
+ MAX1027_V_CHAN(5),
+ MAX1027_V_CHAN(6),
+ MAX1027_V_CHAN(7),
+ MAX1027_V_CHAN(8),
+ MAX1027_V_CHAN(9),
+ MAX1027_V_CHAN(10),
+ MAX1027_V_CHAN(11),
+ MAX1027_V_CHAN(12),
+ MAX1027_V_CHAN(13),
+ MAX1027_V_CHAN(14),
+ MAX1027_V_CHAN(15)
+};
+
+static const unsigned long max1027_available_scan_masks[] = {
+ 0x000001ff,
+ 0x00000000,
+};
+
+static const unsigned long max1029_available_scan_masks[] = {
+ 0x00001fff,
+ 0x00000000,
+};
+
+static const unsigned long max1031_available_scan_masks[] = {
+ 0x0001ffff,
+ 0x00000000,
+};
+
+struct max1027_chip_info {
+ const struct iio_chan_spec *channels;
+ unsigned int num_channels;
+ const unsigned long *available_scan_masks;
+};
+
+static const struct max1027_chip_info max1027_chip_info_tbl[] = {
+ [max1027] = {
+ .channels = max1027_channels,
+ .num_channels = ARRAY_SIZE(max1027_channels),
+ .available_scan_masks = max1027_available_scan_masks,
+ },
+ [max1029] = {
+ .channels = max1029_channels,
+ .num_channels = ARRAY_SIZE(max1029_channels),
+ .available_scan_masks = max1029_available_scan_masks,
+ },
+ [max1031] = {
+ .channels = max1031_channels,
+ .num_channels = ARRAY_SIZE(max1031_channels),
+ .available_scan_masks = max1031_available_scan_masks,
+ },
+};
+
+struct max1027_state {
+ const struct max1027_chip_info *info;
+ struct spi_device *spi;
+ struct iio_trigger *trig;
+ __be16 *buffer;
+ struct mutex lock;
+
+ u8 reg ____cacheline_aligned;
+};
+
+static int max1027_read_single_value(struct iio_dev *indio_dev,
+ struct iio_chan_spec const *chan,
+ int *val)
+{
+ int ret;
+ struct max1027_state *st = iio_priv(indio_dev);
+
+ if (iio_buffer_enabled(indio_dev)) {
+ dev_warn(&indio_dev->dev, "trigger mode already enabled");
+ return -EBUSY;
+ }
+
+ /* Start acquisition on conversion register write */
+ st->reg = MAX1027_SETUP_REG | MAX1027_REF_MODE2 | MAX1027_CKS_MODE2;
+ ret = spi_write(st->spi, &st->reg, 1);
+ if (ret < 0) {
+ dev_err(&indio_dev->dev,
+ "Failed to configure setup register\n");
+ return ret;
+ }
+
+ /* Configure conversion register with the requested chan */
+ st->reg = MAX1027_CONV_REG | MAX1027_CHAN(chan->channel) |
+ MAX1027_NOSCAN | !!(chan->type == IIO_TEMP);
+ ret = spi_write(st->spi, &st->reg, 1);
+ if (ret < 0) {
+ dev_err(&indio_dev->dev,
+ "Failed to configure conversion register\n");
+ return ret;
+ }
+
+ /*
+ * For an unknown reason, when we use the mode "10" (write
+ * conversion register), the interrupt doesn't occur every time.
+ * So we just wait 1 ms.
+ */
+ mdelay(1);
+
+ /* Read result */
+ ret = spi_read(st->spi, st->buffer, (chan->type == IIO_TEMP) ? 4 : 2);
+ if (ret < 0)
+ return ret;
+
+ *val = be16_to_cpu(st->buffer[0]);
+
+ return IIO_VAL_INT;
+}
+
+static int max1027_read_raw(struct iio_dev *indio_dev,
+ struct iio_chan_spec const *chan,
+ int *val, int *val2, long mask)
+{
+ int ret = 0;
+ struct max1027_state *st = iio_priv(indio_dev);
+
+ mutex_lock(&st->lock);
+
+ switch (mask) {
+ case IIO_CHAN_INFO_RAW:
+ ret = max1027_read_single_value(indio_dev, chan, val);
+ break;
+ case IIO_CHAN_INFO_SCALE:
+ switch (chan->type) {
+ case IIO_TEMP:
+ *val = 1;
+ *val2 = 8;
+ ret = IIO_VAL_FRACTIONAL;
+ break;
+ case IIO_VOLTAGE:
+ *val = 2500;
+ *val2 = 10;
+ ret = IIO_VAL_FRACTIONAL_LOG2;
+ break;
+ default:
+ ret = -EINVAL;
+ break;
+ }
+ break;
+ default:
+ ret = -EINVAL;
+ break;
+ }
+
+ mutex_unlock(&st->lock);
+
+ return ret;
+}
+
+static int max1027_debugfs_reg_access(struct iio_dev *indio_dev,
+ unsigned reg, unsigned writeval,
+ unsigned *readval)
+{
+ struct max1027_state *st = iio_priv(indio_dev);
+ u8 *val = (u8 *)st->buffer;
+
+ if (readval != NULL)
+ return -EINVAL;
+
+ *val = (u8)writeval;
+ return spi_write(st->spi, val, 1);
+}
+
+static int max1027_validate_trigger(struct iio_dev *indio_dev,
+ struct iio_trigger *trig)
+{
+ struct max1027_state *st = iio_priv(indio_dev);
+
+ if (st->trig != trig)
+ return -EINVAL;
+
+ return 0;
+}
+
+static int max1027_set_trigger_state(struct iio_trigger *trig, bool state)
+{
+ struct iio_dev *indio_dev = iio_trigger_get_drvdata(trig);
+ struct max1027_state *st = iio_priv(indio_dev);
+ int ret;
+
+ if (state) {
+ /* Start acquisition on cnvst */
+ st->reg = MAX1027_SETUP_REG | MAX1027_CKS_MODE0 |
+ MAX1027_REF_MODE2;
+ ret = spi_write(st->spi, &st->reg, 1);
+ if (ret < 0)
+ return ret;
+
+ /* Scan from 0 to max */
+ st->reg = MAX1027_CONV_REG | MAX1027_CHAN(0) |
+ MAX1027_SCAN_N_M | MAX1027_TEMP;
+ ret = spi_write(st->spi, &st->reg, 1);
+ if (ret < 0)
+ return ret;
+ } else {
+ /* Start acquisition on conversion register write */
+ st->reg = MAX1027_SETUP_REG | MAX1027_CKS_MODE2 |
+ MAX1027_REF_MODE2;
+ ret = spi_write(st->spi, &st->reg, 1);
+ if (ret < 0)
+ return ret;
+ }
+
+ return 0;
+}
+
+static int max1027_validate_device(struct iio_trigger *trig,
+ struct iio_dev *indio_dev)
+{
+ struct iio_dev *indio = iio_trigger_get_drvdata(trig);
+
+ if (indio != indio_dev)
+ return -EINVAL;
+
+ return 0;
+}
+
+static irqreturn_t max1027_trigger_handler(int irq, void *private)
+{
+ struct iio_poll_func *pf = (struct iio_poll_func *)private;
+ struct iio_dev *indio_dev = pf->indio_dev;
+ struct max1027_state *st = iio_priv(indio_dev);
+
+ pr_debug("%s(irq=%d, private=0x%p)\n", __func__, irq, private);
+
+ /* fill buffer with all channel */
+ spi_read(st->spi, st->buffer, indio_dev->masklength * 2);
+
+ iio_push_to_buffers(indio_dev, st->buffer);
+
+ iio_trigger_notify_done(indio_dev->trig);
+
+ return IRQ_HANDLED;
+}
+
+static const struct iio_trigger_ops max1027_trigger_ops = {
+ .owner = THIS_MODULE,
+ .validate_device = &max1027_validate_device,
+ .set_trigger_state = &max1027_set_trigger_state,
+};
+
+static const struct iio_info max1027_info = {
+ .driver_module = THIS_MODULE,
+ .read_raw = &max1027_read_raw,
+ .validate_trigger = &max1027_validate_trigger,
+ .debugfs_reg_access = &max1027_debugfs_reg_access,
+};
+
+static int max1027_probe(struct spi_device *spi)
+{
+ int ret;
+ struct iio_dev *indio_dev;
+ struct max1027_state *st;
+
+ pr_debug("%s: probe(spi = 0x%p)\n", __func__, spi);
+
+ indio_dev = devm_iio_device_alloc(&spi->dev, sizeof(*st));
+ if (indio_dev == NULL) {
+ pr_err("Can't allocate iio device\n");
+ return -ENOMEM;
+ }
+
+ spi_set_drvdata(spi, indio_dev);
+
+ st = iio_priv(indio_dev);
+ st->spi = spi;
+ st->info = &max1027_chip_info_tbl[spi_get_device_id(spi)->driver_data];
+
+ mutex_init(&st->lock);
+
+ indio_dev->name = spi_get_device_id(spi)->name;
+ indio_dev->dev.parent = &spi->dev;
+ indio_dev->info = &max1027_info;
+ indio_dev->modes = INDIO_DIRECT_MODE;
+ indio_dev->channels = st->info->channels;
+ indio_dev->num_channels = st->info->num_channels;
+ indio_dev->available_scan_masks = st->info->available_scan_masks;
+
+ st->buffer = devm_kmalloc(&indio_dev->dev,
+ indio_dev->num_channels * 2,
+ GFP_KERNEL);
+ if (st->buffer == NULL) {
+ dev_err(&indio_dev->dev, "Can't allocate bufffer\n");
+ return -ENOMEM;
+ }
+
+ ret = iio_triggered_buffer_setup(indio_dev, &iio_pollfunc_store_time,
+ &max1027_trigger_handler, NULL);
+ if (ret < 0) {
+ dev_err(&indio_dev->dev, "Failed to setup buffer\n");
+ return ret;
+ }
+
+ st->trig = devm_iio_trigger_alloc(&spi->dev, "%s-trigger",
+ indio_dev->name);
+ if (st->trig == NULL) {
+ ret = -ENOMEM;
+ dev_err(&indio_dev->dev, "Failed to allocate iio trigger\n");
+ goto fail_trigger_alloc;
+ }
+
+ st->trig->ops = &max1027_trigger_ops;
+ st->trig->dev.parent = &spi->dev;
+ iio_trigger_set_drvdata(st->trig, indio_dev);
+ iio_trigger_register(st->trig);
+
+ ret = devm_request_threaded_irq(&spi->dev, spi->irq,
+ iio_trigger_generic_data_rdy_poll,
+ NULL,
+ IRQF_TRIGGER_FALLING,
+ spi->dev.driver->name, st->trig);
+ if (ret < 0) {
+ dev_err(&indio_dev->dev, "Failed to allocate IRQ.\n");
+ goto fail_dev_register;
+ }
+
+ /* Disable averaging */
+ st->reg = MAX1027_AVG_REG;
+ ret = spi_write(st->spi, &st->reg, 1);
+ if (ret < 0) {
+ dev_err(&indio_dev->dev, "Failed to configure averaging register\n");
+ goto fail_dev_register;
+ }
+
+ ret = iio_device_register(indio_dev);
+ if (ret < 0) {
+ dev_err(&indio_dev->dev, "Failed to register iio device\n");
+ goto fail_dev_register;
+ }
+
+ return 0;
+
+fail_dev_register:
+fail_trigger_alloc:
+ iio_triggered_buffer_cleanup(indio_dev);
+
+ return ret;
+}
+
+static int max1027_remove(struct spi_device *spi)
+{
+ struct iio_dev *indio_dev = spi_get_drvdata(spi);
+
+ pr_debug("%s: remove(spi = 0x%p)\n", __func__, spi);
+
+ iio_device_unregister(indio_dev);
+ iio_triggered_buffer_cleanup(indio_dev);
+
+ return 0;
+}
+
+static struct spi_driver max1027_driver = {
+ .driver = {
+ .name = "max1027",
+ .owner = THIS_MODULE,
+ },
+ .probe = max1027_probe,
+ .remove = max1027_remove,
+ .id_table = max1027_id,
+};
+module_spi_driver(max1027_driver);
+
+MODULE_AUTHOR("Philippe Reynes <tremyfr@yahoo.fr>");
+MODULE_DESCRIPTION("MAX1027/MAX1029/MAX1031 ADC");
+MODULE_LICENSE("GPL v2");
--
1.7.4.4


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