Re: [PATCH v2] iio: add support of the max1027

Hartmut Knaack
2014-05-25T22:52:53Z

Philippe Reynes schrieb:
> 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 | 21 +
> drivers/staging/iio/adc/Kconfig | 9 +
> drivers/staging/iio/adc/Makefile | 1 +
> drivers/staging/iio/adc/max1027.c | 553 ++++++++++++++++++++
> 4 files changed, 584 insertions(+), 0 deletions(-)
> create mode 100644 Documentation/devicetree/bindings/iio/adc/max1027-adc.txt
> create mode 100644 drivers/staging/iio/adc/max1027.c
>
> Changelog:
> 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..2e8b9f3
> --- /dev/null
> +++ b/Documentation/devicetree/bindings/iio/adc/max1027-adc.txt
> @@ -0,0 +1,21 @@
> +* Maxim 1027/1029/1031 Analog to Digital Converter (ADC)
> +
> +Required properties:
> + - compatible: Should be "maxim,max1027" or "maxim,max1029" or "maxim,max1031"
> + - reg: Should contain the ADC SPI address
> + - interrupt-parent: the phandle for the gpio controller
> + - interrupts: (gpio) interrupt to which the chip is connected
> +
> +Example:
> +adc@0 {
> + compatible = "maxim,max1027";
> + reg = <0>;
> + interrupt-parent = <&gpio5>;
> + interrupts = <15 IRQ_TYPE_EDGE_RISING>;
> + pinctrl-names = "default";
> + pinctrl-0 = <&pinctrl_max1027>;
> + /* SPI mode = 0 */
> + spi-cpol = <0>;
> + spi-cpha = <0>;
> + spi-max-frequency = <1000000>;
> +};
> diff --git a/drivers/staging/iio/adc/Kconfig b/drivers/staging/iio/adc/Kconfig
> index 3633298..12a78eb 100644
> --- a/drivers/staging/iio/adc/Kconfig
> +++ b/drivers/staging/iio/adc/Kconfig
> @@ -112,6 +112,15 @@ config LPC32XX_ADC
> activate only one via device tree selection. Provides direct access
> via sysfs.
>
> +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 MXS_LRADC
> tristate "Freescale i.MX23/i.MX28 LRADC"
> depends on ARCH_MXS || COMPILE_TEST
> diff --git a/drivers/staging/iio/adc/Makefile b/drivers/staging/iio/adc/Makefile
> index 3e9fb14..22fbd0c 100644
> --- a/drivers/staging/iio/adc/Makefile
> +++ b/drivers/staging/iio/adc/Makefile
> @@ -18,5 +18,6 @@ obj-$(CONFIG_AD7816) += ad7816.o
> obj-$(CONFIG_AD7192) += ad7192.o
> obj-$(CONFIG_AD7280) += ad7280a.o
> obj-$(CONFIG_LPC32XX_ADC) += lpc32xx_adc.o
> +obj-$(CONFIG_MAX1027) += max1027.o
> obj-$(CONFIG_MXS_LRADC) += mxs-lradc.o
> obj-$(CONFIG_SPEAR_ADC) += spear_adc.o
> diff --git a/drivers/staging/iio/adc/max1027.c b/drivers/staging/iio/adc/max1027.c
> new file mode 100644
> index 0000000..c2e5936
> --- /dev/null
> +++ b/drivers/staging/iio/adc/max1027.c
> @@ -0,0 +1,553 @@
> + /*
> + * 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/spi/spi.h>
> +#include <linux/module.h>
> +#include <linux/interrupt.h>
> +#include <linux/mutex.h>
> +#include <linux/of.h>
> +#include <linux/of_gpio.h>
> +#include <linux/platform_device.h>
> +#include <linux/delay.h>
> +#include <linux/gpio.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 0x80
> +#define MAX1027_SETUP_REG 0x40
> +#define MAX1027_AVG_REG 0x20
> +#define MAX1027_RST_REG 0x10
> +
> +/* conversion register */
> +#define MAX1027_TEMP 0x01
> +#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_12 (0x02 << 2)
> +#define MAX1027_NAVG_16 (0x03 << 2)
According to my datasheet (revision 5) [http://datasheets.maximintegrated.com/en/ds/MAX1027-MAX1031.pdf], there is no NAVG_12, but NAVG_16 (0x02 << 2) and NAVG_32 (0x03 << 2).
> +#define MAX1027_AVG_EN (0x01 << 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), \
> + .address = index, \
> + .scan_index = index+1, \
> + .scan_type = { \
> + .sign = 'u', \
> + .realbits = 10, \
> + .storagebits = 16, \
> + .shift = 2, \
> + .endianness = IIO_BE, \
> + }, \
> + }
> +
> +#define MAX1027_T_CHAN(index) \
> + { \
> + .type = IIO_TEMP, \
> + .indexed = 0, \
> + .channel = index, \
> + .info_mask_separate = BIT(IIO_CHAN_INFO_RAW), \
> + .info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE), \
> + .address = index, \
> + .scan_index = index, \
> + .scan_type = { \
> + .sign = 'u', \
> + .realbits = 12, \
> + .storagebits = 16, \
> + .endianness = IIO_BE, \
> + }, \
> + }
> +
> +static const struct iio_chan_spec max1027_channels[] = {
> + MAX1027_T_CHAN(0),
> + 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(0),
> + 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(0),
> + 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 unsigned long max1027_available_scan_masks[] = {
> + 0x00ff,
> + 0x0000,
> +};
> +
> +static unsigned long max1029_available_scan_masks[] = {
> + 0x0fff,
> + 0x0000,
> +};
> +
> +static unsigned long max1031_available_scan_masks[] = {
> + 0xffff,
> + 0x0000,
> +};
> +
> +struct max1027_chip_info {
> + const struct iio_chan_spec *channels;
> + unsigned int num_channels;
> + 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 {
> + struct max1027_chip_info *info;
> + struct spi_device *spi;
> + struct iio_trigger *trig;
> + unsigned short *buffer;
Better use u16 for buffer?
> +};
> +
> +static int max1027_write_register(struct max1027_state *st, unsigned char reg)
> +{
> + int ret;
> +
> + pr_debug("%s(st = 0x%p, reg = 0x%02x)\n", __func__, st, reg);
> +
> + ret = spi_write(st->spi, (void *)&reg, 1);
> + if (ret < 0)
> + pr_err("can't write register\n");
> +
> + return ret;
> +}
As Jonathan pointed out, better get rid of those debug wrapper functions. Otherwise, think about using typedefs like u8 for 8 bit registers.
> +
> +static int max1027_read_value(struct max1027_state *st, int len)
> +{
> + int ret;
> +
> + pr_debug("%s(st = 0x%p, len = %d)\n", __func__, st, len);
> +
> + ret = spi_read(st->spi, st->buffer, len);
> + if (ret < 0)
> + pr_err("can't read value\n");
> +
> + return ret;
> +}
> +
> +static int max1027_read_single_value(struct iio_dev *indio_dev,
> + struct iio_chan_spec const *chan,
> + int *val, int *val2, long mask)
val2 and mask are not used.
> +{
> + int ret;
> + unsigned char reg;
> + struct max1027_state *st = iio_priv(indio_dev);
> +
> + if (iio_buffer_enabled(indio_dev)) {
> + dev_warn(&indio_dev->dev, "trigger mode already enabled");
> + return -EIO;
> + }
> +
> + /* Start acquisition on conversion register write */
> + reg = MAX1027_SETUP_REG | MAX1027_REF_MODE2 | MAX1027_CKS_MODE2;
> + ret = max1027_write_register(st, reg);
> + if (ret < 0) {
> + dev_err(&indio_dev->dev,
> + "Failed to configure setup register\n");
> + return ret;
> + }
> +
> + /* Configure conversion register with the requested chan */
> + reg = MAX1027_CONV_REG | MAX1027_CHAN(chan->channel)
> + | MAX1027_NOSCAN | !!(chan->type == IIO_TEMP);
> + ret = max1027_write_register(st, reg);
> + 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 it doesn't occur every time.
I still don't understand this comment.
> + * So we just wait 1 ms.
> + */
> + mdelay(1);
> +
> + /* Read result */
> + ret = max1027_read_value(st, (chan->type == IIO_TEMP) ? 4 : 2);
I guess I didn't have a look into the datasheet before, when reviewing this part, but could you point me to where it is stated, that temperature measurements take 4 bytes?
> + 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;
> +
> + switch (mask) {
> + case IIO_CHAN_INFO_RAW:
> + ret = max1027_read_single_value(indio_dev, chan,
> + val, val2, mask);
> + 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;
> + };
> +
> + return ret;
> +}
> +
> +static int max1027_update_scan_mode(struct iio_dev *indio_dev,
> + const unsigned long *scan_mask)
> +{
> + pr_debug("%s(indio_dev=0x%p, scan_mask=0x%p)\n",
> + __func__, indio_dev, scan_mask);
> +
> + return 0;
> +}
> +
> +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);
> +
> + if (readval != NULL)
> + return -EINVAL;
> +
> + return max1027_write_register(st, writeval);
> +}
> +
> +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);
> + unsigned char reg;
> + int ret;
> +
> + if (state) {
> + /* Start acquisition on cnvst */
> + reg = MAX1027_SETUP_REG | MAX1027_CKS_MODE0 | MAX1027_REF_MODE2;
> + ret = max1027_write_register(st, reg);
> + if (ret < 0)
> + return ret;
> +
> + /* Scan from 0 to max */
> + reg = MAX1027_CONV_REG | MAX1027_CHAN(0)
> + | MAX1027_SCAN_N_M | MAX1027_TEMP;
> + ret = max1027_write_register(st, reg);
> + if (ret < 0)
> + return ret;
> + } else {
> + /* Start acquisition on conversion register write */
> + reg = MAX1027_SETUP_REG | MAX1027_REF_MODE2 | MAX1027_CKS_MODE2;
Just for improved readability, keep the same order as above (MSB to LSB in your case).
> + ret = max1027_write_register(st, reg);
> + if (ret < 0)
> + return ret;
> + }
> +
> + return 0;
> +}
> +
> +static irqreturn_t max1027_interrupt_handler(int irq, void *private)
> +{
> + struct iio_dev *indio_dev = (struct iio_dev *)private;
> +
> + pr_debug("%s(irq=%d, private=0x%p)\n", __func__, irq, private);
> +
> + if (iio_buffer_enabled(indio_dev))
> + iio_trigger_poll(indio_dev->trig, iio_get_time_ns());
> +
> + return IRQ_HANDLED;
> +}
> +
> +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 */
> + max1027_read_value(st, indio_dev->masklength * 2);
> +
> + iio_push_to_buffers_with_timestamp(indio_dev, st->buffer,
> + iio_get_time_ns());
> +
> + iio_trigger_notify_done(indio_dev->trig);
> +
> + return IRQ_HANDLED;
> +}
> +
> +static const struct iio_trigger_ops max1027_trigger_ops = {
> + .owner = THIS_MODULE,
> + .set_trigger_state = &max1027_set_trigger_state,
> +};
> +
> +static const struct iio_info max1027_info = {
> + .driver_module = THIS_MODULE,
> + .read_raw = &max1027_read_raw,
> + .update_scan_mode = &max1027_update_scan_mode,
> + .debugfs_reg_access = &max1027_debugfs_reg_access,
> +};
> +
> +static int max1027_probe(struct spi_device *spi)
> +{
> + int err;
> + struct iio_dev *indio_dev;
> + struct max1027_state *st;
> +
> + pr_debug("%s: probe(spi = 0x%p)\n", __func__, spi);
> +
> + /* allocate iio device */
> + indio_dev = devm_iio_device_alloc(&spi->dev,
> + sizeof(struct max1027_state));
> + if (!indio_dev) {
> + 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->buffer = NULL;
> + st->info = (struct max1027_chip_info *)
> + &max1027_chip_info_tbl[spi_get_device_id(spi)->driver_data];
> +
> + /* request irq */
> + err = devm_request_threaded_irq(&spi->dev, spi->irq,
> + max1027_interrupt_handler,
> + NULL,
> + IRQF_TRIGGER_FALLING,
> + spi->dev.driver->name, indio_dev);
> + if (err) {
> + dev_err(&indio_dev->dev, "Failed to allocate IRQ.\n");
> + return err;
> + }
> +
> + 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;
> +
> + /* Allocate buffer (data) */
> + st->buffer = devm_kmalloc(&indio_dev->dev,
> + indio_dev->num_channels * 2,
> + GFP_KERNEL);
> + if (st->buffer == NULL) {
As picky as I am, I could ask why you check for successful allocation in a different way than above for indio_dev ;-)
> + dev_err(&indio_dev->dev, "Can't allocate bufffer\n");
> + return -ENOMEM;
> + }
> +
> + /* Allocate buffer */
> + err = iio_triggered_buffer_setup(indio_dev, &iio_pollfunc_store_time,
> + &max1027_trigger_handler, NULL);
> + if (err < 0) {
> + dev_err(&indio_dev->dev, "Failed to setup buffer\n");
> + return err;
> + }
> +
> + /* Allocate trigger */
> + st->trig = devm_iio_trigger_alloc(&spi->dev, "%s-trigger",
> + indio_dev->name);
> + if (st->trig == NULL) {
> + err = -ENOMEM;
> + dev_err(&indio_dev->dev, "Failed to allocate iio trigger\n");
> + goto fail_trigger_alloc;
> + }
> +
> + /* configure and register trigger */
> + 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);
> +
> + /* Disable averaging */
> + err = max1027_write_register(st, MAX1027_AVG_REG);
> + if (err < 0) {
> + dev_err(&indio_dev->dev, "Failed to configure averaging register\n");
> + goto fail_dev_register;
> + }
> +
> + /* Register the device */
> + err = iio_device_register(indio_dev);
> + if (err < 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 err;
> +}
> +
> +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");