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

From: Hartmut Knaack
Date: Mon May 26 2014 - 18:33:44 EST

trem schrieb:
> Hi Hartmut,
>
> First, thanks a lot for this feedback, I really appreciate it.
>
>
> On 26/05/14 00:52, Hartmut Knaack wrote:
>> 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@xxxxxxxx>
>>> ---
>>> .../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).
> My datasheet has the same value, I'll fix this mistake in v3.
>
>>> +#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?
> Yes, fixed in v3.
>
>>> +};
>>> +
>>> +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.
> I've remove this function (and max10247_read_value) in v3.
>
>>> +
>>> +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.
> I'll remove it in v3.
>
>>> +{
>>> + 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.
> For an unknown reason, the max1027 on my armadeus apf27 don't raise
> an it when I use the mode "10" (acquisition started on convertion write).
> In fact, it's weird, there is an IT when I read temperature, but not
> when I read a voltage.
So what is "IT"? "Internally timed" or some abbreviation for interrupt?
>
> # grep max /proc/interrupts
> 223: 110213 gpio-mxc 15 max1027
> 272: 110200 max1027-trigger
>
>
> # cat /sys/bus/iio/devices/iio\:device0/in_voltage0_raw
> 2589
> # grep max /proc/interrupts
> 223: 110213 gpio-mxc 15 max1027
> 272: 110200 max1027-trigger
>
> # cat /sys/bus/iio/devices/iio\:device0/in_temp_raw
> 214
> # grep max /proc/interrupts
> 223: 110214 gpio-mxc 15 max1027
> 272: 110200 max1027-trigger
>
> So with mode "10", I use a delay of 1 ms.
>
>
>
>>> + * 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?
> When the temperature is read, the voltage is also read. So 4 bytes need to be read in the FIFO,
> 2 for the temperature, 2 for the voltage.
>
> This is described in the "Internal FIFO" paragraph.
I read there: "The first 2 bytes of data read out after a temperature measurement always contain the temperature result preceded by four leading zeros, MSB first.". So my interpretation would be, that you could just read those 2 bytes as the temperature and ignore any further data. But that datasheet is not one of the best I've ever read. Any other opinions?
>
>>> + 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).
> You're right, it's better, I'll fix it in v3.
>
>>> + 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 ;-)
> I don't really know, but I'll update it to always use the same way for the "post allocation check".
> I'll update it in v3.
>
>>> + 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@xxxxxxxx>");
>>> +MODULE_DESCRIPTION("MAX1027/MAX1029/MAX1031 ADC");
>>> +MODULE_LICENSE("GPL v2");
>>
> Best regards,
> Philippe
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