> This adds a driver for the Asahi Kasei AK8975 and its sibling
> AMI305 magnetometers. It was deployed on scale in 2009 on a
> multitude of devices. It is distincly different from AK8973
> and AK8975 and needs its own driver.
comments below
> This patch is based on the long lost work of Samu Onkalo at Nokia,
> who made a misc character device driver for the Maemo/MeeGo Nokia
> devices, before the time of the IIO subsystem. It was mounted in e.g.
> the Nokia N950, N8, N86, N97 etc. It is also mounted on the
> ST-Ericsson HREF reference designs.
>
> It works nicely in sysfs:
>
> $ cat in_magn_x_raw && cat in_magn_y_raw && cat in_magn_z_raw
> -55
> -101
> 161
>
> And with buffered reads using a simple HRTimer trigger:
> $ generic_buffer -c10 -a -n ak8974 -t foo
> iio device number being used is 3
> iio trigger number being used is 2
> No channels are enabled, enabling all channels
> Enabling: in_magn_x_en
> Enabling: in_magn_y_en
> Enabling: in_magn_z_en
> Enabling: in_timestamp_en
> /sys/bus/iio/devices/iio:device3 foo
> -58.000000 -102.000000 157.000000 946684970985321044
> -60.000000 -98.000000 159.000000 946684971012237548
> -60.000000 -106.000000 163.000000 946684971032257080
> -62.000000 -94.000000 169.000000 946684971052185058
> -58.000000 -98.000000 163.000000 946684971072204589
> -54.000000 -100.000000 163.000000 946684971092224121
> -53.000000 -103.000000 164.000000 946684971112731933
> -50.000000 -102.000000 165.000000 946684971132232666
> -61.000000 -101.000000 164.000000 946684971152191162
> -57.000000 -99.000000 168.000000 946684971172210693
> Disabling: in_magn_x_en
> Disabling: in_magn_y_en
> Disabling: in_magn_z_en
> Disabling: in_timestamp_en
>
> I cannot currently scale these raw values to gauss. This is
> because of lack of documentation. I have sent a request for
> a datasheet to Asahi Kasei.
>
> The driver can optionally use a DRDY line IRQ to capture data,
> else it will sleep and poll.
>
> Cc: Samu Onkalo <samu.onkalo@xxxxxxxxx>
> Cc: Sebastian Reichel <sre@xxxxxxxxxx>
> Tested-By: Sebastian Reichel <sre@xxxxxxxxxx>
> Signed-off-by: Linus Walleij <linus.walleij@xxxxxxxxxx>
> ---
> ChangeLog v3->v4:
> - Add support for an optional mounting matrix
> ChangeLog v2->v3:
> - Employ the blankline-before-return-if-last-statement-in-a-function
> syntax design pattern.
> - Join dereferencing of state container struct into a single line
> in runtime suspend/resume
> - Fix some missing prefixes for ak8974_avdd_reg; etc
> - Use GOTO try/catch construction in ak8974_runtime_resume()
> - Fix locking issues found by coccinelle
> - Speling
> ChangeLog v1->v2:
> - Drop pointless dependency on GPIOLIB in Kconfig
> - Drop the "clever" ret |= returncode code and bail out directly
> on any regmap errors
> - Add a mutex around measurements so we don't collide, this
> could happen atleast in theory
> - Inline the read_axes() function into the *read_raw() function
> and avoid a pointless helper function
> - Augment HW value buffer to be 8*16 bits = 2*64 bits so that it
> is aligned to 64bit boundary for the triggered buffer
> - Fix a pair of missing if () {} brackets in the runtime resume
> function
> - Drop erroneous AK8974/5 claim in module description
> - Various whitespace fixes
> ---
> MAINTAINERS | 7 +
> drivers/iio/magnetometer/Kconfig | 16 +-
> drivers/iio/magnetometer/Makefile | 1 +
> drivers/iio/magnetometer/ak8974.c | 871 ++++++++++++++++++++++++++++++++++++++
> 4 files changed, 894 insertions(+), 1 deletion(-)
> create mode 100644 drivers/iio/magnetometer/ak8974.c
>
> diff --git a/MAINTAINERS b/MAINTAINERS
> index e1b090f86e0d..ab042b142cef 100644
> --- a/MAINTAINERS
> +++ b/MAINTAINERS
> @@ -1930,6 +1930,13 @@ S: Maintained
> F: drivers/media/i2c/as3645a.c
> F: include/media/i2c/as3645a.h
>
> +ASAHI KASEI AK8974 DRIVER
> +M: Linus Walleij <linus.walleij@xxxxxxxxxx>
> +L: linux-iio@xxxxxxxxxxxxxxx
> +W: http://www.akm.com/
> +S: Supported
> +F: drivers/iio/magnetometer/ak8974.c
> +
> ASC7621 HARDWARE MONITOR DRIVER
> M: George Joseph <george.joseph@xxxxxxxxxxxxx>
> L: linux-hwmon@xxxxxxxxxxxxxxx
> diff --git a/drivers/iio/magnetometer/Kconfig b/drivers/iio/magnetometer/Kconfig
> index 84e6559ccc65..76fcb7b51b45 100644
> --- a/drivers/iio/magnetometer/Kconfig
> +++ b/drivers/iio/magnetometer/Kconfig
> @@ -5,8 +5,22 @@
>
> menu "Magnetometer sensors"
>
> +config AK8974
> + tristate "Asahi Kasei AK8974 3-Axis Magnetometer"
> + depends on I2C
> + depends on OF
> + select REGMAP_I2C
> + select IIO_BUFFER
> + select IIO_TRIGGERED_BUFFER
> + help
> + Say yes here to build support for Asahi Kasei AK8974 or
> + AMI305 I2C-based 3-axis magnetometer chips.
> +
> + To compile this driver as a module, choose M here: the module
> + will be called ak8974.
> +
> config AK8975
> - tristate "Asahi Kasei AK 3-Axis Magnetometer"
> + tristate "Asahi Kasei AK8975 3-Axis Magnetometer"
> depends on I2C
> depends on GPIOLIB || COMPILE_TEST
> select IIO_BUFFER
> diff --git a/drivers/iio/magnetometer/Makefile b/drivers/iio/magnetometer/Makefile
> index 92a745c9a6e8..b86d6cb7f285 100644
> --- a/drivers/iio/magnetometer/Makefile
> +++ b/drivers/iio/magnetometer/Makefile
> @@ -3,6 +3,7 @@
> #
>
> # When adding new entries keep the list in alphabetical order
> +obj-$(CONFIG_AK8974) += ak8974.o
> obj-$(CONFIG_AK8975) += ak8975.o
> obj-$(CONFIG_BMC150_MAGN) += bmc150_magn.o
> obj-$(CONFIG_BMC150_MAGN_I2C) += bmc150_magn_i2c.o
> diff --git a/drivers/iio/magnetometer/ak8974.c b/drivers/iio/magnetometer/ak8974.c
> new file mode 100644
> index 000000000000..e2d66b2f7afe
> --- /dev/null
> +++ b/drivers/iio/magnetometer/ak8974.c
> @@ -0,0 +1,871 @@
> +/*
> + * Driver for the Asahi Kasei EMD Corporation AK8974
> + * and Aichi Steel AMI305 magnetometer chips.
> + * Based on a patch from Samu Onkalo and the AK8975 IIO driver.
> + *
> + * Copyright (C) 2010 Nokia Corporation and/or its subsidiary(-ies).
> + * Copyright (c) 2010 NVIDIA Corporation.
> + * Copyright (C) 2016 Linaro Ltd.
> + *
> + * Author: Samu Onkalo <samu.p.onkalo@xxxxxxxxx>
> + * Author: Linus Walleij <linus.walleij@xxxxxxxxxx>
> + */
> +#include <linux/module.h>
> +#include <linux/kernel.h>
> +#include <linux/i2c.h>
> +#include <linux/interrupt.h>
> +#include <linux/irq.h> /* For irq_get_irq_data() */
> +#include <linux/completion.h>
> +#include <linux/err.h>
> +#include <linux/mutex.h>
> +#include <linux/delay.h>
> +#include <linux/bitops.h>
> +#include <linux/regmap.h>
> +#include <linux/regulator/consumer.h>
> +#include <linux/pm_runtime.h>
> +
> +#include <linux/iio/iio.h>
> +#include <linux/iio/sysfs.h>
> +#include <linux/iio/buffer.h>
> +#include <linux/iio/trigger.h>
> +#include <linux/iio/trigger_consumer.h>
> +#include <linux/iio/triggered_buffer.h>
> +
> +/*
> + * 16-bit registers are little-endian. LSB is at the address defined below
> + * and MSB is at the next higher address.
> + */
> +
> +/* These registers are common for AK8974 and AMI305 */
> +#define AK8974_SELFTEST 0x0C
> +#define AK8974_SELFTEST_IDLE 0x55
> +#define AK8974_SELFTEST_OK 0xAA
> +
> +#define AK8974_INFO 0x0D
> +
> +#define AK8974_WHOAMI 0x0F
> +#define AK8974_WHOAMI_VALUE_AMI305 0x47
> +#define AK8974_WHOAMI_VALUE_AK8974 0x48
> +
> +#define AK8974_DATA_X 0x10
> +#define AK8974_DATA_Y 0x12
> +#define AK8974_DATA_Z 0x14
> +#define AK8974_INT_SRC 0x16
> +#define AK8974_STATUS 0x18
> +#define AK8974_INT_CLEAR 0x1A
> +#define AK8974_CTRL1 0x1B
> +#define AK8974_CTRL2 0x1C
> +#define AK8974_CTRL3 0x1D
> +#define AK8974_INT_CTRL 0x1E
> +#define AK8974_INT_THRES 0x26 /* Absolute any axis value threshold */
> +#define AK8974_PRESET 0x30
> +
> +/* AK8974-specific offsets */
> +#define AK8974_OFFSET_X 0x20
> +#define AK8974_OFFSET_Y 0x22
> +#define AK8974_OFFSET_Z 0x24
> +/* AMI305-specific offsets */
> +#define AMI305_OFFSET_X 0x6C
> +#define AMI305_OFFSET_Y 0x72
> +#define AMI305_OFFSET_Z 0x78
> +
> +/* Different temperature registers */
> +#define AK8974_TEMP 0x31
> +#define AMI305_TEMP 0x60
> +
> +#define AK8974_INT_X_HIGH BIT(7) /* Axis over +threshold */
> +#define AK8974_INT_Y_HIGH BIT(6)
> +#define AK8974_INT_Z_HIGH BIT(5)
> +#define AK8974_INT_X_LOW BIT(4) /* Axis below -threshold */
> +#define AK8974_INT_Y_LOW BIT(3)
> +#define AK8974_INT_Z_LOW BIT(2)
> +#define AK8974_INT_RANGE BIT(1) /* Range overflow (any axis) */
> +
> +#define AK8974_STATUS_DRDY BIT(6) /* Data ready */
> +#define AK8974_STATUS_OVERRUN BIT(5) /* Data overrun */
> +#define AK8974_STATUS_INT BIT(4) /* Interrupt occurred */
> +
> +#define AK8974_CTRL1_POWER BIT(7) /* 0 = standby; 1 = active */
> +#define AK8974_CTRL1_RATE BIT(4) /* 0 = 10 Hz; 1 = 20 Hz */
> +#define AK8974_CTRL1_FORCE_EN BIT(1) /* 0 = normal; 1 = force */
> +#define AK8974_CTRL1_MODE2 BIT(0) /* 0 */
> +
> +#define AK8974_CTRL2_INT_EN BIT(4) /* 1 = enable interrupts */
> +#define AK8974_CTRL2_DRDY_EN BIT(3) /* 1 = enable data ready signal */
> +#define AK8974_CTRL2_DRDY_POL BIT(2) /* 1 = data ready active high */
> +#define AK8974_CTRL2_RESDEF (AK8974_CTRL2_DRDY_POL)
> +
> +#define AK8974_CTRL3_RESET BIT(7) /* Software reset */
> +#define AK8974_CTRL3_FORCE BIT(6) /* Start forced measurement */
> +#define AK8974_CTRL3_SELFTEST BIT(4) /* Set selftest register */
> +#define AK8974_CTRL3_RESDEF 0x00
> +
> +#define AK8974_INT_CTRL_XEN BIT(7) /* Enable interrupt for this axis */
> +#define AK8974_INT_CTRL_YEN BIT(6)
> +#define AK8974_INT_CTRL_ZEN BIT(5)
> +#define AK8974_INT_CTRL_XYZEN (BIT(7)|BIT(6)|BIT(5))
> +#define AK8974_INT_CTRL_POL BIT(3) /* 0 = active low; 1 = active high */
> +#define AK8974_INT_CTRL_PULSE BIT(1) /* 0 = latched; 1 = pulse (50 usec) */
> +#define AK8974_INT_CTRL_RESDEF (AK8974_INT_CTRL_XYZEN | AK8974_INT_CTRL_POL)
> +
> +/* The AMI305 has elaborate FW version and serial number registers */
> +#define AMI305_VER 0xE8
> +#define AMI305_SN 0xEA
> +
> +#define AK8974_MAX_RANGE 2048
> +
> +#define AK8974_POWERON_DELAY 50
> +#define AK8974_ACTIVATE_DELAY 1
> +#define AK8974_SELFTEST_DELAY 1
> +/*
> + * Set the autosuspend to two orders of magnitude larger than the poweron
> + * delay to make sake reasonable power tradeoff savings (5 seconds in
sake?
> + * this case).
> + */
> +#define AK8974_AUTOSUSPEND_DELAY 5000
> +
> +#define AK8974_MEASTIME 3
> +
> +#define AK8974_PWR_ON 1
> +#define AK8974_PWR_OFF 0
> +
> +/**
> + * struct ak8974 - state container for the AK8974 driver
> + * @i2c: parent I2C client
> + * @orientation: mounting matrix, flipped axis etc
> + * @map: regmap to access the AK8974 registers over I2C
> + * @regs: the avdd and dvdd power regulators
> + * @name: the name of the part
> + * @variant: the whoami ID value (for selecting code paths)
> + * @lock: locks the magnetometer for exclusive use during a measurement
> + * @drdy_irq: uses the DRDY IRQ line
> + * @drdy_complete: completion for DRDY
> + * @drdy_active_low: the DRDY IRQ is active low
> + */
> +struct ak8974 {
> + struct i2c_client *i2c;
> + struct iio_mount_matrix orientation;
> + struct regmap *map;
> + struct regulator_bulk_data regs[2];
> + const char *name;
> + u8 variant;
> + struct mutex lock;
> + bool drdy_irq;
> + struct completion drdy_complete;
> + bool drdy_active_low;
> +};
> +
> +static const char ak8974_reg_avdd[] = "avdd";
> +static const char ak8974_reg_dvdd[] = "dvdd";
> +
> +static int ak8974_set_power(struct ak8974 *ak8974, bool mode)
> +{
> + int ret;
> + u8 val;
> +
> + val = mode ? AK8974_CTRL1_POWER : 0;
> + val |= AK8974_CTRL1_FORCE_EN;
> + ret = regmap_write(ak8974->map, AK8974_CTRL1, val);
> + if (ret < 0)
> + return ret;
> +
> + if (mode)
> + msleep(AK8974_ACTIVATE_DELAY);
> +
> + return 0;
> +}
> +
> +static int ak8974_reset(struct ak8974 *ak8974)
> +{
> + int ret;
> +
> + /* Power on to get register access. Sets CTRL1 reg to reset state */
> + ret = ak8974_set_power(ak8974, AK8974_PWR_ON);
> + if (ret)
> + return ret;
> + ret = regmap_write(ak8974->map, AK8974_CTRL2, AK8974_CTRL2_RESDEF);
> + if (ret)
> + return ret;
> + ret = regmap_write(ak8974->map, AK8974_CTRL3, AK8974_CTRL3_RESDEF);
> + if (ret)
> + return ret;
> + ret = regmap_write(ak8974->map, AK8974_INT_CTRL,
> + AK8974_INT_CTRL_RESDEF);
> + if (ret)
> + return ret;
> +
> + /* After reset, power off is default state */
> + return ak8974_set_power(ak8974, AK8974_PWR_OFF);
> +}
> +
> +static int ak8974_configure(struct ak8974 *ak8974)
> +{
> + int ret;
> +
> + ret = regmap_write(ak8974->map, AK8974_CTRL2, AK8974_CTRL2_DRDY_EN |
> + AK8974_CTRL2_INT_EN);
> + if (ret)
> + return ret;
> + ret = regmap_write(ak8974->map, AK8974_CTRL3, 0);
> + if (ret)
> + return ret;
> + ret = regmap_write(ak8974->map, AK8974_INT_CTRL, AK8974_INT_CTRL_POL);
> + if (ret)
> + return ret;
> +
> + return regmap_write(ak8974->map, AK8974_PRESET, 0);
> +}
> +
> +static int ak8974_trigmeas(struct ak8974 *ak8974)
> +{
> + unsigned int clear;
> + u8 mask;
> + u8 val;
> + int ret;
> +
> + /* Clear any previous measurement overflow status */
> + ret = regmap_read(ak8974->map, AK8974_INT_CLEAR, &clear);
> + if (ret)
> + return ret;
> +
> + /* If we have a DRDY IRQ line, use it */
> + if (ak8974->drdy_irq) {
> + mask = AK8974_CTRL2_INT_EN |
> + AK8974_CTRL2_DRDY_EN |
> + AK8974_CTRL2_DRDY_POL;
> + val = AK8974_CTRL2_DRDY_EN;
> +
> + if (!ak8974->drdy_active_low)
> + val |= AK8974_CTRL2_DRDY_POL;
> +
> + init_completion(&ak8974->drdy_complete);
> + ret = regmap_update_bits(ak8974->map, AK8974_CTRL2,
> + mask, val);
> + if (ret)
> + return ret;
> + }
> +
> + /* Force a measurement */
> + return regmap_update_bits(ak8974->map,
> + AK8974_CTRL3,
> + AK8974_CTRL3_FORCE,
> + AK8974_CTRL3_FORCE);
> +}
> +
> +static int ak8974_await_drdy(struct ak8974 *ak8974)
> +{
> + int timeout = 2;
> + unsigned int val;
> + int ret;
> +
> + if (ak8974->drdy_irq) {
> + ret = wait_for_completion_timeout(&ak8974->drdy_complete,
> + 1 + msecs_to_jiffies(1000));
> + if (!ret) {
> + dev_err(&ak8974->i2c->dev,
> + "timeout waiting for DRDY IRQ\n");
> + return -ETIMEDOUT;
> + }
> + return 0;
> + }
> +
> + /* Default delay-based poll loop */
> + do {
> + msleep(AK8974_MEASTIME);
> + ret = regmap_read(ak8974->map, AK8974_STATUS, &val);
> + if (ret < 0)
> + return ret;
> + if (val & AK8974_STATUS_DRDY)
> + return 0;
> + } while (--timeout);
> + if (!timeout) {
> + dev_err(&ak8974->i2c->dev,
> + "timeout waiting for DRDY\n");
> + return -ETIMEDOUT;
> + }
> +
> + return 0;
> +}
> +
> +static int ak8974_getresult(struct ak8974 *ak8974, s16 *result)
> +{
> + unsigned int src;
> + int ret;
> + int i;
> +
> + ret = ak8974_await_drdy(ak8974);
> + if (ret)
> + return ret;
> + ret = regmap_read(ak8974->map, AK8974_INT_SRC, &src);
> + if (ret < 0)
> + return ret;
> +
> + /* Out of range overflow! Strong magnet close? */
> + if (src & AK8974_INT_RANGE) {
> + dev_err(&ak8974->i2c->dev,
should this really be reported as an error?
> + "range overflow in sensor\n");
> + return -ERANGE;
> + }
> +
> + ret = regmap_bulk_read(ak8974->map, AK8974_DATA_X, result, 6);
> + if (ret)
> + return ret;
> + for (i = 0; i < 3; i++)
> + result[i] = le16_to_cpu(result[i]);
I would rather NOT do endianness conversion in buffered mode and instead
set IIO_LE in scan_type
can do endianness conversion for ONE channel below in read_raw()
> +
> + return ret;
> +}
> +
> +static irqreturn_t ak8974_drdy_irq(int irq, void *d)
> +{
> + struct ak8974 *ak8974 = d;
> +
> + if (!ak8974->drdy_irq)
> + return IRQ_NONE;
> +
> + /* TODO: timestamp here to get good measurement stamps */
> + return IRQ_WAKE_THREAD;
> +}
> +
> +static irqreturn_t ak8974_drdy_irq_thread(int irq, void *d)
> +{
> + struct ak8974 *ak8974 = d;
> + unsigned int val;
> + int ret;
> +
> + /* Check if this was a DRDY from us */
> + ret = regmap_read(ak8974->map, AK8974_STATUS, &val);
> + if (ret < 0) {
> + dev_err(&ak8974->i2c->dev, "error reading DRDY status\n");
> + return IRQ_HANDLED;
> + }
> + if (val & AK8974_STATUS_DRDY) {
> + /* Yes this was our IRQ */
> + complete(&ak8974->drdy_complete);
> + return IRQ_HANDLED;
> + }
> +
> + /* We may be on a shared IRQ, let the next client check */
> + return IRQ_NONE;
> +}
> +
> +static int ak8974_selftest(struct ak8974 *ak8974)
> +{
> + struct device *dev = &ak8974->i2c->dev;
> + unsigned int val;
> + int ret;
> +
> + ret = regmap_read(ak8974->map, AK8974_SELFTEST, &val);
> + if (ret)
> + return ret;
> + if (val != AK8974_SELFTEST_IDLE) {
> + dev_err(dev, "selftest not idle before test\n");
> + return -EIO;
> + }
> +
> + /* Trigger self-test */
> + ret = regmap_update_bits(ak8974->map,
> + AK8974_CTRL3,
> + AK8974_CTRL3_SELFTEST,
> + AK8974_CTRL3_SELFTEST);
> + if (ret) {
> + dev_err(dev, "could not write CTRL3\n");
> + return ret;
> + }
> +
> + msleep(AK8974_SELFTEST_DELAY);
> +
> + ret = regmap_read(ak8974->map, AK8974_SELFTEST, &val);
> + if (ret)
> + return ret;
> + if (val != AK8974_SELFTEST_OK) {
> + dev_err(dev, "selftest result NOT OK (%02x)\n", val);
> + return -EIO;
> + }
> +
> + ret = regmap_read(ak8974->map, AK8974_SELFTEST, &val);
> + if (ret)
> + return ret;
> + if (val != AK8974_SELFTEST_IDLE) {
> + dev_err(dev, "selftest not idle after test (%02x)\n", val);
> + return -EIO;
> + }
> + dev_dbg(dev, "passed self-test\n");
> +
> + return 0;
> +}
> +
> +static int ak8974_get_u16_val(struct ak8974 *ak8974, u8 reg, u16 *val)
> +{
> + int ret;
> + u16 bulk;
> +
> + ret = regmap_bulk_read(ak8974->map, reg, &bulk, 2);
> + if (ret)
> + return ret;
> + *val = le16_to_cpu(bulk);
> +
> + return 0;
> +}
> +
> +static int ak8974_detect(struct ak8974 *ak8974)
> +{
> + unsigned int whoami;
> + const char *name;
> + int ret;
> + unsigned int fw;
> + u16 sn;
> +
> + ret = regmap_read(ak8974->map, AK8974_WHOAMI, &whoami);
> + if (ret)
> + return ret;
> +
> + switch (whoami) {
> + case AK8974_WHOAMI_VALUE_AMI305:
> + name = "ami305";
> + ret = regmap_read(ak8974->map, AMI305_VER, &fw);
> + if (ret)
> + return ret;
> + fw &= 0x7f; /* only bits 0 thru 6 valid */
> + ret = ak8974_get_u16_val(ak8974, AMI305_SN, &sn);
> + if (ret)
> + return ret;
> + dev_info(&ak8974->i2c->dev,
> + "detected %s, FW ver %02x, S/N: %04x\n",
> + name, fw, sn);
> + break;
> + case AK8974_WHOAMI_VALUE_AK8974:
> + name = "ak8974";
> + dev_info(&ak8974->i2c->dev, "detected AK8974\n");
> + break;
> + default:
> + dev_err(&ak8974->i2c->dev, "unsupported device (%02x) ",
> + whoami);
> + return -ENODEV;
> + }
> +
> + ak8974->name = name;
> + ak8974->variant = whoami;
> +
> + return 0;
> +}
> +
> +static int ak8974_read_raw(struct iio_dev *indio_dev,
> + struct iio_chan_spec const *chan,
> + int *val, int *val2,
> + long mask)
> +{
> + struct ak8974 *ak8974 = iio_priv(indio_dev);
> + s16 hw_values[3];
> + int ret = -EINVAL;
> +
> + pm_runtime_get_sync(&ak8974->i2c->dev);
> + mutex_lock(&ak8974->lock);
> +
> + switch (mask) {
> + case IIO_CHAN_INFO_RAW:
> + if (chan->address > 2) {
> + dev_err(&ak8974->i2c->dev, "faulty channel address\n");
> + ret = -EIO;
> + goto out_unlock;
> + }
> + ret = ak8974_trigmeas(ak8974);
> + if (ret) {
> + return ret;
> + goto out_unlock;
this doesn't look right, the 'goto' is dead code
> + }
> + ret = ak8974_getresult(ak8974, hw_values);
> + if (ret) {
> + return ret;
> + goto out_unlock;
> + }
> +
> + /*
> + * We read all axes and discard all but one, for optimized
> + * reading, use the triggered buffer.
> + */
> + *val = hw_values[chan->address];
do endianness conversion for one channel here
> +
> + ret = IIO_VAL_INT;
> + }
> +
> + out_unlock:
> + mutex_unlock(&ak8974->lock);
> + pm_runtime_mark_last_busy(&ak8974->i2c->dev);
> + pm_runtime_put_autosuspend(&ak8974->i2c->dev);
> +
> + return ret;
> +}
> +
> +static void ak8974_fill_buffer(struct iio_dev *indio_dev)
> +{
> + struct ak8974 *ak8974 = iio_priv(indio_dev);
> + int ret;
> + s16 hw_values[8]; /* Three axes + 64bit padding */
> +
> + pm_runtime_get_sync(&ak8974->i2c->dev);
> + mutex_lock(&ak8974->lock);
> +
> + ret = ak8974_trigmeas(ak8974);
> + if (ret) {
> + dev_err(&ak8974->i2c->dev, "error triggering measure\n");
> + goto out_unlock;
> + }
> + ret = ak8974_getresult(ak8974, hw_values);
> + if (ret) {
> + dev_err(&ak8974->i2c->dev, "error getting measures\n");
> + goto out_unlock;
> + }
> +
> + iio_push_to_buffers_with_timestamp(indio_dev, hw_values,
> + iio_get_time_ns());
> +
> + out_unlock:
> + mutex_unlock(&ak8974->lock);
> + pm_runtime_mark_last_busy(&ak8974->i2c->dev);
> + pm_runtime_put_autosuspend(&ak8974->i2c->dev);
> +}
> +
> +static irqreturn_t ak8974_handle_trigger(int irq, void *p)
> +{
> + const struct iio_poll_func *pf = p;
> + struct iio_dev *indio_dev = pf->indio_dev;
> +
> + ak8974_fill_buffer(indio_dev);
> + iio_trigger_notify_done(indio_dev->trig);
> +
> + return IRQ_HANDLED;
> +}
> +
> +static const struct iio_mount_matrix *
> +ak8974_get_mount_matrix(const struct iio_dev *indio_dev,
> + const struct iio_chan_spec *chan)
> +{
> + struct ak8974 *ak8974 = iio_priv(indio_dev);
> +
> + return &ak8974->orientation;
> +}
> +
> +static const struct iio_chan_spec_ext_info ak8974_ext_info[] = {
> + IIO_MOUNT_MATRIX(IIO_SHARED_BY_DIR, ak8974_get_mount_matrix),
> + { },
> +};
> +
> +#define AK8974_AXIS_CHANNEL(axis, index) \
> + { \
> + .type = IIO_MAGN, \
> + .modified = 1, \
> + .channel2 = IIO_MOD_##axis, \
> + .info_mask_separate = BIT(IIO_CHAN_INFO_RAW), \
> + .ext_info = ak8974_ext_info, \
> + .address = index, \
> + .scan_index = index, \
> + .scan_type = { \
> + .sign = 's', \
> + .realbits = 16, \
> + .storagebits = 16, \
> + .endianness = IIO_CPU \
> + }, \
> + }
> +
> +static const struct iio_chan_spec ak8974_channels[] = {
> + AK8974_AXIS_CHANNEL(X, 0),
> + AK8974_AXIS_CHANNEL(Y, 1),
> + AK8974_AXIS_CHANNEL(Z, 2),
> + IIO_CHAN_SOFT_TIMESTAMP(3),
> +};
> +
> +static const unsigned long ak8974_scan_masks[] = { 0x7, 0 };
> +
> +static const struct iio_info ak8974_info = {
> + .read_raw = &ak8974_read_raw,
> + .driver_module = THIS_MODULE,
> +};
> +
> +static bool ak8974_writeable_reg(struct device *dev, unsigned int reg)
> +{
> + struct i2c_client *i2c = to_i2c_client(dev);
> + struct iio_dev *indio_dev = i2c_get_clientdata(i2c);
> + struct ak8974 *ak8974 = iio_priv(indio_dev);
> +
> + switch (reg) {
> + case AK8974_CTRL1:
> + case AK8974_CTRL2:
> + case AK8974_CTRL3:
> + case AK8974_INT_CTRL:
> + case AK8974_INT_THRES:
> + case AK8974_INT_THRES + 1:
> + case AK8974_PRESET:
> + case AK8974_PRESET + 1:
> + return true;
> + case AK8974_OFFSET_X:
> + case AK8974_OFFSET_X + 1:
> + case AK8974_OFFSET_Y:
> + case AK8974_OFFSET_Y + 1:
> + case AK8974_OFFSET_Z:
> + case AK8974_OFFSET_Z + 1:
> + if (ak8974->variant == AK8974_WHOAMI_VALUE_AK8974)
> + return true;
> + return false;
> + case AMI305_OFFSET_X:
> + case AMI305_OFFSET_X + 1:
> + case AMI305_OFFSET_Y:
> + case AMI305_OFFSET_Y + 1:
> + case AMI305_OFFSET_Z:
> + case AMI305_OFFSET_Z + 1:
> + if (ak8974->variant == AK8974_WHOAMI_VALUE_AMI305)
> + return true;
> + return false;
> + default:
maybe return false here?
> + break;
> + }
> + return false;
and delete the return
> +}
> +
> +static const struct regmap_config ak8974_regmap_config = {
> + .reg_bits = 8,
> + .val_bits = 8,
> + .max_register = 0xff,
> + .writeable_reg = ak8974_writeable_reg,
> +};
> +
> +static int ak8974_probe(struct i2c_client *i2c,
> + const struct i2c_device_id *id)
> +{
> + struct iio_dev *indio_dev;
> + struct ak8974 *ak8974;
> + unsigned long irq_trig;
> + int irq = i2c->irq;
> + int ret;
> +
> + /* Register with IIO */
> + indio_dev = devm_iio_device_alloc(&i2c->dev, sizeof(*ak8974));
> + if (indio_dev == NULL)
> + return -ENOMEM;
> +
> + ak8974 = iio_priv(indio_dev);
> + i2c_set_clientdata(i2c, indio_dev);
> + ak8974->i2c = i2c;
> + mutex_init(&ak8974->lock);
> +
> + ret = of_iio_read_mount_matrix(&i2c->dev,
> + "mount-matrix",
> + &ak8974->orientation);
> + if (ret)
> + return ret;
> +
> + ak8974->regs[0].supply = ak8974_reg_avdd;
> + ak8974->regs[1].supply = ak8974_reg_dvdd;
> +
> + ret = devm_regulator_bulk_get(&i2c->dev,
> + ARRAY_SIZE(ak8974->regs),
> + ak8974->regs);
> + if (ret < 0) {
> + dev_err(&i2c->dev, "Cannot get regulators\n");
> + return ret;
> + }
> +
> + ret = regulator_bulk_enable(ARRAY_SIZE(ak8974->regs), ak8974->regs);
> + if (ret < 0) {
> + dev_err(&i2c->dev, "Cannot enable regulators\n");
> + return ret;
> + }
mixed upper/lower-case error messages...
> +
> + /* Take runtime PM online */
> + pm_runtime_get_noresume(&i2c->dev);
> + pm_runtime_set_active(&i2c->dev);
> + pm_runtime_enable(&i2c->dev);
> +
> + ak8974->map = devm_regmap_init_i2c(i2c, &ak8974_regmap_config);
> + if (IS_ERR(ak8974->map)) {
> + dev_err(&i2c->dev, "failed to allocate register map\n");
> + return PTR_ERR(ak8974->map);
> + }
> +
> + ret = ak8974_set_power(ak8974, AK8974_PWR_ON);
> + if (ret) {
> + dev_err(&i2c->dev, "could not power on\n");
> + goto power_off;
> + }
> +
> + ret = ak8974_detect(ak8974);
> + if (ret) {
> + dev_err(&i2c->dev, "neither AK8974 nor AMI305 found\n");
> + goto power_off;
> + }
> +
> + ret = ak8974_selftest(ak8974);
> + if (ret)
> + dev_err(&i2c->dev, "selftest failed (continuing anyway)\n");
> +
> + ret = ak8974_reset(ak8974);
> + if (ret) {
> + dev_err(&i2c->dev, "AK8974 reset failed");
missing \n here
> + goto power_off;
> + }
> +
> + pm_runtime_set_autosuspend_delay(&i2c->dev,
> + AK8974_AUTOSUSPEND_DELAY);
> + pm_runtime_use_autosuspend(&i2c->dev);
> + pm_runtime_put(&i2c->dev);
> +
> + indio_dev->dev.parent = &i2c->dev;
> + indio_dev->channels = ak8974_channels;
> + indio_dev->num_channels = ARRAY_SIZE(ak8974_channels);
> + indio_dev->info = &ak8974_info;
> + indio_dev->available_scan_masks = ak8974_scan_masks;
> + indio_dev->modes = INDIO_DIRECT_MODE;
> + indio_dev->name = ak8974->name;
> +
> + ret = iio_triggered_buffer_setup(indio_dev, NULL,
> + ak8974_handle_trigger,
> + NULL);
> + if (ret) {
> + dev_err(&i2c->dev, "triggered buffer setup failed\n");
> + goto disable_pm;
> + }
> +
> + /* If we have a valid DRDY IRQ, make use of it */
> + if (irq > 0) {
> + irq_trig = irqd_get_trigger_type(irq_get_irq_data(irq));
> + if (irq_trig == IRQF_TRIGGER_RISING) {
> + dev_info(&i2c->dev, "enable rising edge DRDY IRQ\n");
> + } else if (irq_trig == IRQF_TRIGGER_FALLING) {
> + ak8974->drdy_active_low = true;
> + dev_info(&i2c->dev, "enable falling edge DRDY IRQ\n");
> + } else {
> + irq_trig = IRQF_TRIGGER_RISING;
> + }
> + irq_trig |= IRQF_ONESHOT;
> + irq_trig |= IRQF_SHARED;
> +
> + ret = devm_request_threaded_irq(&i2c->dev,
> + irq,
> + ak8974_drdy_irq,
> + ak8974_drdy_irq_thread,
> + irq_trig,
> + ak8974->name,
> + ak8974);
> + if (ret) {
> + dev_err(&i2c->dev, "unable to request DRDY IRQ "
> + "- proceeding without IRQ\n");
> + goto no_irq;
> + }
> + ak8974->drdy_irq = true;
> + }
> +
> +no_irq:
> + ret = iio_device_register(indio_dev);
> + if (ret) {
> + dev_err(&i2c->dev, "device register failed\n");
> + goto cleanup_buffer;
> + }
> +
> + return 0;
> +
> +cleanup_buffer:
> + iio_triggered_buffer_cleanup(indio_dev);
> +disable_pm:
> + pm_runtime_put_noidle(&i2c->dev);
> + pm_runtime_disable(&i2c->dev);
> + ak8974_set_power(ak8974, AK8974_PWR_OFF);
> +power_off:
> + regulator_bulk_disable(ARRAY_SIZE(ak8974->regs), ak8974->regs);
> +
> + return ret;
> +}
> +
> +static int __exit ak8974_remove(struct i2c_client *i2c)
> +{
> + struct iio_dev *indio_dev = i2c_get_clientdata(i2c);
> + struct ak8974 *ak8974 = iio_priv(indio_dev);
> +
> + iio_device_unregister(indio_dev);
> + iio_triggered_buffer_cleanup(indio_dev);
> + pm_runtime_get_sync(&i2c->dev);
> + pm_runtime_put_noidle(&i2c->dev);
> + pm_runtime_disable(&i2c->dev);
> + ak8974_set_power(ak8974, AK8974_PWR_OFF);
> + regulator_bulk_disable(ARRAY_SIZE(ak8974->regs), ak8974->regs);
> +
> + return 0;
> +}
> +
> +#ifdef CONFIG_PM
> +static int ak8974_runtime_suspend(struct device *dev)
> +{
> + struct ak8974 *ak8974 =
> + iio_priv(i2c_get_clientdata(to_i2c_client(dev)));
> +
> + ak8974_set_power(ak8974, AK8974_PWR_OFF);
> + regulator_bulk_disable(ARRAY_SIZE(ak8974->regs), ak8974->regs);
> +
> + return 0;
> +}
> +
> +static int ak8974_runtime_resume(struct device *dev)
> +{
> + struct ak8974 *ak8974 =
> + iio_priv(i2c_get_clientdata(to_i2c_client(dev)));
> + int ret;
> +
> + ret = regulator_bulk_enable(ARRAY_SIZE(ak8974->regs), ak8974->regs);
> + if (ret)
> + return ret;
> + msleep(AK8974_POWERON_DELAY);
> + ret = ak8974_set_power(ak8974, AK8974_PWR_ON);
> + if (ret)
> + goto out_regulator_disable;
> +
> + ret = ak8974_configure(ak8974);
> + if (ret)
> + goto out_disable_power;
> +
> + return 0;
> +
> +out_disable_power:
> + ak8974_set_power(ak8974, AK8974_PWR_OFF);
> +out_regulator_disable:
> + regulator_bulk_disable(ARRAY_SIZE(ak8974->regs), ak8974->regs);
> +
> + return ret;
> +}
> +#endif /* CONFIG_PM */
> +
> +static const struct dev_pm_ops ak8974_dev_pm_ops = {
> + SET_SYSTEM_SLEEP_PM_OPS(pm_runtime_force_suspend,
> + pm_runtime_force_resume)
> + SET_RUNTIME_PM_OPS(ak8974_runtime_suspend,
> + ak8974_runtime_resume, NULL)
> +};
> +
> +static const struct i2c_device_id ak8974_id[] = {
> + {"ami305", 0 },
> + {"ak8974", 0 },
> + {}
> +};
> +MODULE_DEVICE_TABLE(i2c, ak8974_id);
> +
> +static const struct of_device_id ak8974_of_match[] = {
> + { .compatible = "asahi-kasei,ak8974", },
> + {}
> +};
> +MODULE_DEVICE_TABLE(of, ak8974_of_match);
> +
> +static struct i2c_driver ak8974_driver = {
> + .driver = {
> + .name = "ak8974",
> + .owner = THIS_MODULE,
> + .pm = &ak8974_dev_pm_ops,
> + .of_match_table = of_match_ptr(ak8974_of_match),
> + },
> + .probe = ak8974_probe,
> + .remove = __exit_p(ak8974_remove),
> + .id_table = ak8974_id,
> +};
> +module_i2c_driver(ak8974_driver);
> +
> +MODULE_DESCRIPTION("AK8974 and AMI305 3-axis magnetometer driver");
> +MODULE_AUTHOR("Samu Onkalo");
> +MODULE_AUTHOR("Linus Walleij");
> +MODULE_LICENSE("GPL v2");
>
--
Peter Meerwald-Stadler
+43-664-2444418 (mobile)
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