Re: [RFC PATCH v2 1/3] input:misc:driver support for Kionix kxte9 accelerometer

[Dmitry Torokhov <dmitry.torokhov@gmail.com>]

Hi Chris,

On Tue, Nov 10, 2009 at 06:11:21PM -0500, chudson@kionix.com wrote:
> From: Chris Hudson <chudson@kionix.com>
> 
> This is a request for comments regarding adding driver support for the Kionix 
> KXTE9 digital tri-axis accelerometer.

Thank you for the patch. Mostly cursory comments at this moment.

>  This part features built-in tilt 
> position (orientation), wake-up and back-to-sleep algorithms, which can trigger 
> a user-configurable physical interrupt.  The driver uses i2c for device 
> communication, a misc node for IOCTLs,

Why ioctl and not sysfs?

> and input nodes for reporting 
> acceleration data and interrupt status information.  Moved to 
> drivers/input/misc after discussion on linux-omap mailing list.
> 
> Signed-off-by: Chris Hudson <chudson@kionix.com>
> ---
>  drivers/input/misc/Kconfig  |   11 +
>  drivers/input/misc/Makefile |    1 +
>  drivers/input/misc/kxte9.c  |  980 +++++++++++++++++++++++++++++++++++++++++++
>  include/linux/kxte9.h       |   95 +++++
>  4 files changed, 1087 insertions(+), 0 deletions(-)
>  create mode 100644 drivers/input/misc/kxte9.c
>  create mode 100644 include/linux/kxte9.h
> 
> diff --git a/drivers/input/misc/Kconfig b/drivers/input/misc/Kconfig
> index a9bb254..a9f957d 100644
> --- a/drivers/input/misc/Kconfig
> +++ b/drivers/input/misc/Kconfig
> @@ -317,4 +317,15 @@ config INPUT_PCAP
>  	  To compile this driver as a module, choose M here: the
>  	  module will be called pcap_keys.
>  
> +config INPUT_KXTE9
> +	tristate "Kionix KXTE9 tri-axis digital accelerometer"
> +	depends on I2C && SYSFS
> +	help
> +	  If you say yes here you get support for the Kionix KXTE9 digital
> +	  tri-axis accelerometer.
> +
> +	  This driver can also be built as a module.  If so, the module
> +	  will be called kxte9.
> +
> +
>  endif
> diff --git a/drivers/input/misc/Makefile b/drivers/input/misc/Makefile
> index a8b8485..010d19b 100644
> --- a/drivers/input/misc/Makefile
> +++ b/drivers/input/misc/Makefile
> @@ -15,6 +15,7 @@ obj-$(CONFIG_INPUT_DM355EVM)		+= dm355evm_keys.o
>  obj-$(CONFIG_HP_SDC_RTC)		+= hp_sdc_rtc.o
>  obj-$(CONFIG_INPUT_IXP4XX_BEEPER)	+= ixp4xx-beeper.o
>  obj-$(CONFIG_INPUT_KEYSPAN_REMOTE)	+= keyspan_remote.o
> +obj-$(CONFIG_SENSORS_KXTE9)		+= kxte9.o
>  obj-$(CONFIG_INPUT_M68K_BEEP)		+= m68kspkr.o
>  obj-$(CONFIG_INPUT_PCAP)		+= pcap_keys.o
>  obj-$(CONFIG_INPUT_PCF50633_PMU)	+= pcf50633-input.o
> diff --git a/drivers/input/misc/kxte9.c b/drivers/input/misc/kxte9.c
> new file mode 100644
> index 0000000..d470f02
> --- /dev/null
> +++ b/drivers/input/misc/kxte9.c
> @@ -0,0 +1,980 @@
> +/*
> + * Copyright (C) 2009 Kionix, Inc.
> + * Written by Chris Hudson <chudson@kionix.com>
> + *
> + * 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.
> + *
> + * This program is distributed in the hope that it will be useful,
> + * but WITHOUT ANY WARRANTY; without even the implied warranty of
> + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
> + * GNU General Public License for more details.
> + *
> + * You should have received a copy of the GNU General Public License
> + * along with this program; if not, write to the Free Software
> + * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
> + * 02111-1307, USA
> + */
> +
> +#include <linux/err.h>
> +#include <linux/errno.h>
> +#include <linux/delay.h>
> +#include <linux/fs.h>
> +#include <linux/i2c.h>
> +#include <linux/input.h>
> +#include <linux/input-polldev.h>

I don' think you are using polled device framework...

> +#include <linux/miscdevice.h>
> +#include <linux/uaccess.h>
> +#include <linux/workqueue.h>
> +#include <linux/irq.h>
> +#include <linux/gpio.h>
> +#include <linux/interrupt.h>
> +#include <linux/kxte9.h>
> +
> +#define NAME			"kxte9"
> +#define G_MAX			2000
> +/* OUTPUT REGISTERS */
> +#define XOUT			0x12
> +#define INT_STATUS_REG		0x16
> +#define INT_SRC_REG2		0x17
> +#define TILT_POS_CUR		0x10
> +#define TILT_POS_PRE		0x11
> +#define INT_REL			0x1A
> +/* CONTROL REGISTERS */
> +#define CTRL_REG1		0x1B
> +#define CTRL_REG3		0x1D
> +#define INT_CTRL1		0x1E
> +#define TILT_TIMER		0x28
> +#define WUF_TIMER		0x29
> +#define B2S_TIMER		0x2A
> +#define WUF_THRESH		0x5A
> +#define B2S_THRESH		0x5B
> +/* CONTROL REGISTER 1 BITS */
> +#define PC1_OFF			0x00
> +#define PC1_ON			0x80
> +/* INTERRUPT SOURCE 1 BITS */
> +#define TPS			0x01
> +#define WUFS			0x02
> +#define B2SS			0x04
> +/* INPUT_ABS CONSTANTS */
> +#define FUZZ			32
> +#define FLAT			32
> +#define I2C_RETRY_DELAY		5
> +#define I2C_RETRIES		5
> +/* RESUME STATE INDICES */
> +#define RES_CTRL_REG1		0
> +#define RES_CTRL_REG3		1
> +#define RES_INT_CTRL1		2
> +#define RES_TILT_TIMER		3
> +#define RES_WUF_TIMER		4
> +#define RES_B2S_TIMER		5
> +#define RES_WUF_THRESH		6
> +#define RES_B2S_THRESH		7
> +#define RES_INTERVAL		8
> +#define RES_CURRENT_ODR		9
> +#define RESUME_ENTRIES		10
> +
> +struct {
> +	unsigned int cutoff;
> +	u8 mask;
> +} kxte9_odr_table[] = {
> +	{
> +	25,	ODR125}, {
> +	100,	ODR40}, {
> +	334,	ODR10}, {
> +	1000,	ODR3}, {
> +	0,	ODR1},};
> +
> +struct kxte9_data {
> +	struct i2c_client *client;
> +	struct kxte9_platform_data *pdata;
> +	struct mutex lock;
> +	struct delayed_work input_work;
> +	struct input_dev *input_dev;
> +	struct work_struct irq_work;
> +	struct workqueue_struct *irq_work_queue;
> +
> +	int hw_initialized;
> +	atomic_t enabled;
> +	u8 resume_state[RESUME_ENTRIES];
> +	int irq;
> +};
> +
> +static struct kxte9_data *kxte9_misc_data;
> +
> +static int kxte9_i2c_read(struct kxte9_data *te9, u8 *buf, int len)
> +{
> +	int err;
> +	int tries = 0;
> +
> +	struct i2c_msg msgs[] = {
> +		{
> +		 .addr = te9->client->addr,
> +		 .flags = te9->client->flags & I2C_M_TEN,
> +		 .len = 1,
> +		 .buf = buf,
> +		 },
> +		{
> +		 .addr = te9->client->addr,
> +		 .flags = (te9->client->flags & I2C_M_TEN) | I2C_M_RD,
> +		 .len = len,
> +		 .buf = buf,
> +		 },
> +	};
> +	do {
> +		err = i2c_transfer(te9->client->adapter, msgs, 2);
> +		if (err != 2)
> +			msleep_interruptible(I2C_RETRY_DELAY);
> +	} while ((err != 2) && (++tries < I2C_RETRIES));
> +
> +	if (err != 2) {
> +		dev_err(&te9->client->dev, "read transfer error\n");
> +		err = -EIO;
> +	} else {
> +		err = 0;
> +	}
> +
> +	return err;
> +}
> +
> +static int kxte9_i2c_write(struct kxte9_data *te9, u8 * buf, int len)
> +{
> +	int err;
> +	int tries = 0;
> +
> +	struct i2c_msg msgs[] = {
> +		{
> +		 .addr = te9->client->addr,
> +		 .flags = te9->client->flags & I2C_M_TEN,
> +		 .len = len + 1,
> +		 .buf = buf,
> +		 },
> +	};
> +	do {
> +		err = i2c_transfer(te9->client->adapter, msgs, 1);
> +		if (err != 1)
> +			msleep_interruptible(I2C_RETRY_DELAY);
> +	} while ((err != 1) && (++tries < I2C_RETRIES));
> +
> +	if (err != 1) {
> +		dev_err(&te9->client->dev, "write transfer error\n");
> +		err = -EIO;
> +	} else {
> +		err = 0;
> +	}
> +
> +	return err;
> +}
> +
> +static int kxte9_hw_init(struct kxte9_data *te9)
> +{
> +	int err = -1;
> +	u8 buf[2] = { CTRL_REG1, PC1_OFF };
> +
> +	err = kxte9_i2c_write(te9, buf, 1);
> +	if (err < 0)
> +		return err;
> +	buf[0] = CTRL_REG3;
> +	buf[1] = te9->resume_state[RES_CTRL_REG3];
> +	err = kxte9_i2c_write(te9, buf, 1);
> +	if (err < 0)
> +		return err;
> +	buf[0] = INT_CTRL1;
> +	buf[1] = te9->resume_state[RES_INT_CTRL1];
> +	err = kxte9_i2c_write(te9, buf, 1);
> +	if (err < 0)
> +		return err;
> +	buf[0] = TILT_TIMER;
> +	buf[1] = te9->resume_state[RES_TILT_TIMER];
> +	err = kxte9_i2c_write(te9, buf, 1);
> +	if (err < 0)
> +		return err;
> +	buf[0] = WUF_TIMER;
> +	buf[1] = te9->resume_state[RES_WUF_TIMER];
> +	err = kxte9_i2c_write(te9, buf, 1);
> +	if (err < 0)
> +		return err;
> +	buf[0] = B2S_TIMER;
> +	buf[1] = te9->resume_state[RES_B2S_TIMER];
> +	err = kxte9_i2c_write(te9, buf, 1);
> +	if (err < 0)
> +		return err;
> +	buf[0] = WUF_THRESH;
> +	buf[1] = te9->resume_state[RES_WUF_THRESH];
> +	err = kxte9_i2c_write(te9, buf, 1);
> +	if (err < 0)
> +		return err;
> +	buf[0] = B2S_THRESH;
> +	buf[1] = te9->resume_state[RES_B2S_THRESH];
> +	err = kxte9_i2c_write(te9, buf, 1);
> +	if (err < 0)
> +		return err;
> +	buf[0] = CTRL_REG1;
> +	buf[1] = (te9->resume_state[RES_CTRL_REG1] | PC1_ON);
> +	err = kxte9_i2c_write(te9, buf, 1);
> +	if (err < 0)
> +		return err;
> +	te9->resume_state[RES_CTRL_REG1] = buf[1];
> +	te9->hw_initialized = 1;
> +
> +	return 0;
> +}
> +
> +static void kxte9_device_power_off(struct kxte9_data *te9)
> +{
> +	int err;
> +	u8 buf[2] = { CTRL_REG1, PC1_OFF };
> +
> +	err = kxte9_i2c_write(te9, buf, 1);
> +	if (err < 0)
> +		dev_err(&te9->client->dev, "soft power off failed\n");
> +	disable_irq_nosync(te9->irq);

Why nosync? THis function is not called from IRQ context.

> +	if (te9->pdata->power_off)
> +		te9->pdata->power_off();
> +	te9->hw_initialized = 0;
> +}
> +
> +static int kxte9_device_power_on(struct kxte9_data *te9)
> +{
> +	int err;
> +
> +	if (te9->pdata->power_on) {
> +		err = te9->pdata->power_on();
> +		if (err < 0)
> +			return err;
> +	}
> +	enable_irq(te9->irq);
> +	if (!te9->hw_initialized) {
> +		mdelay(110);
> +		err = kxte9_hw_init(te9);
> +		if (err < 0) {
> +			kxte9_device_power_off(te9);
> +			return err;
> +		}
> +	}
> +
> +	return 0;
> +}
> +
> +static irqreturn_t kxte9_isr(int irq, void *dev)
> +{
> +	struct kxte9_data *te9 = dev;
> +
> +	disable_irq_nosync(irq);
> +	queue_work(te9->irq_work_queue, &te9->irq_work);
> +

This begs for use of threaded interrupt infrastructure.

> +	return IRQ_HANDLED;
> +}
> +
> +static u8 kxte9_resolve_dir(struct kxte9_data *te9, u8 dir)
> +{
> +	switch (dir) {
> +	case 0x20:	/* -X */
> +		if (te9->pdata->negate_x)
> +			dir = 0x10;
> +		if (te9->pdata->axis_map_y == 0)
> +			dir >>= 2;
> +		if (te9->pdata->axis_map_z == 0)
> +			dir >>= 4;
> +		break;
> +	case 0x10:	/* +X */
> +		if (te9->pdata->negate_x)
> +			dir = 0x20;
> +		if (te9->pdata->axis_map_y == 0)
> +			dir >>= 2;
> +		if (te9->pdata->axis_map_z == 0)
> +			dir >>= 4;
> +		break;
> +	case 0x08:	/* -Y */
> +		if (te9->pdata->negate_y)
> +			dir = 0x04;
> +		if (te9->pdata->axis_map_x == 1)
> +			dir <<= 2;
> +		if (te9->pdata->axis_map_z == 1)
> +			dir >>= 2;
> +		break;
> +	case 0x04:	/* +Y */
> +		if (te9->pdata->negate_y)
> +			dir = 0x08;
> +		if (te9->pdata->axis_map_x == 1)
> +			dir <<= 2;
> +		if (te9->pdata->axis_map_z == 1)
> +			dir >>= 2;
> +		break;
> +	case 0x02:	/* -Z */
> +		if (te9->pdata->negate_z)
> +			dir = 0x01;
> +		if (te9->pdata->axis_map_x == 2)
> +			dir <<= 4;
> +		if (te9->pdata->axis_map_y == 2)
> +			dir <<= 2;
> +		break;
> +	case 0x01:	/* +Z */
> +		if (te9->pdata->negate_z)
> +			dir = 0x02;
> +		if (te9->pdata->axis_map_x == 2)
> +			dir <<= 4;
> +		if (te9->pdata->axis_map_y == 2)
> +			dir <<= 2;
> +		break;
> +	default:
> +		return -EINVAL;
> +	}
> +
> +	return dir;
> +}
> +
> +static void kxte9_irq_work_func(struct work_struct *work)
> +{
> +/*
> + *	int_status output:
> + *	[INT_SRC_REG1][INT_SRC_REG2][TILT_POS_PRE][TILT_POS_CUR]
> + *	INT_SRC_REG2, TILT_POS_PRE, and TILT_POS_CUR directions are translated
> + *	based on platform data variables.
> + */
> +
> +	int err;
> +	int i;
> +	int int_status = 0;
> +	u8 status;
> +	u8 b2s_comp;
> +	u8 wuf_comp;
> +	u8 buf[2];
> +
> +	struct kxte9_data *te9 = container_of(work,
> +						struct kxte9_data, irq_work);
> +	if (!gpio_get_value(te9->pdata->gpio)) {
> +		enable_irq(te9->irq);
> +		return;
> +	}
> +
> +	status = INT_STATUS_REG;
> +	err = kxte9_i2c_read(te9, &status, 1);
> +	if (err < 0)
> +		dev_err(&te9->client->dev, "read err int source\n");
> +	int_status = status << 24;
> +	if ((status & TPS) > 0) {
> +		buf[0] = TILT_POS_CUR;
> +		err = kxte9_i2c_read(te9, buf, 2);
> +		if (err < 0)
> +			dev_err(&te9->client->dev, "read err tilt dir\n");
> +		int_status |= kxte9_resolve_dir(te9, buf[0]);
> +		int_status |= (kxte9_resolve_dir(te9, buf[1])) << 8;
> +	}
> +	if ((status & WUFS) > 0) {
> +		buf[0] = INT_SRC_REG2;
> +		err = kxte9_i2c_read(te9, buf, 1);
> +		if (err < 0)
> +			dev_err(&te9->client->dev, "reading err wuf dir\n");
> +		int_status |= (kxte9_resolve_dir(te9, buf[0])) << 16;
> +		b2s_comp = te9->resume_state[RES_CTRL_REG3] & 0x0C >> 2;
> +		wuf_comp = te9->resume_state[RES_CTRL_REG3] & 0x03;
> +		if (!te9->resume_state[RES_CURRENT_ODR] &&
> +				!(te9->resume_state[RES_CTRL_REG1] & ODR125) &&
> +						!(b2s_comp & wuf_comp)) {
> +			/* set the new poll interval based on wuf odr */
> +			for (i = 1; i < ARRAY_SIZE(kxte9_odr_table); i++) {
> +				te9->pdata->poll_interval =
> +						kxte9_odr_table[i - 1].cutoff;

It is not nice to modify platform data.

> +				if (kxte9_odr_table[i].mask ==	wuf_comp << 3)
> +						break;
> +			}
> +			if (te9->input_dev) {
> +				cancel_delayed_work_sync(&te9->input_work);
> +				schedule_delayed_work(&te9->input_work,
> +						msecs_to_jiffies(te9->pdata->
> +								poll_interval));
> +			}
> +		}
> +	}
> +	if ((status & B2SS) > 0) {
> +		b2s_comp = te9->resume_state[RES_CTRL_REG3] & 0x0C >> 2;
> +		wuf_comp = te9->resume_state[RES_CTRL_REG3] & 0x03;
> +		if (!te9->resume_state[RES_CURRENT_ODR] &&
> +				!(te9->resume_state[RES_CTRL_REG1] & ODR125) &&
> +						!(b2s_comp & wuf_comp)) {
> +			/* set the new poll interval based on b2s odr */
> +			for (i = 1; i < ARRAY_SIZE(kxte9_odr_table); i++) {
> +				te9->pdata->poll_interval =
> +						kxte9_odr_table[i - 1].cutoff;
> +				if (kxte9_odr_table[i].mask == b2s_comp << 3)
> +						break;
> +			}
> +			if (te9->input_dev) {
> +				cancel_delayed_work_sync(&te9->input_work);
> +				schedule_delayed_work(&te9->input_work,
> +						msecs_to_jiffies(te9->pdata->
> +								poll_interval));
> +			}
> +		}
> +	}
> +	input_report_abs(te9->input_dev, ABS_MISC, int_status);
> +	input_sync(te9->input_dev);
> +	buf[0] = INT_REL;
> +	err = kxte9_i2c_read(te9, buf, 1);
> +	if (err < 0)
> +		dev_err(&te9->client->dev, "error clearing interrupt\n");
> +	enable_irq(te9->irq);
> +}
> +
> +static int kxte9_update_odr(struct kxte9_data *te9, int poll_interval)
> +{
> +	int err = -1;
> +	int i;
> +	u8 config[2];
> +
> +	/*
> +	 *  Convert the poll interval into an output data rate configuration
> +	 *  that is as low as possible.  The ordering of these checks must be
> +	 *  maintained due to the cascading cut off values - poll intervals are
> +	 *  checked from shortest to longest.  At each check, if the next lower
> +	 *  ODR cannot support the current poll interval, we stop searching
> +	 */
> +	for (i = 0; i < ARRAY_SIZE(kxte9_odr_table); i++) {
> +		config[1] = kxte9_odr_table[i].mask;
> +		if (poll_interval < kxte9_odr_table[i].cutoff)
> +			break;
> +	}
> +
> +	if (atomic_read(&te9->enabled)) {

Right now it seems to be called from ioctl that is locked, so why is it
atomic?

> +		config[0] = CTRL_REG1;
> +		config[1] |= (te9->resume_state[RES_CTRL_REG1] & ~ODR40);
> +		err = kxte9_i2c_write(te9, config, 1);
> +		if (err < 0)
> +			return err;
> +		/*
> +		 *  Latch on input_dev - indicates that kxte9_input_init passed
> +		 *  and this workqueue is available
> +		 */
> +		if (te9->input_dev) {
> +			cancel_delayed_work_sync(&te9->input_work);
> +			schedule_delayed_work(&te9->input_work,
> +					msecs_to_jiffies(poll_interval));
> +		}
> +	}
> +	te9->resume_state[RES_CTRL_REG1] = config[1];
> +
> +	return 0;
> +}
> +
> +static int kxte9_get_acceleration_data(struct kxte9_data *te9, int *xyz)
> +{
> +	int err = -1;
> +	/* Data bytes from hardware x, y, z */
> +	u8 acc_data[3];
> +	/* x,y,z hardware values */
> +	int hw_d[3] = { 0 };
> +	acc_data[0] = XOUT;
> +
> +	err = kxte9_i2c_read(te9, acc_data, 3);
> +	if (err < 0)
> +		return err;
> +
> +	acc_data[0] >>= 2;
> +	acc_data[1] >>= 2;
> +	acc_data[2] >>= 2;
> +
> +	hw_d[0] = (int) acc_data[0];
> +	hw_d[1] = (int) acc_data[1];
> +	hw_d[2] = (int) acc_data[2];
> +
> +	hw_d[0] -= 32;
> +	hw_d[1] -= 32;
> +	hw_d[2] -= 32;
> +
> +	hw_d[0] <<= 6;
> +	hw_d[1] <<= 6;
> +	hw_d[2] <<= 6;
> +
> +	xyz[0] = ((te9->pdata->negate_x) ? (-hw_d[te9->pdata->axis_map_x])
> +		  : (hw_d[te9->pdata->axis_map_x]));
> +	xyz[1] = ((te9->pdata->negate_y) ? (-hw_d[te9->pdata->axis_map_y])
> +		  : (hw_d[te9->pdata->axis_map_y]));
> +	xyz[2] = ((te9->pdata->negate_z) ? (-hw_d[te9->pdata->axis_map_z])
> +		  : (hw_d[te9->pdata->axis_map_z]));
> +
> +	return err;
> +}
> +
> +static void kxte9_report_values(struct kxte9_data *te9, int *xyz)
> +{
> +	input_report_abs(te9->input_dev, ABS_X, xyz[0]);
> +	input_report_abs(te9->input_dev, ABS_Y, xyz[1]);
> +	input_report_abs(te9->input_dev, ABS_Z, xyz[2]);
> +	input_sync(te9->input_dev);
> +}
> +
> +static int kxte9_enable(struct kxte9_data *te9)
> +{
> +	int err;
> +	int int_status = 0;
> +	u8 buf;
> +
> +	if (!atomic_cmpxchg(&te9->enabled, 0, 1)) {
> +		err = kxte9_device_power_on(te9);
> +		buf = INT_REL;
> +		err = kxte9_i2c_read(te9, &buf, 1);
> +		if (err < 0)
> +			dev_err(&te9->client->dev,
> +					"error clearing interrupt: %d\n", err);
> +		if (err < 0) {
> +			atomic_set(&te9->enabled, 0);
> +			return err;
> +		}
> +		if ((te9->resume_state[RES_CTRL_REG1] & TPS) > 0) {
> +			buf = TILT_POS_CUR;
> +			err = kxte9_i2c_read(te9, &buf, 1);
> +			if (err < 0)
> +				dev_err(&te9->client->dev,
> +					"kxte9 error reading current tilt\n");
> +			int_status |= kxte9_resolve_dir(te9, buf);
> +			input_report_abs(te9->input_dev, ABS_MISC, int_status);
> +			input_sync(te9->input_dev);
> +		}
> +
> +		schedule_delayed_work(&te9->input_work,
> +				      msecs_to_jiffies(te9->
> +						       pdata->poll_interval));
> +	}
> +
> +	return 0;
> +}
> +
> +static int kxte9_disable(struct kxte9_data *te9)
> +{
> +	if (atomic_cmpxchg(&te9->enabled, 1, 0)) {
> +		cancel_delayed_work_sync(&te9->input_work);
> +		kxte9_device_power_off(te9);
> +	}
> +
> +	return 0;
> +}
> +
> +static int kxte9_misc_open(struct inode *inode, struct file *file)
> +{
> +	int err;
> +
> +	err = nonseekable_open(inode, file);
> +	if (err < 0)
> +		return err;
> +	file->private_data = kxte9_misc_data;
> +
> +	return 0;
> +}
> +
> +static int kxte9_misc_ioctl(struct inode *inode, struct file *file,
> +				unsigned int cmd, unsigned long arg)
> +{
> +	void __user *argp = (void __user *)arg;
> +	u8 ctrl[2] = { CTRL_REG1, PC1_OFF };
> +	int err;
> +	int tmp;
> +	struct kxte9_data *te9 = file->private_data;
> +
> +	switch (cmd) {
> +	case KXTE9_IOCTL_GET_DELAY:
> +		tmp = te9->pdata->poll_interval;
> +		if (copy_to_user(argp, &tmp, sizeof(tmp)))
> +			return -EFAULT;
> +		break;
> +	case KXTE9_IOCTL_SET_DELAY:
> +		if (copy_from_user(&tmp, argp, sizeof(tmp)))
> +			return -EFAULT;
> +		if (tmp < 0)
> +			return -EINVAL;
> +		te9->pdata->poll_interval = max(tmp, te9->pdata->min_interval);
> +		err = kxte9_update_odr(te9, te9->pdata->poll_interval);
> +		if (err < 0)
> +			return err;
> +		ctrl[0] = CTRL_REG3;
> +		ctrl[1] = te9->resume_state[RES_CTRL_REG1] & 0x18;
> +		te9->resume_state[RES_CURRENT_ODR] = ctrl[1];
> +		ctrl[1] = (ctrl[1] >> 1) | (ctrl[1] >> 3);
> +		err = kxte9_i2c_write(te9, ctrl, 1);
> +		if (err < 0)
> +			return err;
> +		te9->resume_state[RES_CTRL_REG3] = ctrl[1];
> +		break;
> +	case KXTE9_IOCTL_SET_ENABLE:
> +		if (copy_from_user(&tmp, argp, sizeof(tmp)))
> +			return -EFAULT;
> +		if (tmp < 0 || tmp > 1)
> +			return -EINVAL;
> +
> +		if (tmp)
> +			kxte9_enable(te9);
> +		else
> +			kxte9_disable(te9);
> +		break;
> +	case KXTE9_IOCTL_GET_ENABLE:
> +		tmp = atomic_read(&te9->enabled);
> +		if (copy_to_user(argp, &tmp, sizeof(tmp)))
> +			return -EINVAL;
> +		break;
> +	case KXTE9_IOCTL_SET_TILT_ENABLE:
> +		if (copy_from_user(&tmp, argp, sizeof(tmp)))
> +			return -EFAULT;
> +		if (tmp < 0 || tmp > 1)
> +			return -EINVAL;
> +		if (tmp)
> +			te9->resume_state[RES_CTRL_REG1] |= TPE;
> +
> +		else
> +			te9->resume_state[RES_CTRL_REG1] &= (~TPE);
> +		ctrl[1] = te9->resume_state[RES_CTRL_REG1];
> +		err = kxte9_i2c_write(te9, ctrl, 1);
> +		if (err < 0)
> +			return err;
> +		break;
> +	case KXTE9_IOCTL_SET_WAKE_ENABLE:
> +		if (copy_from_user(&tmp, argp, sizeof(tmp)))
> +			return -EFAULT;
> +		if (tmp < 0 || tmp > 1)
> +			return -EINVAL;
> +		if (tmp) {
> +			te9->resume_state[RES_CTRL_REG1] |= (WUFE | B2SE);
> +			ctrl[1] = te9->resume_state[RES_CTRL_REG1];
> +			err = kxte9_i2c_write(te9, ctrl, 1);
> +			if (err < 0)
> +				return err;
> +		} else {
> +			te9->resume_state[RES_CTRL_REG1] &= (~WUFE & ~B2SE);
> +			ctrl[1] = te9->resume_state[RES_CTRL_REG1];
> +			err = kxte9_i2c_write(te9, ctrl, 1);
> +			if (err < 0)
> +				return err;
> +		}
> +		break;
> +	case KXTE9_IOCTL_SELF_TEST:
> +		if (copy_from_user(&tmp, argp, sizeof(tmp)))
> +			return -EFAULT;
> +		if (tmp < 0 || tmp > 1)
> +			return -EINVAL;
> +		ctrl[0] = 0x3A;
> +		if (tmp) {
> +			ctrl[1] = 0xCA;
> +			err = kxte9_i2c_write(te9, ctrl, 1);
> +			if (err < 0)
> +				return err;
> +		} else {
> +			ctrl[1] = 0x00;
> +			err = kxte9_i2c_write(te9, ctrl, 1);
> +			if (err < 0)
> +				return err;
> +		}
> +		break;
> +	default:
> +		return -EINVAL;
> +	}
> +
> +	return 0;
> +}
> +
> +static const struct file_operations kxte9_misc_fops = {
> +	.owner = THIS_MODULE,
> +	.open = kxte9_misc_open,
> +	.ioctl = kxte9_misc_ioctl,
> +};
> +
> +static struct miscdevice kxte9_misc_device = {
> +	.minor = MISC_DYNAMIC_MINOR,
> +	.name = NAME,
> +	.fops = &kxte9_misc_fops,
> +};
> +
> +static void kxte9_input_work_func(struct work_struct *work)
> +{
> +	struct kxte9_data *te9 = container_of((struct delayed_work *)work,
> +						struct kxte9_data, input_work);
> +	int xyz[3] = { 0 };
> +	int err;
> +
> +	mutex_lock(&te9->lock);
> +	err = kxte9_get_acceleration_data(te9, xyz);
> +	if (err < 0)
> +		dev_err(&te9->client->dev, "get_acceleration_data failed\n");
> +	else
> +		kxte9_report_values(te9, xyz);
> +	schedule_delayed_work(&te9->input_work,
> +			      msecs_to_jiffies(te9->pdata->poll_interval));
> +	mutex_unlock(&te9->lock);
> +}
> +
> +#ifdef KXTE9_OPEN_ENABLE

Why is this code conditional?
 
> +int kxte9_input_open(struct input_dev *input)
> +{
> +	struct kxte9_data *te9 = input_get_drvdata(input);
> +
> +	return kxte9_enable(te9);
> +}
> +
> +void kxte9_input_close(struct input_dev *dev)
> +{
> +	struct kxte9_data *te9 = input_get_drvdata(dev);
> +
> +	kxte9_disable(te9);
> +}
> +#endif
> +
> +static int kxte9_validate_pdata(struct kxte9_data *te9)
> +{
> +	te9->pdata->poll_interval = max(te9->pdata->poll_interval,
> +					te9->pdata->min_interval);
> +	if (te9->pdata->axis_map_x > 2 ||
> +	    te9->pdata->axis_map_y > 2 || te9->pdata->axis_map_z > 2 ||
> +	    te9->pdata->axis_map_x == te9->pdata->axis_map_y ||
> +	    te9->pdata->axis_map_x == te9->pdata->axis_map_z ||
> +	    te9->pdata->axis_map_y == te9->pdata->axis_map_z) {
> +		dev_err(&te9->client->dev,
> +			"invalid axis_map value x:%u y:%u z:%u\n",
> +			te9->pdata->axis_map_x, te9->pdata->axis_map_y,
> +			te9->pdata->axis_map_z);
> +		return -EINVAL;
> +	}
> +	if (te9->pdata->negate_x > 1 || te9->pdata->negate_y > 1 ||
> +	    te9->pdata->negate_z > 1) {
> +		dev_err(&te9->client->dev,
> +			"invalid negate value x:%u y:%u z:%u\n",
> +			te9->pdata->negate_x, te9->pdata->negate_y,
> +			te9->pdata->negate_z);
> +		return -EINVAL;
> +	}
> +
> +	return 0;
> +}
> +
> +static int kxte9_input_init(struct kxte9_data *te9)
> +{
> +	int err;
> +
> +	INIT_DELAYED_WORK(&te9->input_work, kxte9_input_work_func);
> +	te9->input_dev = input_allocate_device();
> +	if (!te9->input_dev) {
> +		err = -ENOMEM;
> +		dev_err(&te9->client->dev, "input device allocate failed\n");
> +		goto err0;
> +	}
> +#ifdef KXTE9_OPEN_ENABLE
> +	te9->input_dev->open = kxte9_input_open;
> +	te9->input_dev->close = kxte9_input_close;
> +#endif
> +	input_set_drvdata(te9->input_dev, te9);
> +
> +	set_bit(EV_ABS, te9->input_dev->evbit);
> +	set_bit(ABS_MISC, te9->input_dev->absbit);
> +
> +	input_set_abs_params(te9->input_dev, ABS_X, -G_MAX, G_MAX, FUZZ, FLAT);
> +	input_set_abs_params(te9->input_dev, ABS_Y, -G_MAX, G_MAX, FUZZ, FLAT);
> +	input_set_abs_params(te9->input_dev, ABS_Z, -G_MAX, G_MAX, FUZZ, FLAT);
> +
> +	te9->input_dev->name = "accelerometer";
> +
> +	err = input_register_device(te9->input_dev);
> +	if (err) {
> +		dev_err(&te9->client->dev,
> +			"unable to register input polled device %s\n",
> +			te9->input_dev->name);
> +		goto err1;
> +	}
> +
> +	return 0;
> +err1:
> +	input_free_device(te9->input_dev);
> +err0:
> +	return err;
> +}
> +
> +static void kxte9_input_cleanup(struct kxte9_data *te9)
> +{
> +	input_unregister_device(te9->input_dev);
> +	input_free_device(te9->input_dev);

No free after unregister.

> +}
> +
> +static int kxte9_probe(struct i2c_client *client,
> +			   const struct i2c_device_id *id)

__devinit

> +{
> +	struct kxte9_data *te9;
> +	int err = -1;
> +
> +	if (client->dev.platform_data == NULL) {
> +		dev_err(&client->dev, "platform data is NULL. exiting.\n");
> +		err = -ENODEV;
> +		goto err0;
> +	}
> +	if (!i2c_check_functionality(client->adapter, I2C_FUNC_I2C)) {
> +		dev_err(&client->dev, "client not i2c capable\n");
> +		err = -ENODEV;
> +		goto err0;
> +	}
> +	te9 = kzalloc(sizeof(*te9), GFP_KERNEL);
> +	if (te9 == NULL) {
> +		dev_err(&client->dev,
> +			"failed to allocate memory for module data\n");
> +		err = -ENOMEM;
> +		goto err0;
> +	}
> +
> +	mutex_init(&te9->lock);
> +	mutex_lock(&te9->lock);
> +	te9->client = client;
> +
> +	INIT_WORK(&te9->irq_work, kxte9_irq_work_func);
> +	te9->irq_work_queue = create_singlethread_workqueue("kxte9_wq");
> +	if (!te9->irq_work_queue) {
> +		err = -ENOMEM;
> +		pr_err("%s: cannot create work queue: %d\n", __func__, err);
> +		goto err1;
> +	}
> +	te9->pdata = kmalloc(sizeof(*te9->pdata), GFP_KERNEL);
> +	if (te9->pdata == NULL)
> +		goto err2;
> +	memcpy(te9->pdata, client->dev.platform_data, sizeof(*te9->pdata));
> +	err = kxte9_validate_pdata(te9);
> +	if (err < 0) {
> +		dev_err(&client->dev, "failed to validate platform data\n");
> +		goto err3;
> +	}
> +	i2c_set_clientdata(client, te9);
> +	if (te9->pdata->init) {
> +		err = te9->pdata->init();
> +		if (err < 0)
> +			goto err3;
> +	}
> +
> +	te9->irq = gpio_to_irq(te9->pdata->gpio);
> +
> +	memset(te9->resume_state, 0, ARRAY_SIZE(te9->resume_state));
> +	te9->resume_state[RES_CTRL_REG1]    = te9->pdata->ctrl_reg1_init;
> +	te9->resume_state[RES_CTRL_REG3]    = te9->pdata->engine_odr_init;
> +	te9->resume_state[RES_INT_CTRL1]    = te9->pdata->int_ctrl_init;
> +	te9->resume_state[RES_TILT_TIMER]   = te9->pdata->tilt_timer_init;
> +	te9->resume_state[RES_WUF_TIMER]    = te9->pdata->wuf_timer_init;
> +	te9->resume_state[RES_B2S_TIMER]    = te9->pdata->b2s_timer_init;
> +	te9->resume_state[RES_WUF_THRESH]   = te9->pdata->wuf_thresh_init;
> +	te9->resume_state[RES_B2S_THRESH]   = te9->pdata->b2s_thresh_init;
> +	te9->resume_state[RES_CURRENT_ODR]  = 0;
> +
> +	err = kxte9_device_power_on(te9);
> +	if (err < 0)
> +		goto err4;
> +	atomic_set(&te9->enabled, 1);
> +	err = kxte9_update_odr(te9, te9->pdata->poll_interval);
> +	if (err < 0) {
> +		dev_err(&client->dev, "update_odr failed\n");
> +		goto err5;
> +	}
> +	err = kxte9_input_init(te9);
> +	if (err < 0)
> +		goto err5;
> +	kxte9_misc_data = te9;
> +	err = misc_register(&kxte9_misc_device);
> +	if (err < 0) {
> +		dev_err(&client->dev, "te9_device register failed\n");
> +		goto err6;
> +	}
> +	kxte9_device_power_off(te9);
> +	atomic_set(&te9->enabled, 0);
> +	err = request_irq(te9->irq, kxte9_isr,
> +			  IRQF_TRIGGER_RISING,
> +			  "kxte9_irq", te9);
> +	if (err < 0) {
> +		pr_err("%s: request irq failed: %d\n", __func__, err);
> +		goto err7;
> +	}
> +	disable_irq_nosync(te9->irq);
> +
> +	mutex_unlock(&te9->lock);
> +
> +	dev_info(&client->dev, "kxte9 probed\n");
> +
> +	return 0;
> +
> +err7:
> +	misc_deregister(&kxte9_misc_device);
> +err6:
> +	kxte9_input_cleanup(te9);
> +err5:
> +	kxte9_device_power_off(te9);
> +err4:
> +	if (te9->pdata->exit)
> +		te9->pdata->exit();
> +err3:
> +	kfree(te9->pdata);
> +err2:
> +	destroy_workqueue(te9->irq_work_queue);
> +err1:
> +	mutex_unlock(&te9->lock);
> +	kfree(te9);
> +err0:
> +	return err;
> +}
> +
> +static int __devexit kxte9_remove(struct i2c_client *client)
> +{
> +	struct kxte9_data *te9 = i2c_get_clientdata(client);
> +
> +	free_irq(te9->irq, te9);
> +	gpio_free(te9->pdata->gpio);
> +	misc_deregister(&kxte9_misc_device);
> +	kxte9_input_cleanup(te9);
> +	kxte9_device_power_off(te9);
> +	if (te9->pdata->exit)
> +		te9->pdata->exit();
> +	kfree(te9->pdata);
> +	destroy_workqueue(te9->irq_work_queue);
> +	kfree(te9);
> +
> +	return 0;
> +}
> +
> +static int kxte9_resume(struct i2c_client *client)
> +{
> +	struct kxte9_data *te9 = i2c_get_clientdata(client);
> +
> +	return kxte9_enable(te9);
> +}
> +
> +static int kxte9_suspend(struct i2c_client *client, pm_message_t mesg)
> +{
> +	struct kxte9_data *te9 = i2c_get_clientdata(client);
> +
> +	return kxte9_disable(te9);
> +}

These are normally guarded by OCNFIG_PM.

> +
> +static const struct i2c_device_id kxte9_id[] = {
> +	{NAME, 0},
> +	{},
> +};
> +
> +MODULE_DEVICE_TABLE(i2c, kxte9_id);
> +
> +static struct i2c_driver kxte9_driver = {
> +	.driver = {
> +		   .name = NAME,
> +		   },
> +	.probe = kxte9_probe,
> +	.remove = __devexit_p(kxte9_remove),
> +	.resume = kxte9_resume,
> +	.suspend = kxte9_suspend,
> +	.id_table = kxte9_id,
> +};
> +
> +static int __init kxte9_init(void)
> +{
> +	pr_info(KERN_INFO "kxte9 accelerometer driver\n");

PLease drop this debug, boot is already cluttered enough.

> +	return i2c_add_driver(&kxte9_driver);
> +}
> +
> +static void __exit kxte9_exit(void)
> +{
> +	i2c_del_driver(&kxte9_driver);
> +	return;

No dummy returns please.

Thanks.

-- 
Dmitry