Re: [RFC] [PATCH 1/2] CMA3000 Accelerometer Driver

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----- Original Message -----
From: "Jonathan Cameron" <jic23@xxxxxxxxx>
>
> Hi Hemanth,
>
> Quick comments below.  I haven't commented much on the
> input aspects, just stuck to the more general driver aspects.

Thanks for the comments, responses inline. I am hoping for
some more wider review.

> As ever at the moment, the should this be in input question is
> open, but if Dmitry is happy to take it then that's fine with me.
>

Dmitry, your thoughts on this

> Jonathan
>
>>>From d2842ba67e142e78b2554cebb01341c76b84b693 Mon Sep 17 00:00:00 2001
>> From: Hemanth V <hemanthv@xxxxxx>
>> Date: Fri, 30 Apr 2010 11:55:10 +0530
>> Subject: [PATCH] CMA3000 Accelerometer Driver
>>
>> This patch adds support for CMA3000 Tri-axis accelerometer, which
>> supports Motion detect, Measurement and Free fall modes.
>> CMA3000 supports both I2C/SPI bus for communication, currently the
>> driver supports I2C based communication.
>>
>> Driver reports acceleration data through input subsystem and supports
>> sysfs for configuration changes.
>>
>> This chip is currently used with OMAP4 based boards
>>
>> Thanks to Ossi Kauppinen <Ossi.Kauppinen@xxxxxx> for the support
>> provided during development
>>
>> Signed-off-by: Hemanth V <hemanthv@xxxxxx>
>> ---
>>  drivers/input/misc/Kconfig           |    9 +
>>  drivers/input/misc/Makefile          |    1 +
>>  drivers/input/misc/cma3000_d0x.c     |  627 ++++++++++++++++++++++++++++++++++
>>  drivers/input/misc/cma3000_d0x.h     |   46 +++
>>  drivers/input/misc/cma3000_d0x_i2c.c |  136 ++++++++
>>  include/linux/i2c/cma3000.h          |   60 ++++
>>  6 files changed, 879 insertions(+), 0 deletions(-)
> General convention is pick a device and name driver after it. Avoids confusion
> in future.

I am not sure I fully understand your comment, cma3000 being the family and cma300_d0x
being the specific chip

>>  create mode 100644 drivers/input/misc/cma3000_d0x.c
>>  create mode 100644 drivers/input/misc/cma3000_d0x.h
>>  create mode 100644 drivers/input/misc/cma3000_d0x_i2c.c
>>  create mode 100644 include/linux/i2c/cma3000.h
>>
>> diff --git a/drivers/input/misc/Kconfig b/drivers/input/misc/Kconfig
>> index 16ec523..4752a00 100644
>> --- a/drivers/input/misc/Kconfig
>> +++ b/drivers/input/misc/Kconfig
>> @@ -319,4 +319,13 @@ config INPUT_PCAP
>>  	  To compile this driver as a module, choose M here: the
>>  	  module will be called pcap_keys.
>>
>> +config INPUT_CMA3000_I2C
>> +	tristate "VTI CMA3000 Tri-axis accelerometer"
>> +	depends on I2C
>> +	help
>> +	  Say Y here if you want to use VTI CMA3000 Accelerometer
>> +	  through I2C interface.
>> +
>> +	  To compile this driver as a module, choose M here: the
>> +	  module will be called cma3000_dxx
>>  endif
>> diff --git a/drivers/input/misc/Makefile b/drivers/input/misc/Makefile
>> index a8b8485..94d6eda 100644
>> --- a/drivers/input/misc/Makefile
>> +++ b/drivers/input/misc/Makefile
>> @@ -30,4 +30,4 @@ obj-$(CONFIG_INPUT_WINBOND_CIR)		+= winbond-cir.o
>>  obj-$(CONFIG_INPUT_WISTRON_BTNS)	+= wistron_btns.o
>>  obj-$(CONFIG_INPUT_WM831X_ON)		+= wm831x-on.o
>>  obj-$(CONFIG_INPUT_YEALINK)		+= yealink.o
>> -
>> +obj-$(CONFIG_INPUT_CMA3000_I2C)		+= cma3000_d0x_i2c.o cma3000_d0x.o
>> diff --git a/drivers/input/misc/cma3000_d0x.c b/drivers/input/misc/cma3000_d0x.c
>> new file mode 100644
>> index 0000000..c0d0ea1
>> --- /dev/null
>> +++ b/drivers/input/misc/cma3000_d0x.c
>> @@ -0,0 +1,627 @@
>> +/*
>> + * cma3000_d0x.c
>> + * VTI CMA3000_D0x Accelerometer driver
>> + * 	Supports I2C/SPI interfaces
> The device, might but I'm not seeing SPI here.  Please clear out the define bits about
> i2c in the code as they aren't currently relevant.

Yes, will add defines related to SPI.


>> + *
>> + * Copyright (C) 2010 Texas Instruments
>> + * Author: Hemanth V <hemanthv@xxxxxx>
>> + *
>> + * 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, see <http://www.gnu.org/licenses/>.
>> + */
>> +
>> +#include <linux/interrupt.h>
>> +#include <linux/delay.h>
>> +#include <linux/input.h>
>> +#include <linux/platform_device.h>
>> +#include <linux/i2c/cma3000.h>
>> +
>> +#include "cma3000_d0x.h"
>> +
>> +#define CMA3000_WHOAMI      0x00
>> +#define CMA3000_REVID       0x01
>> +#define CMA3000_CTRL        0x02
>> +#define CMA3000_STATUS      0x03
>> +#define CMA3000_RSTR        0x04
>> +#define CMA3000_INTSTATUS   0x05
>> +#define CMA3000_DOUTX       0x06
>> +#define CMA3000_DOUTY       0x07
>> +#define CMA3000_DOUTZ       0x08
>> +#define CMA3000_MDTHR       0x09
>> +#define CMA3000_MDFFTMR     0x0A
>> +#define CMA3000_FFTHR       0x0B
>> +
>> +#define CMA3000_RANGE2G    (1 << 7)
>> +#define CMA3000_RANGE8G    (0 << 7)
>> +#define CMA3000_MODEMASK    (7 << 1)
>> +#define CMA3000_GRANGEMASK  (1 << 7)
>> +
>> +#define CMA3000_STATUS_PERR    1
>> +#define CMA3000_INTSTATUS_FFDET (1 << 2)
>> +
>> +/* Settling time delay in ms */
>> +#define CMA3000_SETDELAY    30
>> +
>> +/* Delay for clearing interrupt in us */
>> +#define CMA3000_INTDELAY    44
>> +
>> +
>> +/*
>> + * Bit weights in mg for each of the seven bits,
>> + * eight bit is the sign bit
>> + */
>> +static int bit_to_2g[7] = {18, 36, 71, 143, 286, 571, 1142};
>> +static int bit_to_8g[7] = {71, 143, 286, 571, 1142, 2286, 4571};
>> +
>> +/*
>> + * Conversion for each of the eight modes to g, depending
>> + * on G range i.e 2G or 8G
>> + */
>> +
>> +static int *mode_to_mg[8][2] = {
>> +	{NULL, NULL },
>> +	{bit_to_8g, bit_to_2g},
>> +	{bit_to_8g, bit_to_2g},
>> +	{bit_to_8g, bit_to_8g},
>> +	{bit_to_8g, bit_to_8g},
>> +	{bit_to_8g, bit_to_2g},
>> +	{bit_to_8g, bit_to_2g},
>> +	{NULL, NULL },
>> +};
>
> This arrary looks suspicious.  Why the 8g's in the second column?
> If they are real can we have an explanatory comment.

Yes will add explanation, basically in some modes even if the
range is set as 2G, it really operates in 8G.


>> +
>> +static ssize_t cma3000_show_attr_mode(struct device *dev,
>> +				     struct device_attribute *attr,
>> +				     char *buf)
>> +{
>> +	ssize_t ret = 0;
>> +	uint8_t mode;
>> +	struct platform_device *pdev = to_platform_device(dev);
>> +	struct cma3000_accl_data *data = platform_get_drvdata(pdev);
>> +
>> +	mode = cma3000_read(data, CMA3000_CTRL, "ctrl");
>> +	ret = sprintf(buf, "%d\n", (mode & CMA3000_MODEMASK) >> 1);
>> +	return ret;
> Roll previous 2 lines into 1.

Agreed.

>> +}
>> +
>
> Well into the realms of magic numbers here.  At the very least this needs
> some abi documenation.

If you are referring to attribute values,
they are explained as part of the header file cma3000.h.
I am thinking if it would be better to add a
documentation file


>> +static ssize_t cma3000_store_attr_mode(struct device *dev,
>> +				     struct device_attribute *attr,
>> +				     const char *buf, size_t count)
>> +{
>> +	struct platform_device *pdev = to_platform_device(dev);
>> +	struct cma3000_accl_data *data = platform_get_drvdata(pdev);
>> +	unsigned long val;
>> +	int error;
>> +	uint8_t ctrl;
>> +
>> +	error = strict_strtoul(buf, 0, &val);
>> +	if (error)
>> +		return error;
>> +
>> +	if (val < CMAMODE_DEFAULT || val > CMAMODE_POFF)
>> +		return -EINVAL;
>> +
>> +	mutex_lock(&data->mutex);
>> +	val &= (CMA3000_MODEMASK >> 1);
>> +	ctrl = cma3000_read(data, CMA3000_CTRL, "ctrl");
>> +	ctrl &= ~CMA3000_MODEMASK;
>> +	ctrl |= (val << 1);
>> +
>> +	data->pdata.mode = val;
>> +
>> +	disable_irq(data->client->irq);
>> +	cma3000_set(data, CMA3000_CTRL, ctrl, "ctrl");
> Personally I would have allowed the error that might result from this to be split
> into two (i2c_smbus_write_byte_data failed: (error code) then, "Ctrl register set failed".
> Thus no need to pass magic looking strings around.  Doesn't really matter though.
> Also no handling of error codes that this fuction can return.  These should be passed
> directly up to userspace.
>

Yes will pass error codes to upper layer

>> +
>> +	/* Settling time delay required after mode change */
>> +	msleep(CMA3000_SETDELAY);
>> +
>> +	enable_irq(data->client->irq);
>> +	mutex_unlock(&data->mutex);
>> +
>> +	return count;
>> +}
>> +
> More magic numbers.  Please document.

Yes, refer previous comments

>> +static ssize_t cma3000_show_attr_grange(struct device *dev,
>> +				       struct device_attribute *attr,
>> +				       char *buf)
>> +{
>> +	ssize_t ret = 0;
>> +	uint8_t mode;
>> +	int g_range;
>> +
>> +	struct platform_device *pdev = to_platform_device(dev);
>> +	struct cma3000_accl_data *data = platform_get_drvdata(pdev);
>> +
>> +	mode = cma3000_read(data, CMA3000_CTRL, "ctrl");
>> +	g_range = (mode & CMA3000_GRANGEMASK) ? CMARANGE_2G : CMARANGE_8G;
>> +	ret = sprintf(buf, "%d\n", g_range);
>> +
>> +	return ret;
>> +}
>> +
>> +static ssize_t cma3000_store_attr_grange(struct device *dev,
>> +				     struct device_attribute *attr,
>> +				     const char *buf, size_t count)
>> +{
>> +	struct platform_device *pdev = to_platform_device(dev);
>> +	struct cma3000_accl_data *data = platform_get_drvdata(pdev);
>> +	unsigned long val;
>> +	int error, g_range, fuzz_x, fuzz_y, fuzz_z;
>> +	uint8_t ctrl;
>> +
>> +	error = strict_strtoul(buf, 0, &val);
>> +	if (error)
>> +		return error;
>> +
>> +	mutex_lock(&data->mutex);
>> +	ctrl = cma3000_read(data, CMA3000_CTRL, "ctrl");
>> +	ctrl &= ~CMA3000_GRANGEMASK;
>> +
>> +	if (val == CMARANGE_2G) {
>> +		ctrl |= CMA3000_RANGE2G;
>> +		data->pdata.g_range = CMARANGE_2G;
>> +	} else if (val == CMARANGE_8G) {
>> +		ctrl |= CMA3000_RANGE8G;
>> +		data->pdata.g_range = CMARANGE_8G;
>> +	} else {
>> +		error = -EINVAL;
>> +		goto err_op_failed;
>> +	}
>> +
>
> Why not just pass these directly into the following functions?

This is to make it more readable, rather than having
large arguments.

>> +	g_range = data->pdata.g_range;
>> +	fuzz_x = data->pdata.fuzz_x;
>> +	fuzz_y = data->pdata.fuzz_y;
>> +	fuzz_z = data->pdata.fuzz_z;
>> +
>> +	disable_irq(data->client->irq);
>> +	cma3000_set(data, CMA3000_CTRL, ctrl, "ctrl");
>> +
>> +	input_set_abs_params(data->input_dev, ABS_X, -g_range,
>> +				g_range, fuzz_x, 0);
>> +	input_set_abs_params(data->input_dev, ABS_Y, -g_range,
>> +				g_range, fuzz_y, 0);
>> +	input_set_abs_params(data->input_dev, ABS_Z, -g_range,
>> +				g_range, fuzz_z, 0);
>> +
>> +	enable_irq(data->client->irq);
>> +	mutex_unlock(&data->mutex);
>> +
>> +	return count;
>> +
>> +err_op_failed:
>> +	mutex_unlock(&data->mutex);
>> +	return error;
>> +}
>> +
>> +static ssize_t cma3000_show_attr_mdthr(struct device *dev,
>> +				      struct device_attribute *attr,
>> +				      char *buf)
>> +{
>> +	ssize_t ret = 0;
>> +	uint8_t mode;
>> +
>> +	struct platform_device *pdev = to_platform_device(dev);
>> +	struct cma3000_accl_data *data = platform_get_drvdata(pdev);
>> +
>> +	mode = cma3000_read(data, CMA3000_MDTHR, "mdthr");
>> +	ret = sprintf(buf, "%d\n", mode);
>> +
>> +	return ret;
> Again roll lines together. Lots more of these below.  Add code for
> no gain in my view.

Yes, agreed

>> +}
>> +
>> +static ssize_t cma3000_store_attr_mdthr(struct device *dev,
>> +				       struct device_attribute *attr,
>> +				       const char *buf, size_t count)
>> +{
>> +	struct platform_device *pdev = to_platform_device(dev);
>> +	struct cma3000_accl_data *data = platform_get_drvdata(pdev);
>> +	unsigned long val;
>> +	int error;
>> +
> Why not specify the base? Pretty much anything will work so why
> make a fair bit of code run to guess what is right.

Can u clarify which base u are referring to.


>> +	error = strict_strtoul(buf, 0, &val);
>> +	if (error)
>> +		return error;
>> +
>> +	mutex_lock(&data->mutex);
>> +	data->pdata.mdthr = val;
>> +
>> +	disable_irq(data->client->irq);
>> +	cma3000_set(data, CMA3000_MDTHR, val, "mdthr");
>> +	enable_irq(data->client->irq);
>> +	mutex_unlock(&data->mutex);
>> +
>> +	return count;
>> +}
>> +
>> +static ssize_t cma3000_show_attr_mdfftmr(struct device *dev,
>> +					struct device_attribute *attr,
>> +					char *buf)
>> +{
>> +	ssize_t ret = 0;
>> +	uint8_t mode;
>> +
>> +	struct platform_device *pdev = to_platform_device(dev);
>> +	struct cma3000_accl_data *data = platform_get_drvdata(pdev);
>> +
>> +	mode = cma3000_read(data, CMA3000_MDFFTMR, "mdfftmr");
>> +	ret = sprintf(buf, "%d\n", mode);
>> +
>> +	return ret;
>> +}
>> +
>> +static ssize_t cma3000_store_attr_mdfftmr(struct device *dev,
>> +					struct device_attribute *attr,
>> +					const char *buf, size_t count)
>> +{
>> +	struct platform_device *pdev = to_platform_device(dev);
>> +	struct cma3000_accl_data *data = platform_get_drvdata(pdev);
>> +	unsigned long val;
>> +	int error;
>> +
>> +	error = strict_strtoul(buf, 0, &val);
>> +	if (error)
>> +		return error;
>> +
>> +	mutex_lock(&data->mutex);
>> +	data->pdata.mdfftmr = val;
>> +
>> +	disable_irq(data->client->irq);
>> +	cma3000_set(data, CMA3000_MDFFTMR, val, "mdthr");
> Again handle the error code returned by this.

Yes, agreed

>> +	enable_irq(data->client->irq);
>> +	mutex_unlock(&data->mutex);
>> +
>> +	return count;
>> +}
>> +
> More documentation needed. I've no idea what this one is!

yes, agreed

>> +static ssize_t cma3000_show_attr_ffthr(struct device *dev,
>> +					struct device_attribute *attr,
>> +					char *buf)
>> +{
>> +	ssize_t ret = 0;
>> +	uint8_t mode;
>> +
>> +	struct platform_device *pdev = to_platform_device(dev);
>> +	struct cma3000_accl_data *data = platform_get_drvdata(pdev);
>> +
>> +	mode = cma3000_read(data, CMA3000_FFTHR, "ffthr");
>> +	ret = sprintf(buf, "%d\n", mode);
>> +
>> +	return ret;
>> +}
>> +
>> +static ssize_t cma3000_store_attr_ffthr(struct device *dev,
>> +				       struct device_attribute *attr,
>> +				       const char *buf, size_t count)
>> +{
>> +	struct platform_device *pdev = to_platform_device(dev);
>> +	struct cma3000_accl_data *data = platform_get_drvdata(pdev);
>> +	unsigned long val;
>> +	int error;
>> +
>> +	error = strict_strtoul(buf, 0, &val);
>> +	if (error)
>> +		return error;
>> +
>> +	mutex_lock(&data->mutex);
>> +	data->pdata.ffthr = val;
>> +
>> +	disable_irq(data->client->irq);
>> +	cma3000_set(data, CMA3000_FFTHR, val, "mdthr");
> more error codes not handled.

yes, agreed

>> +	enable_irq(data->client->irq);
>> +	mutex_unlock(&data->mutex);
>> +
>> +	return count;
>> +}
>> +
>
> All need documentation.  What they should be called is a little
> open to debate. I'd argue in favour of the iio naming conventions,
> but then I wrote most of them :)

Dmity, your thoughts on this

>
>> +static DEVICE_ATTR(mode, S_IWUSR | S_IRUGO,
>> +		cma3000_show_attr_mode, cma3000_store_attr_mode);
>> +
>> +static DEVICE_ATTR(grange, S_IWUSR | S_IRUGO,
>> +		cma3000_show_attr_grange, cma3000_store_attr_grange);
>> +
>> +static DEVICE_ATTR(mdthr, S_IWUSR | S_IRUGO,
>> +		cma3000_show_attr_mdthr, cma3000_store_attr_mdthr);
>> +
>> +static DEVICE_ATTR(mdfftmr, S_IWUSR | S_IRUGO,
>> +		cma3000_show_attr_mdfftmr, cma3000_store_attr_mdfftmr);
>> +
>> +static DEVICE_ATTR(ffthr, S_IWUSR | S_IRUGO,
>> +		cma3000_show_attr_ffthr, cma3000_store_attr_ffthr);
>> +
>> +
>> +static struct attribute *cma_attrs[] = {
>> +	&dev_attr_mode.attr,
>> +	&dev_attr_grange.attr,
>> +	&dev_attr_mdthr.attr,
>> +	&dev_attr_mdfftmr.attr,
>> +	&dev_attr_ffthr.attr,
>> +	NULL,
>> +};
>> +
>> +static struct attribute_group cma3000_attr_group = {
>> +	.attrs = cma_attrs,
>> +};
>> +
>> +static void cma3000_create_sysfs(struct cma3000_accl_data *data)
>> +{
>> +	int ret;
>> +	ret = sysfs_create_group(&data->client->dev.kobj, &cma3000_attr_group);
>> +	if (ret)
>> +		dev_err(&data->client->dev,
>> +			"failed to create sysfs entries\n");
> This is a void returning function?  Surely it failing should stop the driver
> loading and exit nicely?

Yes, agreed

>> +
>> +}
>> +
>> +static void cma3000_remove_sysfs(struct cma3000_accl_data *data)
>> +{
>> +	sysfs_remove_group(&data->client->dev.kobj, &cma3000_attr_group);
>> +}
>> +
>> +static void decode_mg(struct cma3000_accl_data *data, int *datax,
>> +				int *datay, int *dataz)
>> +{
>> +	int i, tmpx = 0, tmpy = 0, tmpz = 0;
>> +
>
> Can this get rolled into a function per channel? Would be easier to read.

Will check if this can be further optimized.

>> +	for (i = 0; i < 7; ++i) {
>> +		tmpx += (((*datax) & BIT(i)) >> i) * (data->bit_to_mg[i]);
>> +		tmpy += (((*datay) & BIT(i)) >> i) * (data->bit_to_mg[i]);
>> +		tmpz += (((*dataz) & BIT(i)) >> i) * (data->bit_to_mg[i]);
>> +
>> +	}
>> +
>> +	if ((*datax) & BIT(7))
>> +		*datax = -tmpx;
>> +	else
>> +		*datax = tmpx;
>> +
>> +	if ((*datay) & BIT(7))
>> +		*datay = -tmpy;
>> +	else
>> +		*datay = tmpy;
>> +
>> +	if ((*dataz) & BIT(7))
>> +		*dataz = -tmpz;
>> +	else
>> +		*dataz = tmpz;
>> +}
>> +
>> +static irqreturn_t cma3000_thread_irq(int irq, void *dev_id)
>> +{
>> +	struct cma3000_accl_data *data = dev_id;
>> +	int  datax, datay, dataz;
>> +	u8 ctrl, mode, range, intr_status;
>> +
>> +	intr_status = cma3000_read(data, CMA3000_INTSTATUS, "interrupt status");
>> +
>> +	/* Check if free fall is detected, report immediately */
>> +	if (intr_status & CMA3000_INTSTATUS_FFDET) {
>> +		input_report_abs(data->input_dev, ABS_MISC, 1);
>> +		input_sync(data->input_dev);
>> +	} else {
>> +		input_report_abs(data->input_dev, ABS_MISC, 0);
>> +	}
>> +
>> +
>> +	/* Delay required between each read for interrupt clearing */
> Weird... Not your fault obviously! Got to love vti parts sometimes.
> Can you just confirm that the chip really sends out a data ready for each
> channel?  That to put it lightly would be very unusual.

As per product specs there is no data ready per channel. The information I received from VTI support
is that if there are continuous reads for all 3 channel there are issues with interrupt clearing
hence a delay is added between each channel read.


>> +	datax = cma3000_read(data, CMA3000_DOUTX, "X");
>> +	udelay(CMA3000_INTDELAY);
>> +	datay = cma3000_read(data, CMA3000_DOUTY, "Y");
>> +	udelay(CMA3000_INTDELAY);
>> +	dataz = cma3000_read(data, CMA3000_DOUTZ, "Z");
>> +
>> +	ctrl = cma3000_read(data, CMA3000_CTRL, "ctrl");
>> +	mode = (ctrl & CMA3000_MODEMASK) >> 1;
>> +	range = (ctrl & CMA3000_GRANGEMASK) >> 7;
> Please can you cache this ctrl register.  Silly to read it every time
> when I think you should be able to know in advance what it is set to.

Modes can change dynamically, for example from motion detect to measurement
hence the need to get the current mode from register read.

>> +
>> +	data->bit_to_mg = mode_to_mg[mode][range];
>> +
>> +	/* Interrupt not for this device */
>> +	if (data->bit_to_mg == NULL)
>> +		return IRQ_NONE;
>> +
>> +	/* Decode register values to milli g */
>> +	decode_mg(data, &datax, &datay, &dataz);
>> +
>> +	input_report_abs(data->input_dev, ABS_X, datax);
>> +	input_report_abs(data->input_dev, ABS_Y, datay);
>> +	input_report_abs(data->input_dev, ABS_Z, dataz);
>> +	input_sync(data->input_dev);
>> +
>> +	return IRQ_HANDLED;
>> +}
>> +
>> +static int cma3000_reset(struct cma3000_accl_data *data)
>> +{
>> +	int ret;
>> +
>> +	/* Reset sequence */
>> +	cma3000_set(data, CMA3000_RSTR, 0x02, "Reset");
>> +	cma3000_set(data, CMA3000_RSTR, 0x0A, "Reset");
>> +	cma3000_set(data, CMA3000_RSTR, 0x04, "Reset");
>> +
>> +	/* Settling time delay */
>> +	mdelay(10);
>> +
>> +	ret = cma3000_read(data, CMA3000_STATUS, "Status");
>> +	if ((ret < 0) || (ret & CMA3000_STATUS_PERR)) {
>> +		dev_err(&data->client->dev, "Reset failed\n");
> Why kill the perfectly good error code from cma3000_read?

It could be a read error or reset failed, hence the error code

>> +		return -EIO;
>> +	}
>> +
>> +	return 0;
>> +}
>> +
>> +int cma3000_poweron(struct cma3000_accl_data *data)
>> +{
>> +	uint8_t ctrl = 0, mdthr, mdfftmr, ffthr, mode;
>> +	int g_range, ret;
>> +
>
> Any reason for local copies?

For easier reading

>> +	g_range = data->pdata.g_range;
>> +	mode = data->pdata.mode;
>> +	mdthr = data->pdata.mdthr;
>> +	mdfftmr = data->pdata.mdfftmr;
>> +	ffthr = data->pdata.ffthr;
>> +
>> +	if (mode < CMAMODE_DEFAULT || mode > CMAMODE_POFF) {
>> +		data->pdata.mode = CMAMODE_MOTDET;
>> +		mode = data->pdata.mode;
>> +		dev_info(&data->client->dev,
>> +			"Invalid mode specified, assuming Motion Detect\n");
>> +	}
>> +
>> +	if (g_range == CMARANGE_2G) {
>> +		ctrl = (mode << 1) | CMA3000_RANGE2G;
>> +	} else if (g_range == CMARANGE_8G) {
>> +		ctrl = (mode << 1) | CMA3000_RANGE8G;
>> +	} else {
>> +		dev_info(&data->client->dev,
>> +			"Invalid G range specified, assuming 8G\n");
>> +		ctrl = (mode << 1) | CMA3000_RANGE8G;
>> +		data->pdata.g_range = CMARANGE_8G;
>> +	}
>> +
>> +
>> +	cma3000_set(data, CMA3000_MDTHR, mdthr, "Motion Detect Threshold");
>> +	cma3000_set(data, CMA3000_MDFFTMR, mdfftmr, "Time register");
>> +	cma3000_set(data, CMA3000_FFTHR, ffthr, "Free fall threshold");
>> +	ret = cma3000_set(data, CMA3000_CTRL, ctrl, "Mode setting");
>> +	if (ret < 0)
>> +		return -EIO;
>> +
>> +	mdelay(CMA3000_SETDELAY);
>> +
>> +	return 0;
>> +}
>> +
>> +int cma3000_poweroff(struct cma3000_accl_data *data)
>> +{
>> +	int ret;
>> +
>> +	ret = cma3000_set(data, CMA3000_CTRL, CMAMODE_POFF, "Mode setting");
>> +	mdelay(CMA3000_SETDELAY);
>> +
>> +	return ret;
>> +}
>> +
>> +int cma3000_init(struct cma3000_accl_data *data)
>> +{
>> +	int ret = 0, fuzz_x, fuzz_y, fuzz_z, g_range;
>> +	uint32_t irqflags;
>> +
>> +	if (data->client->dev.platform_data == NULL) {
>> +		dev_err(&data->client->dev, "platform data not found \n");
>> +		goto err_op2_failed;
>> +	}
>> +
> Why the local copy?  Isn't data->client->dev.platform_data always available?

platform data is marked as __initdata

>> +	memcpy(&(data->pdata), data->client->dev.platform_data,
>> +		sizeof(struct cma3000_platform_data));
>> +
>> +	ret = cma3000_reset(data);
>> +	if (ret)
>> +		goto err_op2_failed;
>> +
>> +	ret = cma3000_read(data, CMA3000_REVID, "Revid");
>> +	if (ret < 0)
>> +		goto err_op2_failed;
>> +
>> +	pr_info("CMA3000 Acclerometer : Revision %x\n", ret);
>> +
>> +	/* Bring it out of default power down state */
>> +	ret = cma3000_poweron(data);
>> +	if (ret < 0)
>> +		goto err_op2_failed;
>> +
>> +	fuzz_x = data->pdata.fuzz_x;
>> +	fuzz_y = data->pdata.fuzz_y;
>> +	fuzz_z = data->pdata.fuzz_z;
>> +	g_range = data->pdata.g_range;
>> +	irqflags = data->pdata.irqflags;
>> +
>> +	data->input_dev = input_allocate_device();
>> +	if (data->input_dev == NULL) {
>> +		ret = -ENOMEM;
>> +		dev_err(&data->client->dev,
>> +			"Failed to allocate input device\n");
>> +		goto err_op2_failed;
>> +	}
>> +
>> +	data->input_dev->name = "cma3000-acclerometer";
>> +
>> +#ifdef CONFIG_INPUT_CMA3000_I2C
>> +	data->input_dev->id.bustype = BUS_I2C;
>> +#endif
>> +
>> +	 __set_bit(EV_ABS, data->input_dev->evbit);
>> +	 __set_bit(EV_MSC, data->input_dev->evbit);
>> +
>> +	input_set_abs_params(data->input_dev, ABS_X, -g_range,
>> +				g_range, fuzz_x, 0);
>> +	input_set_abs_params(data->input_dev, ABS_Y, -g_range,
>> +				g_range, fuzz_y, 0);
>> +	input_set_abs_params(data->input_dev, ABS_Z, -g_range,
>> +				g_range, fuzz_z, 0);
>> +	input_set_abs_params(data->input_dev, ABS_MISC, 0,
>> +				1, 0, 0);
>> +
>> +	ret = input_register_device(data->input_dev);
>> +	if (ret) {
>> +		dev_err(&data->client->dev,
>> +			"Unable to register input device\n");
>> +		goto err_op2_failed;
>> +	}
>> +
>> +	mutex_init(&data->mutex);
>> +
>> +	if (data->client->irq) {
>> +		ret = request_threaded_irq(data->client->irq, NULL,
>> +					cma3000_thread_irq,
>> +					irqflags | IRQF_ONESHOT,
>> +					data->client->name, data);
>> +
>> +		if (ret < 0) {
>> +			dev_err(&data->client->dev,
>> +				"request_threaded_irq failed\n");
>> +			goto err_op1_failed;
>> +		}
>> +	}
>> +
>> +	cma3000_create_sysfs(data);
>> +
>> +	return 0;
>> +
>> +err_op1_failed:
>> +	mutex_destroy(&data->mutex);
>> +	input_unregister_device(data->input_dev);
>> +err_op2_failed:
>> +	if (data != NULL) {
>> +		if (data->input_dev != NULL)
>> +			input_free_device(data->input_dev);
>> +	}
>> +
>> +	return ret;
>> +}
>> +
>> +int cma3000_exit(struct cma3000_accl_data *data)
>> +{
>> +	int ret;
>> +
>> +	ret = cma3000_poweroff(data);
>> +
>> +	if (data->client->irq)
>> +		free_irq(data->client->irq, data);
>> +
>> +	mutex_destroy(&data->mutex);
>> +	input_unregister_device(data->input_dev);
>> +	input_free_device(data->input_dev);
>> +	cma3000_remove_sysfs(data);
>> +
>> +	return ret;
>> +}
>> diff --git a/drivers/input/misc/cma3000_d0x.h b/drivers/input/misc/cma3000_d0x.h
>> new file mode 100644
>> index 0000000..906d29e
>> --- /dev/null
>> +++ b/drivers/input/misc/cma3000_d0x.h
>> @@ -0,0 +1,46 @@
>> +/*
>> + * cma3000_d0x.h
>> + * VTI CMA3000_D0x Accelerometer driver
>> + *
>> + * Copyright (C) 2010 Texas Instruments
>> + * Author: Hemanth V <hemanthv@xxxxxx>
>> + *
>> + * 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, see <http://www.gnu.org/licenses/>.
>> + */
>> +
>> +#ifndef INPUT_CMA3000_H
>> +#define INPUT_CMA3000_H
>> +
>> +#include <linux/i2c.h>
>> +#include <linux/input.h>
>> +
>> +struct cma3000_accl_data {
>> +#ifdef CONFIG_INPUT_CMA3000_I2C
>> +	struct i2c_client *client;
>> +#endif
>> +	struct input_dev *input_dev;
>> +	struct cma3000_platform_data pdata;
>> +
>> +	/* mutex for sysfs operations */
>> +	struct mutex mutex;
>> +	int *bit_to_mg;
>> +};
>> +
>> +int cma3000_set(struct cma3000_accl_data *, u8, u8, char *);
>> +int cma3000_read(struct cma3000_accl_data *, u8, char *);
>> +int cma3000_init(struct cma3000_accl_data *);
>> +int cma3000_exit(struct cma3000_accl_data *);
>> +int cma3000_poweron(struct cma3000_accl_data *);
>> +int cma3000_poweroff(struct cma3000_accl_data *);
>> +
>> +#endif
>> diff --git a/drivers/input/misc/cma3000_d0x_i2c.c b/drivers/input/misc/cma3000_d0x_i2c.c
>> new file mode 100644
>> index 0000000..d2ad638
>> --- /dev/null
>> +++ b/drivers/input/misc/cma3000_d0x_i2c.c
>> @@ -0,0 +1,136 @@
>> +/*
>> + * cma3000_d0x_i2c.c
>> + *
>> + * Implements I2C interface for VTI CMA300_D0x Accelerometer driver
>> + *
>> + * Copyright (C) 2010 Texas Instruments
>> + * Author: Hemanth V <hemanthv@xxxxxx>
>> + *
>> + * 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, see <http://www.gnu.org/licenses/>.
>> + */
>> +
>> +#include <linux/module.h>
>> +#include <linux/i2c.h>
>> +#include <linux/i2c/cma3000.h>
>> +#include "cma3000_d0x.h"
>> +
>> +int cma3000_set(struct cma3000_accl_data *accl, u8 reg, u8 val, char *msg)
>> +{
>> +	int ret = i2c_smbus_write_byte_data(accl->client, reg, val);
>> +	if (ret < 0)
>> +		dev_err(&accl->client->dev,
>> +			"i2c_smbus_write_byte_data failed (%s)\n", msg);
>> +	return ret;
>> +}
>> +
>> +int cma3000_read(struct cma3000_accl_data *accl, u8 reg, char *msg)
>> +{
>> +	int ret = i2c_smbus_read_byte_data(accl->client, reg);
>> +	if (ret < 0)
>> +		dev_err(&accl->client->dev,
>> +			"i2c_smbus_read_byte_data failed (%s)\n", msg);
>> +	return ret;
>> +}
>> +
>> +static int __devinit cma3000_accl_probe(struct i2c_client *client,
>> +					const struct i2c_device_id *id)
>> +{
>> +	int ret;
>> +	struct cma3000_accl_data *data = NULL;
>> +
>> +	data = kzalloc(sizeof(*data), GFP_KERNEL);
>> +	if (data == NULL) {
>> +		ret = -ENOMEM;
>> +		goto err_op_failed;
>> +	}
>> +
>> +	data->client = client;
>> +	i2c_set_clientdata(client, data);
>> +
>> +	ret = cma3000_init(data);
>> +	if (ret)
>> +		goto err_op_failed;
>> +
>> +	return 0;
>> +
>> +err_op_failed:
>> +
>> +	if (data != NULL)
>> +		kfree(data);
>> +
>> +	return ret;
>> +}
>> +
>> +static int __devexit cma3000_accl_remove(struct i2c_client *client)
>> +{
>> +	struct cma3000_accl_data *data = i2c_get_clientdata(client);
>> +	int ret;
>> +
>> +	ret = cma3000_exit(data);
>> +	i2c_set_clientdata(client, NULL);
>> +	kfree(data);
>> +
>> +	return ret;
>> +}
>> +
>> +#ifdef CONFIG_PM
>> +static int cma3000_accl_suspend(struct i2c_client *client, pm_message_t mesg)
>> +{
>> +	struct cma3000_accl_data *data = i2c_get_clientdata(client);
>> +
>> +	return cma3000_poweroff(data);
>> +}
>> +
>> +static int cma3000_accl_resume(struct i2c_client *client)
>> +{
>> +	struct cma3000_accl_data *data = i2c_get_clientdata(client);
>> +
>> +	return cma3000_poweron(data);
>> +}
>> +#endif
>> +
>> +static const struct i2c_device_id cma3000_id[] = {
>> +	{ "cma3000_accl", 0 },
>> +	{ },
>> +};
>> +
>> +static struct i2c_driver cma3000_accl_driver = {
>> +	.probe		= cma3000_accl_probe,
>> +	.remove		= cma3000_accl_remove,
>> +	.id_table	= cma3000_id,
>> +#ifdef CONFIG_PM
>> +	.suspend	= cma3000_accl_suspend,
>> +	.resume		= cma3000_accl_resume,
>> +#endif
>> +	.driver = {
>> +		.name = "cma3000_accl"
>> +	},
>> +};
>> +
>> +static int __init cma3000_accl_init(void)
>> +{
> Bonus white line,

Will remove

>> +	return i2c_add_driver(&cma3000_accl_driver);
>> +}
>> +
>> +static void __exit cma3000_accl_exit(void)
>> +{
>> +	i2c_del_driver(&cma3000_accl_driver);
>> +}
>> +
>> +module_init(cma3000_accl_init);
>> +module_exit(cma3000_accl_exit);
>> +
>> +MODULE_DESCRIPTION("CMA3000-D0x Accelerometer Driver");
>> +MODULE_LICENSE("GPL");
>> +MODULE_AUTHOR("Hemanth V <hemanthv@xxxxxx>");
>> diff --git a/include/linux/i2c/cma3000.h b/include/linux/i2c/cma3000.h
>> new file mode 100644
>> index 0000000..50aa3fc
>> --- /dev/null
>> +++ b/include/linux/i2c/cma3000.h
>> @@ -0,0 +1,60 @@
>> +/*
>> + * cma3000.h
>> + * VTI CMA300_Dxx Accelerometer driver
>> + *
>> + * Copyright (C) 2010 Texas Instruments
>> + * Author: Hemanth V <hemanthv@xxxxxx>
>> + *
>> + * 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, see <http://www.gnu.org/licenses/>.
>> + */
>> +
>> +#ifndef _LINUX_CMA3000_I2C_H
>> +#define _LINUX_CMA3000_I2C_H
>> +
>> +#define CMAMODE_DEFAULT    0
>> +#define CMAMODE_MEAS100    1
>> +#define CMAMODE_MEAS400    2
>> +#define CMAMODE_MEAS40     3
>> +#define CMAMODE_MOTDET     4
>> +#define CMAMODE_FF100      5
>> +#define CMAMODE_FF400      6
>> +#define CMAMODE_POFF       7
>> +
>> +#define CMARANGE_2G   2000
>> +#define CMARANGE_8G   8000
>> +
>> +/**
>> + * struct cma3000_i2c_platform_data - CMA3000 Platform data
>> + * @fuzz_x: Noise on X Axis
>> + * @fuzz_y: Noise on Y Axis
>> + * @fuzz_z: Noise on Z Axis
>> + * @g_range: G range in milli g i.e 2000 or 8000
>> + * @mode: Operating mode
>> + * @mdthr: Motion detect threshold value
>> + * @mdfftmr: Motion detect and free fall time value
>> + * @ffthr: Free fall threshold value
>> + */
>> +
>> +struct cma3000_platform_data {
>> +	int fuzz_x;
>> +	int fuzz_y;
>> +	int fuzz_z;
>> +	int g_range;
>> +	uint8_t  mode;
>> +	uint8_t  mdthr;
>> +	uint8_t  mdfftmr;
>> +	uint8_t  ffthr;
>> +	uint32_t  irqflags;
>> +};
>> +
>> +#endif
>
>


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