Re: [PATCH] iio: add driver for si114x ambient light / proximity sensors

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On 10/17/2012 04:44 PM, Peter Meerwald wrote:
> Hello,
>
>> There is a slightly confusing divide between the trigger and the buffer
>> configuration but this is hardly the first device where that line has
>> been blurred.  Also why run with all channels enabled whenever the buffer
>> is turned off?
>
> thank you for the comments and the suggestion regarding the irq top/bottom
> half handler;
>
> I'll change the all-channels-enabled default; more replies inline
>
> p.
>
>>> the si114x supports x=1,2,3 IR LEDs for proximity sensing together with
>>> visible and IR ambient light sensing (ALS)
>>>
>>> arranging 3 IR LEDs in a triangular shape can be used for detection of swipe
>>> gestures (the present driver only measures the intensities, it does not process
>>> the data); there is an affordable reference design (via Digikey), see
>>> http://www.silabs.com/products/sensors/Pages/HID-USB-to-IR-Reference-Design.aspx
>>>
>>> v2: based on comments by Jonathan Cameron and Lars-Peter Clausen
>>> * description of the chip's functionality (above) as requested
>>> * kerneldocs for the data structure
>>> * drop platform data (use of irq is determined by i2c_client->irq;
>>>   irq_flags is TRIGGER_FALLING always)
>>> * provide comment and referene for _compress()/_uncompress()
>>> * drop timestamp from iio_push_to_buffer() call
>>> * select from constant attribute structs, no dynamic allocation
>>> * use constant channels array with proximity channels last,
>>>   compute num_channels based on chip part
>>> * drop update_scan_mode(), use local buffer in trigger function
>>> * cleanup access function to chip parameter values
>>> * simplify switches for readability
>>> * more testing and fixes
>>>
>>> Signed-off-by: Peter Meerwald <pmeerw@xxxxxxxxxx>
>>> ---
>>>  drivers/iio/light/Kconfig  |   13 +
>>>  drivers/iio/light/si114x.c | 1185 ++++++++++++++++++++++++++++++++++++++++++++
>>>  2 files changed, 1198 insertions(+)
>>>  create mode 100644 drivers/iio/light/si114x.c
>>>
>>> diff --git a/drivers/iio/light/Kconfig b/drivers/iio/light/Kconfig
>>> index 1763c9b..9ad512f 100644
>>> --- a/drivers/iio/light/Kconfig
>>> +++ b/drivers/iio/light/Kconfig
>>> @@ -32,6 +32,19 @@ config SENSORS_LM3533
>>>  	  changes. The ALS-control output values can be set per zone for the
>>>  	  three current output channels.
>>>
>>> +config SI114X
>>> +	tristate "SI114x combined ALS and proximity sensor"
>>> +	depends on I2C
>>> +	default n
>>> +	---help---
>>> +	  Say Y here if you want to build a driver for the Silicon Labs SI114x
>>> +	  combined ambient light and proximity sensor chips (SI1141, SI1142,
>>> +	  SI1143). The driver supports forced (with and w/o IRQ) and autonomous
>>> +	  measurements (with IRQ only).
>>> +
>>> +	  To compile this driver as a module, choose M here: the
>>> +	  module will be called si114x.
>>> +
>>>  config VCNL4000
>>>  	tristate "VCNL4000 combined ALS and proximity sensor"
>>>  	depends on I2C
>>> diff --git a/drivers/iio/light/si114x.c b/drivers/iio/light/si114x.c
>>> new file mode 100644
>>> index 0000000..1636c0e
>>> --- /dev/null
>>> +++ b/drivers/iio/light/si114x.c
>>> @@ -0,0 +1,1185 @@
>>> +/*
>>> + * si114x.c - Support for Silabs si114x combined ambient light and
>>> + * proximity sensor
>>> + *
>>> + * Copyright 2012 Peter Meerwald <pmeerw@xxxxxxxxxx>
>>> + *
>>> + * This file is subject to the terms and conditions of version 2 of
>>> + * the GNU General Public License.  See the file COPYING in the main
>>> + * directory of this archive for more details.
>>> + *
>>> + * IIO driver for si114x (7-bit I2C slave address 0x5a) with sequencer
>>> + * version >= A03
>>> + *
>>> + * driver supports IRQ and non-IRQ mode; an IRQ is required for
>>> + * autonomous measurement mode
>>> + * TODO:
>>> + *   thresholds
>>
>> Out of curiosity are thresholds the reason you enable all channels
>> when not in buffered mode?  Thinking about it, with the multiple buffer
>> code I haven't covered the case where the scan mode changes for reasons
>> other than the channels being wanted by some buffer.  That's going
>> to be 'interesting' to handle properly.  Might have to cheat with some
>> pseudo buffer just to enforce channels being read and then do rip down
>> and setup as the enabled threshold interrupts
>> changes.  Oh well, one for another day.
>
> the interrupt can be configured to fired
> (i) upon each completed measurement (this is supported), or
> (ii) when a measurement value if above a threshold, or
> (iii) a measurement value crosses a threshold
>
> threshold can be per-channel
Good, that's nice and adaptable.
>
> further, the chip supports different measurement rates: e.g. the proximity
> channels are sampled 10 times/sec while the ALS is sampled only every 10th
> measurement (not supported by the driver)
That's uggly from a buffering point of view.  Either don't support it (as
you do now) or separate the device into two iio_devs each with their own buffer.
The chances of wanting sychronized light and proximity readings is pretty low.
I guess which option to go for long term is dependent on whether the power
savings of not turing the proximity LEDs on are significant.
>
>>> + *   power management (measurement rate zero)
>>> + */
>>> +
>>> +#include <linux/module.h>
>>> +#include <linux/i2c.h>
>>> +#include <linux/err.h>
>>> +#include <linux/slab.h>
>>> +#include <linux/delay.h>
>>> +#include <linux/irq.h>
>>> +#include <linux/gpio.h>
>>> +
>>> +#include <linux/iio/iio.h>
>>> +#include <linux/iio/sysfs.h>
>>> +#include <linux/iio/trigger.h>
>>> +#include <linux/iio/trigger_consumer.h>
>>> +#include <linux/iio/triggered_buffer.h>
>>> +#include <linux/iio/buffer.h>
>>> +
>>> +#define SI114X_REG_PART_ID		0x00
>>> +#define SI114X_REG_REV_ID		0x01
>>> +#define SI114X_REG_SEQ_ID		0x02
>>> +#define SI114X_REG_INT_CFG		0x03
>>> +#define SI114X_REG_IRQ_ENABLE		0x04
>>> +#define SI114X_REG_IRQ_MODE1		0x05
>>> +#define SI114X_REG_IRQ_MODE2		0x06
>>> +#define SI114X_REG_HW_KEY		0x07
>>> +/* RATE stores a 16 bit value compressed to 8 bit */
>>> +#define SI114X_REG_MEAS_RATE		0x08
>>> +#define SI114X_REG_ALS_RATE		0x09
>>> +#define SI114X_REG_PS_RATE		0x0a
>>> +#define SI114X_REG_ALS_LOW_TH0		0x0b
>>> +#define SI114X_REG_ALS_LOW_TH1		0x0c
>>> +#define SI114X_REG_ALS_HI_TH0		0x0d
>>> +#define SI114X_REG_ALS_HI_TH1		0x0e
>>> +#define SI114X_REG_PS_LED21		0x0f
>>> +#define SI114X_REG_PS_LED3		0x10
>>> +/*
>>> + * for rev A10 and below TH0 stores a 16 bit value compressed to 8 bit and
>>> + * TH1 is not used; newer revision have the LSB in TH0 and the MSB in TH1
>>> + */
>>> +#define SI114X_REG_PS1_TH0		0x11
>>> +#define SI114X_REG_PS1_TH1		0x12
>>> +#define SI114X_REG_PS2_TH0		0x13
>>> +#define SI114X_REG_PS2_TH1		0x11
>>> +#define SI114X_REG_PS3_TH0		0x15
>>> +#define SI114X_REG_PS3_TH1		0x16
>>> +#define SI114X_REG_PARAM_WR		0x17
>>> +#define SI114X_REG_COMMAND		0x18
>>> +#define SI114X_REG_RESPONSE		0x20
>>> +#define SI114X_REG_IRQ_STATUS		0x21
>>> +#define SI114X_REG_ALSVIS_DATA0		0x22
>>> +#define SI114X_REG_ALSVIS_DATA1		0x23
>>> +#define SI114X_REG_ALSIR_DATA0		0x24
>>> +#define SI114X_REG_ALSIR_DATA1		0x25
>>> +#define SI114X_REG_PS1_DATA0		0x26
>>> +#define SI114X_REG_PS1_DATA1		0x27
>>> +#define SI114X_REG_PS2_DATA0		0x28
>>> +#define SI114X_REG_PS2_DATA1		0x29
>>> +#define SI114X_REG_PS3_DATA0		0x2a
>>> +#define SI114X_REG_PS3_DATA1		0x2b
>>> +#define SI114X_REG_AUX_DATA0		0x2c
>>> +#define SI114X_REG_AUX_DATA1		0x2d
>>> +#define SI114X_REG_PARAM_RD		0x2e
>>> +#define SI114X_REG_CHIP_STAT		0x30
>>> +
>>> +/* helper to figure out PS_LED register / shift per channel */
>>> +#define SI114X_PS_LED_REG(ch) \
>>> +	(((ch) == 2) ? SI114X_REG_PS_LED3 : SI114X_REG_PS_LED21)
>>> +#define SI114X_PS_LED_SHIFT(ch) \
>>> +	(((ch) == 1) ? 4 : 0)
>>> +
>>> +/* Parameter offsets */
>>> +#define SI114X_PARAM_I2C_ADDR		0x00
>>> +#define SI114X_PARAM_CHLIST		0x01
>>> +#define SI114X_PARAM_PSLED12_SELECT	0x02
>>> +#define SI114X_PARAM_PSLED3_SELECT	0x03
>>> +#define SI114X_PARAM_FILTER_EN		0x04
>>> +#define SI114X_PARAM_PS_ENCODING	0x05
>>> +#define SI114X_PARAM_ALS_ENCODING	0x06
>>> +#define SI114X_PARAM_PS1_ADC_MUX	0x07
>>> +#define SI114X_PARAM_PS2_ADC_MUX	0x08
>>> +#define SI114X_PARAM_PS3_ADC_MUX	0x09
>>> +#define SI114X_PARAM_PS_ADC_COUNTER	0x0a
>>> +#define SI114X_PARAM_PS_ADC_GAIN	0x0b
>>> +#define SI114X_PARAM_PS_ADC_MISC	0x0c
>>> +#define SI114X_PARAM_ALS_ADC_MUX	0x0d
>>> +#define SI114X_PARAM_ALSIR_ADC_MUX	0x0e
>>> +#define SI114X_PARAM_AUX_ADC_MUX	0x0f
>>> +#define SI114X_PARAM_ALSVIS_ADC_COUNTER	0x10
>>> +#define SI114X_PARAM_ALSVIS_ADC_GAIN	0x11
>>> +#define SI114X_PARAM_ALSVIS_ADC_MISC	0x12
>>> +#define SI114X_PARAM_ALS_HYST		0x16
>>> +#define SI114X_PARAM_PS_HYST		0x17
>>> +#define SI114X_PARAM_PS_HISTORY		0x18
>>> +#define SI114X_PARAM_ALS_HISTORY	0x19
>>> +#define SI114X_PARAM_ADC_OFFSET		0x1a
>>> +#define SI114X_PARAM_SLEEP_CTRL		0x1b
>>> +#define SI114X_PARAM_LED_RECOVERY	0x1c
>>> +#define SI114X_PARAM_ALSIR_ADC_COUNTER	0x1d
>>> +#define SI114X_PARAM_ALSIR_ADC_GAIN	0x1e
>>> +#define SI114X_PARAM_ALSIR_ADC_MISC	0x1f
>>> +
>>> +/* Channel enable masks for CHLIST parameter */
>>> +#define SI114X_CHLIST_EN_PS1		0x01
>>> +#define SI114X_CHLIST_EN_PS2		0x02
>>> +#define SI114X_CHLIST_EN_PS3		0x04
>>> +#define SI114X_CHLIST_EN_ALSVIS		0x10
>>> +#define SI114X_CHLIST_EN_ALSIR		0x20
>>> +#define SI114X_CHLIST_EN_AUX		0x40
>>> +
>>> +/* Signal range mask for ADC_MISC parameter */
>>> +#define SI114X_MISC_RANGE		0x20
>>> +
>>> +/* Commands for REG_COMMAND */
>>> +#define SI114X_CMD_NOP			0x00
>>> +#define SI114X_CMD_RESET		0x01
>>> +#define SI114X_CMD_BUSADDR		0x02
>>> +#define SI114X_CMD_PS_FORCE		0x05
>>> +#define SI114X_CMD_ALS_FORCE		0x06
>>> +#define SI114X_CMD_PSALS_FORCE		0x07
>>> +#define SI114X_CMD_PS_PAUSE		0x09
>>> +#define SI114X_CMD_ALS_PAUSE		0x0a
>>> +#define SI114X_CMD_PSALS_PAUSE		0x0b
>>> +#define SI114X_CMD_PS_AUTO		0x0d
>>> +#define SI114X_CMD_ALS_AUTO		0x0e
>>> +#define SI114X_CMD_PSALS_AUTO		0x0f
>>> +#define SI114X_CMD_PARAM_QUERY		0x80
>>> +#define SI114X_CMD_PARAM_SET		0xa0
>>> +#define SI114X_CMD_PARAM_AND		0xc0
>>> +#define SI114X_CMD_PARAM_OR		0xe0
>>> +
>>> +/* Interrupt configuration masks for INT_CFG register */
>>> +#define SI114X_INT_CFG_OE		0x01 /* enable interrupt */
>>> +#define SI114X_INT_CFG_MODE		0x02 /* auto reset interrupt pin */
>>> +
>>> +/* Interrupt enable masks for IRQ_ENABLE register */
>>> +#define SI114X_CMD_IE			0x20
>>> +#define SI114X_PS3_IE			0x10
>>> +#define SI114X_PS2_IE			0x08
>>> +#define SI114X_PS1_IE			0x04
>>> +#define SI114X_ALS_INT1_IE		0x02
>>> +#define SI114X_ALS_INT0_IE		0x01
>>> +
>>> +/* Interrupt mode masks for IRQ_MODE1 register */
>>> +#define SI114X_PS2_IM_GREATER		0xc0
>>> +#define SI114X_PS2_IM_CROSS		0x40
>>> +#define SI114X_PS1_IM_GREATER		0x30
>>> +#define SI114X_PS1_IM_CROSS		0x10
>>> +
>>> +/* Interrupt mode masks for IRQ_MODE2 register */
>>> +#define SI114X_CMD_IM_ERROR		0x04
>>> +#define SI114X_PS3_IM_GREATER		0x03
>>> +#define SI114X_PS3_IM_CROSS		0x01
>>> +
>>> +/* Measurement rate settings */
>>> +#define SI114X_MEAS_RATE_FORCED		0x00
>>> +#define SI114X_MEAS_RATE_10MS		0x84
>>> +#define SI114X_MEAS_RATE_20MS		0x94
>>> +#define SI114X_MEAS_RATE_100MS		0xb9
>>> +#define SI114X_MEAS_RATE_496MS		0xdf
>>> +#define SI114X_MEAS_RATE_1984MS		0xff
>>> +
>>> +/* ALS rate settings relative to measurement rate */
>>> +#define SI114X_ALS_RATE_OFF		0x00
>>> +#define SI114X_ALS_RATE_1X		0x08
>>> +#define SI114X_ALS_RATE_10X		0x32
>>> +#define SI114X_ALS_RATE_100X		0x69
>>> +
>>> +/* PS rate settings relative to measurement rate */
>>> +#define SI114X_PS_RATE_OFF		0x00
>>> +#define SI114X_PS_RATE_1X		0x08
>>> +#define SI114X_PS_RATE_10X		0x32
>>> +#define SI114X_PS_RATE_100X		0x69
>>> +
>>> +/* Sequencer revision from SEQ_ID */
>>> +#define SI114X_SEQ_REV_A01		0x01
>>> +#define SI114X_SEQ_REV_A02		0x02
>>> +#define SI114X_SEQ_REV_A03		0x03
>>> +#define SI114X_SEQ_REV_A10		0x08
>>> +#define SI114X_SEQ_REV_A11		0x09
>>> +
>>> +#define SI114X_DRV_NAME "si114x"
>>> +
>>> +/**
>>> + * struct si114x_data - si114x chip state data
>>> + * @client:	I2C client
>>> + * @mutex:	mutex to protect multi-step I2C accesses and state changes
>>> + * @part:	chip part number (0x41, 0x42, 0x43) for 1 to 3 LEDs version
>>> + * @seq:	sequencer firmware revision determines chip features
>>> + * @data_avail:	wait queue for single measurement IRQ completion
>>> + * @got_data:	wait condition variable
>>> + * @use_irq:	set when IRQ is available
>>> + * @autonomous:	set when chip performs autonomous measurements (only when
>>> + *		IRQ available)
>>> + * @trig:	IIO trigger (only when IRQ available)
>>> + *
>>> + * The driver supports polling and IRQ operation for single and buffered
>>> + * measurements. A device trigger enables autonomous measurements are when
>>> + * an IRQ is available.
>>> + **/
>>> +struct si114x_data {
>>> +	struct i2c_client *client;
>>> +	struct mutex mutex;
>>> +	u8 part;
>>> +	u8 seq;
>>> +	wait_queue_head_t data_avail;
>>> +	bool got_data;
>>> +	bool use_irq;
>>> +	bool autonomous;
>>> +	struct iio_trigger *trig;
>>> +};
>>> +
>>> +/* expand 8 bit compressed value to 16 bit, see Silabs AN498 */
>>> +static u16 si114x_uncompress(u8 x)
>>> +{
>>> +	u16 result = 0;
>>> +	u8 exponent = 0;
>>> +
>>> +	if (x < 8)
>>> +		return 0;
>>> +
>>> +	exponent = (x & 0xf0) >> 4;
>>> +	result = 0x10 | (x & 0x0f);
>>> +
>>> +	if (exponent >= 4)
>>> +		return result << (exponent - 4);
>>> +	return result >> (4 - exponent);
>>> +}
>>> +
>>> +/* compress 16 bit to 8 bit using 4 bit exponent and 4 bit fraction,
>>> + * see Silabs AN498 */
>>> +static u8 si114x_compress(u16 x)
>>> +{
>>> +	u32 exponent = 0;
>>> +	u32 significand = 0;
>>> +	u32 tmp = x;
>>> +
>>> +	if (x == 0x0000)
>>> +		return 0x00;
>>> +	if (x == 0x0001)
>>> +		return 0x08;
>>> +
>>> +	while (1) {
>>> +		tmp >>= 1;
>>> +		exponent += 1;
>>> +		if (tmp == 1)
>>> +			break;
>>> +	}
>>> +
>>> +	if (exponent < 5) {
>>> +		significand = x << (4 - exponent);
>>> +		return (exponent << 4) | (significand & 0xF);
>>> +	}
>>> +
>>> +	significand = x >> (exponent - 5);
>>> +	if (significand & 1) {
>>> +		significand += 2;
>>> +		if (significand & 0x0040) {
>>> +			exponent += 1;
>>> +			significand >>= 1;
>>> +		}
>>> +	}
>>> +
>>> +	return (exponent << 4) | ((significand >> 1) & 0xF);
>>> +}
>>> +
>>> +/* helper function to operate on parameter values: op can be query/set/or/and */
>>> +static int si114x_param_op(struct si114x_data *data, u8 op, u8 param, u8 value)
>>> +{
>>> +	struct i2c_client *client = data->client;
>>> +	int ret;
>>> +
>>> +	mutex_lock(&data->mutex);
>>> +
>>> +	if (op != SI114X_CMD_PARAM_QUERY) {
>>> +		ret = i2c_smbus_write_byte_data(client,
>>> +			SI114X_REG_PARAM_WR, value);
>>> +		if (ret < 0)
>>> +			goto error;
>>> +	}
>>> +
>>> +	ret = i2c_smbus_write_byte_data(client, SI114X_REG_COMMAND,
>>> +		op | (param & 0x1F));
>>> +	if (ret < 0)
>>> +		goto error;
>>> +
>>> +	ret = i2c_smbus_read_byte_data(client, SI114X_REG_PARAM_RD);
>>> +	if (ret < 0)
>>> +		return ret;
>>> +
>>> +	mutex_unlock(&data->mutex);
>>> +
>>> +	return ret & 0xff;
>>> +error:
>>> +	mutex_unlock(&data->mutex);
>>> +	return ret;
>>> +}
>>> +
>>> +static irqreturn_t si114x_trigger_handler(int irq, void *private)
>>> +{
>>> +	struct iio_poll_func *pf = private;
>>> +	struct iio_dev *indio_dev = pf->indio_dev;
>>> +	struct si114x_data *data = iio_priv(indio_dev);
>>> +	/* maximum buffer size:
>>> +	 * 6*2 bytes channels data + 4 bytes alignment +
>>> +	 * 8 bytes timestamp
>>> +	 */
>>> +	u8 buffer[24];
>>> +	int len = 0;
>>> +	int i, j = 0;
>>> +	int ret;
>
>> Can this actually happen?  Autonomous seems to be turned on as
>> part of trigger set state.  Also the trigger handler is running
>> in response to an interrupt that I'd assumed was comming from the device?
>> Or is this to do with whether the device is using it's own trigger?
>> If so that should be checked directly rather than via this route
>> that just means something is using that trigger (perhaps another driver).
>
> I am not sure if I understand correctly; the
> "if (!data->autonomous)" block is here to handle the case when an external
> trigger is used (such as iio-trig-sysfs)
> so si114x_trigger_handler() does not necessarily run in response to an
> interrupt generated by the device
>
> "should be checked directly" is not clear to me
Consider the following.

For some reason we want synchronized proximity and accelerometer readings.
To do this we set both the accelerometer and the proximity sensor to use
the trigger provided by the proximity driver.  So far so good.
Then we decided to stop the proximity buffering and switch to the sysfs
trigger.  Thus the accelerometer is still using the si114x trigger but the
si114x is no longer doing so.  This is valid if odd.

I think that will mess up what we have here?  Hence I was suggesting
checking the current trigger (iio_dev->trigger == si114x_data->trigger)
rather than having that autonomous variable to indicate the same thing
(more or less).

Of course things get very confusing if this occurs. It may be better to
block it by preventing the trigger from enabling if the si114x device
isn't using it.

>
>>> +	if (!data->autonomous) {
>>> +		ret = i2c_smbus_write_byte_data(data->client,
>>> +			SI114X_REG_COMMAND, SI114X_CMD_PSALS_FORCE);
>>> +		if (ret < 0)
>>> +			goto done;
>>> +		msleep(20);
>>> +	}
>>> +
>>> +	for_each_set_bit(i, indio_dev->active_scan_mask,
>>> +		indio_dev->masklength) {
>>> +		ret = i2c_smbus_read_word_data(data->client,
>>> +			indio_dev->channels[i].address);
>>> +		if (ret < 0)
>>> +			goto done;
>>> +
>>> +		((u16 *) buffer)[j++] = ret & 0xffff;
>>> +		len += 2;
>>> +	}
>>> +
>>> +	if (indio_dev->scan_timestamp)
>>> +		*(s64 *)(buffer + ALIGN(len, sizeof(s64)))
>>> +			= iio_get_time_ns();
>>> +	iio_push_to_buffer(indio_dev->buffer, buffer);
>>> +
>>> +done:
>>> +	iio_trigger_notify_done(indio_dev->trig);
>>> +
>>> +	return IRQ_HANDLED;
>>> +}
>>> +
>>> +static irqreturn_t si114x_irq(int irq, void *private)
>>> +{
>>> +	struct iio_dev *indio_dev = private;
>>> +	struct si114x_data *data = iio_priv(indio_dev);
>>> +	int ret;
>>> +
>>> +	ret = i2c_smbus_read_byte_data(data->client,
>>> +		SI114X_REG_IRQ_STATUS);
>>> +	if (ret < 0 || !(ret & (SI114X_PS3_IE | SI114X_PS2_IE | SI114X_PS1_IE |
>>> +		SI114X_ALS_INT1_IE | SI114X_ALS_INT0_IE)))
>>> +		return IRQ_HANDLED;
>>> +
>>> +	if (iio_buffer_enabled(indio_dev))
>>> +		iio_trigger_poll_chained(indio_dev->trig, 0);
>>> +	else {
>>> +		data->got_data = true;
>>> +		wake_up_interruptible(&data->data_avail);
>>> +	}
>>> +
>>> +	/* clearing IRQ */
>>> +	ret = i2c_smbus_write_byte_data(data->client,
>>> +		SI114X_REG_IRQ_STATUS, ret & 0x1f);
>>> +	if (ret < 0)
>>> +		dev_err(&data->client->dev, "clearing irq failed\n");
>>> +
>>> +	return IRQ_HANDLED;
>>> +}
>>> +
>>> +static int si114x_trigger_set_state(struct iio_trigger *trig, bool
> state)
>>> +{
>>> +	struct iio_dev *indio_dev = trig->private_data;
>>> +	struct si114x_data *data = iio_priv(indio_dev);
>>> +	int ret;
>>> +	int cmd;
>>> +
>>> +	/* configure autonomous mode */
>>> +	cmd = state ? SI114X_CMD_PSALS_AUTO :
>>> +		SI114X_CMD_PSALS_PAUSE;
>>> +
>>> +	ret = i2c_smbus_write_byte_data(data->client,
>>> +		SI114X_REG_COMMAND, cmd);
>>> +	if (ret < 0)
>>> +		return ret;
>>> +
>>> +	data->autonomous = state;
>>> +
>>> +	return 0;
>>> +}
>>> +
>>> +static const struct iio_trigger_ops si114x_trigger_ops = {
>>> +	.owner = THIS_MODULE,
>>> +	.set_trigger_state = si114x_trigger_set_state,
>>> +};
>>> +
>>> +static int si114x_probe_trigger(struct iio_dev *indio_dev)
>>> +{
>>> +	struct si114x_data *data = iio_priv(indio_dev);
>>> +	int ret;
>>> +
>>> +	data->trig = iio_trigger_alloc("si114x-dev%d", indio_dev->id);
>>> +	if (!data->trig)
>>> +		return -ENOMEM;
>>> +
>>> +	data->trig->dev.parent = &data->client->dev;
>>> +	data->trig->ops = &si114x_trigger_ops;
>>> +	data->trig->private_data = indio_dev;
>>> +	ret = iio_trigger_register(data->trig);
>>> +	if (ret)
>>> +		goto error_free_trig;
>>> +
>>> +	/* select default trigger */
>>> +	indio_dev->trig = data->trig;
>>> +
>>> +	return 0;
>>> +
>>> +error_free_trig:
>>> +	iio_trigger_free(data->trig);
>>> +	return ret;
>>> +}
>>> +
>>> +static void si114x_remove_trigger(struct iio_dev *indio_dev)
>>> +{
>>> +	struct si114x_data *data = iio_priv(indio_dev);
>>> +
>>> +	iio_trigger_unregister(data->trig);
>>> +	iio_trigger_free(data->trig);
>>> +}
>>> +
>>> +static int si114x_read_raw(struct iio_dev *indio_dev,
>>> +				struct iio_chan_spec const *chan,
>>> +				int *val, int *val2, long mask)
>>> +{
>>> +	struct si114x_data *data = iio_priv(indio_dev);
>>> +	int ret = -EINVAL;
>>> +	u8 cmd, reg;
>>> +
>>> +	switch (mask) {
>>> +	case IIO_CHAN_INFO_RAW:
>>> +		switch (chan->type) {
>>> +		case IIO_INTENSITY:
>>> +		case IIO_PROXIMITY:
>>> +		case IIO_TEMP:
>>> +			if (iio_buffer_enabled(indio_dev))
>>> +				return -EBUSY;
>>> +
>>> +			if (chan->type == IIO_PROXIMITY)
>>> +				cmd = SI114X_CMD_PS_FORCE;
>>> +			else
>>> +				cmd = SI114X_CMD_ALS_FORCE;
>>> +			ret = i2c_smbus_write_byte_data(data->client,
>>> +				SI114X_REG_COMMAND, cmd);
>>> +			if (ret < 0)
>>> +				return ret;
>>> +			if (data->use_irq) {
>>> +				ret = wait_event_interruptible_timeout(
>>> +					data->data_avail, data->got_data,
>>> +					msecs_to_jiffies(1000));
>>> +				data->got_data = false;
>>> +				if (ret == 0)
>>> +					ret = -ETIMEDOUT;
>>> +			} else
>>> +				msleep(20);
>>> +			if (ret < 0)
>>> +				return ret;
>>> +
>>> +			ret = i2c_smbus_read_word_data(data->client,
>>> +				chan->address);
>>> +			if (ret < 0)
>>> +				return ret;
>>> +
>>> +			*val = ret & 0xffff;
>>> +
>>> +			ret = IIO_VAL_INT;
>>> +			break;
>>> +		case IIO_CURRENT:
>>> +			ret = i2c_smbus_read_byte_data(data->client,
>>> +				SI114X_PS_LED_REG(chan->channel));
>>> +			if (ret < 0)
>>> +				return ret;
>>> +
>>> +			*val = (ret >> SI114X_PS_LED_SHIFT(chan->channel))
>>> +				& 0x0f;
>>> +
>>> +			ret = IIO_VAL_INT;
>>> +			break;
>>> +		default:
>>> +			break;
>>> +		}
>>> +		break;
>>> +	case IIO_CHAN_INFO_HARDWAREGAIN:
>>> +		switch (chan->type) {
>>> +		case IIO_PROXIMITY:
>>> +			reg = SI114X_PARAM_PS_ADC_GAIN;
>>> +			break;
>>> +		case IIO_INTENSITY:
>>> +			if (chan->channel2 == IIO_MOD_LIGHT_IR)
>>> +				reg = SI114X_PARAM_ALSIR_ADC_GAIN;
>>> +			else
>>> +				reg = SI114X_PARAM_ALSVIS_ADC_GAIN;
>>> +			break;
>>> +		default:
>>> +			return -EINVAL;
>>> +		}
>>> +
>>> +		ret = si114x_param_op(data, SI114X_CMD_PARAM_QUERY, reg, 0);
>>> +		if (ret < 0)
>>> +			return ret;
>>> +
>>> +		*val = ret & 0x07;
>>> +
>>> +		ret = IIO_VAL_INT;
>>> +		break;
>>> +	}
>>> +
>>> +	return ret;
>>> +}
>>> +
>>> +static int si114x_write_raw(struct iio_dev *indio_dev,
>>> +			       struct iio_chan_spec const *chan,
>>> +			       int val, int val2, long mask)
>>> +{
>>> +	struct si114x_data *data = iio_priv(indio_dev);
>>> +	u8 reg1, reg2, shift;
>>> +	int ret = -EINVAL;
>>> +
>>> +	switch (mask) {
>>> +	case IIO_CHAN_INFO_HARDWAREGAIN:
>>> +		switch (chan->type) {
>>> +		case IIO_PROXIMITY:
>>> +			if (val < 0 || val > 5)
>>> +				return -EINVAL;
>>> +			reg1 = SI114X_PARAM_PS_ADC_GAIN;
>>> +			reg2 = SI114X_PARAM_PS_ADC_COUNTER;
>>> +			break;
>>> +		case IIO_INTENSITY:
>>> +			if (val < 0 || val > 7)
>>> +				return -EINVAL;
>>> +			if (chan->channel2 == IIO_MOD_LIGHT_IR) {
>>> +				reg1 = SI114X_PARAM_ALSIR_ADC_GAIN;
>>> +				reg2 = SI114X_PARAM_ALSIR_ADC_COUNTER;
>>> +			} else {
>>> +				reg1 = SI114X_PARAM_ALSVIS_ADC_GAIN;
>>> +				reg2 = SI114X_PARAM_ALSVIS_ADC_COUNTER;
>>> +			}
>>> +			break;
>>> +		default:
>>> +			return -EINVAL;
>>> +		}
>>> +
>>> +		ret = si114x_param_op(data, SI114X_CMD_PARAM_SET,
>>> +			reg1, val);
>>> +		if (ret < 0)
>>> +			return ret;
>>> +		/* set recovery period to one's complement of gain */
>>> +		ret = si114x_param_op(data, SI114X_CMD_PARAM_SET,
>>> +			reg2, (~val & 0x07) << 4);
>>> +		break;
>>> +	case IIO_CHAN_INFO_RAW:
>>> +		if (chan->type != IIO_CURRENT)
>>> +			return -EINVAL;
>>> +
>>> +		if (val < 0 || val > 0xf)
>>> +			return -EINVAL;
>>> +
>>> +		reg1 = SI114X_PS_LED_REG(chan->channel);
>>> +		shift = SI114X_PS_LED_SHIFT(chan->channel);
>>> +		ret = i2c_smbus_read_byte_data(data->client, reg1);
>>> +		if (ret < 0)
>>> +			return ret;
>>> +		ret = i2c_smbus_write_byte_data(data->client, reg1,
>>> +			(ret & ~(0x0f << shift)) |
>>> +			((val & 0x0f) << shift));
>>> +		break;
>>> +	}
>>> +	return ret;
>>> +}
>>> +
>>> +#if defined(CONFIG_DEBUG_FS)
>>> +static int si114x_reg_access(struct iio_dev *indio_dev,
>>> +			      unsigned reg, unsigned writeval,
>>> +			      unsigned *readval)
>>> +{
>>> +	struct si114x_data *data = iio_priv(indio_dev);
>>> +	int ret;
>>> +
>>> +	if (readval) {
>>> +		ret = i2c_smbus_read_byte_data(data->client, reg);
>>> +		if (ret < 0)
>>> +			return ret;
>>> +		*readval = ret;
>>> +		ret = 0;
>>> +	} else
>>> +		ret = i2c_smbus_write_byte_data(data->client, reg, writeval);
>>> +
>>> +	return ret;
>>> +}
>>> +#endif
>>> +
>>> +static int si114x_revisions(struct si114x_data *data)
>>> +{
>>> +	int ret = i2c_smbus_read_byte_data(data->client, SI114X_REG_PART_ID);
>>> +	if (ret < 0)
>>> +		return ret;
>>> +
>>> +	switch (ret) {
>>> +	case 0x41:
>>> +	case 0x42:
>>> +	case 0x43:
>>> +		data->part = ret;
>>> +		break;
>>> +	default:
>>> +		dev_err(&data->client->dev, "invalid part\n");
>>> +		return -EINVAL;
>>> +	}
>>> +
>>> +	ret = i2c_smbus_read_byte_data(data->client, SI114X_REG_SEQ_ID);
>>> +	if (ret < 0)
>>> +		return ret;
>>> +	data->seq = ret;
>>> +
>>> +	if (data->seq < SI114X_SEQ_REV_A03)
>>> +		dev_info(&data->client->dev, "WARNING: old sequencer revision\n");
>>> +
>>> +	return 0;
>>> +}
>>> +
>>> +static inline unsigned int si114x_leds(struct si114x_data *data)
>>> +{
>>> +	return data->part - 0x40;
>>> +}
>>> +
>>> +#define SI114X_INTENSITY_CHANNEL(_si) { \
>>> +	.type = IIO_INTENSITY, \
>>> +	.info_mask = IIO_CHAN_INFO_RAW_SEPARATE_BIT | \
>>> +		IIO_CHAN_INFO_HARDWAREGAIN_SEPARATE_BIT, \
>>> +	.scan_type = IIO_ST('u', 16, 16, 0), \
>>> +	.scan_index = _si, \
>>> +	.address = SI114X_REG_ALSVIS_DATA0, \
>>> +}
>>> +
>>> +#define SI114X_INTENSITY_IR_CHANNEL(_si) { \
>>> +	.type = IIO_INTENSITY, \
>>> +	.info_mask = IIO_CHAN_INFO_RAW_SEPARATE_BIT | \
>>> +		IIO_CHAN_INFO_HARDWAREGAIN_SEPARATE_BIT, \
>>> +	.modified = 1, \
>>> +	.channel2 = IIO_MOD_LIGHT_IR, \
>>> +	.scan_type = IIO_ST('u', 16, 16, 0), \
>>> +	.scan_index = _si, \
>>> +	.address = SI114X_REG_ALSIR_DATA0 \
>>> +}
>>> +
>>> +#define SI114X_TEMP_CHANNEL(_si) { \
>>> +	.type = IIO_TEMP, \
>>> +	.info_mask = IIO_CHAN_INFO_RAW_SEPARATE_BIT, \
>>> +	.scan_type = IIO_ST('u', 16, 16, 0), \
>>> +	.scan_index = _si, \
>>> +	.address = SI114X_REG_AUX_DATA0 \
>>> +}
>>> +
>>> +#define SI114X_PROXIMITY_CHANNEL(_si, _ch) { \
>>> +	.type = IIO_PROXIMITY, \
>>> +	.indexed = 1, \
>>> +	.channel = _ch, \
>>> +	.info_mask = IIO_CHAN_INFO_RAW_SEPARATE_BIT | \
>>> +		IIO_CHAN_INFO_HARDWAREGAIN_SHARED_BIT, \
>>> +	.scan_type = IIO_ST('u', 16, 16, 0), \
>>> +	.scan_index = _si, \
>>> +	.address = SI114X_REG_PS1_DATA0 + _ch*2 \
>>> +}
>>> +
>>> +#define SI114X_CURRENT_CHANNEL(_ch) { \
>>> +	.type = IIO_CURRENT, \
>>> +	.indexed = 1, \
>>> +	.channel = _ch, \
>>> +	.output = 1, \
>>> +	.info_mask = IIO_CHAN_INFO_RAW_SEPARATE_BIT \
>>> +}
>>> +
>>> +static const struct iio_chan_spec si114x_channels[] = {
>>> +	IIO_CHAN_SOFT_TIMESTAMP(0),
>>> +	SI114X_INTENSITY_CHANNEL(1),
>>> +	SI114X_INTENSITY_IR_CHANNEL(2),
>>> +	SI114X_TEMP_CHANNEL(3),
>>> +	SI114X_PROXIMITY_CHANNEL(4, 0),
>>> +	SI114X_CURRENT_CHANNEL(0),
>>> +	SI114X_PROXIMITY_CHANNEL(5, 1),
>>> +	SI114X_CURRENT_CHANNEL(1),
>>> +	SI114X_PROXIMITY_CHANNEL(6, 2),
>>> +	SI114X_CURRENT_CHANNEL(2),
>>> +};
>>> +
>>> +static ssize_t si114x_range_store(struct device *dev,
>>> +				struct device_attribute *attr,
>>> +				const char *buf, size_t len)
>>> +{
>>> +	struct iio_dev *indio_dev = dev_to_iio_dev(dev);
>>> +	struct iio_dev_attr *dev_attr = to_iio_dev_attr(attr);
>>> +	struct si114x_data *data = iio_priv(indio_dev);
>>> +	int ret;
>>> +
>>> +	if (sysfs_streq(buf, "normal"))
>>> +		ret = si114x_param_op(data, SI114X_CMD_PARAM_AND,
>>> +			dev_attr->address, ~SI114X_MISC_RANGE);
>>> +	else if (sysfs_streq(buf, "high"))
>>> +		ret = si114x_param_op(data, SI114X_CMD_PARAM_OR,
>>> +			dev_attr->address, SI114X_MISC_RANGE);
>>> +	else
>>> +		return -EINVAL;
>>> +
>>> +	return ret ? ret : len;
>>> +}
>>> +
>>> +static ssize_t si114x_range_show(struct device *dev,
>>> +			struct device_attribute *attr,
>>> +			char *buf)
>>> +{
>>> +	struct iio_dev *indio_dev = dev_to_iio_dev(dev);
>>> +	struct iio_dev_attr *dev_attr = to_iio_dev_attr(attr);
>>> +	struct si114x_data *data = iio_priv(indio_dev);
>>> +	int ret;
>>> +
>>> +	ret = si114x_param_op(data, SI114X_CMD_PARAM_QUERY,
>>> +		dev_attr->address, 0);
>>> +	if (ret < 0)
>>> +		return ret;
>>> +
>>> +	return sprintf(buf, "%s\n",
>>> +		(ret & SI114X_MISC_RANGE) ? "high" : "normal");
>>> +}
>>> +
>>> +static IIO_DEVICE_ATTR(in_proximity_range, S_IRUGO | S_IWUSR,
>>> +			si114x_range_show,
>>> +			si114x_range_store,
>>> +			SI114X_PARAM_PS_ADC_MISC);
>>> +
>>> +static IIO_DEVICE_ATTR(in_intensity_range, S_IRUGO | S_IWUSR,
>>> +			si114x_range_show,
>>> +			si114x_range_store,
>>> +			SI114X_PARAM_ALSVIS_ADC_MISC);
>>> +
>>> +static IIO_DEVICE_ATTR(in_intensity_ir_range, S_IRUGO | S_IWUSR,
>>> +			si114x_range_show,
>>> +			si114x_range_store,
>>> +			SI114X_PARAM_ALSIR_ADC_MISC);
>
>> Range is normally defined as numeric.  Any way of mapping these to appropriate
>> numbers?
>
> range is a bit that influences the ADC stage (there are two modes: 'normal
> signal range' and 'high signal range', in the later case the gain is
> internally divided by 14.5) -- so maybe rename the attribute to 'mode'
> instead of 'range'?
No, just set the gain to 1 and 14.5.  (14.5 is a novel divider :)
>
>>> +static IIO_CONST_ATTR(in_proximity_range_available, "normal high");
>>> +static IIO_CONST_ATTR(in_intensity_range_available, "normal high");
>>> +static IIO_CONST_ATTR(in_intensity_ir_range_available, "normal high");
>>> +
>>> +static int si114x_set_chlist(struct iio_dev *indio_dev, bool all)
>>> +{
>>> +	struct si114x_data *data = iio_priv(indio_dev);
>>> +	u8 reg = 0;
>>> +	int i;
>>> +
>>> +	if (all) {
>>> +		reg = SI114X_CHLIST_EN_ALSVIS | SI114X_CHLIST_EN_ALSIR |
>>> +			SI114X_CHLIST_EN_AUX;
>>> +		switch (si114x_leds(data)) {
>>> +		case 3:
>>> +			reg |= SI114X_CHLIST_EN_PS3;
>>> +		case 2:
>>> +			reg |= SI114X_CHLIST_EN_PS2;
>>> +		case 1:
>>> +			reg |= SI114X_CHLIST_EN_PS1;
>>> +			break;
>>> +		}
>>> +	} else
>>> +		for_each_set_bit(i, indio_dev->active_scan_mask,
>>> +			indio_dev->masklength) {
>>> +			switch (indio_dev->channels[i].address) {
>>> +			case SI114X_REG_ALSVIS_DATA0:
>>> +				reg |= SI114X_CHLIST_EN_ALSVIS;
>>> +				break;
>>> +			case SI114X_REG_ALSIR_DATA0:
>>> +				reg |= SI114X_CHLIST_EN_ALSIR;
>>> +				break;
>>> +			case SI114X_REG_PS1_DATA0:
>>> +				reg |= SI114X_CHLIST_EN_PS1;
>>> +				break;
>>> +			case SI114X_REG_PS2_DATA0:
>>> +				reg |= SI114X_CHLIST_EN_PS2;
>>> +				break;
>>> +			case SI114X_REG_PS3_DATA0:
>>> +				reg |= SI114X_CHLIST_EN_PS3;
>>> +				break;
>>> +			case SI114X_REG_AUX_DATA0:
>>> +				reg |= SI114X_CHLIST_EN_AUX;
>>> +				break;
>>> +			}
>>> +		}
>>> +
>>> +	return si114x_param_op(data, SI114X_CMD_PARAM_SET,
>>> +		SI114X_PARAM_CHLIST, reg);
>>> +}
>>> +
>>> +static int si114x_initialize(struct iio_dev *indio_dev)
>>> +{
>>> +	struct si114x_data *data = iio_priv(indio_dev);
>>> +	struct i2c_client *client = data->client;
>>> +	int ret;
>>> +
>>> +	/* send reset command */
>>> +	ret = i2c_smbus_write_byte_data(client, SI114X_REG_COMMAND,
>>> +		SI114X_CMD_RESET);
>>> +	if (ret < 0)
>>> +		return ret;
>>> +	msleep(20);
>>> +
>>> +	/* hardware key, magic value */
>>> +	ret = i2c_smbus_write_byte_data(client, SI114X_REG_HW_KEY, 0x17);
>>> +	if (ret < 0)
>>> +		return ret;
>>> +	msleep(20);
>>> +
>>> +	/* interrupt configuration, interrupt output enable */
>>> +	ret = i2c_smbus_write_byte_data(client, SI114X_REG_INT_CFG,
>>> +		data->use_irq ? SI114X_INT_CFG_OE : 0);
>>> +	if (ret < 0)
>>> +		return ret;
>>> +
>>> +	/* enable interrupt for certain activities */
>> A little odd if the interrupt isn't there?
>
> I'll rearrange the code to setup interrupts only when use_irq is true
>
>>> +	ret = i2c_smbus_write_byte_data(client, SI114X_REG_IRQ_ENABLE,
>>> +		SI114X_PS3_IE | SI114X_PS2_IE | SI114X_PS1_IE |
>>> +		SI114X_ALS_INT0_IE);
>>> +	if (ret < 0)
>>> +		return ret;
>>> +
>>> +	/* in autonomous mode, wakeup every 100 ms */
>>> +	ret = i2c_smbus_write_byte_data(client, SI114X_REG_MEAS_RATE,
>>> +	    SI114X_MEAS_RATE_100MS);
>>> +	if (ret < 0)
>>> +		return ret;
>>> +
>>> +	/* measure ALS every time device wakes up */
>>> +	ret = i2c_smbus_write_byte_data(client, SI114X_REG_ALS_RATE,
>>> +		SI114X_ALS_RATE_1X);
>>> +	if (ret < 0)
>>> +		return ret;
>>> +
>>> +	/* measure proximity every time device wakes up */
>>> +	ret = i2c_smbus_write_byte_data(client, SI114X_REG_PS_RATE,
>>> +		SI114X_PS_RATE_1X);
>>> +	if (ret < 0)
>>> +		return ret;
>>> +
>>> +	/* set LED currents to maximum */
>>> +	switch (si114x_leds(data)) {
>>> +	case 3:
>>> +		ret = i2c_smbus_write_byte_data(client,
>>> +			SI114X_REG_PS_LED3, 0x0f);
>>> +		if (ret < 0)
>>> +			return ret;
>>> +		ret = i2c_smbus_write_byte_data(client,
>>> +			SI114X_REG_PS_LED21, 0xff);
>>> +		break;
>>> +	case 2:
>>> +		ret = i2c_smbus_write_byte_data(client,
>>> +			SI114X_REG_PS_LED21, 0xff);
>>> +		break;
>>> +	case 1:
>>> +		ret = i2c_smbus_write_byte_data(client,
>>> +			SI114X_REG_PS_LED21, 0x0f);
>>> +		break;
>>> +	}
>>> +	if (ret < 0)
>>> +		return ret;
>>> +
>>> +	ret = si114x_set_chlist(indio_dev, true);
>>> +	if (ret < 0)
>>> +		return ret;
>
>> Given this only effects slow sysfs reading I'd be tempted not
>> to put the device in autonomous mode but rather trigger a sample
>> whenever one is requested...  Is there a reason not to do this?
>
> set_chlist() configures the channels to sample during a measurement event
> (a measurement can be forced (as is done for a sysfs read) or performed
> automomously at a configured rate);
> the idea was to enable all channels per default so that no reprogramming
> is necessary for a sysfs channel read (a bit wasteful since all channels
> are sampled, but only one value is reported)
Arguably the slow nature of i2c may mean that reading those unwanted values
is the most expensive part.
>
> I can change this behaviour: default to no enabled channels and do the
> chlist() setup specific to each sysfs read (with proper locking)
Yes. Personally I'd prefer that mostly because it lines up closer with
what we see in other drivers (where the single channel read has more obvious
advantages in the hardware).
>
>>> +
>>> +	/* set normal proximity measurement mode, set high signal range
>>> +	 * PS measurement */
>>> +	ret = si114x_param_op(data, SI114X_CMD_PARAM_SET,
>>> +		SI114X_PARAM_PS_ADC_MISC, 0x20 | 0x04);
>>> +	if (ret < 0)
>>> +		return ret;
>>> +
>>> +	return 0;
>>> +}
>>> +
>>> +static ssize_t si114x_read_frequency(struct device *dev,
>>> +					struct device_attribute *attr,
>>> +					char *buf)
>>> +{
>>> +	struct iio_dev *indio_dev = dev_to_iio_dev(dev);
>>> +	struct si114x_data *data = iio_priv(indio_dev);
>>> +	int ret;
>>> +	u16 rate;
>>> +
>>> +	ret = i2c_smbus_read_byte_data(data->client, SI114X_REG_MEAS_RATE);
>>> +	if (ret < 0)
>>> +		return ret;
>>> +
>>> +	if (ret == 0)
>>> +		rate = 0;
>>> +	else
>>> +		rate = 32000 / si114x_uncompress(ret);
>>> +
>>> +	return sprintf(buf, "%d\n", rate);
>>> +}
>>> +
>>> +static ssize_t si114x_write_frequency(struct device *dev,
>>> +					 struct device_attribute *attr,
>>> +					 const char *buf, size_t len)
>>> +{
>>> +	struct iio_dev *indio_dev = dev_to_iio_dev(dev);
>>> +	struct si114x_data *data = iio_priv(indio_dev);
>>> +	unsigned long val;
>>> +	int ret;
>>> +	u8 rate;
>>> +
>>> +	ret = kstrtoul(buf, 10, &val);
>>> +	if (ret)
>>> +		return ret;
>>> +
>>> +	switch (val) {
>>> +	case 250:
>>> +	case 100:
>>> +	case 50:
>>> +	case 25:
>>> +	case 10:
>>> +	case 5:
>>> +	case 2:
>>> +	case 1:
>>> +		rate = si114x_compress(32000 / val);
>>> +		break;
>>> +	case 0:
>>> +		rate = 0;
>>> +		break;
>>> +	default:
>>> +		return -EINVAL;
>>> +	}
>>> +
>>> +	ret = i2c_smbus_write_byte_data(data->client, SI114X_REG_MEAS_RATE,
>>> +		rate);
>>> +
>>> +	return ret ? ret : len;
>>> +}
>>> +
>>> +/* sysfs attributes if IRQ available */
>>> +static IIO_DEV_ATTR_SAMP_FREQ(S_IWUSR | S_IRUGO,
>>> +			      si114x_read_frequency,
>>> +			      si114x_write_frequency);
>>> +
>>> +static IIO_CONST_ATTR_SAMP_FREQ_AVAIL("1 2 5 10 25 50 100 250");
>>> +
>>> +static struct attribute *si114x_attrs_trigger[] = {
>>> +	&iio_dev_attr_in_proximity_range.dev_attr.attr,
>>> +	&iio_const_attr_in_proximity_range_available.dev_attr.attr,
>>> +	&iio_dev_attr_in_intensity_range.dev_attr.attr,
>>> +	&iio_const_attr_in_intensity_range_available.dev_attr.attr,
>>> +	&iio_dev_attr_in_intensity_ir_range.dev_attr.attr,
>>> +	&iio_const_attr_in_intensity_ir_range_available.dev_attr.attr,
>>> +	&iio_dev_attr_sampling_frequency.dev_attr.attr,
>>> +	&iio_const_attr_sampling_frequency_available.dev_attr.attr,
>
>> If sampling frequency has not other effect on the reading (other than
>> how often it is taken) it should probably be an attribute of the trigger
>> not the full device.  Often we have it here because it also effects
>> filtering etc and hence readings even when not using the trigger.
>
> I'll move the attribute to the trigger
>
>>> +	NULL
>>> +};
>>> +
>>> +static struct attribute_group si114x_attr_group_trigger = {
>>> +	.attrs = si114x_attrs_trigger
>>> +};
>>> +
>>> +static const struct iio_info si114x_info_trigger = {
>>> +	.read_raw = si114x_read_raw,
>>> +	.write_raw = si114x_write_raw,
>>> +#if defined(CONFIG_DEBUG_FS)
>>> +	.debugfs_reg_access = si114x_reg_access,
>>> +#endif
>>> +	.driver_module = THIS_MODULE,
>>> +	.attrs = &si114x_attr_group_trigger
>>> +};
>>> +
>>> +/* sysfs attributes if no IRQ available */
>>> +static struct attribute *si114x_attrs_no_trigger[] = {
>>> +	&iio_dev_attr_in_proximity_range.dev_attr.attr,
>>> +	&iio_const_attr_in_proximity_range_available.dev_attr.attr,
>>> +	&iio_dev_attr_in_intensity_range.dev_attr.attr,
>>> +	&iio_const_attr_in_intensity_range_available.dev_attr.attr,
>>> +	&iio_dev_attr_in_intensity_ir_range.dev_attr.attr,
>>> +	&iio_const_attr_in_intensity_ir_range_available.dev_attr.attr,
>>> +	NULL
>>> +};
>>> +
>>> +static struct attribute_group si114x_attr_group_no_trigger = {
>>> +	.attrs = si114x_attrs_no_trigger
>>> +};
>>> +
>>> +static const struct iio_info si114x_info_no_trigger = {
>>> +	.read_raw = si114x_read_raw,
>>> +	.write_raw = si114x_write_raw,
>>> +#if defined(CONFIG_DEBUG_FS)
>>> +	.debugfs_reg_access = si114x_reg_access,
>>> +#endif
>>> +	.driver_module = THIS_MODULE,
>>> +	.attrs = &si114x_attr_group_no_trigger
>>> +};
>>> +
>>> +static int si114x_buffer_preenable(struct iio_dev *indio_dev)
>>> +{
>>> +	struct iio_buffer *buffer = indio_dev->buffer;
>>> +
>>> +	/* at least one channel besides the timestamp must be enabled */
>
>> Why?  Presumably because the interrupt won't occur otherwise, but that
>> should be stated here.  Might be better to have the trigger start fail
>> unless the channel is enabled as it is there that the restriction occurs
>> not here in the buffer code.
>
> correct: no measurement, to interrupt
Definitely fail to start the trigger if that's the case.
>
>>> +	if (!bitmap_weight(buffer->scan_mask, indio_dev->masklength))
>>> +		return -EINVAL;
>>> +
>>> +	return iio_sw_buffer_preenable(indio_dev);
>>> +}
>>> +
>>> +static int si114x_buffer_postenable(struct iio_dev *indio_dev)
>>> +{
>>> +	int ret;
>>> +
>>> +	ret = iio_triggered_buffer_postenable(indio_dev);
>>> +	if (ret < 0)
>>> +		return ret;
>>> +
>>> +	/* measure only enabled channels */
>> Why would we measure other channels?  Very similar otherwise to
>> using the update_scan_mode callback.
>
> chlist is configured to all channels per default; this will change...
>
>>> +	ret = si114x_set_chlist(indio_dev, false);
>>> +	if (ret < 0)
>>> +		return ret;
>>> +
>>> +	return 0;
>>> +}
>>> +
>>> +static int si114x_buffer_predisable(struct iio_dev *indio_dev)
>>> +{
>>> +	int ret;
>>> +
>>> +	/* measure all channels */
>> Why? Or do you mean set it to measure all channels on next request?
>> Why can't we set it to the approriate value on read request?
>
> will do as suggested (issue also discussed above)
>
>>> +	ret = si114x_set_chlist(indio_dev, true);
>>> +	if (ret < 0)
>>> +		return ret;
>>> +
>>> +	return iio_triggered_buffer_predisable(indio_dev);
>>> +}
>>> +
>>> +static const struct iio_buffer_setup_ops si114x_buffer_setup_ops = {
>>> +	.preenable = si114x_buffer_preenable,
>>> +	.postenable = si114x_buffer_postenable,
>>> +	.predisable = si114x_buffer_predisable,
>>> +};
>>> +
>>> +static int __devinit si114x_probe(struct i2c_client *client,
>>> +					const struct i2c_device_id *id)
>>> +{
>>> +	struct si114x_data *data;
>>> +	struct iio_dev *indio_dev;
>>> +	int ret;
>>> +
>>> +	indio_dev = iio_device_alloc(sizeof(*data));
>>> +	if (!indio_dev)
>>> +		return -ENOMEM;
>>> +
>>> +	data = iio_priv(indio_dev);
>>> +	i2c_set_clientdata(client, indio_dev);
>>> +	data->client = client;
>>> +	data->use_irq = client->irq != 0;
>>> +
>>> +	ret = si114x_revisions(data);
>>> +	if (ret < 0)
>>> +		goto error_free_dev;
>>> +
>>> +	dev_info(&client->dev, "Si11%02x Ambient light/proximity sensor, Seq: %02x\n",
>>> +		data->part, data->seq);
>>> +
>>> +	indio_dev->dev.parent = &client->dev;
>>> +	indio_dev->name = SI114X_DRV_NAME;
>>> +	indio_dev->channels = si114x_channels;
>> /*
>>  * Compute
>>
>>> +	/* Compute number of channels: use of last six channels depends on
>>> +	 * the number of proximity LEDs supported (determined by the part
>>> +	 * number: si1141, si1142, si114x).
>>> +	 * Each proximity LED has an input intensity and output voltage
>>> +	 * channel.
>>> +	 */
>>> +	indio_dev->num_channels = ARRAY_SIZE(si114x_channels) -
>>> +		6 + si114x_leds(data)*2;
>>> +	indio_dev->info = data->use_irq ?
>>> +		&si114x_info_trigger : &si114x_info_no_trigger;
>>> +	indio_dev->modes = INDIO_DIRECT_MODE;
>
>> Do you ever add the buffered mode to this?
>> Without that you won't get the trigger consumer stuff so won't be able
>> to change the trigger...
>
> indio_dev->modes |= INDIO_BUFFER_TRIGGERED;
> is done in iio_triggered_buffer_setup(), called below
Ah, good point! sorry I'd forgotten about that.
>
>>> +
>>> +	mutex_init(&data->mutex);
>>> +	init_waitqueue_head(&data->data_avail);
>>> +
>>> +	ret = si114x_initialize(indio_dev);
>>> +	if (ret < 0)
>>> +		goto error_free_dev;
>>> +
>>> +	ret = iio_triggered_buffer_setup(indio_dev, NULL,
>>> +		si114x_trigger_handler, &si114x_buffer_setup_ops);
>>> +	if (ret < 0)
>>> +		goto error_free_dev;
>>> +
>>> +	if (data->use_irq) {
>>> +		ret = request_threaded_irq(client->irq,
>>> +			   NULL, si114x_irq,
>>> +			   IRQF_TRIGGER_FALLING | IRQF_ONESHOT,
>>> +			   "si114x_irq", indio_dev);
>>> +		if (ret < 0) {
>>> +			dev_err(&client->dev, "irq request failed\n");
>>> +			goto error_free_buffer;
>>> +		}
>>> +
>>> +		ret = si114x_probe_trigger(indio_dev);
>>> +		if (ret < 0)
>>> +			goto error_free_irq;
>>> +	} else
>>> +		dev_info(&client->dev, "no irq, using polling\n");
>
>> I wonder if more detail would be useful in this message.  What
>> is it polling for?
>
> my suggestion: "no irq, using data ready polling"
better.
>
>>> +
>>> +	ret = iio_device_register(indio_dev);
>>> +	if (ret < 0)
>>> +		goto error_free_trigger;
>>> +
>>> +	return 0;
>>> +
>>> +error_free_trigger:
>>> +	if (data->use_irq)
>>> +		si114x_remove_trigger(indio_dev);
>>> +error_free_irq:
>>> +	if (data->use_irq)
>>> +		free_irq(client->irq, indio_dev);
>>> +error_free_buffer:
>>> +	iio_triggered_buffer_cleanup(indio_dev);
>>> +error_free_dev:
>>> +	iio_device_free(indio_dev);
>>> +	return ret;
>>> +}
>>> +
>>> +static const struct i2c_device_id si114x_id[] = {
>>> +	{ "si114x", 0 },
>>> +	{ }
>>> +};
>>> +MODULE_DEVICE_TABLE(i2c, si114x_id);
>>> +
>>> +static int __devexit si114x_remove(struct i2c_client *client)
>>> +{
>>> +	struct iio_dev *indio_dev = i2c_get_clientdata(client);
>>> +	struct si114x_data *data = iio_priv(indio_dev);
>>> +
>>> +	iio_device_unregister(indio_dev);
>>> +	iio_triggered_buffer_cleanup(indio_dev);
>>> +	if (data->use_irq) {
>>> +		si114x_remove_trigger(indio_dev);
>>> +		free_irq(client->irq, indio_dev);
>>> +	}
>> small point but I'd normally expect the ordering in here to be the same as the
>> error conditions for probe (and hence reverse of the setup in probe). That
>> would I think mean the iio_triggered_buffer_cleanup would be after the
>> irq cleanup?
>
> will do
>
>>> +	iio_device_free(indio_dev);
>>> +
>>> +	return 0;
>>> +}
>>> +
>>> +static struct i2c_driver si114x_driver = {
>>> +	.driver = {
>>> +		.name   = SI114X_DRV_NAME,
>>> +		.owner  = THIS_MODULE,
>>> +	},
>>> +	.probe  = si114x_probe,
>>> +	.remove = __devexit_p(si114x_remove),
>>> +	.id_table = si114x_id,
>>> +};
>>> +
>>> +module_i2c_driver(si114x_driver);
>>> +
>>> +MODULE_AUTHOR("Peter Meerwald <pmeerw@xxxxxxxxxx>");
>>> +MODULE_DESCRIPTION("Silabs si114x proximity/ambient light sensor driver");
>>> +MODULE_LICENSE("GPL");
>>>
>
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