Re: [PATCH v4 3/4] iio: cros_ec_accel_legacy: Use cros_ec_sensors_core

[Enric Balletbo i Serra <enric.balletbo@collabora.com>]

Hi Gwendal,

One comment below

On 28/6/19 21:17, Gwendal Grignou wrote:
> Remove duplicate code in cros-ec-accel-legacy,
> use cros-ec-sensors-core functions and structures when possible.
> 
> On glimmer, check the 2 accelerometers are presented and working.
> 
> Signed-off-by: Gwendal Grignou <gwendal@chromium.org>
> ---
>  drivers/iio/accel/Kconfig                |   4 +-
>  drivers/iio/accel/cros_ec_accel_legacy.c | 333 ++++-------------------
>  2 files changed, 53 insertions(+), 284 deletions(-)
> 
> diff --git a/drivers/iio/accel/Kconfig b/drivers/iio/accel/Kconfig
> index 62a970a20219..7d0848f9ea45 100644
> --- a/drivers/iio/accel/Kconfig
> +++ b/drivers/iio/accel/Kconfig
> @@ -201,9 +201,7 @@ config HID_SENSOR_ACCEL_3D
>  
>  config IIO_CROS_EC_ACCEL_LEGACY
>  	tristate "ChromeOS EC Legacy Accelerometer Sensor"
> -	select IIO_BUFFER
> -	select IIO_TRIGGERED_BUFFER
> -	select CROS_EC_LPC_REGISTER_DEVICE
> +	depends on IIO_CROS_EC_SENSORS_CORE
>  	help
>  	  Say yes here to get support for accelerometers on Chromebook using
>  	  legacy EC firmware.
> diff --git a/drivers/iio/accel/cros_ec_accel_legacy.c b/drivers/iio/accel/cros_ec_accel_legacy.c
> index ad19d9c716f4..2399f0cbdf2b 100644
> --- a/drivers/iio/accel/cros_ec_accel_legacy.c
> +++ b/drivers/iio/accel/cros_ec_accel_legacy.c
> @@ -12,6 +12,7 @@
>  #include <linux/delay.h>
>  #include <linux/device.h>
>  #include <linux/iio/buffer.h>
> +#include <linux/iio/common/cros_ec_sensors_core.h>
>  #include <linux/iio/iio.h>
>  #include <linux/iio/kfifo_buf.h>
>  #include <linux/iio/trigger_consumer.h>
> @@ -25,191 +26,50 @@
>  
>  #define DRV_NAME	"cros-ec-accel-legacy"
>  
> +#define CROS_EC_SENSOR_LEGACY_NUM 2
>  /*
>   * Sensor scale hard coded at 10 bits per g, computed as:
>   * g / (2^10 - 1) = 0.009586168; with g = 9.80665 m.s^-2
>   */
>  #define ACCEL_LEGACY_NSCALE 9586168
>  
> -/* Indices for EC sensor values. */
> -enum {
> -	X,
> -	Y,
> -	Z,
> -	MAX_AXIS,
> -};
> -
> -/* State data for cros_ec_accel_legacy iio driver. */
> -struct cros_ec_accel_legacy_state {
> -	struct cros_ec_device *ec;
> -
> -	/*
> -	 * Array holding data from a single capture. 2 bytes per channel
> -	 * for the 3 channels plus the timestamp which is always last and
> -	 * 8-bytes aligned.
> -	 */
> -	s16 capture_data[8];
> -	s8 sign[MAX_AXIS];
> -	u8 sensor_num;
> -};
> -
> -static int ec_cmd_read_u8(struct cros_ec_device *ec, unsigned int offset,
> -			  u8 *dest)
> -{
> -	return ec->cmd_readmem(ec, offset, 1, dest);
> -}
> -
> -static int ec_cmd_read_u16(struct cros_ec_device *ec, unsigned int offset,
> -			   u16 *dest)
> -{
> -	__le16 tmp;
> -	int ret = ec->cmd_readmem(ec, offset, 2, &tmp);
> -
> -	*dest = le16_to_cpu(tmp);
> -
> -	return ret;
> -}
> -
> -/**
> - * read_ec_until_not_busy() - Read from EC status byte until it reads not busy.
> - * @st: Pointer to state information for device.
> - *
> - * This function reads EC status until its busy bit gets cleared. It does not
> - * wait indefinitely and returns -EIO if the EC status is still busy after a
> - * few hundreds milliseconds.
> - *
> - * Return: 8-bit status if ok, -EIO on error
> - */
> -static int read_ec_until_not_busy(struct cros_ec_accel_legacy_state *st)
> -{
> -	struct cros_ec_device *ec = st->ec;
> -	u8 status;
> -	int attempts = 0;
> -
> -	ec_cmd_read_u8(ec, EC_MEMMAP_ACC_STATUS, &status);
> -	while (status & EC_MEMMAP_ACC_STATUS_BUSY_BIT) {
> -		/* Give up after enough attempts, return error. */
> -		if (attempts++ >= 50)
> -			return -EIO;
> -
> -		/* Small delay every so often. */
> -		if (attempts % 5 == 0)
> -			msleep(25);
> -
> -		ec_cmd_read_u8(ec, EC_MEMMAP_ACC_STATUS, &status);
> -	}
> -
> -	return status;
> -}
> -
> -/**
> - * read_ec_accel_data_unsafe() - Read acceleration data from EC shared memory.
> - * @st:        Pointer to state information for device.
> - * @scan_mask: Bitmap of the sensor indices to scan.
> - * @data:      Location to store data.
> - *
> - * This is the unsafe function for reading the EC data. It does not guarantee
> - * that the EC will not modify the data as it is being read in.
> - */
> -static void read_ec_accel_data_unsafe(struct cros_ec_accel_legacy_state *st,
> -				      unsigned long scan_mask, s16 *data)
> -{
> -	int i = 0;
> -	int num_enabled = bitmap_weight(&scan_mask, MAX_AXIS);
> -
> -	/* Read all sensors enabled in scan_mask. Each value is 2 bytes. */
> -	while (num_enabled--) {
> -		i = find_next_bit(&scan_mask, MAX_AXIS, i);
> -		ec_cmd_read_u16(st->ec,
> -				EC_MEMMAP_ACC_DATA +
> -				sizeof(s16) *
> -				(1 + i + st->sensor_num * MAX_AXIS),
> -				data);
> -		*data *= st->sign[i];
> -		i++;
> -		data++;
> -	}
> -}
> -
> -/**
> - * read_ec_accel_data() - Read acceleration data from EC shared memory.
> - * @st:        Pointer to state information for device.
> - * @scan_mask: Bitmap of the sensor indices to scan.
> - * @data:      Location to store data.
> - *
> - * This is the safe function for reading the EC data. It guarantees that
> - * the data sampled was not modified by the EC while being read.
> - *
> - * Return: 0 if ok, -ve on error
> - */
> -static int read_ec_accel_data(struct cros_ec_accel_legacy_state *st,
> -			      unsigned long scan_mask, s16 *data)
> -{
> -	u8 samp_id = 0xff;
> -	u8 status = 0;
> -	int ret;
> -	int attempts = 0;
> -
> -	/*
> -	 * Continually read all data from EC until the status byte after
> -	 * all reads reflects that the EC is not busy and the sample id
> -	 * matches the sample id from before all reads. This guarantees
> -	 * that data read in was not modified by the EC while reading.
> -	 */
> -	while ((status & (EC_MEMMAP_ACC_STATUS_BUSY_BIT |
> -			  EC_MEMMAP_ACC_STATUS_SAMPLE_ID_MASK)) != samp_id) {
> -		/* If we have tried to read too many times, return error. */
> -		if (attempts++ >= 5)
> -			return -EIO;
> -
> -		/* Read status byte until EC is not busy. */
> -		ret = read_ec_until_not_busy(st);
> -		if (ret < 0)
> -			return ret;
> -		status = ret;
> -
> -		/*
> -		 * Store the current sample id so that we can compare to the
> -		 * sample id after reading the data.
> -		 */
> -		samp_id = status & EC_MEMMAP_ACC_STATUS_SAMPLE_ID_MASK;
> -
> -		/* Read all EC data, format it, and store it into data. */
> -		read_ec_accel_data_unsafe(st, scan_mask, data);
> -
> -		/* Read status byte. */
> -		ec_cmd_read_u8(st->ec, EC_MEMMAP_ACC_STATUS, &status);
> -	}
> -
> -	return 0;
> -}
> -
>  static int cros_ec_accel_legacy_read(struct iio_dev *indio_dev,
>  				     struct iio_chan_spec const *chan,
>  				     int *val, int *val2, long mask)
>  {
> -	struct cros_ec_accel_legacy_state *st = iio_priv(indio_dev);
> +	struct cros_ec_sensors_core_state *st = iio_priv(indio_dev);
>  	s16 data = 0;
> -	int ret = IIO_VAL_INT;
> +	int ret;
> +	int idx = chan->scan_index;
> +
> +	mutex_lock(&st->cmd_lock);
>  
>  	switch (mask) {
>  	case IIO_CHAN_INFO_RAW:
> -		ret = read_ec_accel_data(st, (1 << chan->scan_index), &data);
> -		if (ret)
> -			return ret;
> +		ret = st->read_ec_sensors_data(indio_dev, 1 << idx, &data);
> +		if (ret < 0)
> +			break;
> +		ret = IIO_VAL_INT;
>  		*val = data;
> -		return IIO_VAL_INT;
> +		break;
>  	case IIO_CHAN_INFO_SCALE:
> +		WARN_ON(st->type != MOTIONSENSE_TYPE_ACCEL);
>  		*val = 0;
>  		*val2 = ACCEL_LEGACY_NSCALE;
> -		return IIO_VAL_INT_PLUS_NANO;
> +		ret = IIO_VAL_INT_PLUS_NANO;
> +		break;
>  	case IIO_CHAN_INFO_CALIBBIAS:
>  		/* Calibration not supported. */
>  		*val = 0;
>  		return IIO_VAL_INT;

This can end on a return without unlock the mutex. You should change also the
return logic here.

>  	default:
> -		return -EINVAL;
> +		ret = cros_ec_sensors_core_read(st, chan, val, val2,
> +				mask);
> +		break;
>  	}
> +	mutex_unlock(&st->cmd_lock);
> +
> +	return ret;
>  }
>  
>  static int cros_ec_accel_legacy_write(struct iio_dev *indio_dev,
> @@ -231,86 +91,14 @@ static const struct iio_info cros_ec_accel_legacy_info = {
>  	.write_raw = &cros_ec_accel_legacy_write,
>  };
>  
> -/**
> - * cros_ec_accel_legacy_capture() - The trigger handler function
> - * @irq: The interrupt number.
> - * @p:   Private data - always a pointer to the poll func.
> - *
> - * On a trigger event occurring, if the pollfunc is attached then this
> - * handler is called as a threaded interrupt (and hence may sleep). It
> - * is responsible for grabbing data from the device and pushing it into
> - * the associated buffer.
> - *
> - * Return: IRQ_HANDLED
> +/*
> + * Present the channel using HTML5 standard:
> + * need to invert X and Y and invert some lid axis.
>   */
> -static irqreturn_t cros_ec_accel_legacy_capture(int irq, void *p)
> -{
> -	struct iio_poll_func *pf = p;
> -	struct iio_dev *indio_dev = pf->indio_dev;
> -	struct cros_ec_accel_legacy_state *st = iio_priv(indio_dev);
> -
> -	/* Clear capture data. */
> -	memset(st->capture_data, 0, sizeof(st->capture_data));
> -
> -	/*
> -	 * Read data based on which channels are enabled in scan mask. Note
> -	 * that on a capture we are always reading the calibrated data.
> -	 */
> -	read_ec_accel_data(st, *indio_dev->active_scan_mask, st->capture_data);
> -
> -	iio_push_to_buffers_with_timestamp(indio_dev, (void *)st->capture_data,
> -					   iio_get_time_ns(indio_dev));
> -
> -	/*
> -	 * Tell the core we are done with this trigger and ready for the
> -	 * next one.
> -	 */
> -	iio_trigger_notify_done(indio_dev->trig);
> -
> -	return IRQ_HANDLED;
> -}
> -
> -static char *cros_ec_accel_legacy_loc_strings[] = {
> -	[MOTIONSENSE_LOC_BASE] = "base",
> -	[MOTIONSENSE_LOC_LID] = "lid",
> -	[MOTIONSENSE_LOC_MAX] = "unknown",
> -};
> -
> -static ssize_t cros_ec_accel_legacy_loc(struct iio_dev *indio_dev,
> -					uintptr_t private,
> -					const struct iio_chan_spec *chan,
> -					char *buf)
> -{
> -	struct cros_ec_accel_legacy_state *st = iio_priv(indio_dev);
> -
> -	return sprintf(buf, "%s\n",
> -		       cros_ec_accel_legacy_loc_strings[st->sensor_num +
> -							MOTIONSENSE_LOC_BASE]);
> -}
> -
> -static ssize_t cros_ec_accel_legacy_id(struct iio_dev *indio_dev,
> -				       uintptr_t private,
> -				       const struct iio_chan_spec *chan,
> -				       char *buf)
> -{
> -	struct cros_ec_accel_legacy_state *st = iio_priv(indio_dev);
> -
> -	return sprintf(buf, "%d\n", st->sensor_num);
> -}
> -
> -static const struct iio_chan_spec_ext_info cros_ec_accel_legacy_ext_info[] = {
> -	{
> -		.name = "id",
> -		.shared = IIO_SHARED_BY_ALL,
> -		.read = cros_ec_accel_legacy_id,
> -	},
> -	{
> -		.name = "location",
> -		.shared = IIO_SHARED_BY_ALL,
> -		.read = cros_ec_accel_legacy_loc,
> -	},
> -	{ }
> -};
> +#define CROS_EC_ACCEL_ROTATE_AXIS(_axis)				\
> +	((_axis) == CROS_EC_SENSOR_Z ? CROS_EC_SENSOR_Z :		\
> +	 ((_axis) == CROS_EC_SENSOR_X ? CROS_EC_SENSOR_Y :		\
> +	  CROS_EC_SENSOR_X))
>  
>  #define CROS_EC_ACCEL_LEGACY_CHAN(_axis)				\
>  	{								\
> @@ -321,28 +109,28 @@ static const struct iio_chan_spec_ext_info cros_ec_accel_legacy_ext_info[] = {
>  			BIT(IIO_CHAN_INFO_RAW) |			\
>  			BIT(IIO_CHAN_INFO_CALIBBIAS),			\
>  		.info_mask_shared_by_all = BIT(IIO_CHAN_INFO_SCALE),	\
> -		.ext_info = cros_ec_accel_legacy_ext_info,		\
> +		.ext_info = cros_ec_sensors_ext_info,			\
>  		.scan_type = {						\
>  			.sign = 's',					\
> -			.realbits = 16,					\
> -			.storagebits = 16,				\
> +			.realbits = CROS_EC_SENSOR_BITS,		\
> +			.storagebits = CROS_EC_SENSOR_BITS,		\
>  		},							\
> +		.scan_index = CROS_EC_ACCEL_ROTATE_AXIS(_axis),		\
>  	}								\
>  
> -static struct iio_chan_spec ec_accel_channels[] = {
> -	CROS_EC_ACCEL_LEGACY_CHAN(X),
> -	CROS_EC_ACCEL_LEGACY_CHAN(Y),
> -	CROS_EC_ACCEL_LEGACY_CHAN(Z),
> -	IIO_CHAN_SOFT_TIMESTAMP(MAX_AXIS)
> +static const struct iio_chan_spec cros_ec_accel_legacy_channels[] = {
> +		CROS_EC_ACCEL_LEGACY_CHAN(CROS_EC_SENSOR_X),
> +		CROS_EC_ACCEL_LEGACY_CHAN(CROS_EC_SENSOR_Y),
> +		CROS_EC_ACCEL_LEGACY_CHAN(CROS_EC_SENSOR_Z),
> +		IIO_CHAN_SOFT_TIMESTAMP(CROS_EC_SENSOR_MAX_AXIS)
>  };
>  
>  static int cros_ec_accel_legacy_probe(struct platform_device *pdev)
>  {
>  	struct device *dev = &pdev->dev;
>  	struct cros_ec_dev *ec = dev_get_drvdata(dev->parent);
> -	struct cros_ec_sensor_platform *sensor_platform = dev_get_platdata(dev);
>  	struct iio_dev *indio_dev;
> -	struct cros_ec_accel_legacy_state *state;
> +	struct cros_ec_sensors_core_state *state;
>  	int ret;
>  
>  	if (!ec || !ec->ec_dev) {
> @@ -350,46 +138,29 @@ static int cros_ec_accel_legacy_probe(struct platform_device *pdev)
>  		return -EINVAL;
>  	}
>  
> -	if (!ec->ec_dev->cmd_readmem) {
> -		dev_warn(&pdev->dev, "EC does not support direct reads.\n");
> -		return -EINVAL;
> -	}
> -
>  	indio_dev = devm_iio_device_alloc(&pdev->dev, sizeof(*state));
>  	if (!indio_dev)
>  		return -ENOMEM;
>  
> -	platform_set_drvdata(pdev, indio_dev);
> -	state = iio_priv(indio_dev);
> -	state->ec = ec->ec_dev;
> -	state->sensor_num = sensor_platform->sensor_num;
> -
> -	indio_dev->dev.parent = dev;
> -	indio_dev->name = pdev->name;
> -	indio_dev->channels = ec_accel_channels;
> -	/*
> -	 * Present the channel using HTML5 standard:
> -	 * need to invert X and Y and invert some lid axis.
> -	 */
> -	ec_accel_channels[X].scan_index = Y;
> -	ec_accel_channels[Y].scan_index = X;
> -	ec_accel_channels[Z].scan_index = Z;
> +	ret = cros_ec_sensors_core_init(pdev, indio_dev, true);
> +	if (ret)
> +		return ret;
>  
> -	state->sign[Y] = 1;
> +	indio_dev->info = &cros_ec_accel_legacy_info;
> +	state = iio_priv(indio_dev);
>  
> -	if (state->sensor_num == MOTIONSENSE_LOC_LID)
> -		state->sign[X] = state->sign[Z] = -1;
> -	else
> -		state->sign[X] = state->sign[Z] = 1;
> +	state->read_ec_sensors_data = cros_ec_sensors_read_lpc;
>  
> -	indio_dev->num_channels = ARRAY_SIZE(ec_accel_channels);
> -	indio_dev->dev.parent = &pdev->dev;
> -	indio_dev->info = &cros_ec_accel_legacy_info;
> -	indio_dev->modes = INDIO_DIRECT_MODE;
> +	indio_dev->channels = cros_ec_accel_legacy_channels;
> +	indio_dev->num_channels = ARRAY_SIZE(cros_ec_accel_legacy_channels);
> +	/* The lid sensor needs to be presented inverted. */
> +	if (state->loc == MOTIONSENSE_LOC_LID) {
> +		state->sign[CROS_EC_SENSOR_X] = -1;
> +		state->sign[CROS_EC_SENSOR_Z] = -1;
> +	}
>  
>  	ret = devm_iio_triggered_buffer_setup(dev, indio_dev, NULL,
> -					      cros_ec_accel_legacy_capture,
> -					      NULL);
> +			cros_ec_sensors_capture, NULL);
>  	if (ret)
>  		return ret;
>  
>