Message-Id: <20190620185259.142133-3-gwendal@chromium.org>
Date:   Thu, 20 Jun 2019 11:52:59 -0700
From:   Gwendal Grignou <gwendal@...omium.org>
To:     jic23@...nel.org, bleung@...omium.org,
        enric.balletbo@...labora.com, groeck@...omium.org
Cc:     linux-iio@...r.kernel.org, linux-kernel@...r.kernel.org,
        Gwendal Grignou <gwendal@...omium.org>
Subject: [PATCH 2/2] iio: cros_ec : Extend legacy support to ARM device

Add support to ARM based device, that lack LPC access code.
Allow cros-ec-accel-legacy to use cros-ec-sensors-core, add specific
command to capture sensor data.

TEST=On veyron minnie, check chrome detect tablet mode and rotate
screen in tablet mode.
Same tests on glimmer.
Check only a subset of the attributes are presented.

Signed-off-by: Gwendal Grignou <gwendal@...omium.org>
---
 drivers/iio/accel/Kconfig                |   4 +-
 drivers/iio/accel/cros_ec_accel_legacy.c | 350 +++++------------------
 2 files changed, 79 insertions(+), 275 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 46bb2e421bb9..575d7e4c685c 100644
--- a/drivers/iio/accel/cros_ec_accel_legacy.c
+++ b/drivers/iio/accel/cros_ec_accel_legacy.c
@@ -5,13 +5,14 @@
  * Copyright 2017 Google, Inc
  *
  * This driver uses the memory mapper cros-ec interface to communicate
- * with the Chrome OS EC about accelerometer data.
+ * with the Chrome OS EC about accelerometer data or older commands.
  * Accelerometer access is presented through iio sysfs.
  */
 
 #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>
@@ -25,160 +26,41 @@
 
 #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)
+int cros_ec_accel_legacy_read_cmd(struct iio_dev *indio_dev,
+				  unsigned long scan_mask, s16 *data)
 {
-	u8 samp_id = 0xff;
-	u8 status = 0;
+	struct cros_ec_sensors_core_state *st = iio_priv(indio_dev);
 	int ret;
-	int attempts = 0;
+	unsigned int i;
+	u8 sensor_num;
 
 	/*
-	 * 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.
+	 * Read all sensor data through a command.
+	 * Save sensor_num, it is assumed to stay.
 	 */
-	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);
+	sensor_num = st->param.info.sensor_num;
+	st->param.cmd = MOTIONSENSE_CMD_DUMP;
+	st->param.dump.max_sensor_count = CROS_EC_SENSOR_LEGACY_NUM;
+	ret = cros_ec_motion_send_host_cmd(st,
+			sizeof(st->resp->dump) + CROS_EC_SENSOR_LEGACY_NUM *
+			sizeof(struct ec_response_motion_sensor_data));
+	st->param.info.sensor_num = sensor_num;
+	if (ret != 0) {
+		dev_warn(&indio_dev->dev, "Unable to read sensor data\n");
+		return ret;
+	}
 
-		/* Read status byte. */
-		ec_cmd_read_u8(st->ec, EC_MEMMAP_ACC_STATUS, &status);
+	for_each_set_bit(i, &scan_mask, indio_dev->masklength) {
+		*data = st->resp->dump.sensor[sensor_num].data[i] *
+			st->sign[i];
+		data++;
 	}
 
 	return 0;
@@ -188,28 +70,39 @@ 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;
 	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 +124,14 @@ 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)				\
 	{								\
@@ -319,31 +140,30 @@ static const struct iio_chan_spec_ext_info cros_ec_accel_legacy_ext_info[] = {
 		.modified = 1,					        \
 		.info_mask_separate =					\
 			BIT(IIO_CHAN_INFO_RAW) |			\
-			BIT(IIO_CHAN_INFO_SCALE) |			\
 			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) {
@@ -351,46 +171,32 @@ 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;
+	if (state->ec->cmd_readmem != NULL)
+		state->read_ec_sensors_data = cros_ec_sensors_read_lpc;
 	else
-		state->sign[X] = state->sign[Z] = 1;
-
-	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;
+		state->read_ec_sensors_data = cros_ec_accel_legacy_read_cmd;
+
+	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;
 
-- 
2.22.0.410.gd8fdbe21b5-goog

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