[PATCH v3 2/2] iio: cros_ec: Extend legacy support to ARM device

Gwendal Grignou
2019-06-24T22:53:27Z

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.

On rk3288-veyron-minnie, check chrome detect tablet mode and rotates
screen when in tablet mode.

Check only a subset of the attributes are presented.

Signed-off-by: Gwendal Grignou <gwendal@chromium.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