Re: [PATCH 04/10] iio: cros_ec: Add common functions for cros_ec sensors.
From: Enric Balletbo Serra
Date: Wed Jul 20 2016 - 03:57:38 EST
Hi Peter and Jonathan,
Thanks for the review, I'll add the changes in v2, some answers below ...
2016-07-18 17:51 GMT+02:00 Jonathan Cameron <jic23@xxxxxxxxxx>:
> On 18/07/16 08:29, Peter Meerwald-Stadler wrote:
>>
>>> Add the core functions to be able to support the sensors attached behind
>>> the ChromeOS Embedded Controller and used by other IIO cros-ec sensor
>>> drivers.
>>
>> comments below from a quick read
>> there is plenty on undocumented private API
> Few more comments from me. Peter is of course quite correct, its the
> new, undocumented ABI, which is the biggest issue.
>
> Interesting looking device. Any docs out there?
>
No afaik, maybe the chromium guys can add something here?
> Jonathan
>>
>>> The cros_ec_sensor_core driver matches with current driver in ChromeOS
>>> 4.4 tree, so it includes all the fixes at the moment. The support for
>>> this driver was made by Gwendal Grignou. The original patch and all the
>>> fixes has been squashed and rebased on top of mainline.
>>>
>>> Signed-off-by: Gwendal Grignou <gwendal@xxxxxxxxxxxx>
>>> Signed-off-by: Guenter Roeck <groeck@xxxxxxxxxxxx>
>>> [eballetbo: split, squash and rebase on top of mainline the patches
>>> found in ChromeOS tree]
>>> Signed-off-by: Enric Balletbo i Serra <enric.balletbo@xxxxxxxxxxxxx>
>>> ---
>>> drivers/iio/common/Kconfig | 1 +
>>> drivers/iio/common/Makefile | 1 +
>>> drivers/iio/common/cros_ec_sensors/Kconfig | 14 +
>>> drivers/iio/common/cros_ec_sensors/Makefile | 5 +
>>> .../common/cros_ec_sensors/cros_ec_sensors_core.c | 564 +++++++++++++++++++++
>>> .../common/cros_ec_sensors/cros_ec_sensors_core.h | 155 ++++++
>>> 6 files changed, 740 insertions(+)
>>> create mode 100644 drivers/iio/common/cros_ec_sensors/Kconfig
>>> create mode 100644 drivers/iio/common/cros_ec_sensors/Makefile
>>> create mode 100644 drivers/iio/common/cros_ec_sensors/cros_ec_sensors_core.c
>>> create mode 100644 drivers/iio/common/cros_ec_sensors/cros_ec_sensors_core.h
>>>
>>> diff --git a/drivers/iio/common/Kconfig b/drivers/iio/common/Kconfig
>>> index 26a6026..e108996 100644
>>> --- a/drivers/iio/common/Kconfig
>>> +++ b/drivers/iio/common/Kconfig
>>> @@ -2,6 +2,7 @@
>>> # IIO common modules
>>> #
>>>
>>> +source "drivers/iio/common/cros_ec_sensors/Kconfig"
>>> source "drivers/iio/common/hid-sensors/Kconfig"
>>> source "drivers/iio/common/ms_sensors/Kconfig"
>>> source "drivers/iio/common/ssp_sensors/Kconfig"
>>> diff --git a/drivers/iio/common/Makefile b/drivers/iio/common/Makefile
>>> index 585da6a..6fa760e 100644
>>> --- a/drivers/iio/common/Makefile
>>> +++ b/drivers/iio/common/Makefile
>>> @@ -7,6 +7,7 @@
>>> #
>>>
>>> # When adding new entries keep the list in alphabetical order
>>> +obj-y += cros_ec_sensors/
>>> obj-y += hid-sensors/
>>> obj-y += ms_sensors/
>>> obj-y += ssp_sensors/
>>> diff --git a/drivers/iio/common/cros_ec_sensors/Kconfig b/drivers/iio/common/cros_ec_sensors/Kconfig
>>> new file mode 100644
>>> index 0000000..a30f41e
>>> --- /dev/null
>>> +++ b/drivers/iio/common/cros_ec_sensors/Kconfig
>>> @@ -0,0 +1,14 @@
>>> +#
>>> +# Chrome OS Embedded Controller managed sensors library
>>> +#
>>> +config IIO_CROS_EC_SENSORS_CORE
>>> + tristate "ChromeOS EC Sensors Core"
>>> + depends on SYSFS && MFD_CROS_EC
>>> + select IIO_BUFFER
>>> + select IIO_TRIGGERED_BUFFER
>>> + help
>>> + Base module for the ChromeOS EC Sensors module.
>>> + Contains core functions used by other IIO CrosEC sensor
>>> + driver.
>>
>> 'drivers' probably
>>
>>> + Define common attributes and sysfs interrupt handler.
>>> +
>>> diff --git a/drivers/iio/common/cros_ec_sensors/Makefile b/drivers/iio/common/cros_ec_sensors/Makefile
>>> new file mode 100644
>>> index 0000000..95b6901
>>> --- /dev/null
>>> +++ b/drivers/iio/common/cros_ec_sensors/Makefile
>>> @@ -0,0 +1,5 @@
>>> +#
>>> +# Makefile for sensors seen through the ChromeOS EC sensor hub.
>>> +#
>>> +
>>> +obj-$(CONFIG_IIO_CROS_EC_SENSORS_CORE) += cros_ec_sensors_core.o
>>> diff --git a/drivers/iio/common/cros_ec_sensors/cros_ec_sensors_core.c b/drivers/iio/common/cros_ec_sensors/cros_ec_sensors_core.c
>>> new file mode 100644
>>> index 0000000..cb3de8f
>>> --- /dev/null
>>> +++ b/drivers/iio/common/cros_ec_sensors/cros_ec_sensors_core.c
>>> @@ -0,0 +1,564 @@
>>> +/*
>>> + * cros_ec_sensors_core - Common function for Chrome OS EC sensor driver.
>>> + *
>>> + * Copyright (C) 2015 Google, Inc
>>> + *
>>> + * This software is licensed under the terms of the GNU General Public
>>> + * License version 2, as published by the Free Software Foundation, and
>>> + * may be copied, distributed, and modified under those terms.
>>> + *
>>> + * 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.
>>> + *
>>> + * This driver uses the cros-ec interface to communicate with the Chrome OS
>>> + * EC about accelerometer data. Accelerometer access is presented through
>>> + * iio sysfs.
>>> + */
>>> +
>>> +#include <linux/delay.h>
>>> +#include <linux/device.h>
>>> +#include <linux/iio/buffer.h>
>>> +#include <linux/iio/iio.h>
>>> +#include <linux/iio/kfifo_buf.h>
>>> +#include <linux/iio/trigger_consumer.h>
>>> +#include <linux/kernel.h>
>>> +#include <linux/mfd/cros_ec.h>
>>> +#include <linux/mfd/cros_ec_commands.h>
>>> +#include <linux/module.h>
>>> +#include <linux/slab.h>
>>> +#include <linux/sysfs.h>
>>> +#include <linux/platform_device.h>
>>> +
>>> +#include "cros_ec_sensors_core.h"
>>> +
>>> +static char *cros_ec_loc[] = {
>>> + [MOTIONSENSE_LOC_BASE] = "base",
>>> + [MOTIONSENSE_LOC_LID] = "lid",
>>> + [MOTIONSENSE_LOC_MAX] = "unknown",
>>> +};
>>> +
>>> +/*
>>> + * cros_ec_sensors_core_init
>>> + *
>>> + * Initialize core sensor strucure, fill the response are
>>> + * with the return of Sensor info.
>>
>> rephrase please
>>
>>> + *
>>> + * @pdev plarform device created for the sensors
>>
>> platform
>>
>>> + * @indio_dev iio device structure of the device
>>> + * @physical_device True if the device refers to a physical device.
>>> + */
>>> +int cros_ec_sensors_core_init(struct platform_device *pdev,
>>> + struct iio_dev *indio_dev,
>>> + bool physical_device)
>>> +{
>>> + struct device *dev = &pdev->dev;
>>> + struct cros_ec_sensors_core_state *state = iio_priv(indio_dev);
>>> + struct cros_ec_dev *ec = dev_get_drvdata(pdev->dev.parent);
>>> + struct cros_ec_sensor_platform *sensor_platform = dev_get_platdata(dev);
>>> +
>>> + platform_set_drvdata(pdev, indio_dev);
>>> +
>>> + state->ec = ec->ec_dev;
>>> + state->msg = devm_kzalloc(&pdev->dev,
>>> + max((u16)sizeof(struct ec_params_motion_sense),
>>> + state->ec->max_response), GFP_KERNEL);
>>> + if (!state->msg)
>>> + return -ENOMEM;
>>> +
>>> + state->resp = (struct ec_response_motion_sense *)state->msg->data;
>>> +
>>> + mutex_init(&state->cmd_lock);
>>> + /* Set up the host command structure. */
>>> + state->msg->version = 2;
>>> + state->msg->command = EC_CMD_MOTION_SENSE_CMD + ec->cmd_offset;
>>> + state->msg->outsize = sizeof(struct ec_params_motion_sense);
>>> +
>>> + indio_dev->dev.parent = &pdev->dev;
>>> + indio_dev->name = pdev->name;
>>> +
>>> + if (physical_device) {
>>> + indio_dev->modes = INDIO_DIRECT_MODE;
>>> +
>>> + state->param.cmd = MOTIONSENSE_CMD_INFO;
>>> + state->param.info.sensor_num = sensor_platform->sensor_num;
>>> + if (cros_ec_motion_send_host_cmd(state, 0)) {
>>> + dev_warn(dev, "Can not access sensor info\n");
>>> + return -EIO;
>>> + }
>>> + state->type = state->resp->info.type;
>>> + state->loc = state->resp->info.location;
>>> + }
>>> + return 0;
>>> +}
>>> +EXPORT_SYMBOL_GPL(cros_ec_sensors_core_init);
>>> +
>>> +/*
>>> + * cros_ec_motion_send_host_cmd - send motion sense host command
>>> + *
>>> + * @st Pointer to state information for device.
>>
>> @state
>> opt_length is not documented
>>
>>> + * @return 0 if ok, -ve on error.
>>
>> what is -ve?
>>
I would mean negative number, I'll replace the -ve for a more
appropiate explanation :)
>>> + *
>>> + * Note, when called, the sub-command is assumed to be set in param->cmd.
>>> + */
>>> +int cros_ec_motion_send_host_cmd(struct cros_ec_sensors_core_state *state,
>>> + u16 opt_length)
>>> +{
>>> + int ret;
>>> +
>>> + if (opt_length)
>>> + state->msg->insize = min(opt_length, state->ec->max_response);
>>> + else
>>> + state->msg->insize = state->ec->max_response;
>>> +
>>> + memcpy(state->msg->data, &state->param, sizeof(state->param));
>>> + /* Send host command. */
>>
>> comment needed?
>>
Probably not, I'll remove it
>>> + ret = cros_ec_cmd_xfer_status(state->ec, state->msg);
>>> + if (ret < 0)
>>> + return -EIO;
>>> +
>>> + if (ret &&
>>> + state->resp != (struct ec_response_motion_sense *)state->msg->data)
>>> + memcpy(state->resp, state->msg->data, ret);
>>> +
>>> + return 0;
>>> +}
>>> +EXPORT_SYMBOL_GPL(cros_ec_motion_send_host_cmd);
>>> +
>>> +static ssize_t __maybe_unused cros_ec_sensors_flush(struct iio_dev *indio_dev,
>>> + uintptr_t private, const struct iio_chan_spec *chan,
>>> + const char *buf, size_t len)
>>> +{
>>> + struct cros_ec_sensors_core_state *st = iio_priv(indio_dev);
>>> + int ret = 0;
>>
>> initialization not needed
>>
>>> + bool flush;
>>> +
>>> + ret = strtobool(buf, &flush);
>>> + if (ret < 0)
>>> + return ret;
>>> + if (!flush)
>>> + return -EINVAL;
>>> +
>>> + mutex_lock(&st->cmd_lock);
>>> + st->param.cmd = MOTIONSENSE_CMD_FIFO_FLUSH;
>>> + ret = cros_ec_motion_send_host_cmd(st, 0);
>>> + if (ret != 0)
>>> + dev_warn(&indio_dev->dev, "Unable to flush sensor\n");
>>> + mutex_unlock(&st->cmd_lock);
> blank line here (nitpick of the day)
>>> + return ret ? ret : len;
>>> +}
>>> +
>>> +static ssize_t cros_ec_sensors_calibrate(struct iio_dev *indio_dev,
>>> + uintptr_t private, const struct iio_chan_spec *chan,
>>> + const char *buf, size_t len)
>>> +{
>>> + struct cros_ec_sensors_core_state *st = iio_priv(indio_dev);
>>> + int ret, i;
>>> + bool calibrate;
>>> +
>>> + ret = strtobool(buf, &calibrate);
>>> + if (ret < 0)
>>> + return ret;
>>> + if (!calibrate)
>>> + return -EINVAL;
>>> +
>>> + mutex_lock(&st->cmd_lock);
>>> + st->param.cmd = MOTIONSENSE_CMD_PERFORM_CALIB;
>>> + ret = cros_ec_motion_send_host_cmd(st, 0);
>>> + if (ret != 0) {
>>> + dev_warn(&indio_dev->dev, "Unable to calibrate sensor\n");
>>> + } else {
>>> + /* Save values */
>>> + for (i = X; i < MAX_AXIS; i++)
>>
>> what is X here?
>>
I'll change for the proper define ...
>>> + st->calib[i].offset = st->resp->perform_calib.offset[i];
>>> + }
>>> + mutex_unlock(&st->cmd_lock);
>>> + return ret ? ret : len;
>>> +}
>>> +
>>> +static ssize_t cros_ec_sensors_id(struct iio_dev *indio_dev,
>>> + uintptr_t private, const struct iio_chan_spec *chan,
>>> + char *buf)
>>> +{
>>> + struct cros_ec_sensors_core_state *st = iio_priv(indio_dev);
>>> +
>>> + return sprintf(buf, "%d\n", st->param.info.sensor_num);
>>
>> can't we be a bit more careful with buffer sizes here (and below)?
>>
I'm not sure I get what you mean here.
>>> +}
>>> +
>>> +static ssize_t cros_ec_sensors_loc(struct iio_dev *indio_dev,
>>> + uintptr_t private, const struct iio_chan_spec *chan,
>>> + char *buf)
>>> +{
>>> + struct cros_ec_sensors_core_state *st = iio_priv(indio_dev);
>>> +
>>> + return sprintf(buf, "%s\n", cros_ec_loc[st->loc]);
>>> +}
>>> +
>>> +const struct iio_chan_spec_ext_info cros_ec_sensors_ext_info[] = {
>>> +#ifdef CONFIG_IIO_CROS_EC_SENSORS_RING
>>> + {
>>> + .name = "flush",
>>> + .shared = IIO_SHARED_BY_ALL,
>>> + .write = cros_ec_sensors_flush
>>> + },
>>> +#endif
>>> + {
>>> + .name = "calibrate",
>>> + .shared = IIO_SHARED_BY_ALL,
>>> + .write = cros_ec_sensors_calibrate
>>> + },
>>> + {
>>> + .name = "id",
>>> + .shared = IIO_SHARED_BY_ALL,
>>> + .read = cros_ec_sensors_id
>>> + },
>>> + {
>>> + .name = "location",
>>> + .shared = IIO_SHARED_BY_ALL,
>>> + .read = cros_ec_sensors_loc
>>> + },
>>> + { },
>>> +};
>>> +EXPORT_SYMBOL_GPL(cros_ec_sensors_ext_info);
>>> +
>>> +const struct iio_chan_spec_ext_info cros_ec_sensors_limited_info[] = {
>>> + {
>>> + .name = "id",
> These all need documentation.. Any ABI needs an entry in
> Documentation/ABI/testing/sysfs-bus-iio-* before any real discussion can
> start.
>
Ok, I'll include the documentation in order to start the discussion in v2.
>>> + .shared = IIO_SHARED_BY_ALL,
>>> + .read = cros_ec_sensors_id
>>> + },
>>> + {
>>> + .name = "location",
>>> + .shared = IIO_SHARED_BY_ALL,
>>> + .read = cros_ec_sensors_loc
>>> + },
>>> + { },
>>> +};
>>> +EXPORT_SYMBOL_GPL(cros_ec_sensors_limited_info);
>>> +/*
>>> + * idx_to_reg - convert sensor index into offset in shared memory region.
>>> + *
>>> + * @st: private data
>>> + * @idx: sensor index (should be element of enum sensor_index)
>>> + * @return address to read at.
>>> + */
>>> +static unsigned int idx_to_reg(struct cros_ec_sensors_core_state *st,
>>
>> cros_ec_ prefix please (here and below)
>>
>>> + unsigned int idx)
>>> +{
>>> + /*
>>> + * When using LPC interface, only space for 2 Accel and one Gyro.
>>> + * First halfword of MOTIONSENSE_TYPE_ACCEL is used by angle.
>>> + */
>>> + if (st->type == MOTIONSENSE_TYPE_ACCEL)
>>> + return EC_MEMMAP_ACC_DATA + sizeof(u16) *
>>> + (1 + idx + st->param.info.sensor_num *
>>> + MAX_AXIS);
>>> + else
>>> + return EC_MEMMAP_GYRO_DATA + sizeof(u16) * idx;
>>> +}
>>> +
>>> +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)
>>> +{
>>> + u16 tmp;
> __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.
>>> + * @return 8-bit status if ok, -ve on error
>>> + */
>>> +static int read_ec_until_not_busy(struct cros_ec_sensors_core_state *st)
>>> +{
>>> + struct cros_ec_device *ec = st->ec;
>>> + u8 status;
>>> + int attempts = 0;
>>> +
>>> + ec_cmd_read_u8(ec, EC_MEMMAP_ACC_STATUS, &status);
>>
>> check return value (here and below)?
>>
Ok, I will do.
>>> + 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_sensors_data_unsafe - read acceleration data from EC shared memory.
>>> + *
>>> + * @st Pointer to state information for device.
>>
>> @indio_dev? here and below
>>
Yep, I tried to fix all the documentation style in v2.
>>> + * @scan_mask Bitmap of the sensor indices to scan.
>>> + * @data Location to store data.
>>> + *
>>> + * Note 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_sensors_data_unsafe(struct iio_dev *indio_dev,
>>> + unsigned long scan_mask, s16 *data)
>>> +{
>>> + struct cros_ec_sensors_core_state *st = iio_priv(indio_dev);
>>> + struct cros_ec_device *ec = st->ec;
>>> + unsigned int i = 0;
>>
>> init not needed
>>
>>> +
>>> + /*
>>> + * Read all sensors enabled in scan_mask. Each value is 2
>>> + * bytes.
>>> + */
>>> + for_each_set_bit(i, &scan_mask, indio_dev->masklength) {
>>> + ec_cmd_read_u16(ec, idx_to_reg(st, i), data);
>>
>> no return value?
>>
Changed
>>> + data++;
>>> + }
> Hmm. So this one has random access unlike below. Interesting...
>>> +}
>>> +
>>> +/*
>>> + * cros_ec_sensors_read_lpc - 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.
>>> + * @return 0 if ok, -ve on error
>>> + *
>>> + * Note: 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.
>>> + */
>>> +int cros_ec_sensors_read_lpc(struct iio_dev *indio_dev,
>>> + unsigned long scan_mask, s16 *data)
>>> +{
>>> + struct cros_ec_sensors_core_state *st = iio_priv(indio_dev);
>>> + struct cros_ec_device *ec = st->ec;
>>> + u8 samp_id = 0xff, status = 0;
>>> + 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.
>>> + */
> kind of papers over any overwrites that have occured though...
> Unfortunately there is no particularly good solution to this. Oh for a hardware
> fifo!
>
>>> + 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. */
>>> + status = read_ec_until_not_busy(st);
>>> + if (status < 0)
>>> + return status;
> Any chance this can spin for ever? (I don't think so but worth checking).
No
>>> +
>>> + /*
>>> + * 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_sensors_data_unsafe(indio_dev, scan_mask, data);
>>> +
>>> + /* Read status byte. */
>>> + ec_cmd_read_u8(ec, EC_MEMMAP_ACC_STATUS, &status);
>>> + }
>>> +
>>> + return 0;
>>> +}
>>> +EXPORT_SYMBOL_GPL(cros_ec_sensors_read_lpc);
>>> +
>>> +int cros_ec_sensors_read_cmd(struct iio_dev *indio_dev,
>>> + unsigned long scan_mask, s16 *data)
>>> +{
>>> + struct cros_ec_sensors_core_state *st = iio_priv(indio_dev);
>>> + int ret;
>>> + unsigned int i = 0;
>>> +
>>> + /*
>>> + * read all sensor data through a command.
>>
>> start with uppercase as everywhere else
>>
>>> + */
>>> + st->param.cmd = MOTIONSENSE_CMD_DATA;
>>> + ret = cros_ec_motion_send_host_cmd(st, sizeof(st->resp->data));
>>> + if (ret != 0) {
>>> + dev_warn(&indio_dev->dev, "Unable to read sensor data\n");
>>> + return ret;
>>> + }
>>> +
>>> + for_each_set_bit(i, &scan_mask, indio_dev->masklength) {
>>> + *data = st->resp->data.data[i];
>>> + data++;
>>> + }
> So the device spits out a whole record every time? If so let the demux
> in the IIO core handle this step. Chances are you'll end up with
> clients of this datastream down the line and demuxing everything twice
> + that implementation has a few little tricks up it's sleeve ;)
>
> Provide available_scan_masks and then just throw the whole scan at it every
> time.
>
>>> + return 0;
>>> +}
>>> +EXPORT_SYMBOL_GPL(cros_ec_sensors_read_cmd);
>>> +
>>> +irqreturn_t cros_ec_sensors_capture(int irq, void *p)
>>> +{
>>> + struct iio_poll_func *pf = p;
>>> + struct iio_dev *indio_dev = pf->indio_dev;
>>> + struct cros_ec_sensors_core_state *st = iio_priv(indio_dev);
>>> +
>>> + mutex_lock(&st->cmd_lock);
>>> + /* Clear capture data. */
>>> + memset(st->samples, 0, indio_dev->scan_bytes);
>>> +
>>> + /* Read data based on which channels are enabled in scan mask. */
>>> + st->read_ec_sensors_data(indio_dev, *(indio_dev->active_scan_mask),
>>> + (s16 *)st->samples);
>>
>> no return value?
>>
Checking return value in v2.
>>> +
>>> + /* Store the timestamp last 8 bytes of data. */
>>> + if (indio_dev->scan_timestamp)
>>> + *(s64 *)&st->samples[round_down(indio_dev->scan_bytes -
>>> + sizeof(s64),
>>> + sizeof(s64))] = iio_get_time_ns();
>>> +
>>> + iio_push_to_buffers(indio_dev, st->samples);
>>
>> use iio_push_to_buffers_with_timestamp()
> but make sure you obey the slightly odd space requirements for the buffer
> passed into this function.
>>
>>> +
>>> + /*
>>> + * Tell the core we are done with this trigger and ready for the
>>> + * next one.
>>> + */
>>> + iio_trigger_notify_done(indio_dev->trig);
>>> + mutex_unlock(&st->cmd_lock);
>>> +
>>> + return IRQ_HANDLED;
>>> +}
>>> +EXPORT_SYMBOL_GPL(cros_ec_sensors_capture);
>>> +
>>> +int cros_ec_sensors_core_read(struct cros_ec_sensors_core_state *st,
>>> + struct iio_chan_spec const *chan,
>>> + int *val, int *val2, long mask)
>>> +{
>>> + int ret = IIO_VAL_INT;
>>> +
>>> + switch (mask) {
>>> + case IIO_CHAN_INFO_SAMP_FREQ:
>>> + st->param.cmd = MOTIONSENSE_CMD_EC_RATE;
>>> + st->param.ec_rate.data =
>>> + EC_MOTION_SENSE_NO_VALUE;
>>> +
>>> + if (cros_ec_motion_send_host_cmd(st, 0))
>>> + ret = -EIO;
>>> + else
>>> + *val = st->resp->ec_rate.ret;
>>> + break;
>>> + case IIO_CHAN_INFO_FREQUENCY:
>>> + st->param.cmd = MOTIONSENSE_CMD_SENSOR_ODR;
>>> + st->param.sensor_odr.data =
>>> + EC_MOTION_SENSE_NO_VALUE;
>>> +
>>> + if (cros_ec_motion_send_host_cmd(st, 0))
>>> + ret = -EIO;
>>> + else
>>> + *val = st->resp->sensor_odr.ret;
>>> + break;
>>> + default:
>>> + break;
>>> + }
>>> + return ret;
>>> +}
>>> +EXPORT_SYMBOL_GPL(cros_ec_sensors_core_read);
>>> +
>>> +int cros_ec_sensors_core_write(struct cros_ec_sensors_core_state *st,
>>> + struct iio_chan_spec const *chan,
>>> + int val, int val2, long mask)
>>> +{
>>> + int ret = 0;
>>> +
>>> + switch (mask) {
>>> + case IIO_CHAN_INFO_FREQUENCY:
> This needs explanation... The frequency chan info element has so far only
> applied to output sensors where we are controlling a signal generator of
> some type.
>>> + st->param.cmd = MOTIONSENSE_CMD_SENSOR_ODR;
>>> + st->param.sensor_odr.data = val;
>>> +
>>> + /* Always roundup, so caller gets at least what it asks for. */
>>> + st->param.sensor_odr.roundup = 1;
>>> +
>>> + if (cros_ec_motion_send_host_cmd(st, 0))
>>> + ret = -EIO;
>>> + break;
>>> + case IIO_CHAN_INFO_SAMP_FREQ:
>>> + st->param.cmd = MOTIONSENSE_CMD_EC_RATE;
>>> + st->param.ec_rate.data = val;
>>> +
>>> + if (cros_ec_motion_send_host_cmd(st, 0))
>>> + ret = -EIO;
>>> + else
>>> + st->curr_sampl_freq = val;
>>> + break;
>>> + default:
>>> + ret = -EINVAL;
>>> + break;
>>> + }
>>> + return ret;
>>> +}
>>> +EXPORT_SYMBOL_GPL(cros_ec_sensors_core_write);
>>> +
>>> +static int __maybe_unused cros_ec_sensors_prepare(struct device *dev)
>>> +{
>>> + struct platform_device *pdev = to_platform_device(dev);
>>> + struct iio_dev *indio_dev = platform_get_drvdata(pdev);
>>> + struct cros_ec_sensors_core_state *st = iio_priv(indio_dev);
>>> +
>>> + if (st->curr_sampl_freq == 0)
>>> + return 0;
>>> +
>>> + /*
>>> + * If the sensors are sampled at high frequency, we will not be able to
>>> + * sleep. Set to sampling to a long period if necessary.
>>> + */
>>> + if (st->curr_sampl_freq < CROS_EC_MIN_SUSPEND_SAMPLING_FREQUENCY) {
>>> + mutex_lock(&st->cmd_lock);
>>> + st->param.cmd = MOTIONSENSE_CMD_EC_RATE;
>>> + st->param.ec_rate.data = CROS_EC_MIN_SUSPEND_SAMPLING_FREQUENCY;
>>> + cros_ec_motion_send_host_cmd(st, 0);
>>> + mutex_unlock(&st->cmd_lock);
>>> + }
>>> + return 0;
>>> +}
>>> +
>>> +static void __maybe_unused cros_ec_sensors_complete(struct device *dev)
>>> +{
>>> + struct platform_device *pdev = to_platform_device(dev);
>>> + struct iio_dev *indio_dev = platform_get_drvdata(pdev);
>>> + struct cros_ec_sensors_core_state *st = iio_priv(indio_dev);
>>> +
>>> + if (st->curr_sampl_freq == 0)
>>> + return;
>>> +
>>> + if (st->curr_sampl_freq < CROS_EC_MIN_SUSPEND_SAMPLING_FREQUENCY) {
>>> + mutex_lock(&st->cmd_lock);
>>> + st->param.cmd = MOTIONSENSE_CMD_EC_RATE;
>>> + st->param.ec_rate.data = st->curr_sampl_freq;
>>> + cros_ec_motion_send_host_cmd(st, 0);
>>> + mutex_unlock(&st->cmd_lock);
>>> + }
>>> +}
>>> +
>>> +#ifdef CONFIG_PM_SLEEP
>>> +const struct dev_pm_ops cros_ec_sensors_pm_ops = {
>>> + .prepare = cros_ec_sensors_prepare,
>>> + .complete = cros_ec_sensors_complete
>>> +};
> Hmm. You meet something new everyday. I don't feel nearly as comfortable
> reviewing these as the callbacks we tend to get as first time I've encountered
> them...
>
>>> +#else
>>> +const struct dev_pm_ops cros_ec_sensors_pm_ops = { };
>>> +#endif
>>> +EXPORT_SYMBOL_GPL(cros_ec_sensors_pm_ops);
>>> +
>>> +MODULE_DESCRIPTION("ChromeOS EC sensor hub core functions");
>>> +MODULE_LICENSE("GPL v2");
>>> diff --git a/drivers/iio/common/cros_ec_sensors/cros_ec_sensors_core.h b/drivers/iio/common/cros_ec_sensors/cros_ec_sensors_core.h
>>> new file mode 100644
>>> index 0000000..53e09e1
>>> --- /dev/null
>>> +++ b/drivers/iio/common/cros_ec_sensors/cros_ec_sensors_core.h
>>> @@ -0,0 +1,155 @@
>>> +/*
>>> + * ChromeOS EC sensor hub
>>> + *
>>> + * Copyright (C) 2015 Google, Inc
>>> + *
>>> + * This software is licensed under the terms of the GNU General Public
>>> + * License version 2, as published by the Free Software Foundation, and
>>> + * may be copied, distributed, and modified under those terms.
>>> + *
>>> + * 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.
>>> + */
>>> +
>>> +#ifndef __CROS_EC_SENSORS_CORE_H
>>> +#define __CROS_EC_SENSORS_CORE_H
>>> +
>>> +#include <linux/irqreturn.h>
>>> +
>>> +enum {
>>> + X,
>>
>> such short #defines scare me :)
> Absolutely - prefix these to avoid likely future crashes..
>>
>>> + Y,
>>> + Z,
>>> + MAX_AXIS,
>>> +};
>>> +
>>> +/*
>>> + * EC returns sensor values using signed 16 bit registers
>>> + */
>>> +#define CROS_EC_SENSOR_BITS 16
>>> +
>>> +/*
>>> + * 4 16 bit channels are allowed.
>>> + * Good enough for current sensors, thye use up to 3 16 bit vectors.
>>
>> they
>>
>>> + */
>>> +#define CROS_EC_SAMPLE_SIZE (sizeof(s64) * 2)
>>> +
>>> +/*
>>> + * minimum sampling period to use when device is suspending.
>>
>> Minimum (uppercase)
> Comment syntax as well :)
>>
>>> + */
>>> +#define CROS_EC_MIN_SUSPEND_SAMPLING_FREQUENCY 1000 /* 1 second */
>>> +
>>> +/*
>>> + * Function to read the sensor data.
>>> + *
>>> + * Data can be retrieve using the cros ec command protocol.
>>> + * Some machines also allow accessing some sensor data via
>>> + * IO space.
>>> + */
>>> +typedef int (cros_ec_sensors_read_t)(struct iio_dev *indio_dev,
>>> + unsigned long scan_mask, s16 *data);
>>> +
>>> +cros_ec_sensors_read_t cros_ec_sensors_read_lpc;
>>> +cros_ec_sensors_read_t cros_ec_sensors_read_cmd;
>>> +
>>> +/* State data for ec_sensors iio driver. */
>>> +struct cros_ec_sensors_core_state {
>>> + struct cros_ec_device *ec;
>>> + /*
>>> + * Location to store command and response to the EC.
>>> + */
> Please fix comment style throughout. If not I'll get a dozen fixes within
> the first week and it'll be merge pain for everyone. Yeah, we are fussy
> about this, but it does make life less painful in the long run.
>>> + struct mutex cmd_lock;
>>> +
>>> + /*
>>> + * Statically allocated command structure that holds parameters
>>> + * and response.
>>> + */
>>> + struct cros_ec_command *msg;
>>> + struct ec_params_motion_sense param;
>>> + struct ec_response_motion_sense *resp;
>>> +
>>> + /* Type of sensor */
>>> + enum motionsensor_type type;
>>> + enum motionsensor_location loc;
>>> +
>>> + /*
>>> + * Calibration parameters. Note that trigger captured data will always
>>> + * provide the calibrated values.
>>> + */
>>> + struct calib_data {
>>> + s16 offset;
>>> + } calib[MAX_AXIS];
>>> +
>>> + /*
>>> + * Static array to hold data from a single capture. For each
>>> + * channel we need 2 bytes, except for the timestamp. The timestamp
>>> + * is always last and is always 8-byte aligned.
>>> + */
>>> + u8 samples[CROS_EC_SAMPLE_SIZE];
>>> +
>>> + /* Pointer to function used for accessing sensors values. */
>>> + cros_ec_sensors_read_t *read_ec_sensors_data;
>>> +
>>> + /* Current sampling period */
>>> + int curr_sampl_freq;
>>> +};
>>> +
>>> +/* Basic initialization of the core structure. */
>>> +int cros_ec_sensors_core_init(struct platform_device *pdev,
>>> + struct iio_dev *indio_dev,
>>> + bool physical_device);
>>> +
>>> +/*
>>> + * cros_ec_sensors_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.
>>> + */
>>> +irqreturn_t cros_ec_sensors_capture(int irq, void *p);
>>> +
>>> +
>>> +/*
>>> + * cros_ec_motion_send_host_cmd - send motion sense host command
>>> + *
>>> + * @st Pointer to state information for device.
>>> + * @opt_length: optional length: to reduce the response size,
>>> + * useful on the data path.
>>> + * Otherwise, the maximal allowed response size is used.
>>> + * @return 0 if ok, -ve on error.
>>> + *
>>> + * Note, when called, the sub-command is assumed to be set in param->cmd.
>>> + */
>>> +int cros_ec_motion_send_host_cmd(struct cros_ec_sensors_core_state *st,
>>> + u16 opt_length);
>>> +
>>> +/*
>>> + * cros_ec_sensors_core_read/write: handler for core attributes.
>>> + *
>>> + * Handler for attributes identical among sensors:
>>> + * - frequency,
>>> + * - sampling_frequency.
>>> + *
>>> + * cmd_lock lock must be held.
> Full kerneldoc preferred for descriptions of functions etc. Lets us
> do pretty printed manuals nice and easily ;)
>>> + */
>>> +int cros_ec_sensors_core_read(struct cros_ec_sensors_core_state *st,
>>> + struct iio_chan_spec const *chan,
>>> + int *val, int *val2, long mask);
>>> +
>>> +int cros_ec_sensors_core_write(struct cros_ec_sensors_core_state *st,
>>> + struct iio_chan_spec const *chan,
>>> + int val, int val2, long mask);
>>> +
>>> +extern const struct dev_pm_ops cros_ec_sensors_pm_ops;
>>> +
>>> +/* List of extended channel specification for all sensors */
>>> +extern const struct iio_chan_spec_ext_info cros_ec_sensors_ext_info[];
>>> +extern const struct iio_chan_spec_ext_info cros_ec_sensors_limited_info[];
>>> +
>>> +#endif /* __CROS_EC_SENSORS_CORE_H */
>>>
>>
>
Thanks, I'll do some rework on this series and send v2 asap.
Enric