Re: [PATCH 01/13] mfd: cros_ec: Add sensor_count and make check_features public

Enric Balletbo i Serra
2019-09-30T13:15:21Z

Hi Gwendal,

Many thanks for the patches.

On 22/9/19 19:50, Gwendal Grignou wrote:
> Add a new function to return the number of MEMS sensors available in a
> ChromeOS Embedded Controller.
> It uses MOTIONSENSE_CMD_DUMP if available or a specific memory map ACPI
> registers to find out.
>
> Also, make check_features public as it can be useful for other drivers
> to know whant the Embedded Controller supports.
>
> Signed-off-by: Gwendal Grignou <gwendal@chromium.org>
> ---
> drivers/mfd/cros_ec_dev.c | 61 ++++++++++++++++++++++++++++++++++++-
> include/linux/mfd/cros_ec.h | 17 +++++++++++
> 2 files changed, 77 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/mfd/cros_ec_dev.c b/drivers/mfd/cros_ec_dev.c
> index 6e6dfd6c1871..3be80183ccaa 100644
> --- a/drivers/mfd/cros_ec_dev.c
> +++ b/drivers/mfd/cros_ec_dev.c
> @@ -112,7 +112,7 @@ static const struct mfd_cell cros_ec_vbc_cells[] = {
> { .name = "cros-ec-vbc", }
> };
>
> -static int cros_ec_check_features(struct cros_ec_dev *ec, int feature)
> +int cros_ec_check_features(struct cros_ec_dev *ec, int feature)
> {
> struct cros_ec_command *msg;
> int ret;
> @@ -143,12 +143,71 @@ static int cros_ec_check_features(struct cros_ec_dev *ec, int feature)
>
> return ec->features[feature / 32] & EC_FEATURE_MASK_0(feature);
> }
> +EXPORT_SYMBOL_GPL(cros_ec_check_features);
>
> static void cros_ec_class_release(struct device *dev)
> {
> kfree(to_cros_ec_dev(dev));
> }
>
> +int cros_ec_get_sensor_count(struct cros_ec_dev *ec)
> +{
> + /*
> + * Issue a command to get the number of sensor reported.
> + * If not supported, check for legacy mode.
> + */
> + int ret, sensor_count;
> + struct ec_params_motion_sense *params;
> + struct ec_response_motion_sense *resp;
> + struct cros_ec_command *msg;
> + struct cros_ec_device *ec_dev = ec->ec_dev;
> + u8 status;
> +
> + msg = kzalloc(sizeof(struct cros_ec_command) +
> + max(sizeof(*params), sizeof(*resp)), GFP_KERNEL);
> + if (msg == NULL)
> + return -ENOMEM;
> +
> + msg->version = 1;
> + msg->command = EC_CMD_MOTION_SENSE_CMD + ec->cmd_offset;
> + msg->outsize = sizeof(*params);
> + msg->insize = sizeof(*resp);
> +
> + params = (struct ec_params_motion_sense *)msg->data;
> + params->cmd = MOTIONSENSE_CMD_DUMP;
> +
> + ret = cros_ec_cmd_xfer(ec->ec_dev, msg);
> + if (ret < 0) {
> + sensor_count = ret;
> + } else if (msg->result != EC_RES_SUCCESS) {
> + sensor_count = -EPROTO;
> + } else {
> + resp = (struct ec_response_motion_sense *)msg->data;
> + sensor_count = resp->dump.sensor_count;
> + }
> + kfree(msg);
> +
> + /*
> + * Check legacy mode: Let's find out if sensors are accessible
> + * via LPC interface.
> + */
> + if (sensor_count == -EPROTO &&
> + ec->cmd_offset == 0 &&
> + ec_dev->cmd_readmem) {
> + ret = ec_dev->cmd_readmem(ec_dev, EC_MEMMAP_ACC_STATUS,
> + 1, &status);
> + if ((ret >= 0) &&
> + (status & EC_MEMMAP_ACC_STATUS_PRESENCE_BIT)) {
> + /*
> + * We have 2 sensors, one in the lid, one in the base.
> + */
> + sensor_count = 2;
> + }
> + }
> + return sensor_count;
> +}
> +EXPORT_SYMBOL_GPL(cros_ec_get_sensor_count);
> +
> static void cros_ec_sensors_register(struct cros_ec_dev *ec)
> {
> /*
> diff --git a/include/linux/mfd/cros_ec.h b/include/linux/mfd/cros_ec.h
> index 61c2875c2a40..578e0bbcafdc 100644
> --- a/include/linux/mfd/cros_ec.h
> +++ b/include/linux/mfd/cros_ec.h
> @@ -32,4 +32,21 @@ struct cros_ec_dev {
>
> #define to_cros_ec_dev(dev) container_of(dev, struct cros_ec_dev, class_dev)
>
> +/**
> + * cros_ec_check_features - Test for the presence of EC features
> + *
> + * Call this function to test whether the ChromeOS EC supports a feature.
> + *
> + * @ec_dev: EC device
> + * @msg: One of ec_feature_code values
> + * @return: 1 if supported, 0 if not
> + */
> +int cros_ec_check_features(struct cros_ec_dev *ec, int feature);
> +
> +/*
> + * Return the number of MEMS sensors supported.
> + * Return < 0 in case of error.
> + */
> +int cros_ec_get_sensor_count(struct cros_ec_dev *ec);
> +

I am wondering if we should take this opportunity to move these two functions
from drivers/mfd/cros_ec_dev to drivers/platform/chrome/cros_ec_proto.c and
include/linux/platform_data/cros_ec_proto.h

I think this part is more suitable for core part that actually resides in
platform/chrome than the mfd device itself. What do you think? Do you see any
problem on doing this?

Thanks,
Enric

> #endif /* __LINUX_MFD_CROS_EC_H */
>