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From:   Gwendal Grignou <gwendal@google.com>
Date:   Wed, 21 Feb 2018 15:49:15 -0800
Message-ID: <CAMHSBOVX_B47hmAwQA0oSr=-CXyf4Am5fBZt7M3TQZr78-n-Ug@mail.gmail.com>
Subject: Re: [PATCH 4/6] mfd: cros_ec_dev: Register cros_ec_accel_legacy
 driver as a subdevice.
To:     Enric Balletbo i Serra <enric.balletbo@collabora.com>
Cc:     Lee Jones <lee.jones@linaro.org>,
        Guenter Roeck <groeck@chromium.org>,
        Gwendal Grignou <gwendal@chromium.org>,
        Benson Leung <bleung@chromium.org>,
        Linux Kernel <linux-kernel@vger.kernel.org>,
        kernel@collabora.com
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Sender: linux-kernel-owner@vger.kernel.org
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On Mon, Feb 19, 2018 at 2:46 PM, Enric Balletbo i Serra
<enric.balletbo@collabora.com> wrote:
> With this patch, the cros_ec_ctl driver will register the legacy
> accelerometer driver (named cros_ec_accel_legacy) if it fails to
> register sensors through the usual path cros_ec_sensors_register().
> This legacy device is present on Chromebook devices with older EC
> firmware only supporting deprecated EC commands (Glimmer based devices).
>
> Tested-by: Gwendal Grignou <gwendal@chromium.org>
> Signed-off-by: Enric Balletbo i Serra <enric.balletbo@collabora.com>
Reviewed-by: Gwendal Grignou <gwendal@chromium.org>
> ---
>  drivers/mfd/cros_ec_dev.c | 60 +++++++++++++++++++++++++++++++++++++++++++++++
>  1 file changed, 60 insertions(+)
>
> diff --git a/drivers/mfd/cros_ec_dev.c b/drivers/mfd/cros_ec_dev.c
> index e0c604ab380f..fc98e0564061 100644
> --- a/drivers/mfd/cros_ec_dev.c
> +++ b/drivers/mfd/cros_ec_dev.c
> @@ -389,6 +389,63 @@ static void cros_ec_sensors_register(struct cros_ec_dev *ec)
>         kfree(msg);
>  }
>
> +#define CROS_EC_SENSOR_LEGACY_NUM 2
> +static struct mfd_cell cros_ec_accel_legacy_cells[CROS_EC_SENSOR_LEGACY_NUM];
> +
> +static void cros_ec_accel_legacy_register(struct cros_ec_dev *ec)
> +{
> +       struct cros_ec_device *ec_dev = ec->ec_dev;
> +       u8 status;
> +       int i, ret;
> +       struct cros_ec_sensor_platform
> +               sensor_platforms[CROS_EC_SENSOR_LEGACY_NUM];
> +
> +       /*
> +        * EC that need legacy support are the main EC, directly connected to
> +        * the AP.
> +        */
> +       if (ec->cmd_offset != 0)
> +               return;
> +
> +       /*
> +        * Check if EC supports direct memory reads and if EC has
> +        * accelerometers.
> +        */
> +       if (!ec_dev->cmd_readmem)
> +               return;
> +
> +       ret = ec_dev->cmd_readmem(ec_dev, EC_MEMMAP_ACC_STATUS, 1, &status);
> +       if (ret < 0) {
> +               dev_warn(ec->dev, "EC does not support direct reads.\n");
> +               return;
> +       }
> +
> +       /* Check if EC has accelerometers. */
> +       if (!(status & EC_MEMMAP_ACC_STATUS_PRESENCE_BIT)) {
> +               dev_info(ec->dev, "EC does not have accelerometers.\n");
> +               return;
> +       }
> +
> +       /*
> +        * Register 2 accelerometers
> +        */
> +       for (i = 0; i < CROS_EC_SENSOR_LEGACY_NUM; i++) {
> +               cros_ec_accel_legacy_cells[i].name = "cros-ec-accel-legacy";
> +               sensor_platforms[i].sensor_num = i;
> +               cros_ec_accel_legacy_cells[i].id = i;
> +               cros_ec_accel_legacy_cells[i].platform_data =
> +                       &sensor_platforms[i];
> +               cros_ec_accel_legacy_cells[i].pdata_size =
> +                       sizeof(struct cros_ec_sensor_platform);
> +       }
> +       ret = mfd_add_devices(ec->dev, PLATFORM_DEVID_AUTO,
> +                             cros_ec_accel_legacy_cells,
> +                             CROS_EC_SENSOR_LEGACY_NUM,
> +                             NULL, 0, NULL);
> +       if (ret)
> +               dev_err(ec_dev->dev, "failed to add EC sensors\n");
> +}
> +
>  static const struct mfd_cell cros_ec_rtc_cell = {
>         .name = "cros-ec-rtc",
>  };
> @@ -440,6 +497,9 @@ static int ec_device_probe(struct platform_device *pdev)
>         /* check whether this EC is a sensor hub. */
>         if (cros_ec_check_features(ec, EC_FEATURE_MOTION_SENSE))
>                 cros_ec_sensors_register(ec);
> +       else
> +               /* Workaroud for older EC firmware */
> +               cros_ec_accel_legacy_register(ec);
>
>         /* check whether this EC instance has RTC host command support */
>         if (cros_ec_check_features(ec, EC_FEATURE_RTC)) {
> --
> 2.16.1
>