linux-kernel - Re: [PATCH 3/3] platform/chrome: mfd/cros_ec_dev: Add sysfs entry to set keyboard wake lid angle

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Date:   Wed, 21 Feb 2018 17:16:51 +0200
From:   Andy Shevchenko <andy.shevchenko@...il.com>
To:     Enric Balletbo i Serra <enric.balletbo@...labora.com>
Cc:     Lee Jones <lee.jones@...aro.org>,
        Benson Leung <bleung@...omium.org>,
        Linux Kernel Mailing List <linux-kernel@...r.kernel.org>,
        kernel@...labora.com, groeck@...omium.org, gwendal@...omium.org
Subject: Re: [PATCH 3/3] platform/chrome: mfd/cros_ec_dev: Add sysfs entry to
 set keyboard wake lid angle

On Wed, Feb 21, 2018 at 4:50 PM, Enric Balletbo i Serra
<enric.balletbo@...labora.com> wrote:
> From: Gwendal Grignou <gwendal@...omium.org>
>
> This adds a sysfs attribute (/sys/class/chromeos/cros_ec/kb_wake_angle)
> used to set and get the keyboard wake lid angle. This attribute is
> present only if 2 accelerometers are controlled by the EC.
>
> This patch also moves the cros_ec features check before the device is
> added so the features map obtained from the EC is ready on time.

> +/* Keyboard wake angle control */
> +static ssize_t show_kb_wake_angle(struct device *dev,
> +                                 struct device_attribute *attr, char *buf)
> +{
> +       struct ec_response_motion_sense *resp;
> +       struct ec_params_motion_sense *param;
> +       struct cros_ec_command *msg;
> +       int ret;

> +       struct cros_ec_dev *ec = container_of(
> +                       dev, struct cros_ec_dev, class_dev);

First of all, do not split lines like this.
Second, consider just to add a preparatory patch which introduces

#define to_cros_ec_dev(dev)  container_of(dev, struct cros_ec_dev, class_dev)

and use it here.

> +
> +       msg = kmalloc(sizeof(*msg) + EC_HOST_PARAM_SIZE, GFP_KERNEL);
> +       if (!msg)
> +               return -ENOMEM;
> +
> +       param = (struct ec_params_motion_sense *)msg->data;
> +       msg->command = EC_CMD_MOTION_SENSE_CMD + ec->cmd_offset;
> +       msg->version = 2;
> +       param->cmd = MOTIONSENSE_CMD_KB_WAKE_ANGLE;
> +       param->kb_wake_angle.data = EC_MOTION_SENSE_NO_VALUE;
> +       msg->outsize = sizeof(*param);
> +       msg->insize = sizeof(*resp);
> +       ret = cros_ec_cmd_xfer_status(ec->ec_dev, msg);
> +       if (ret < 0)
> +               goto exit;
> +       resp = (struct ec_response_motion_sense *)msg->data;

> +       ret = scnprintf(buf, PAGE_SIZE, "%d\n",
> +                       resp->kb_wake_angle.ret);

Looks like one line.

> +exit:
> +       kfree(msg);
> +       return ret;
> +}
> +
> +static ssize_t store_kb_wake_angle(struct device *dev,
> +                                  struct device_attribute *attr,
> +                                  const char *buf, size_t count)
> +{
> +       struct ec_params_motion_sense *param;
> +       struct cros_ec_command *msg;
> +       int ret;
> +       struct cros_ec_dev *ec = container_of(
> +                       dev, struct cros_ec_dev, class_dev);
> +       u16 angle;
> +
> +       ret = kstrtou16(buf, 0, &angle);
> +       if (ret)
> +               return ret;
> +
> +       msg = kmalloc(sizeof(*msg) + EC_HOST_PARAM_SIZE, GFP_KERNEL);
> +       if (!msg)
> +               return -ENOMEM;
> +
> +       param = (struct ec_params_motion_sense *)msg->data;
> +       msg->command = EC_CMD_MOTION_SENSE_CMD + ec->cmd_offset;
> +       msg->version = 2;
> +       param->cmd = MOTIONSENSE_CMD_KB_WAKE_ANGLE;
> +       param->kb_wake_angle.data = angle;
> +       msg->outsize = sizeof(*param);
> +       msg->insize = sizeof(struct ec_response_motion_sense);
> +       ret = cros_ec_cmd_xfer_status(ec->ec_dev, msg);
> +       kfree(msg);
> +       if (ret < 0)
> +               return ret;
> +       return count;
> +}
> +
>  /* Module initialization */
>
>  static DEVICE_ATTR(reboot, S_IWUSR | S_IRUGO, show_ec_reboot, store_ec_reboot);
>  static DEVICE_ATTR(version, S_IRUGO, show_ec_version, NULL);
>  static DEVICE_ATTR(flashinfo, S_IRUGO, show_ec_flashinfo, NULL);
> +static DEVICE_ATTR(kb_wake_angle, S_IWUSR | S_IRUGO, show_kb_wake_angle,
> +                  store_kb_wake_angle);

Consider to switch to

DEVICE_ATTR_RO()
DEVICE_ATTR_RW()

-- 
With Best Regards,
Andy Shevchenko