platform/chrome: cros_ec_debugfs: Control uptime information request

When EC does not support uptime command (EC_CMD_GET_UPTIME_INFO),
do not create the uptime sysfs entry point.
User space application will not probe the file needlessly.

The EC console log will not contain EC_CMD_GET_UPTIME_INFO anymore.

Signed-off-by: Gwendal Grignou <gwendal@chromium.org>
Signed-off-by: Enric Balletbo i Serra <enric.balletbo@collabora.com>

diff --git a/drivers/platform/chrome/cros_ec_debugfs.c b/drivers/platform/chrome/cros_ec_debugfs.c
index ecfada0..272c898 100644 (file)
--- a/drivers/platform/chrome/cros_ec_debugfs.c
+++ b/drivers/platform/chrome/cros_ec_debugfs.c
@@ -242,6 +242,25 @@ static ssize_t cros_ec_pdinfo_read(struct file *file,
                                       read_buf, p - read_buf);
 }
 
+static bool cros_ec_uptime_is_supported(struct cros_ec_device *ec_dev)
+{
+       struct {
+               struct cros_ec_command cmd;
+               struct ec_response_uptime_info resp;
+       } __packed msg = {};
+       int ret;
+
+       msg.cmd.command = EC_CMD_GET_UPTIME_INFO;
+       msg.cmd.insize = sizeof(msg.resp);
+
+       ret = cros_ec_cmd_xfer_status(ec_dev, &msg.cmd);
+       if (ret == -EPROTO && msg.cmd.result == EC_RES_INVALID_COMMAND)
+               return false;
+
+       /* Other errors maybe a transient error, do not rule about support. */
+       return true;
+}
+
 static ssize_t cros_ec_uptime_read(struct file *file, char __user *user_buf,
                                   size_t count, loff_t *ppos)
 {
@@ -444,8 +463,9 @@ static int cros_ec_debugfs_probe(struct platform_device *pd)
        debugfs_create_file("pdinfo", 0444, debug_info->dir, debug_info,
                            &cros_ec_pdinfo_fops);
 
-       debugfs_create_file("uptime", 0444, debug_info->dir, debug_info,
-                           &cros_ec_uptime_fops);
+       if (cros_ec_uptime_is_supported(ec->ec_dev))
+               debugfs_create_file("uptime", 0444, debug_info->dir, debug_info,
+                                   &cros_ec_uptime_fops);
 
        debugfs_create_x32("last_resume_result", 0444, debug_info->dir,
                           &ec->ec_dev->last_resume_result);