On Thu, Nov 22, 2018 at 12:33:56PM +0100, Enric Balletbo i Serra wrote: > Due to the way attribute groups visibility work, the function > cros_ec_lightbar_attrs_are_visible is called multiple times, once per > attribute, and each of these calls makes an EC transaction. For what is > worth the EC log reports multiple errors on boot when the lightbar is > not available. Instead, check if the EC has a lightbar in the probe > function and only instantiate the device. > > Ideally we should have instantiate the driver only if the > EC_FEATURE_LIGHTBAR is defined, but that's not possible because that flag > is not in the very first Pixel Chromebook (Link), only on Samus. So, the > driver is instantiated by his parent always. > > This patch changes a bit the actual behaviour. Before the patch if an EC > doesn't have a lightbar an empty lightbar folder is created in > /sys/class/chromeos/<ec device>, after the patch the empty folder is not > created, so, the folder is only created if the lightbar exists. > > Signed-off-by: Enric Balletbo i Serra <enric.balle...@collabora.com>
Guess this is the answer to the suggestion I had before. Maybe the two patches should be merged together ? Or do others think that they should be kept separate ? Additional comment below. Thanks, Guenter > --- > > drivers/platform/chrome/cros_ec_lightbar.c | 29 +++++++++------------- > 1 file changed, 12 insertions(+), 17 deletions(-) > > diff --git a/drivers/platform/chrome/cros_ec_lightbar.c > b/drivers/platform/chrome/cros_ec_lightbar.c > index 31d22f594fac..d255264eb082 100644 > --- a/drivers/platform/chrome/cros_ec_lightbar.c > +++ b/drivers/platform/chrome/cros_ec_lightbar.c > @@ -567,37 +567,28 @@ static struct attribute *__lb_cmds_attrs[] = { > NULL, > }; > > -static bool ec_has_lightbar(struct cros_ec_dev *ec) > +static bool cros_ec_has_lightbar(struct cros_ec_dev *ec_dev) > { > - return !!get_lightbar_version(ec, NULL, NULL); > -} > - > -static umode_t cros_ec_lightbar_attrs_are_visible(struct kobject *kobj, > - struct attribute *a, int n) > -{ > - struct device *dev = container_of(kobj, struct device, kobj); > - struct cros_ec_dev *ec = to_cros_ec_dev(dev); > - struct platform_device *pdev = to_platform_device(ec->dev); > + struct platform_device *pdev = to_platform_device(ec_dev->dev); > struct cros_ec_platform *pdata = pdev->dev.platform_data; > int is_cros_ec; > > is_cros_ec = strcmp(pdata->ec_name, CROS_EC_DEV_NAME); > Can this now ever be false ? > if (is_cros_ec != 0) > - return 0; > + return false; > > - /* Only instantiate this stuff if the EC has a lightbar */ > - if (ec_has_lightbar(ec)) { > - ec_with_lightbar = ec; > - return a->mode; > + if (!!get_lightbar_version(ec_dev, NULL, NULL)) { > + ec_with_lightbar = ec_dev; Is this variable (and the associated check in lb_manual_suspend_ctrl) still necessary ? > + return true; > } > - return 0; > + > + return false; > } > > struct attribute_group cros_ec_lightbar_attr_group = { > .name = "lightbar", > .attrs = __lb_cmds_attrs, > - .is_visible = cros_ec_lightbar_attrs_are_visible, > }; > > static int cros_ec_lightbar_probe(struct platform_device *pd) > @@ -611,6 +602,10 @@ static int cros_ec_lightbar_probe(struct platform_device > *pd) > return -EINVAL; > } > > + /* Only instantiate this stuff if the EC has a lightbar */ > + if (!cros_ec_has_lightbar(ec_dev)) > + return -ENODEV; > + > /* Take control of the lightbar from the EC. */ > lb_manual_suspend_ctrl(ec_dev, 1); >