Messages in this thread | | | Subject | Re: [PATCH 7/7] platform/chrome: cros_ec_lightbar: instantiate only if the EC has a lightbar. | From | Enric Balletbo i Serra <> | Date | Fri, 23 Nov 2018 12:10:15 +0100 |
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Hi Guenter,
On 22/11/18 20:25, Guenter Roeck wrote: > 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.balletbo@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 ? >
I did in a separate patch because it changes a bit the current behaviour (i.e after that patch the lightbar directory will not appear if is not detected). Having in a separate patch will allow us to revert cleanly if for some weird reason we still want the old behaviour. So in general, first I moved the attributes and then I did a follow up patch with the probe change. This also happens with vbc driver.
Said that, I don't mind to merge the two patches.
> 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 ? >
Yes, this happens for example on Samus, where there are two ECs, the first one is named "cros_ec" and the second one is "cros_pd", so will fail in the second case. Gwendal, correct me if I am wrong, but AFAIK this is a bit of hack because some initial versions of Samus (coded Link I guess) have no support for the EC_LIGHTBAR_FEATURE so we can't really use the features thing.
>> 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 ? >
Hmm, right, I will double check and remove in next version.
>> + 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); >> >
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