From mboxrd@z Thu Jan 1 00:00:00 1970 From: Pavel Machek Subject: Re: [PATCH] platform/chrome: Add Wilco EC keyboard backlight LEDs support Date: Fri, 8 Mar 2019 22:08:43 +0100 Message-ID: <20190308210843.GA16125@amd> References: <20190308203801.57920-1-ncrews@chromium.org> Mime-Version: 1.0 Content-Type: multipart/signed; micalg=pgp-sha1; protocol="application/pgp-signature"; boundary="ReaqsoxgOBHFXBhH" Return-path: Content-Disposition: inline In-Reply-To: <20190308203801.57920-1-ncrews@chromium.org> Sender: linux-kernel-owner@vger.kernel.org To: Nick Crews Cc: enric.balletbo@collabora.com, bleung@chromium.org, linux-leds@vger.kernel.org, jacek.anaszewski@gmail.com, linux-kernel@vger.kernel.org, dlaurie@chromium.org, derat@google.com, groeck@google.com, dtor@google.com List-Id: linux-leds@vger.kernel.org --ReaqsoxgOBHFXBhH Content-Type: text/plain; charset=us-ascii Content-Disposition: inline Content-Transfer-Encoding: quoted-printable On Fri 2019-03-08 13:38:02, Nick Crews wrote: > This patch is meant to be applied on top of the for-next > branch of the platform/chrome repository, as it uses some of > the code staged there. >=20 > The EC is in charge of controlling the keyboard backlight on > the Wilco platform. We expose a standard LED class device at > /sys/class/leds/wilco::kbd_backlight. This driver is modeled > after the standard Chrome OS keyboard backlight driver at > drivers/platform/chrome/cros_kbd_led_backlight.c Can you make it "platform::kbd_backlight"? We want some consistency there. > Some Wilco devices do not support a keyboard backlight. This > is checked in probe(), and in this case the sysfs entry will > not appear, and everything will behave normally. Good. > When the EC is reset (loses all AC and battery power), it will > restart in some unpredictable state. The brightness on the > keyboard could be anything, and reading the brightness > from the EC is undefined behavior. Therefore, at startup the > brightness should be set, and then everything will work. Really? Undefined behavior?=20 > index e09e4cebe9b4..15b56f5ce090 100644 > --- a/drivers/platform/chrome/wilco_ec/Kconfig > +++ b/drivers/platform/chrome/wilco_ec/Kconfig > @@ -18,3 +18,12 @@ config WILCO_EC_DEBUGFS > manipulation and allow for testing arbitrary commands. This > interface is intended for debug only and will not be present > on production devices. > + > +config WILCO_EC_KBD_BACKLIGHT > + tristate "Enable keyboard led backlight control" Delete "led" or make it "LED". > + depends on WILCO_EC > + help > + If you say Y here, you get support to set the keyboard backlight led Same here. > +#define DRV_NAME "wilco-kbd-backlight" > + > +#define EC_COMMAND_KB_BKLIGHT 0x75 > +#define KBBL_MSG_SIZE 16 > +/* The EC can set the backlight brightness in several different modes. > +The mode we care about is PWM mode, where we separately supply a > +literal percentage to set the brightness to. We need to set the proper > +KBBL_PWM_MODE flag in the KBBL_MODE_INDEX-th byte in the message, and > +then supply the percentage within the KBBL_BRIGHTNESS_INDEX-th byte > +within the message. When we read the brightness, the percentage is > +returned in this same byte location. */ Please use comment style specified in CodingStyle. Best regards, Pavel --=20 (english) http://www.livejournal.com/~pavelmachek (cesky, pictures) http://atrey.karlin.mff.cuni.cz/~pavel/picture/horses/blo= g.html --ReaqsoxgOBHFXBhH Content-Type: application/pgp-signature; name="signature.asc" Content-Description: Digital signature -----BEGIN PGP SIGNATURE----- Version: GnuPG v1 iEYEARECAAYFAlyC2dsACgkQMOfwapXb+vLqDwCfWEk3QW//F3XG6WrdOqGyEUt3 uvAAoIittL7JdDnqPtKLU43LUVzDGBsh =2nf1 -----END PGP SIGNATURE----- --ReaqsoxgOBHFXBhH--