From mboxrd@z Thu Jan 1 00:00:00 1970 From: Siarhei Siamashka Date: Mon, 9 Feb 2015 05:54:04 +0200 Subject: [U-Boot] [PATCH 17/17] sunxi: Hookup OTG USB controller support In-Reply-To: <20150131045447.26e1eebc@i7> References: <1421004895-10896-1-git-send-email-hdegoede@redhat.com> <1421004895-10896-18-git-send-email-hdegoede@redhat.com> <20150131045447.26e1eebc@i7> Message-ID: <20150209055404.1d09f14a@i7> List-Id: MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit To: u-boot@lists.denx.de On Sat, 31 Jan 2015 04:54:47 +0200 Siarhei Siamashka wrote: > On Sun, 11 Jan 2015 20:34:55 +0100 > Hans de Goede wrote: > > > Hookup OTG USB controller support and enable the otg controller + USB-keyb > > on various tablets. > > > > This allows tablet owners to interact with u-boot without needing to solder > > a serial console onto their tablet PCB. > > Thanks. Works great on my Primo73 and Primo81 tablets. However I have > just one naive question before happily taking it into use by default. > > Is the hardcoded otg host mode (without checking the id pin) always > safe? For example, what happens if somebody connects a charger instead > of a usb keyboard to the tablet? So, does anyone have any idea if it is theoretically safe to have two USB hosts connected to each other and both driving VBUS at +5V? A somewhat realistic scenario is booting an Allwinner tablet over USB using the FEL mode. Is it a good idea for such tablet to have CONFIG_USB_MUSB_SUNXI=y and CONFIG_USB0_VBUS_PIN="axp_drivebus" in defconfig? -- Best regards, Siarhei Siamashka