Hello Peter, On Mon, May 23, 2016 at 11:02:53AM -0700, Peter Hurley wrote: > On 05/23/2016 02:09 AM, Uwe Kleine-König wrote: > >> gpios->port = port; > >> > > >> > @@ -193,7 +202,7 @@ struct mctrl_gpios *mctrl_gpio_init(struct uart_port *port, unsigned int idx) > >> > dev_err(port->dev, > >> > "failed to find corresponding irq for %s (idx=%d, err=%d)\n", > >> > mctrl_gpios_desc[i].name, idx, ret); > >> > - return ERR_PTR(ret); > >> > + return NULL; > > > > Ditto, if a GPIO is used as handshake line and it doesn't have a > > corresponding irq, polling must be set up instead of simply ignoring the > > missing irq. > > I agree that none of the "return NULL" changes are necessary. > > However, note that it's not really possible to recover here by polling; > some of the gpios may have been claimed and some not when the irq > claim failure occurs. > How to know which gpios were claimed? I don't understand this. You cannot recover if a GPIO is used by a different driver/device. If a given GPIO doesn't support triggering an irq, polling can help, it must of course be implemented correctly. And if gpio_mctrl implements this (which is the right thing to do, as it is independant from the actual driver) all necessary knowledge is there. Best regards Uwe -- Pengutronix e.K. | Uwe Kleine-König | Industrial Linux Solutions | http://www.pengutronix.de/ | -- To unsubscribe from this list: send the line "unsubscribe linux-omap" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
