----- Original Message ----- From: Juan García Pastor [mailto:jgp@xxxxxxxxxxxxx] To: 'Maarten Brock' [mailto:m.brock@xxxxxxxxxxxxx] Cc: linux-serial@xxxxxxxxxxxxxxx Sent: Fri, 29 Apr 2016 16:32:09 +0200 Subject: RE: Raspberry compute module does not find ttySC0 and ttySC1 with SC16IS752 > Dear Maarten, > > Thanks for your support. > > Following your comment, I have found some different ways to configure the > "interrupt" parameters in .dts file: > > interrupt-parent = <&gpio3>; I don't think this is correct. gpio3 is no interrupt controller. But gpio is: interrupt-parent = <&gpio>; > interrupts = <7 IRQ_TYPE_EDGE_FALLING>; > # OR > interrupts = <255 2>; /* high-to-low edge triggered */ > # OR > interrupts = <23 0x2>; /* falling edge */ IRQ_TYPE_EDGE_FALLING doesn't seem to work in a device tree overlay. > I understand the interrupt signal from sc16is752 is cabled to GPIO3 in the > Raspberry. If the interrupt line from the SC16IS752 is connected to gpio3 the first number must be 3: interrupts = <3 2>; /* falling edge */ Whether you use hexadecimal notation or not is up to you. > About parameter "interrupts", do you have any information about the possible > values to take and what do they mean? Is there a reference manual where this > information is available? > > The fact that the ttySC0 and ttySC1 devices are not displayed in > Raspberry´s /dev folder let me think that something else in .dts file is > not properly settled. As far as I know, the i2c communication is initiated > by the master device (Raspberry), so no interrupt signal should be necessary > to initiate communication and allow the operating system discover the UARTs > ports behind the sc16is752. Please correct me if I am wrong. Did you build your own kernel? Are you sure you're even using a device tree? Does /proc/device-tree exist? > I include the .dts file. I hope this time outlook does not scramble the text > (set to text without format): > // Definitions for SC16IS752 UART > /dts-v1/; > /plugin/; > / { > compatible = "brcm,bcm2708"; > fragment@0 { > target = <&i2c1>; > __overlay__ { > #address-cells = <1>; > #size-cells = <0>; > status = "okay"; > sc16is752: sc16is752@4d { > /*4d is the address identified with i2cdetect command*/ > compatible = "nxp,sc16is752"; > reg = <0x4D>; > clocks = <&klok>; > interrupt-parent = <&gpio>; > interrupts = <23 0x2>; /* falling edge */ > klok: klok { > compatible = "fixed-clock"; > #clock-cells = <0>; > clock-frequency = <100000>; > }; > }; > }; > }; > }; Depending on the kernel version klok may have to moved to the <&clocks> node in a separate fragment. > Dealing with "/boot/config.txt” file, which of following options is the > right one?: > #Option 1 > dtparam=i2c_arm=on > #Option 2 > dtparam=i2c0=on > dtparam=i2c1=on I'm pretty sure you need Option 1. > > Thanks again for your support. > > Regards, > Juan. > > -----Mensaje original----- > De: Maarten Brock [mailto:m.brock@xxxxxxxxxxxxx] > Enviado el: viernes, 29 de abril de 2016 11:58 > Para: Juan García Pastor; linux-serial@xxxxxxxxxxxxxxx > Asunto: Re: Raspberry compute module does not find ttySC0 and ttySC1 with > SC16IS752 > > Hello Juan, > > Apart from the two I2C connections you will also need an interrupt signal. > And this one also requires a pull up. > > Maarten -- To unsubscribe from this list: send the line "unsubscribe linux-serial" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
