Dear Marteen,
Thanks for your support.
I go over your last proposal:
> > interrupts = <255 2>; /* high-to-low edge triggered */
> You probably used 22 instead of 255 here according to below info.
I use then:
interrupts = <22 2>; /* high-to-low edge triggered */
In config.txt file, I have tried with both:
dtoverlay=sc16is752-i2c,clkrate=100000,irqpin=22
# and
dtoverlay=sc16is752-i2c,clkrate=1843200,irqpin=22
But I am not sure if this clock must match the one from the .dts file. I thought 1.8432Mhz is the clock input to the sc16is752, and the clkrate is the communication speed between the compute module and the sc16is752, but you may know better which is which. I have tested with all combinations with no good result.
We have also removed "fragment@2" section and "__overrides__ " section from .dts according to:
-----------------------------
> fragment@2 {
> target = <&gpio>;
> __overlay__ {
> sc16is752_pins: sc16is752_pins {
> brcm,pins = <255>;
> brcm,function = <0>; /* in */
> };
> };
> };
Why is this fragment here? The raspberry pi doesn't have 255 gpio pins.
> __overrides__ {
> clkrate = <&sc16is752_clock>,"clock-frequency:0";
> irqpin = <&sc16is752>,"interrupts:0",
> <&sc16is752_pins>,"brcm,pins:0";
> };
> };
And what is this supposed to do? I use the SC16IS740 in SPI mode and I don't have something like this.
-----------------------------
I got these two sections from a previous example found in raspberry.org forum. I do not really understand the point on them, but when I delete them I get some error messages (see below). I just try to understand the meaning of every variable, but I am having a very hard time finding complete information, so I basically try to execute already tested configurations. I do not find any other better way.
My .dts file is:
-----------------------------
// Overlay for the SC16IS752 I2C-connected UART
/dts-v1/;
/plugin/;
/ {
compatible = "brcm,bcm2708";
fragment@0 {
target = <&i2c_arm>;
__overlay__ {
#address-cells = <1>;
#size-cells = <0>;
status = "okay";
sc16is752: sc16is752@4D {
compatible = "nxp,sc16is752";
reg = <0x4D>;
clocks = <&sc16is752_clock>;
interrupt-parent = <&gpio>;
interrupts = <22 2>; /* high-to-low edge triggered */
gpio-controller;
#gpio-cells = <2>;
};
};
};
fragment@1 {
target = <&clocks>;
__overlay__ {
#address-cells = <1>;
#size-cells = <0>;
status = "okay";
sc16is752_clock: sc16is752_clock@10 {
compatible = "fixed-clock";
reg = <10>;
#clock-cells = <0>;
clock-output-name = "sc16is752";
clock-frequency = <1843200>;
};
};
};
};
-----------------------------
By doing so, I get some error messages related with "__overrides__ node not foung"
-----------------------------
012806.864: Loaded overlay 'sc16is752-i2c'
012806.883: dtparam: clkrate=100000
012807.045: dtdebug: /__overrides__ node not found
012808.276: dtdebug: /__overrides__ has no clkrate property
012808.289: Unknown dtparam 'clkrate' - ignored
012808.304: dtparam: irqpin=22
012808.465: dtdebug: /__overrides__ node not found
012809.721: dtdebug: /__overrides__ has no irqpin property
012809.733: Unknown dtparam 'irqpin' - ignored
012809.799: dtdebug: Found fragment 0 (offset 36)
012813.194: dtdebug: merge_fragment(/soc/i2c@7e804000,/fragment@0/__overlay__)
012813.219: dtdebug: +prop(#address-cells)
012813.597: dtdebug: +prop(#size-cells)
012813.977: dtdebug: +prop(status)
012815.764: dtdebug: merge_fragment(/soc/i2c@7e804000/sc16is752@4D,/fragment@0/__overlay__/sc16is752@4D)
012815.787: dtdebug: +prop(compatible)
012816.142: dtdebug: +prop(reg)
012816.531: dtdebug: +prop(clocks)
012816.926: dtdebug: +prop(interrupt-parent)
012817.302: dtdebug: +prop(interrupts)
012817.724: dtdebug: +prop(gpio-controller)
012818.167: dtdebug: +prop(#gpio-cells)
012818.617: dtdebug: +prop(linux,phandle)
012819.070: dtdebug: +prop(phandle)
012819.531: dtdebug: merge_fragment() end
012819.565: dtdebug: merge_fragment() end
012819.639: dtdebug: Found fragment 1 (offset 324)
012824.176: dtdebug: merge_fragment(/clocks,/fragment@1/__overlay__)
012824.201: dtdebug: +prop(#address-cells)
012824.470: dtdebug: +prop(#size-cells)
012824.743: dtdebug: +prop(status)
012827.053: dtdebug: merge_fragment(/clocks/sc16is752_clock@10,/fragment@1/__overlay__/sc16is752_clock@10)
012827.078: dtdebug: +prop(compatible)
012827.355: dtdebug: +prop(reg)
012827.666: dtdebug: +prop(#clock-cells)
012828.070: dtdebug: +prop(clock-output-name)
012828.548: dtdebug: +prop(clock-frequency)
012828.955: dtdebug: +prop(linux,phandle)
012829.322: dtdebug: +prop(phandle)
012829.693: dtdebug: merge_fragment() end
012829.726: dtdebug: merge_fragment() end
012829.884: dtparam: cache_line_size=32
012831.087: dtdebug: Found override cache_line_size
012831.126: dtdebug: override cache_line_size: cell target cache-line-size @ offset 0 (size 4)
012834.163: dtdebug: delete_node(/hat)
-----------------------------
> Is the sc16is7xx driver compiled into the kernel? Or as a module? And if so, is it in:
> /lib/modules/4.1.13/kernel/drivers/tty/serial/sc16is7xx.ko
Sc16is7xx driver is compiled as a module and loaded to file:
/lib/modules/4.1.13/kernel/drivers/tty/serial/sc16is7xx.ko
We are still missing ttySC0 and ttySC1.
Any other suggestion?.
Thanks so much for your time.
Juan.
-----Mensaje original-----
De: Maarten Brock [mailto:m.brock@xxxxxxxxxxxxx]
Enviado el: lunes, 02 de mayo de 2016 10:17
Para: Juan García Pastor
CC: linux-serial@xxxxxxxxxxxxxxx
Asunto: RE: Raspberry compute module does not find ttySC0 and ttySC1 with SC16IS752
Hello Juan,
----- Original Message -----
From: Juan García Pastor [mailto:jgp@xxxxxxxxxxxxx]
To: 'Maarten Brock' [mailto:m.brock@xxxxxxxxxxxxx]
Cc: linux-serial@xxxxxxxxxxxxxxx
Sent: Mon, 02 May 2016 00:23:14 +0200
Subject: RE: Raspberry compute module does not find ttySC0 and ttySC1 with SC16IS752
> Dear Maarten,
>
> According to you last answer I have changed in config.txt:
> dtparam=i2c_arm=on
>
> In addition to:
> # Debug active
> dtdebug=1
> # Additional overlays and parameters are documented
> /boot/overlays/README
> dtoverlay=sc16is752-i2c,clkrate=100000,irqpin=22
>
> I have changed interrupt configuration to <&gpio>. The
> sc16is752-i2c-overlay.dts file is (If you cannot read it properly due
> to email agent - it is supposed to be plain text-, I can send it some
> other
> way):
> ----------------------------------------------------------------------
> ------------ // Overlay for the SC16IS752 I2C-connected UART /dts-v1/;
> /plugin/;
>
> / {
> compatible = "brcm,bcm2708";
> fragment@0 {
> target = <&i2c_arm>;
> __overlay__ {
> #address-cells = <1>;
> #size-cells = <0>;
> status = "okay";
>
> sc16is752: sc16is752@4D {
> compatible = "nxp,sc16is752";
> reg = <0x4D>;
> clocks = <&sc16is752_clock>;
> interrupt-parent = <&gpio>;
> interrupts = <255 2>; /* high-to-low edge triggered */
You probably used 22 instead of 255 here according to below info.
> gpio-controller;
> #gpio-cells = <2>;
> };
> };
> };
>
> fragment@1 {
> target = <&clocks>;
> __overlay__ {
> #address-cells = <1>;
> #size-cells = <0>;
> status = "okay";
>
> sc16is752_clock: sc16is752_clock@10 {
> compatible = "fixed-clock";
> reg = <10>;
> #clock-cells = <0>;
> clock-output-name = "sc16is752";
> clock-frequency = <100000>;
I very much doubt that your fixed clock run at 100 kHz. That is not a very baudrate friendly frequency. I would expect something like 1.8432 MHz.
> };
> };
> };
>
> fragment@2 {
> target = <&gpio>;
> __overlay__ {
> sc16is752_pins: sc16is752_pins {
> brcm,pins = <255>;
> brcm,function = <0>; /* in */
> };
> };
> };
Why is this fragment here? The raspberry pi doesn't have 255 gpio pins.
> __overrides__ {
> clkrate = <&sc16is752_clock>,"clock-frequency:0";
> irqpin = <&sc16is752>,"interrupts:0",
> <&sc16is752_pins>,"brcm,pins:0";
> };
> };
And what is this supposed to do? I use the SC16IS740 in SPI mode and I don't have something like this.
> ----------------------------------------------------------------------
> ------------
>
>
> I use Device Tree. When executing:
>
> "dtc -I fs /proc/device-tree"
>
> I get following output (I only include lines related with sc16is752):
> ----------------------------------------------------------------------
> --------------
> soc {
> compatible = "simple-bus";
> ranges = <0x7e000000 0x20000000 0x1000000>;
> #address-cells = <0x1>;
> phandle = <0x1d>;
> #size-cells = <0x1>;
> linux,phandle = <0x1d>;
> ...
> i2c@7e804000 {
> reg = <0x7e804000 0x1000>;
> interrupts = <0x2 0x15>;
> pinctrl-0 = <0xd>;
> compatible = "brcm,bcm2708-i2c";
> clock-frequency = <0x186a0>;
> clocks = <0x4>;
> status = "okay";
> #address-cells = <0x1>;
> phandle = <0x1a>;
> #size-cells = <0x0>;
> pinctrl-names = "default";
> linux,phandle = <0x1a>;
>
> sc16is752@4D {
> reg = <0x4d>;
> interrupts = <0x16 0x2>;
> #gpio-cells = <0x2>;
> compatible = "nxp,sc16is752";
> clocks = <0x28>;
> phandle = <0x29>;
> gpio-controller;
> linux,phandle = <0x29>;
> interrupt-parent = <0xf>;
> };
> };
> ....
> gpio@7e200000 {
> reg = <0x7e200000 0xb4>;
> interrupts = <0x2 0x11 0x2 0x12>;
> #gpio-cells = <0x2>;
> compatible = "brcm,bcm2835-gpio";
> #interrupt-cells = <0x2>;
> phandle = <0xf>;
> interrupt-controller;
> gpio-controller;
> linux,phandle = <0xf>;
> ....
> sc16is752_pins {
> phandle = <0x2a>;
> brcm,function = <0x0>;
> brcm,pins = <0x16>;
> linux,phandle = <0x2a>;
> };
> };
> };
>
> clocks {
> compatible = "simple-bus";
> status = "okay";
> #address-cells = <0x1>;
> phandle = <0x27>;
> #size-cells = <0x0>;
> linux,phandle = <0x27>;
> ....
> sc16is752_clock@10 {
> reg = <0xa>;
> #clock-cells = <0x0>;
> clock-output-name = "sc16is752";
> compatible = "fixed-clock";
> clock-frequency = <0x186a0>;
> phandle = <0x28>;
> linux,phandle = <0x28>;
> };
> };
Looks ok apart from the fixed clock frequency.
> -------------------------------------------------------------------
>
> I also include the log generated by command:
> "sudo vcdbg log msg" ( without dtdebug=1 ):
> ----------------------------------------------------------------------
> ------------
> 012803.616: Loaded overlay 'sc16is752-i2c'
> 012803.633: dtparam: clkrate=100000
> 012804.198: dtparam: irqpin=22
> 012805.091: dtparam: i2c_arm=on
> ----------------------------------------------------------------------
> ------------
>
> And by command:
> "sudo vcdbg log msg" ( with dtdebug=1 ):
> ----------------------------------------------------------------------
> ------------
> 012808.179: Loaded overlay 'sc16is752-i2c'
> 012808.198: dtparam: clkrate=100000
> 012808.371: dtdebug: Found override clkrate
> 012808.408: dtdebug: override clkrate: cell target clock-frequency @
> offset 0 (size 4)
> 012808.827: dtparam: irqpin=22
> 012809.004: dtdebug: Found override irqpin
> 012809.040: dtdebug: override irqpin: cell target interrupts @ offset 0
> (size 4)
> 012809.289: dtdebug: override irqpin: cell target brcm,pins @ offset 0
> (size 4)
> 012809.851: dtdebug: Found fragment 0 (offset 36)
> 012813.252: dtdebug:
> merge_fragment(/soc/i2c@7e804000,/fragment@0/__overlay__)
> 012813.278: dtdebug: +prop(#address-cells)
> 012813.656: dtdebug: +prop(#size-cells)
> 012814.036: dtdebug: +prop(status)
> 012815.823: dtdebug:
> merge_fragment(/soc/i2c@7e804000/sc16is752@4D,/fragment@0/__overlay__/sc16is752@4D)
> 012815.848: dtdebug: +prop(compatible)
> 012816.204: dtdebug: +prop(reg)
> 012816.594: dtdebug: +prop(clocks)
> 012816.989: dtdebug: +prop(interrupt-parent)
> 012817.366: dtdebug: +prop(interrupts)
> 012817.787: dtdebug: +prop(gpio-controller)
> 012818.230: dtdebug: +prop(#gpio-cells)
> 012818.681: dtdebug: +prop(linux,phandle)
> 012819.134: dtdebug: +prop(phandle)
> 012819.597: dtdebug: merge_fragment() end
> 012819.631: dtdebug: merge_fragment() end
> 012819.705: dtdebug: Found fragment 1 (offset 324)
> 012824.304: dtdebug: merge_fragment(/clocks,/fragment@1/__overlay__)
> 012824.329: dtdebug: +prop(#address-cells)
> 012824.598: dtdebug: +prop(#size-cells)
> 012824.872: dtdebug: +prop(status)
> 012827.205: dtdebug:
> merge_fragment(/clocks/sc16is752_clock@10,/fragment@1/__overlay__/sc16is752_clock@10)
> 012827.230: dtdebug: +prop(compatible)
> 012827.508: dtdebug: +prop(reg)
> 012827.820: dtdebug: +prop(#clock-cells)
> 012828.225: dtdebug: +prop(clock-output-name)
> 012828.703: dtdebug: +prop(clock-frequency)
> 012829.110: dtdebug: +prop(linux,phandle)
> 012829.478: dtdebug: +prop(phandle)
> 012829.847: dtdebug: merge_fragment() end
> 012829.881: dtdebug: merge_fragment() end
> 012829.957: dtdebug: Found fragment 2 (offset 588)
> 012831.658: dtdebug:
> merge_fragment(/soc/gpio@7e200000,/fragment@2/__overlay__)
> 012833.036: dtdebug:
> merge_fragment(/soc/gpio@7e200000/sc16is752_pins,/fragment@2/__overlay__/sc16is752_pins)
> 012833.060: dtdebug: +prop(brcm,pins)
> 012833.651: dtdebug: +prop(brcm,function)
> 012834.249: dtdebug: +prop(linux,phandle)
> 012834.832: dtdebug: +prop(phandle)
> 012835.429: dtdebug: merge_fragment() end
> 012835.458: dtdebug: merge_fragment() end
> 012835.626: dtparam: cache_line_size=32
> 012836.835: dtdebug: Found override cache_line_size
> 012836.874: dtdebug: override cache_line_size: cell target cache-line-size
> @ offset 0 (size 4)
> 012839.921: dtdebug: delete_node(/hat)
> ----------------------------------------------------------------------
> ------------
>
>
> We are still missing the ttySC0 and ttySC1 in /dev folder. Somehow the
> sc16is752 is not correctly recognized.
>
> I am using kernel version 4.1.13. Should I use 4.4?
I don't think you have to for I2C, but I have no experience with that version.
Is the sc16is7xx driver compiled into the kernel? Or as a module? And if so, is it in:
/lib/modules/4.1.13/kernel/drivers/tty/serial/sc16is7xx.ko
> Any other suggestion?.
>
> Thanks for your support.
> Juan.
You're welcome,
Maarten
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