2012-11-28 15:09:19

by sander van ginkel

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Subject: [PATCH] add hardware I2C support for ARM IMX23

The I2C hardware in the IMX233 is currently not supported,
however the i2c-mxs driver seems to be suitable.
To use the i2c-mxs driver it has to be added to the devicetree
for the IMX23.


Signed-off-by: Sander van Ginkel <[email protected]>
---
diff -Naur linux-3.7-rc6/arch/arm/boot/dts/imx23-olinuxino.dts
linux-3.7-rc6-i2c/arch/arm/boot/dts/imx23-olinuxino.dts
--- linux-3.7-rc6/arch/arm/boot/dts/imx23-olinuxino.dts 2012-11-17
01:42:40.000000000 +0000
+++ linux-3.7-rc6-i2c/arch/arm/boot/dts/imx23-olinuxino.dts 2012-11-24
22:40:51.000000000 +0000
@@ -50,6 +50,13 @@
};

apbx@80040000 {
+
+ i2c0: i2c@80058000 {
+ pinctrl-names = "default";
+ pinctrl-0 = <&i2c0_pins_a>;
+ status = "okay";
+ };
+
duart: serial@80070000 {
pinctrl-names = "default";
pinctrl-0 = <&duart_pins_a>;
diff -Naur linux-3.7-rc6/arch/arm/boot/dts/imx23.dtsi
linux-3.7-rc6-i2c/arch/arm/boot/dts/imx23.dtsi
--- linux-3.7-rc6/arch/arm/boot/dts/imx23.dtsi 2012-11-17
01:42:40.000000000 +0000
+++ linux-3.7-rc6-i2c/arch/arm/boot/dts/imx23.dtsi 2012-11-24
22:40:51.000000000 +0000
@@ -144,6 +144,17 @@
fsl,pull-up = <0>;
};

+ i2c0_pins_a: i2c0@0 {
+ reg = <0>;
+ fsl,pinmux-ids = <
+ 0x1171 /* MX23_PAD_LCD_ENABLE__I2C_SCL */
+ 0x1181 /* MX23_PAD_LCD_HSYNC__I2C_SDA */
+ >;
+ fsl,drive-strength = <1>;
+ fsl,voltage = <1>;
+ fsl,pull-up = <1>;
+ };
+
auart0_2pins_a: auart0-2pins@0 {
reg = <0>;
fsl,pinmux-ids = <
@@ -387,9 +398,15 @@
status = "disabled";
};

- i2c@80058000 {
+ i2c0: i2c@80058000 {
+ #address-cells = <2>;
+ #size-cells = <1>;
+ compatible = "fsl,imx28-i2c";
reg = <0x80058000 0x2000>;
+ interrupts = <26 27>;
+ clock-frequency = <100000>;
status = "disabled";
+ fsl,i2c-dma-channel = <3>;
};

rtc@8005c000 {


2012-11-28 15:08:57

by Wolfram Sang

[permalink] [raw]
Subject: Re: [PATCH] add hardware I2C support for ARM IMX23

On Wed, Nov 28, 2012 at 03:24:03PM +0100, sander van ginkel wrote:
> The I2C hardware in the IMX233 is currently not supported,
> however the i2c-mxs driver seems to be suitable.
> To use the i2c-mxs driver it has to be added to the devicetree
> for the IMX23.

Have you tested it? There have been problems reported when using
i2cdetect...

--
Pengutronix e.K. | Wolfram Sang |
Industrial Linux Solutions | http://www.pengutronix.de/ |


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2012-11-28 16:10:46

by sander van ginkel

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Subject: Re: [PATCH] add hardware I2C support for ARM IMX23

Citeren "Wolfram Sang" <[email protected]>:

> Have you tested it? There have been problems reported when using
> i2cdetect...
>
> --
> Pengutronix e.K. | Wolfram Sang
|
> Industrial Linux Solutions |
http://www.pengutronix.de/ |
>

I've tested it with multiple configs.
i2cdetect -l gives me:
i2c-0 i2c MXS I2C adapter I2C adapter


2012-11-28 16:24:57

by Wolfram Sang

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Subject: Re: [PATCH] add hardware I2C support for ARM IMX23


> I've tested it with multiple configs.

Please specify a bit more what you tested and what configs mean. It is
especially important to talk to slaves since this is where DMA problems
occured.

> i2cdetect -l gives me:
> i2c-0 i2c MXS I2C adapter I2C adapter

'i2cdetect -r ...' would be more interesting to see communication with
slaves happening :) Also, what kernel did you test?

Thanks,

Wolfram

--
Pengutronix e.K. | Wolfram Sang |
Industrial Linux Solutions | http://www.pengutronix.de/ |


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2012-11-28 16:45:11

by sander van ginkel

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Subject: Re: [PATCH] add hardware I2C support for ARM IMX23

tested with:
CONFIG_I2C_MXS=m
CONFIG_I2C_MXS=y

in combination with CONFIG_GPIO_MXS enabled and disabled

used kernels: 3.6 and 3.7.0-rc6

My I2C slave is a PCF8575 i/o expander with some LEDs at the output.
These are controlled through sysfs.

Just tested with "i2cdetc -y -r 0" that crashes with "BUG: soft lockup
- CPU#0 stuck for 22s!"
according to the docs (IMX23RM.pdf) the interrupts for I2C are 26 and 27
that why I assigned these two in the dts.





2012-11-28 17:09:16

by Wolfram Sang

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Subject: Re: [PATCH] add hardware I2C support for ARM IMX23

Hi,

(adding the i2c list)

On Wed, Nov 28, 2012 at 05:44:49PM +0100, Sander van Ginkel wrote:
> tested with:
> CONFIG_I2C_MXS=m
> CONFIG_I2C_MXS=y
>
> in combination with CONFIG_GPIO_MXS enabled and disabled
>
> used kernels: 3.6 and 3.7.0-rc6
>
> My I2C slave is a PCF8575 i/o expander with some LEDs at the output.
> These are controlled through sysfs.

Thanks, this is useful info.

> Just tested with "i2cdetc -y -r 0" that crashes with "BUG: soft
> lockup - CPU#0 stuck for 22s!"
> according to the docs (IMX23RM.pdf) the interrupts for I2C are 26
> and 27 that why I assigned these two in the dts.

You might want to try my for-next branch or wait for 3.8-rc1, maybe the
DMA termination patch helps? Also enabling I2C debug messages is
probably worth it.

Regards,

Wolfram

--
Pengutronix e.K. | Wolfram Sang |
Industrial Linux Solutions | http://www.pengutronix.de/ |


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2012-11-28 17:34:54

by sander van ginkel

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Subject: Re: [PATCH] add hardware I2C support for ARM IMX23

Citeren "Wolfram Sang" <[email protected]>:

>
> You might want to try my for-next branch or wait for 3.8-rc1, maybe
the
> DMA termination patch helps? Also enabling I2C debug messages is
> probably worth it.
>
> Regards,
>
> Wolfram
>
> --
> Pengutronix e.K. | Wolfram Sang
|
> Industrial Linux Solutions |
http://www.pengutronix.de/ |
>

Ok I will dig into this, your for-next branch contains the DMA
termination patch, I presume?

2012-11-28 18:58:27

by sander van ginkel

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Subject: Re: [PATCH] add hardware I2C support for ARM IMX23

> Sander,
>
> Just tested with "i2cdetc -y -r 0" that crashes with "BUG: soft
lockup -
>> CPU#0 stuck for 22s!"
>> according to the docs (IMX23RM.pdf) the interrupts for I2C are 26
and 27
>> that why I assigned these two in the dts.
>>
>
> In your dts, is it 26, 27? Order matters, it should be 27, 26.
Error ISR,
> DMA.
>

Hi Tim,

Thanks for your suggestion. I swapped the numbers and it solved the crash.
However I still have to debug some more because it gives now :
mxs-i2c 80058000.i2c: Failed to get PIO reg. write descriptor.

Thanks,

Sander

2012-11-30 16:32:40

by sander van ginkel

[permalink] [raw]
Subject: Re: [PATCH] add hardware I2C support for ARM IMX23

> You might want to try my for-next branch or wait for 3.8-rc1, maybe
the
> DMA termination patch helps? Also enabling I2C debug messages is
> probably worth it.
>
> Regards,
>
> Wolfram
>
> --
> Pengutronix e.K. | Wolfram Sang
|
> Industrial Linux Solutions |
http://www.pengutronix.de/ |
>

I've tested your git tree, with the same config as I used for the
3.7.0-rc6 release (IMX i2c build in)
It's not a 100% fix

If I do "i2cdetect -y -r 0" with 3.7.0-rc6, i2cdetect gets confused
and the kernel keeps dumping "mxs-i2c 80058000.i2c: Failed to get PIO
reg. write descriptor."
If I do the same with your git release I get the same result, but only
when i2cdetect is running. When it's finished or I terminate, the
kprint will also disappear.
So there is some improvement but not 100% yet.