dt-bindings: i2c: i2c-mt65xx: Update binding example

Example uses values for MT6589 SoC, but MT6577 was specified in "compatible" property.

Signed-off-by Boris Lysov <[email protected]>

---
 Documentation/devicetree/bindings/i2c/i2c-mt65xx.txt | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

Documentation/devicetree/bindings/i2c/i2c-mt65xx.txt +1 -1

index 7f0194fdd0cc..acf3d4d28b98 100644
@@ -36,7 +36,7 @@ Optional properties:
 Example:
 
 	i2c0: i2c@1100d000 {
-			compatible = "mediatek,mt6577-i2c";
+			compatible = "mediatek,mt6589-i2c";
 			reg = <0x1100d000 0x70>,
 			      <0x11000300 0x80>;
 			interrupts = <GIC_SPI 44 IRQ_TYPE_LEVEL_LOW>;

Quoted 2 lines · Boris Lysov

Example uses values for MT6589 SoC, but MT6577 was specified in "compatible" property.

Why do you think the example is MT6589 SoC, not MT6577?

#define I2C0_BASE 0xF100D000

.end = IO_VIRT_TO_PHYS(I2C0_BASE) + 0x70,

i2c->pdmabase = AP_DMA_BASE + 0x300 + (0x80*(i2c->id));

#define MT_I2C0_IRQ_ID (GIC_PRIVATE_SIGNALS + 44)

interrupts = <GIC_SPI 44 IRQ_TYPE_LEVEL_LOW>;

#define I2C0_BASE 0xF1012000

#define MT_I2C0_IRQ_ID (GIC_PRIVATE_SIGNALS + 49)

Quoted 6 lines · On Mon, 7 Sep 2020 09:28:07 +0800 Qii Wang <[email protected]> wrote:

Quoted 2 lines · Boris Lysov

Example uses values for MT6589 SoC, but MT6577 was specified in "compatible" property.

Why do you think the example is MT6589 SoC, not MT6577?

The best way to explain why it's for MT6589 instead of MT6577 is to provide an example ;) I will refer to various downstream Linux kernel sources, I hope sharing GitHub links is appropriate.

This is the kernel source code of Lenovo P780 (MT6589)
https://github.com/andreya108/bindu-kernel-mediatek

mediatek/platform/mt6589/kernel/core/include/mach/mt_reg_base.h , line 115:

Quoted 1 line

#define I2C0_BASE 0xF100D000

This address is virtual, and it translates into physical address 0x1100D000 0x1100D000 equals to the value in example

mediatek/platform/mt6589/kernel/core/mt_devs.c , line 846:

Quoted 1 line

.end = IO_VIRT_TO_PHYS(I2C0_BASE) + 0x70,

0x70 shows length of memory region, which also equals to the value in example

mediatek/platform/mt6589/kernel/drivers/i2c/i2c.c , line 1140:

Quoted 1 line

i2c->pdmabase = AP_DMA_BASE + 0x300 + (0x80*(i2c->id));

For id=0, physical pdmabase is 0x11000300 which also matches the address in example

mediatek/platform/mt6589/kernel/core/include/mach/mt_irq.h , line 29:

Quoted 1 line

#define MT_I2C0_IRQ_ID (GIC_PRIVATE_SIGNALS + 44)

The IRQ ID (44) equals to one specified in dt-binding example:

Quoted 1 line

interrupts = <GIC_SPI 44 IRQ_TYPE_LEVEL_LOW>;

These values are same for other MT6589 devices, here are few other repositories containing same lines of code as above (line numbers might be off for a few lines, but the values I am referring to are same):
Micromax A116 (MT6589) - https://github.com/neomanu/NeoKernel-MT6589-A116
Acer V370 (MT6589) - https://github.com/Shr3ps/android_kernel_acer_V370_MT6589
bq Aquaris 5.7 (MT6589) - https://github.com/luckasfb/aquaris-5.7

Now lets take a look at MT6577 devices. This is the kernel source code of ZTE v970:
https://github.com/dragonpt/Kernel_3.4.67_KK_ZTE_v970

mediatek/platform/mt6589/kernel/core/include/mach/mt_reg_base.h , line 68:

Quoted 1 line

#define I2C0_BASE 0xF1012000

This address is virtual, and it translates into physical address 0xC1012000 0xC1012000 does not equal to 0x1100d000 listed in example!

mediatek/platform/mt6577/kernel/drivers/i2c/i2c.c
No mentions of pdmabase. There are no DMA addresses in this file!

mediatek/platform/mt6577/kernel/core/include/mach/mt_irq.h , line 70:

Quoted 1 line

#define MT_I2C0_IRQ_ID (GIC_PRIVATE_SIGNALS + 49)

The IRQ ID (49) does not match the ID (44) specified in example!

Other MT6577 kernels with same values:
Acer V360 (MT6577) - https://github.com/aquila-dev/mt6577_kernel3.4
Acer C10 (MT6577) - https://github.com/Dr-Shadow/android_kernel_acer_c10
Wiko Cink Slim (MT6577) - https://github.com/theboleslaw/kernel_wiko_s8073

As you can see, current dt-binding example represents MT6589 SoC values, not MT6577. I have sent additional email about i2c-mt65xx and MT6577 compatibility, where I voiced my concerns about I2C DMA on that SoC. I hope you can look into it.

None of the examples you cited are the upstream code of our official release

, and the name of customer's SOC cannot be accurately evaluated.