Subject: Re: [PATCH v13 2/3] i2c: aspeed: support AST2600 i2c new register
mode driver

On Fri, Aug 23, 2024 at 06:23:54AM +0000, Ryan Chen wrote:

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On Thu, Aug 22, 2024 at 02:24:26AM +0000, Ryan Chen wrote:

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On Wed, Aug 21, 2024 at 06:43:01AM +0000, Ryan Chen wrote:

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On Mon, Aug 19, 2024 at 05:28:49PM +0800, Ryan Chen wrote:

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+	if (i2c_bus->mode == BUFF_MODE) {
+		i2c_bus->buf_base =

devm_platform_get_and_ioremap_resource(pdev, 1, &res);

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+		if (!IS_ERR_OR_NULL(i2c_bus->buf_base))
+			i2c_bus->buf_size = resource_size(res) / 2;
+		else
+			i2c_bus->mode = BYTE_MODE;

What's wrong with positive conditional? And is it even
possible to have NULL here?

Yes, if dtsi fill not following yaml example have reg 1, that
will failure at buffer

mode.

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And I can swith to byte mode.

reg = <0x80 0x80>, <0xc00 0x20>;

I was asking about if (!IS_ERR_OR_NULL(...)) line:
1) Why 'if (!foo) {} else {}' instead of 'if (foo) {} else {}'?

I will update to following.
		if (IS_ERR(i2c_bus->buf_base))
			i2c_bus->mode = BYTE_MODE;
		else
			i2c_bus->buf_size = resource_size(res) / 2;

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2) Why _NULL?

	If dtsi file is claim only 1 reg offset. reg = <0x80 0x80>; that
will goto byte

mode.

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	reg = <0x80 0x80>, <0xc00 0x20>; can support buffer mode.
	due to 2nd is buffer register offset.

I have asked why IS_ERR_OR_NULL() and not IS_ERR().

OH, I will doing by this.
		if (IS_ERR_OR_NULL(i2c_bus->buf_base))

The question about _NULL remains unanswered...

Sorry, I may not catch your point.
So, Do you mean I should passive coding by following?

If (i2c_bus->buf_base > 0)
	i2c_bus->buf_size = resource_size(res) / 2;
else
    i2c_bus->mode = BYTE_MODE;

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			i2c_bus->mode = BYTE_MODE;
		else
			i2c_bus->buf_size = resource_size(res) / 2;

--
With Best Regards,
Andy Shevchenko