[RFC PATCH] i2c: new bus driver for efm32

Hi Wolfram,

On Thu, Mar 13, 2014 at 11:14:33PM +0100, Wolfram Sang wrote:

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Huh? Is this an accepted binding? Doesn't look like it because of a
generic name and IMO a specific use-case. BTW the binding documentation
for this driver is missing.

Regarding the generic name: I don't care much, but I don't have a
problem with it. IMHO it's implicitly name-spaced by the compatible
string which starts with "efm32," and so is fine. I'd like to have the
same property name for all efm32 device drivers and "location" matches
the hardware reference manual (apart from capitalization).

I would in deed have expected a binding like "efm32,location" to
emphasize this is an efm32 specific thing. I know vendor-specific
"setup" bindings from elsewhere. Since it has been accepted already in
other places, we should keep it likes this.

Assuming you know the dt stuff better than me (and noone objects) I'd
fix the intree drivers to use efm32,location, too.

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+	if (resource_size(res) < 0x42) {
+		dev_err(&pdev->dev, "memory resource too small\n");
+		return -EINVAL;
+	}

I'd drop this check since, but I won't force you to.

I'd understand your sentence with s/since//, not sure about it as is.
Anyhow, I like this check.

A leftover. I was about to write "since the check is somewhat heuristic
and does not proof much". But then I decided it is not worth spending
too much discussion on it :)

I'd say it's heuristic to *not* check the boundary. It doesn't apply
here, but consider a driver using a register space > PAGE_SIZE on an MMU
platform. It accesses base + PAGE_SIZE + 0x42 even if dt only gave a
register range of PAGE_SIZE / 2. It's like gets(3).

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+	clkdiv = DIV_ROUND_UP(rate, 8 * ddata->pdata.frequency) - 1;
+	if (clkdiv >= 0x200) {
+		dev_err(&pdev->dev,
+				"input clock too fast (%lu) to divide down to bus freq (%lu)",
+				rate, ddata->pdata.frequency);
+		ret = -EIO;
+		goto err_disable_clk;
+	}

-EIO for clocks errors? Is this common?

Changed to ENODEV. Ok?

Nope, then the driver core will silent drop the error. -EINVAL?

agreed

Uwe

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Pengutronix e.K.                           | Uwe Kleine-K?nig            |
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