[PATCH 2/2] bootcount: Add driver model I2C driver

[Philip Oberfichtner]

Hello Heiko,

On Fri, Oct 13, 2023 at 01:28:47PM +0200, Heiko Schocher wrote:
> [...]
> > 
> > 	bootcount {
> > 		compatible = "u-boot,bootcount-i2c";
> > 		i2c-bus = <&i2c1>;
> > 		address = <0x52>;
> 
> Hmm.. do we really need this here with DTS. Why not using a phandle
> to a real i2c device? Something like this for example:
> 
> 		i2cbcdev = &i2c_rtc;
> 
> with
> 
> &i2c1 {
>         i2c_rtc: rtc at 68 {
> [...]
> 
> and so there is no need for knowing the bus and address ...
> 

Yeah I agree that would be much better, but ...

> [...]
> 
> when you use a phandle, you can replace the part from reading "offset"
> with this:
> 
> 	uclass_get_device_by_phandle(UCLASS_I2C, dev, "i2cbcdev", &priv->bcdev);
> 
> of course plus error checking...

This does not work, UCLASS_I2C is used for the *bus above* the device we
actually want.

Next thing I thougt about: Why not use the UCLASS_I2C_GENERIC. But this
expects a "i2c-chip" compatible string, which our rtc or whatever device
obviously does not have.

I think using UCLASS_I2C_GENERIC might indeed be the best approach.
Maybe using something like 'device_bind_driver()'. But again, this
expects the parent device to be there already as far as I can tell.

Any suggestions?

Best regards,
Philip


> 
> > +
> > +	return 0;
> > +}
> > +
> > +static const struct bootcount_ops bootcount_i2c_ops = {
> > +	.get = bootcount_i2c_get,
> > +	.set = bootcount_i2c_set,
> > +};
> > +
> > +static const struct udevice_id bootcount_i2c_ids[] = {
> > +	{ .compatible = "u-boot,bootcount-i2c" },
> > +	{ }
> > +};
> > +
> > +U_BOOT_DRIVER(bootcount_i2c) = {
> > +	.name		= "bootcount-i2c",
> > +	.id		= UCLASS_BOOTCOUNT,
> > +	.priv_auto	= sizeof(struct bootcount_i2c_priv),
> > +	.probe		= bootcount_i2c_probe,
> > +	.of_match	= bootcount_i2c_ids,
> > +	.ops		= &bootcount_i2c_ops,
> > +};
> > 
> 
> bye,
> Heiko
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