Hello Lee,
On 01/22/2015 09:42 AM, Lee Jones wrote:
>> >
>> > I don't think the drivers you mentioned above do anything practical.
>> > For instance, they are not SPI/IC2/etc drivers. They should only
>> > offer some abstraction layers which are used to communicate with the
>> > device. The driver you are submitting looks a lot more like a device
>> > driver, which should live somewhere else. Don't ask me where though,
>> > I'm not even sure what a Low Pin Controller does.
>> >
>>
>> The driver added by $subject doesn't really do anything practical either.
>> LPC [0] is just another transport method like i2c or spi that is used on
>> x86 Chromebooks to access the Embedded Controller.
>
> I'm not sure that's true. It's pretty simple I grant you, but it
> still looks like a driver, rather than an abstraction layer.
>
> I would expect to see something more like:
>
> static int cros_ec_lpc_readmem(...)
> {
> return call_to_driver_to_read_memory(...);
>
> }
>
> ... instead of all those memory/register reads/writes.
>
Yeah... in that sense I've to admit that is more complex than the I2C and SPI
drivers, yet those have a subsystem in the kernel with helpers functions to
do most of the communication:
static int cros_ec_cmd_xfer_i2c(struct cros_ec_device *ec_dev,
struct cros_ec_command *msg)
{
...
ret = i2c_transfer(client->adapter, i2c_msg, 2);
...
}
static int cros_ec_cmd_xfer_spi(struct cros_ec_device *ec_dev,
struct cros_ec_command *ec_msg)
{
...
spi_message_add_tail(&trans, &msg);
ret = spi_sync(ec_spi->spi, &msg);
...
}
But there doesn't seem to be a LPC subsystem in the kernel so we don't have a
nice abstraction layer in this case.
> Are there any other Low Pin Count drivers in the kernel?
>
I don't know tbh, I didn't even know what LPC was before I picked this patch
to push it upstream. I searched in the Linux codebase for other LPC drivers
but I didn't find anything, that doesn't mean that it doesn't exist though.
Best regards,
Javier
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