Hi Masahiro,
On 3 December 2014 at 08:52, Masahiro YAMADA yamada.m@jp.panasonic.com wrote:
Hi Simon,
2014-12-04 0:23 GMT+09:00 Simon Glass sjg@chromium.org:
-/* Probe to see if a chip is present. */ -static int tegra_i2c_probe(struct i2c_adapter *adap, uchar chip) +static int tegra_i2c_set_offset_len(struct udevice *dev, const uint olen) {
struct i2c_bus *bus;int rc;uchar reg;debug("i2c_probe: addr=0x%x\n", chip);bus = tegra_i2c_get_bus(adap);if (!bus)return 1;reg = 0;rc = i2c_write_data(bus, chip, ®, 1, false);if (rc) {debug("Error probing 0x%x.\n", chip);return 1;}return 0;-}
if (olen < 4)return 0;The maximum length 4 is not tegra-specific. I can't find good reason to have .set_offset_len handler.
It's not needed here as 4 is the maximum supported by the uclass. Some drivers may support less though, so perhaps we should keep the method?
I think this handler is totally useless.
Moreover, the offset address within a chip is out of the scope of I2C protocol. I think it is odd for each of I2C drivers to care about it.
The Intel SPI driver requires us to figure out the offset from the spi_xfer() call, and it is painful. I wondered if there might be I2C drivers that need to do the same thing. I have not looked.
Regards, Simon