Hi Mike,
On Sat, Nov 5, 2011 at 10:13 AM, Mike Frysinger <vap...@gentoo.org> wrote:
> On Saturday 05 November 2011 10:36:30 Simon Glass wrote:
>> On Thu, Nov 3, 2011 at 6:36 PM, Mike Frysinger wrote:
>> > On Thursday 03 November 2011 18:41:34 Simon Glass wrote:
>> >> --- /dev/null
>> >> +++ b/drivers/spi/tegra2_spi.c
>> >>
>> >> +int spi_cs_is_valid(unsigned int bus, unsigned int cs)
>> >> +{
>> >> + /* Tegra2 SPI-Flash - only 1 device ('bus/cs') */
>> >> + if (bus > 0 && cs != 0)
>> >> + return 0;
>> >> + else
>> >> + return 1;
>> >> +}
>> >
>> > shouldn't that be "||" and not "&&" ?
>>
>> This function should be removed as it doesn't print enough errors.
>
> this func is part of the SPI API. you can't remove it ;).
OK - it seems to only be used by the mmc_spi command which Tegra isn't
using. But I will add it back in. (Should it be called in
spi_flash_probe(), for example?)
>
>> >> +struct spi_slave *spi_setup_slave(unsigned int bus, unsigned int cs,
>> >> + unsigned int max_hz, unsigned int mode)
>> >> +{
>> >> + struct tegra_spi_slave *spi;
>> >> +
>> >> + if (!spi_cs_is_valid(bus, cs))
>> >> + return NULL;
>> >> +
>> >> + if (bus != 0) {
>> >> + printf("SPI error: unsupported bus %d\n", bus);
>> >> + return NULL;
>> >> + }
>> >> + if (cs != 0) {
>> >> + printf("SPI error: unsupported chip select %d on bus
>> >> %d\n", + cs, bus);
>> >> + return NULL;
>> >> + }
>> >
>> > doesn't spi_cs_is_valid() make these two later checks redundant ?
>>
>> Yes - have removed the function.
>
> i think this is the wrong direction ... other SPI buses are not warning about
> invalid bus/cs combos and that seems to be fine. i don't think the tegra spi
> bus needs to be uniquely verbose.
OK, I was lead astray by the OMAP code which does this. I will revert
and resend this patch.
>
>> >> + reg = readl(®s->status);
>> >> + writel(reg, ®s->status); /* Clear all SPI events via R/W */
>> >
>> > are these R1C or W1C bits ? if the latter, you could just write -1 and
>> > avoid the read altogether ...
>>
>> The next line is:
>>
>> debug("spi_xfer entry: STATUS = %08x\n", reg);
>>
>> and I didn't want to remove that, so I need to keep the read
>> unfortunately. It could perhaps be this if you are keen:
>>
>> writel(-1, ®s->status); /* Clear all SPI events via R/W */
>> debug("spi_xfer entry: STATUS = %08x\n", readl(®->status));
>
> what you have now is fine if you prefer it that way
> -mike
>
OK - I will leave it. I have already modified Tom's driver more than is polite.
Regards,
Simon
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