Dear Mike Frysinger,
i dont have a problem with going through the env as a hook, but it doesnt seem to scale. what if you have 2 fram devices and a winbond spi flash ? perhaps the name spec should be: fram_dev.<bus>.<cs>
then you can signal that only certain<bus>.<cs> locations should get special treatment. and it wont inadvertently clobber other devices or detect devices that dont exist without explicit permission.
Makes sense.
+{
- struct ramtron_spi_fram *sn = to_ramtron_spi_fram(flash);
- u8 cmd[4];
- u8 cmd_len = 1;
- int ret;
the majority of this function seems to match the write() func ... perhaps the body should be unified in a local static "setup" func and let gcc determine whether to inline its body ?
OK
no space after "getenv". i'd also delay the call to the point where you actually check "device_name" ...
Right.
--- a/drivers/mtd/spi/spi_flash.c +++ b/drivers/mtd/spi/spi_flash.c @@ -116,6 +116,19 @@ goto err_claim_bus; }
+#ifdef CONFIG_SPI_FRAM_RAMTRON
- /*
* not all RAMTRON FRAMs do have a READ_ID command,* let the ramtron code figure out details*/- flash = spi_fram_probe_ramtron(spi);
- if (flash) {
spi_release_bus(spi);return flash;- }
- /* if spi_fram_probe did not find anything, continue normal probe */
+#endif
- /* Read the ID codes */ ret = spi_flash_cmd(spi, CMD_READ_ID,&idcode, sizeof(idcode)); if (ret)
you hook early to handle extended idcode reads and for devices that dont respect the idcode command.
for the first, we can extend the idcode length yet again, but perhaps this time temper it: #if defined(CONFIG_SPI_FRAM_RAMTRON) # define IDCODE_LEN 10 #else # define IDCODE_LEN 5 #endif
OK, see below. Can't we have it 10 generally? The impact should be negligible?
for the second, what do you get back when you issue the idcode ? 0xff ? we already have a fall back case for this with stmicro, so perhaps we should generalize this further too. after the vendor id switch statement, we do:
If MISO has no pull-up the result is indeterminate, the chip simply lets MISO float when it does not honor the read-id command.
I'll add a comment to that file that a pull-up is required for non-standard devices to be detected. Otherwise, depending on random noise, a false detection of a standard device is not entirely impossible.
On a side note: its beyond my comprehension why ramtron's newest and densest variant FM25H20 has no read-id command (while all devices before that except for the really old and small ones do have it)....
Reinhard