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b7fb7729c9
This bug was noticed while re-implementing parts of the kernel
driver in userspace using spidev. The goal was to enable some
of the errata workarounds that Microchip describes in their
errata sheet [1].
Both the errata sheet and the regular datasheet of e.g. the KSZ8795
imply that you need to do this for indirect register accesses:
- write a 16-bit value to a control register pair (this value
consists of the indirect register table, and the offset inside
the table)
- either read or write an 8-bit value from the data storage
register (indicated by REG_IND_BYTE in the kernel)
The current implementation has the order swapped. It can be
proven, by reading back some indirect register with known content
(the EEE register modified in ksz8_handle_global_errata() is one of
these), that this implementation does not work.
Private discussion with Oleksij Rempel of Pengutronix has revealed
that the workaround was apparantly never tested on actual hardware.
[1] https://ww1.microchip.com/downloads/aemDocuments/documents/OTH/ProductDocuments/Errata/KSZ87xx-Errata-DS80000687C.pdf
Signed-off-by: Tobias Jakobi (Compleo) <tobias.jakobi.compleo@gmail.com>
Reviewed-by: Oleksij Rempel <o.rempel@pengutronix.de>
Fixes:
|
||
|---|---|---|
| .. | ||
| Kconfig | ||
| ksz8.h | ||
| ksz8795_reg.h | ||
| ksz8795.c | ||
| ksz8863_smi.c | ||
| ksz9477_acl.c | ||
| ksz9477_i2c.c | ||
| ksz9477_reg.h | ||
| ksz9477_tc_flower.c | ||
| ksz9477.c | ||
| ksz9477.h | ||
| ksz_common.c | ||
| ksz_common.h | ||
| ksz_ptp_reg.h | ||
| ksz_ptp.c | ||
| ksz_ptp.h | ||
| ksz_spi.c | ||
| lan937x_main.c | ||
| lan937x_reg.h | ||
| lan937x.h | ||
| Makefile | ||