spi: cadence-quadspi: Abort read if dummy cycles required are too many

[ Upstream commit ceeda328edeeeeac7579e9dbf0610785a3b83d39 ]

The controller can only support up to 31 dummy cycles. If the command
requires more it falls back to using 31. This command is likely to fail
because the correct number of cycles are not waited upon. Rather than
silently issuing an incorrect command, fail loudly so the caller can get
a chance to find out the command can't be supported by the controller.

Fixes: 1406234105 ("mtd: spi-nor: Add driver for Cadence Quad SPI Flash Controller")
Signed-off-by: Pratyush Yadav <p.yadav@ti.com>
Link: https://lore.kernel.org/r/20201222184425.7028-3-p.yadav@ti.com
Signed-off-by: Mark Brown <broonie@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
This commit is contained in:
Pratyush Yadav 2020-12-23 00:14:20 +05:30 committed by Greg Kroah-Hartman
parent a8594ec0bb
commit d8d37cdde2

View File

@ -461,7 +461,7 @@ static int cqspi_read_setup(struct cqspi_flash_pdata *f_pdata,
/* Setup dummy clock cycles */
dummy_clk = op->dummy.nbytes * 8;
if (dummy_clk > CQSPI_DUMMY_CLKS_MAX)
dummy_clk = CQSPI_DUMMY_CLKS_MAX;
return -EOPNOTSUPP;
if (dummy_clk)
reg |= (dummy_clk & CQSPI_REG_RD_INSTR_DUMMY_MASK)