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| author | Geert Uytterhoeven <geert+renesas@glider.be> | 2019-05-27 14:19:35 +0200 |
|---|---|---|
| committer | Mark Brown <broonie@kernel.org> | 2019-05-28 15:57:03 +0100 |
| commit | 635bdb7a3e1fe1531573ff87b92c2506adafe7f7 (patch) | |
| tree | d48f80b767751cec21a05a7c76f63c07551e3296 /drivers/spi | |
| parent | d9424d6d48c8b6c4e8d9c38e2565bcaf90f4d184 (diff) | |
| download | linux-635bdb7a3e1fe1531573ff87b92c2506adafe7f7.tar.bz2 | |
spi: sh-msiof: Reduce delays in sh_msiof_modify_ctr_wait()
While the Hardware User Manual does not document the maximum time needed
for modifying bits in the MSIOF Control Register, experiments on R-Car
Gen2/Gen3 and SH-Mobile AG5 revealed the following typical modification
times for the various bits:
- CTR.TXE and CTR.RXE: no delay,
- CTR.TSCKE: less than 10 ns,
- CTR.TFSE: up to a few hundred ns (depending on SPI transfer clock,
i.e. less for faster transfers).
There are no reasons to believe these figures are different for
SH-MobileR2 SoCs (SH7723/SH7724).
Hence the minimum busy-looping delay of 10 µs is excessive.
Reduce the delay per loop iteration from 10 to 1 us, and the maximum
delay from 1000 to 100 µs.
Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
Signed-off-by: Mark Brown <broonie@kernel.org>
Diffstat (limited to 'drivers/spi')
| -rw-r--r-- | drivers/spi/spi-sh-msiof.c | 2 |
1 files changed, 1 insertions, 1 deletions
diff --git a/drivers/spi/spi-sh-msiof.c b/drivers/spi/spi-sh-msiof.c index 6aab7b2136db..b50bdbc27e58 100644 --- a/drivers/spi/spi-sh-msiof.c +++ b/drivers/spi/spi-sh-msiof.c @@ -229,7 +229,7 @@ static int sh_msiof_modify_ctr_wait(struct sh_msiof_spi_priv *p, sh_msiof_write(p, CTR, data); return readl_poll_timeout_atomic(p->mapbase + CTR, data, - (data & mask) == set, 10, 1000); + (data & mask) == set, 1, 100); } static irqreturn_t sh_msiof_spi_irq(int irq, void *data) |