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| author | David Brownell <david-b@pacbell.net> | 2006-04-06 22:25:56 -0700 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@suse.de> | 2006-05-16 14:33:58 -0700 |
| commit | 1e316d7566b63767aa18902235c719e9e95465d0 (patch) | |
| tree | 506783a779e1b06b20de0bc03e4b0008f77704e8 | |
| parent | 9708c121c38fe864eb6f5a119f7525729686e095 (diff) | |
| download | linux-3.10-1e316d7566b63767aa18902235c719e9e95465d0.tar.gz linux-3.10-1e316d7566b63767aa18902235c719e9e95465d0.tar.bz2 linux-3.10-1e316d7566b63767aa18902235c719e9e95465d0.zip | |
[PATCH] SPI: spi_bitbang: clocking fixes
This fixes two problems triggered by the MMC stack updating clocks:
- SPI masters driver should accept a max clock speed of zero; that's one
convention for marking idle devices. (Presumably that helps controllers
that don't autogate clocks to "off" when not in use.)
- There are more than 1000 nanoseconds per millisecond; setting the clock
down to 125 KHz now works properly.
Showing once again that Zero (http://en.wikipedia.org/wiki/Zero) is still
an inexhaustible number of bugs.
Signed-off-by: David Brownell <dbrownell@users.sourceforge.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
| -rw-r--r-- | drivers/spi/spi_bitbang.c | 24 |
1 files changed, 14 insertions, 10 deletions
diff --git a/drivers/spi/spi_bitbang.c b/drivers/spi/spi_bitbang.c index 0f7f5c64391..dd2f950b21a 100644 --- a/drivers/spi/spi_bitbang.c +++ b/drivers/spi/spi_bitbang.c @@ -167,9 +167,11 @@ int spi_bitbang_setup_transfer(struct spi_device *spi, struct spi_transfer *t) /* nsecs = (clock period)/2 */ if (!hz) hz = spi->max_speed_hz; - cs->nsecs = (1000000000/2) / hz; - if (cs->nsecs > MAX_UDELAY_MS * 1000) - return -EINVAL; + if (hz) { + cs->nsecs = (1000000000/2) / hz; + if (cs->nsecs > (MAX_UDELAY_MS * 1000 * 1000)) + return -EINVAL; + } return 0; } @@ -184,9 +186,6 @@ int spi_bitbang_setup(struct spi_device *spi) struct spi_bitbang *bitbang; int retval; - if (!spi->max_speed_hz) - return -EINVAL; - bitbang = spi_master_get_devdata(spi->master); /* REVISIT: some systems will want to support devices using lsb-first @@ -216,7 +215,7 @@ int spi_bitbang_setup(struct spi_device *spi) if (retval < 0) return retval; - dev_dbg(&spi->dev, "%s, mode %d, %u bits/w, %u nsec\n", + dev_dbg(&spi->dev, "%s, mode %d, %u bits/w, %u nsec/bit\n", __FUNCTION__, spi->mode & (SPI_CPOL | SPI_CPHA), spi->bits_per_word, 2 * cs->nsecs); @@ -405,6 +404,7 @@ int spi_bitbang_transfer(struct spi_device *spi, struct spi_message *m) { struct spi_bitbang *bitbang; unsigned long flags; + int status = 0; m->actual_length = 0; m->status = -EINPROGRESS; @@ -414,11 +414,15 @@ int spi_bitbang_transfer(struct spi_device *spi, struct spi_message *m) return -ESHUTDOWN; spin_lock_irqsave(&bitbang->lock, flags); - list_add_tail(&m->queue, &bitbang->queue); - queue_work(bitbang->workqueue, &bitbang->work); + if (!spi->max_speed_hz) + status = -ENETDOWN; + else { + list_add_tail(&m->queue, &bitbang->queue); + queue_work(bitbang->workqueue, &bitbang->work); + } spin_unlock_irqrestore(&bitbang->lock, flags); - return 0; + return status; } EXPORT_SYMBOL_GPL(spi_bitbang_transfer); |