Commit 1e316d75 authored by David Brownell's avatar David Brownell Committed by Greg Kroah-Hartman
Browse files

[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: default avatarDavid Brownell <dbrownell@users.sourceforge.net>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@suse.de>
parent 9708c121

drivers/spi/spi_bitbang.c

+14 −10
Original line number Diff line number Diff line
@@ -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;

	if (hz) {

		cs->nsecs = (1000000000/2) / hz;

	if (cs->nsecs > MAX_UDELAY_MS * 1000)

		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);

	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);

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