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Commit 9a7867e1 authored by Luotao Fu's avatar Luotao Fu Committed by Linus Torvalds
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mpc52xx_psc_spi: fix block transfer 



The block transfer routine in the mpc52xx psc spi driver misinterpret
the datasheet.  According to the processor datasheet the chipselect is
held as long as the EOF is not written.

Theoretically blocks of any sizes can be transferred in this way.  The
old routine however writes an EOF after every word, which has the size
of size_of_word.  This makes the transfer slow.

Also fixed some duplicate code.

Signed-off-by: default avatarLuotao Fu <l.fu@pengutronix.de>
Signed-off-by: default avatarDavid Brownell <dbrownell@users.sourceforge.net>
Cc: <stable@kernel.org>		[2.6.25.x, 2.6.26.x]
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent 78a34ae2

drivers/spi/mpc52xx_psc_spi.c

+7 −15
Original line number Diff line number Diff line
@@ -148,7 +148,6 @@ static int mpc52xx_psc_spi_transfer_rxtx(struct spi_device *spi, 
	unsigned rfalarm;

	unsigned send_at_once = MPC52xx_PSC_BUFSIZE;

	unsigned recv_at_once;

	unsigned bpw = mps->bits_per_word / 8;



	if (!t->tx_buf && !t->rx_buf && t->len)

		return -EINVAL;
@@ -164,23 +163,16 @@ static int mpc52xx_psc_spi_transfer_rxtx(struct spi_device *spi, 
		}



		dev_dbg(&spi->dev, "send %d bytes...\n", send_at_once);

		if (tx_buf) {

		for (; send_at_once; sb++, send_at_once--) {

				/* set EOF flag */

				if (mps->bits_per_word

						&& (sb + 1) % bpw == 0)

			/* set EOF flag before the last word is sent */

			if (send_at_once == 1)

				out_8(&psc->ircr2, 0x01);



			if (tx_buf)

				out_8(&psc->mpc52xx_psc_buffer_8, tx_buf[sb]);

			}

		} else {

			for (; send_at_once; sb++, send_at_once--) {

				/* set EOF flag */

				if (mps->bits_per_word

						&& ((sb + 1) % bpw) == 0)

					out_8(&psc->ircr2, 0x01);

			else

				out_8(&psc->mpc52xx_psc_buffer_8, 0);

		}

		}





		/* enable interrupts and wait for wake up