Donate to e Foundation | Murena handsets with /e/OS | Own a part of Murena! Learn more

Commit 0398fb70 authored by Joakim Tjernlund's avatar Joakim Tjernlund Committed by Grant Likely
Browse files

spi/spi_mpc8xxx: Fix QE mode Litte Endian 



QE mode uses Little Endian so words > 8 bits are byte swapped.
Workaround this by always enforcing wordsize 8 for words
> 8 bits. Unfortunately this will not work for LSB transfers
where wordsize is > 8 bits so disable these for now.

Also move the different quirks into its own function to keep
mpc8xxx_spi_setup_transfer() sane.

Signed-off-by: default avatarJoakim Tjernlund <Joakim.Tjernlund@transmode.se>
Acked-by: default avatarAnton Vorontsov <cbouatmailru@gmail.com>
Signed-off-by: default avatarGrant Likely <grant.likely@secretlab.ca>
parent f9218c2a

drivers/spi/spi_mpc8xxx.c

+70 −31
Original line number Diff line number Diff line
@@ -286,36 +286,12 @@ static void mpc8xxx_spi_chipselect(struct spi_device *spi, int value) 
	}

}



static

int mpc8xxx_spi_setup_transfer(struct spi_device *spi, struct spi_transfer *t)

static int

mspi_apply_cpu_mode_quirks(struct spi_mpc8xxx_cs *cs,

			   struct spi_device *spi,

			   struct mpc8xxx_spi *mpc8xxx_spi,

			   int bits_per_word)

{

	struct mpc8xxx_spi *mpc8xxx_spi;

	u8 bits_per_word, pm;

	u32 hz;

	struct spi_mpc8xxx_cs	*cs = spi->controller_state;



	mpc8xxx_spi = spi_master_get_devdata(spi->master);



	if (t) {

		bits_per_word = t->bits_per_word;

		hz = t->speed_hz;

	} else {

		bits_per_word = 0;

		hz = 0;

	}



	/* spi_transfer level calls that work per-word */

	if (!bits_per_word)

		bits_per_word = spi->bits_per_word;



	/* Make sure its a bit width we support [4..16, 32] */

	if ((bits_per_word < 4)

	    || ((bits_per_word > 16) && (bits_per_word != 32)))

		return -EINVAL;



	if (!hz)

		hz = spi->max_speed_hz;



	cs->rx_shift = 0;

	cs->tx_shift = 0;

	if (bits_per_word <= 8) {
@@ -346,12 +322,75 @@ int mpc8xxx_spi_setup_transfer(struct spi_device *spi, struct spi_transfer *t) 
		else

			cs->rx_shift = 0;

	}



	mpc8xxx_spi->rx_shift = cs->rx_shift;

	mpc8xxx_spi->tx_shift = cs->tx_shift;

	mpc8xxx_spi->get_rx = cs->get_rx;

	mpc8xxx_spi->get_tx = cs->get_tx;



	return bits_per_word;

}



static int

mspi_apply_qe_mode_quirks(struct spi_mpc8xxx_cs *cs,

			  struct spi_device *spi,

			  int bits_per_word)

{

	/* QE uses Little Endian for words > 8

	 * so transform all words > 8 into 8 bits

	 * Unfortnatly that doesn't work for LSB so

	 * reject these for now */

	/* Note: 32 bits word, LSB works iff

	 * tfcr/rfcr is set to CPMFCR_GBL */

	if (spi->mode & SPI_LSB_FIRST &&

	    bits_per_word > 8)

		return -EINVAL;

	if (bits_per_word > 8)

		return 8; /* pretend its 8 bits */

	return bits_per_word;

}



static

int mpc8xxx_spi_setup_transfer(struct spi_device *spi, struct spi_transfer *t)

{

	struct mpc8xxx_spi *mpc8xxx_spi;

	int bits_per_word;

	u8 pm;

	u32 hz;

	struct spi_mpc8xxx_cs	*cs = spi->controller_state;



	mpc8xxx_spi = spi_master_get_devdata(spi->master);



	if (t) {

		bits_per_word = t->bits_per_word;

		hz = t->speed_hz;

	} else {

		bits_per_word = 0;

		hz = 0;

	}



	/* spi_transfer level calls that work per-word */

	if (!bits_per_word)

		bits_per_word = spi->bits_per_word;



	/* Make sure its a bit width we support [4..16, 32] */

	if ((bits_per_word < 4)

	    || ((bits_per_word > 16) && (bits_per_word != 32)))

		return -EINVAL;



	if (!hz)

		hz = spi->max_speed_hz;



	if (!(mpc8xxx_spi->flags & SPI_CPM_MODE))

		bits_per_word = mspi_apply_cpu_mode_quirks(cs, spi,

							   mpc8xxx_spi,

							   bits_per_word);

	else if (mpc8xxx_spi->flags & SPI_QE)

		bits_per_word = mspi_apply_qe_mode_quirks(cs, spi,

							  bits_per_word);



	if (bits_per_word < 0)

		return bits_per_word;



	if (bits_per_word == 32)

		bits_per_word = 0;

	else