From f29ab1845f3e2684ba1c6de6c3bd5198e4b1459c Mon Sep 17 00:00:00 2001 From: Stephan Olbrich Date: Tue, 9 Feb 2016 19:10:33 +0100 Subject: spi: bcm2835aux: disable tx fifo empty irq The tx empty irq can be disabled when all data was copied. This prevents unnecessary interrupts while the last bytes are sent. Signed-off-by: Stephan Olbrich Reviewed-by: Eric Anholt Signed-off-by: Mark Brown --- drivers/spi/spi-bcm2835aux.c | 6 ++++++ 1 file changed, 6 insertions(+) (limited to 'drivers/spi/spi-bcm2835aux.c') diff --git a/drivers/spi/spi-bcm2835aux.c b/drivers/spi/spi-bcm2835aux.c index 7de6f8472a81..e1b2fec1db63 100644 --- a/drivers/spi/spi-bcm2835aux.c +++ b/drivers/spi/spi-bcm2835aux.c @@ -212,6 +212,12 @@ static irqreturn_t bcm2835aux_spi_interrupt(int irq, void *dev_id) ret = IRQ_HANDLED; } + if (!bs->tx_len) { + /* disable tx fifo empty interrupt */ + bcm2835aux_wr(bs, BCM2835_AUX_SPI_CNTL1, bs->cntl[1] | + BCM2835_AUX_SPI_CNTL1_IDLE); + } + /* and if rx_len is 0 then wake up completion and disable spi */ if (!bs->rx_len) { bcm2835aux_spi_reset_hw(bs); -- cgit From b4e2adef62062cf716d1c81adc12ad6def516f72 Mon Sep 17 00:00:00 2001 From: Stephan Olbrich Date: Sun, 14 Feb 2016 11:04:28 +0100 Subject: spi: bcm2835aux: set up spi-mode before asserting cs-gpio When using reverse polarity for clock (spi-cpol) on a device the clock line gets altered after chip-select has been asserted resulting in an additional clock beat, which confuses hardware. This happens due to the fact, the the hardware was initialized and reset at the begin and end of each transfer which results in default state for all lines except chip-select which is handled by the spi-subsystem as gpio-cs is used. To avoid this situation this patch moves the setup of polarity (spi-cpol and spi-cpha) outside of the chip-select into prepare_message, which is run prior to asserting chip-select. Signed-off-by: Stephan Olbrich Reviewed-by: Martin Sperl Tested-by: Martin Sperl Reviewed-by: Eric Anholt Signed-off-by: Mark Brown --- drivers/spi/spi-bcm2835aux.c | 57 +++++++++++++++++++++++++++++++------------- 1 file changed, 41 insertions(+), 16 deletions(-) (limited to 'drivers/spi/spi-bcm2835aux.c') diff --git a/drivers/spi/spi-bcm2835aux.c b/drivers/spi/spi-bcm2835aux.c index e1b2fec1db63..a6e25c6c66ca 100644 --- a/drivers/spi/spi-bcm2835aux.c +++ b/drivers/spi/spi-bcm2835aux.c @@ -218,9 +218,9 @@ static irqreturn_t bcm2835aux_spi_interrupt(int irq, void *dev_id) BCM2835_AUX_SPI_CNTL1_IDLE); } - /* and if rx_len is 0 then wake up completion and disable spi */ + /* and if rx_len is 0 then disable interrupts and wake up completion */ if (!bs->rx_len) { - bcm2835aux_spi_reset_hw(bs); + bcm2835aux_wr(bs, BCM2835_AUX_SPI_CNTL1, bs->cntl[1]); complete(&master->xfer_completion); } @@ -313,9 +313,6 @@ static int bcm2835aux_spi_transfer_one_poll(struct spi_master *master, } } - /* Transfer complete - reset SPI HW */ - bcm2835aux_spi_reset_hw(bs); - /* and return without waiting for completion */ return 0; } @@ -336,10 +333,6 @@ static int bcm2835aux_spi_transfer_one(struct spi_master *master, * resulting (potentially) in more interrupts when transferring * more than 12 bytes */ - bs->cntl[0] = BCM2835_AUX_SPI_CNTL0_ENABLE | - BCM2835_AUX_SPI_CNTL0_VAR_WIDTH | - BCM2835_AUX_SPI_CNTL0_MSBF_OUT; - bs->cntl[1] = BCM2835_AUX_SPI_CNTL1_MSBF_IN; /* set clock */ spi_hz = tfr->speed_hz; @@ -354,17 +347,13 @@ static int bcm2835aux_spi_transfer_one(struct spi_master *master, } else { /* the slowest we can go */ speed = BCM2835_AUX_SPI_CNTL0_SPEED_MAX; } + /* mask out old speed from previous spi_transfer */ + bs->cntl[0] &= ~(BCM2835_AUX_SPI_CNTL0_SPEED); + /* set the new speed */ bs->cntl[0] |= speed << BCM2835_AUX_SPI_CNTL0_SPEED_SHIFT; spi_used_hz = clk_hz / (2 * (speed + 1)); - /* handle all the modes */ - if (spi->mode & SPI_CPOL) - bs->cntl[0] |= BCM2835_AUX_SPI_CNTL0_CPOL; - if (spi->mode & SPI_CPHA) - bs->cntl[0] |= BCM2835_AUX_SPI_CNTL0_CPHA_OUT | - BCM2835_AUX_SPI_CNTL0_CPHA_IN; - /* set transmit buffers and length */ bs->tx_buf = tfr->tx_buf; bs->rx_buf = tfr->rx_buf; @@ -388,6 +377,40 @@ static int bcm2835aux_spi_transfer_one(struct spi_master *master, return bcm2835aux_spi_transfer_one_irq(master, spi, tfr); } +static int bcm2835aux_spi_prepare_message(struct spi_master *master, + struct spi_message *msg) +{ + struct spi_device *spi = msg->spi; + struct bcm2835aux_spi *bs = spi_master_get_devdata(master); + + bs->cntl[0] = BCM2835_AUX_SPI_CNTL0_ENABLE | + BCM2835_AUX_SPI_CNTL0_VAR_WIDTH | + BCM2835_AUX_SPI_CNTL0_MSBF_OUT; + bs->cntl[1] = BCM2835_AUX_SPI_CNTL1_MSBF_IN; + + /* handle all the modes */ + if (spi->mode & SPI_CPOL) + bs->cntl[0] |= BCM2835_AUX_SPI_CNTL0_CPOL; + if (spi->mode & SPI_CPHA) + bs->cntl[0] |= BCM2835_AUX_SPI_CNTL0_CPHA_OUT | + BCM2835_AUX_SPI_CNTL0_CPHA_IN; + + bcm2835aux_wr(bs, BCM2835_AUX_SPI_CNTL1, bs->cntl[1]); + bcm2835aux_wr(bs, BCM2835_AUX_SPI_CNTL0, bs->cntl[0]); + + return 0; +} + +static int bcm2835aux_spi_unprepare_message(struct spi_master *master, + struct spi_message *msg) +{ + struct bcm2835aux_spi *bs = spi_master_get_devdata(master); + + bcm2835aux_spi_reset_hw(bs); + + return 0; +} + static void bcm2835aux_spi_handle_err(struct spi_master *master, struct spi_message *msg) { @@ -416,6 +439,8 @@ static int bcm2835aux_spi_probe(struct platform_device *pdev) master->num_chipselect = -1; master->transfer_one = bcm2835aux_spi_transfer_one; master->handle_err = bcm2835aux_spi_handle_err; + master->prepare_message = bcm2835aux_spi_prepare_message; + master->unprepare_message = bcm2835aux_spi_unprepare_message; master->dev.of_node = pdev->dev.of_node; bs = spi_master_get_devdata(master); -- cgit From e9dd4edcc98593bbcdffc0c4f37545b8fd0ad3ea Mon Sep 17 00:00:00 2001 From: Stephan Olbrich Date: Sun, 14 Feb 2016 11:04:29 +0100 Subject: spi: bcm2835aux: fix CPOL/CPHA setting The auxiliary spi supports only CPHA=0 modes as the first bit is always output to the pin before the first clock cycle. In CPHA=1 modes the first clock edge outputs the second bit hence the slave can never read the first bit. Also the CPHA registers switch between clocking data in/out on rising/falling edge hence depend on the CPOL setting. Signed-off-by: Stephan Olbrich Reviewed-by: Eric Anholt Signed-off-by: Mark Brown --- drivers/spi/spi-bcm2835aux.c | 19 ++++++++----------- 1 file changed, 8 insertions(+), 11 deletions(-) (limited to 'drivers/spi/spi-bcm2835aux.c') diff --git a/drivers/spi/spi-bcm2835aux.c b/drivers/spi/spi-bcm2835aux.c index a6e25c6c66ca..496f9adb9fc1 100644 --- a/drivers/spi/spi-bcm2835aux.c +++ b/drivers/spi/spi-bcm2835aux.c @@ -64,9 +64,9 @@ #define BCM2835_AUX_SPI_CNTL0_VAR_WIDTH 0x00004000 #define BCM2835_AUX_SPI_CNTL0_DOUTHOLD 0x00003000 #define BCM2835_AUX_SPI_CNTL0_ENABLE 0x00000800 -#define BCM2835_AUX_SPI_CNTL0_CPHA_IN 0x00000400 +#define BCM2835_AUX_SPI_CNTL0_IN_RISING 0x00000400 #define BCM2835_AUX_SPI_CNTL0_CLEARFIFO 0x00000200 -#define BCM2835_AUX_SPI_CNTL0_CPHA_OUT 0x00000100 +#define BCM2835_AUX_SPI_CNTL0_OUT_RISING 0x00000100 #define BCM2835_AUX_SPI_CNTL0_CPOL 0x00000080 #define BCM2835_AUX_SPI_CNTL0_MSBF_OUT 0x00000040 #define BCM2835_AUX_SPI_CNTL0_SHIFTLEN 0x0000003F @@ -92,9 +92,6 @@ #define BCM2835_AUX_SPI_POLLING_LIMIT_US 30 #define BCM2835_AUX_SPI_POLLING_JIFFIES 2 -#define BCM2835_AUX_SPI_MODE_BITS (SPI_CPOL | SPI_CPHA | SPI_CS_HIGH \ - | SPI_NO_CS) - struct bcm2835aux_spi { void __iomem *regs; struct clk *clk; @@ -389,12 +386,12 @@ static int bcm2835aux_spi_prepare_message(struct spi_master *master, bs->cntl[1] = BCM2835_AUX_SPI_CNTL1_MSBF_IN; /* handle all the modes */ - if (spi->mode & SPI_CPOL) + if (spi->mode & SPI_CPOL) { bs->cntl[0] |= BCM2835_AUX_SPI_CNTL0_CPOL; - if (spi->mode & SPI_CPHA) - bs->cntl[0] |= BCM2835_AUX_SPI_CNTL0_CPHA_OUT | - BCM2835_AUX_SPI_CNTL0_CPHA_IN; - + bs->cntl[0] |= BCM2835_AUX_SPI_CNTL0_OUT_RISING; + } else { + bs->cntl[0] |= BCM2835_AUX_SPI_CNTL0_IN_RISING; + } bcm2835aux_wr(bs, BCM2835_AUX_SPI_CNTL1, bs->cntl[1]); bcm2835aux_wr(bs, BCM2835_AUX_SPI_CNTL0, bs->cntl[0]); @@ -434,7 +431,7 @@ static int bcm2835aux_spi_probe(struct platform_device *pdev) } platform_set_drvdata(pdev, master); - master->mode_bits = BCM2835_AUX_SPI_MODE_BITS; + master->mode_bits = (SPI_CPOL | SPI_CS_HIGH | SPI_NO_CS); master->bits_per_word_mask = SPI_BPW_MASK(8); master->num_chipselect = -1; master->transfer_one = bcm2835aux_spi_transfer_one; -- cgit