diff options
Diffstat (limited to 'drivers/spi/spi-bcm2835aux.c')
| -rw-r--r-- | drivers/spi/spi-bcm2835aux.c | 70 |
1 files changed, 32 insertions, 38 deletions
diff --git a/drivers/spi/spi-bcm2835aux.c b/drivers/spi/spi-bcm2835aux.c index 7428091d3f5b..e075712c501e 100644 --- a/drivers/spi/spi-bcm2835aux.c +++ b/drivers/spi/spi-bcm2835aux.c @@ -178,19 +178,14 @@ static void bcm2835aux_spi_reset_hw(struct bcm2835aux_spi *bs) BCM2835_AUX_SPI_CNTL0_CLEARFIFO); } -static irqreturn_t bcm2835aux_spi_interrupt(int irq, void *dev_id) +static void bcm2835aux_spi_transfer_helper(struct bcm2835aux_spi *bs) { - struct spi_master *master = dev_id; - struct bcm2835aux_spi *bs = spi_master_get_devdata(master); - irqreturn_t ret = IRQ_NONE; + u32 stat = bcm2835aux_rd(bs, BCM2835_AUX_SPI_STAT); /* check if we have data to read */ - while (bs->rx_len && - (!(bcm2835aux_rd(bs, BCM2835_AUX_SPI_STAT) & - BCM2835_AUX_SPI_STAT_RX_EMPTY))) { + for (; bs->rx_len && (stat & BCM2835_AUX_SPI_STAT_RX_LVL); + stat = bcm2835aux_rd(bs, BCM2835_AUX_SPI_STAT)) bcm2835aux_rd_fifo(bs); - ret = IRQ_HANDLED; - } /* check if we have data to write */ while (bs->tx_len && @@ -198,16 +193,21 @@ static irqreturn_t bcm2835aux_spi_interrupt(int irq, void *dev_id) (!(bcm2835aux_rd(bs, BCM2835_AUX_SPI_STAT) & BCM2835_AUX_SPI_STAT_TX_FULL))) { bcm2835aux_wr_fifo(bs); - ret = IRQ_HANDLED; } +} - /* and check if we have reached "done" */ - while (bs->rx_len && - (!(bcm2835aux_rd(bs, BCM2835_AUX_SPI_STAT) & - BCM2835_AUX_SPI_STAT_BUSY))) { - bcm2835aux_rd_fifo(bs); - ret = IRQ_HANDLED; - } +static irqreturn_t bcm2835aux_spi_interrupt(int irq, void *dev_id) +{ + struct spi_master *master = dev_id; + struct bcm2835aux_spi *bs = spi_master_get_devdata(master); + + /* IRQ may be shared, so return if our interrupts are disabled */ + if (!(bcm2835aux_rd(bs, BCM2835_AUX_SPI_CNTL1) & + (BCM2835_AUX_SPI_CNTL1_TXEMPTY | BCM2835_AUX_SPI_CNTL1_IDLE))) + return IRQ_NONE; + + /* do common fifo handling */ + bcm2835aux_spi_transfer_helper(bs); if (!bs->tx_len) { /* disable tx fifo empty interrupt */ @@ -221,8 +221,7 @@ static irqreturn_t bcm2835aux_spi_interrupt(int irq, void *dev_id) complete(&master->xfer_completion); } - /* and return */ - return ret; + return IRQ_HANDLED; } static int __bcm2835aux_spi_transfer_one_irq(struct spi_master *master, @@ -268,7 +267,6 @@ static int bcm2835aux_spi_transfer_one_poll(struct spi_master *master, { struct bcm2835aux_spi *bs = spi_master_get_devdata(master); unsigned long timeout; - u32 stat; /* configure spi */ bcm2835aux_wr(bs, BCM2835_AUX_SPI_CNTL1, bs->cntl[1]); @@ -279,24 +277,9 @@ static int bcm2835aux_spi_transfer_one_poll(struct spi_master *master, /* loop until finished the transfer */ while (bs->rx_len) { - /* read status */ - stat = bcm2835aux_rd(bs, BCM2835_AUX_SPI_STAT); - /* fill in tx fifo with remaining data */ - if ((bs->tx_len) && (!(stat & BCM2835_AUX_SPI_STAT_TX_FULL))) { - bcm2835aux_wr_fifo(bs); - continue; - } - - /* read data from fifo for both cases */ - if (!(stat & BCM2835_AUX_SPI_STAT_RX_EMPTY)) { - bcm2835aux_rd_fifo(bs); - continue; - } - if (!(stat & BCM2835_AUX_SPI_STAT_BUSY)) { - bcm2835aux_rd_fifo(bs); - continue; - } + /* do common fifo handling */ + bcm2835aux_spi_transfer_helper(bs); /* there is still data pending to read check the timeout */ if (bs->rx_len && time_after(jiffies, timeout)) { @@ -433,7 +416,18 @@ static int bcm2835aux_spi_probe(struct platform_device *pdev) platform_set_drvdata(pdev, master); master->mode_bits = (SPI_CPOL | SPI_CS_HIGH | SPI_NO_CS); master->bits_per_word_mask = SPI_BPW_MASK(8); - master->num_chipselect = -1; + /* even though the driver never officially supported native CS + * allow a single native CS for legacy DT support purposes when + * no cs-gpio is configured. + * Known limitations for native cs are: + * * multiple chip-selects: cs0-cs2 are all simultaniously asserted + * whenever there is a transfer - this even includes SPI_NO_CS + * * SPI_CS_HIGH: is ignores - cs are always asserted low + * * cs_change: cs is deasserted after each spi_transfer + * * cs_delay_usec: cs is always deasserted one SCK cycle after + * a spi_transfer + */ + 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; |