diff options
Diffstat (limited to 'drivers/spi/xilinx_spi.c')
-rw-r--r-- | drivers/spi/xilinx_spi.c | 118 |
1 files changed, 87 insertions, 31 deletions
diff --git a/drivers/spi/xilinx_spi.c b/drivers/spi/xilinx_spi.c index 135a3a5931a4..b927812822c1 100644 --- a/drivers/spi/xilinx_spi.c +++ b/drivers/spi/xilinx_spi.c @@ -27,7 +27,7 @@ /* Register definitions as per "OPB Serial Peripheral Interface (SPI) (v1.00e) * Product Specification", DS464 */ -#define XSPI_CR_OFFSET 0x60 /* 16-bit Control Register */ +#define XSPI_CR_OFFSET 0x60 /* Control Register */ #define XSPI_CR_ENABLE 0x02 #define XSPI_CR_MASTER_MODE 0x04 @@ -38,8 +38,9 @@ #define XSPI_CR_RXFIFO_RESET 0x40 #define XSPI_CR_MANUAL_SSELECT 0x80 #define XSPI_CR_TRANS_INHIBIT 0x100 +#define XSPI_CR_LSB_FIRST 0x200 -#define XSPI_SR_OFFSET 0x64 /* 8-bit Status Register */ +#define XSPI_SR_OFFSET 0x64 /* Status Register */ #define XSPI_SR_RX_EMPTY_MASK 0x01 /* Receive FIFO is empty */ #define XSPI_SR_RX_FULL_MASK 0x02 /* Receive FIFO is full */ @@ -47,8 +48,8 @@ #define XSPI_SR_TX_FULL_MASK 0x08 /* Transmit FIFO is full */ #define XSPI_SR_MODE_FAULT_MASK 0x10 /* Mode fault error */ -#define XSPI_TXD_OFFSET 0x68 /* 8-bit Data Transmit Register */ -#define XSPI_RXD_OFFSET 0x6c /* 8-bit Data Receive Register */ +#define XSPI_TXD_OFFSET 0x68 /* Data Transmit Register */ +#define XSPI_RXD_OFFSET 0x6c /* Data Receive Register */ #define XSPI_SSR_OFFSET 0x70 /* 32-bit Slave Select Register */ @@ -68,6 +69,7 @@ #define XSPI_INTR_TX_UNDERRUN 0x08 /* TxFIFO was underrun */ #define XSPI_INTR_RX_FULL 0x10 /* RxFIFO is full */ #define XSPI_INTR_RX_OVERRUN 0x20 /* RxFIFO was overrun */ +#define XSPI_INTR_TX_HALF_EMPTY 0x40 /* TxFIFO is half empty */ #define XIPIF_V123B_RESETR_OFFSET 0x40 /* IPIF reset register */ #define XIPIF_V123B_RESET_MASK 0x0a /* the value to write */ @@ -81,15 +83,61 @@ struct xilinx_spi { u32 irq; - u32 speed_hz; /* SCK has a fixed frequency of speed_hz Hz */ - u8 *rx_ptr; /* pointer in the Tx buffer */ const u8 *tx_ptr; /* pointer in the Rx buffer */ int remaining_bytes; /* the number of bytes left to transfer */ + u8 bits_per_word; unsigned int (*read_fn) (void __iomem *); void (*write_fn) (u32, void __iomem *); + void (*tx_fn) (struct xilinx_spi *); + void (*rx_fn) (struct xilinx_spi *); }; +static void xspi_tx8(struct xilinx_spi *xspi) +{ + xspi->write_fn(*xspi->tx_ptr, xspi->regs + XSPI_TXD_OFFSET); + xspi->tx_ptr++; +} + +static void xspi_tx16(struct xilinx_spi *xspi) +{ + xspi->write_fn(*(u16 *)(xspi->tx_ptr), xspi->regs + XSPI_TXD_OFFSET); + xspi->tx_ptr += 2; +} + +static void xspi_tx32(struct xilinx_spi *xspi) +{ + xspi->write_fn(*(u32 *)(xspi->tx_ptr), xspi->regs + XSPI_TXD_OFFSET); + xspi->tx_ptr += 4; +} + +static void xspi_rx8(struct xilinx_spi *xspi) +{ + u32 data = xspi->read_fn(xspi->regs + XSPI_RXD_OFFSET); + if (xspi->rx_ptr) { + *xspi->rx_ptr = data & 0xff; + xspi->rx_ptr++; + } +} + +static void xspi_rx16(struct xilinx_spi *xspi) +{ + u32 data = xspi->read_fn(xspi->regs + XSPI_RXD_OFFSET); + if (xspi->rx_ptr) { + *(u16 *)(xspi->rx_ptr) = data & 0xffff; + xspi->rx_ptr += 2; + } +} + +static void xspi_rx32(struct xilinx_spi *xspi) +{ + u32 data = xspi->read_fn(xspi->regs + XSPI_RXD_OFFSET); + if (xspi->rx_ptr) { + *(u32 *)(xspi->rx_ptr) = data; + xspi->rx_ptr += 4; + } +} + static void xspi_init_hw(struct xilinx_spi *xspi) { void __iomem *regs_base = xspi->regs; @@ -107,8 +155,8 @@ static void xspi_init_hw(struct xilinx_spi *xspi) /* Disable the transmitter, enable Manual Slave Select Assertion, * put SPI controller into master mode, and enable it */ xspi->write_fn(XSPI_CR_TRANS_INHIBIT | XSPI_CR_MANUAL_SSELECT | - XSPI_CR_MASTER_MODE | XSPI_CR_ENABLE, - regs_base + XSPI_CR_OFFSET); + XSPI_CR_MASTER_MODE | XSPI_CR_ENABLE | XSPI_CR_TXFIFO_RESET | + XSPI_CR_RXFIFO_RESET, regs_base + XSPI_CR_OFFSET); } static void xilinx_spi_chipselect(struct spi_device *spi, int is_on) @@ -141,18 +189,20 @@ static void xilinx_spi_chipselect(struct spi_device *spi, int is_on) /* spi_bitbang requires custom setup_transfer() to be defined if there is a * custom txrx_bufs(). We have nothing to setup here as the SPI IP block - * supports just 8 bits per word, and SPI clock can't be changed in software. - * Check for 8 bits per word. Chip select delay calculations could be + * supports 8 or 16 bits per word which cannot be changed in software. + * SPI clock can't be changed in software either. + * Check for correct bits per word. Chip select delay calculations could be * added here as soon as bitbang_work() can be made aware of the delay value. */ static int xilinx_spi_setup_transfer(struct spi_device *spi, struct spi_transfer *t) { + struct xilinx_spi *xspi = spi_master_get_devdata(spi->master); u8 bits_per_word; bits_per_word = (t && t->bits_per_word) ? t->bits_per_word : spi->bits_per_word; - if (bits_per_word != 8) { + if (bits_per_word != xspi->bits_per_word) { dev_err(&spi->dev, "%s, unsupported bits_per_word=%d\n", __func__, bits_per_word); return -EINVAL; @@ -163,17 +213,16 @@ static int xilinx_spi_setup_transfer(struct spi_device *spi, static int xilinx_spi_setup(struct spi_device *spi) { - struct spi_bitbang *bitbang; - struct xilinx_spi *xspi; - int retval; - - xspi = spi_master_get_devdata(spi->master); - bitbang = &xspi->bitbang; - - retval = xilinx_spi_setup_transfer(spi, NULL); - if (retval < 0) - return retval; - + /* always return 0, we can not check the number of bits. + * There are cases when SPI setup is called before any driver is + * there, in that case the SPI core defaults to 8 bits, which we + * do not support in some cases. But if we return an error, the + * SPI device would not be registered and no driver can get hold of it + * When the driver is there, it will call SPI setup again with the + * correct number of bits per transfer. + * If a driver setups with the wrong bit number, it will fail when + * it tries to do a transfer + */ return 0; } @@ -185,11 +234,10 @@ static void xilinx_spi_fill_tx_fifo(struct xilinx_spi *xspi) sr = xspi->read_fn(xspi->regs + XSPI_SR_OFFSET); while ((sr & XSPI_SR_TX_FULL_MASK) == 0 && xspi->remaining_bytes > 0) { if (xspi->tx_ptr) - xspi->write_fn(*xspi->tx_ptr++, - xspi->regs + XSPI_TXD_OFFSET); + xspi->tx_fn(xspi); else xspi->write_fn(0, xspi->regs + XSPI_TXD_OFFSET); - xspi->remaining_bytes--; + xspi->remaining_bytes -= xspi->bits_per_word / 8; sr = xspi->read_fn(xspi->regs + XSPI_SR_OFFSET); } } @@ -260,12 +308,7 @@ static irqreturn_t xilinx_spi_irq(int irq, void *dev_id) /* Read out all the data from the Rx FIFO */ sr = xspi->read_fn(xspi->regs + XSPI_SR_OFFSET); while ((sr & XSPI_SR_RX_EMPTY_MASK) == 0) { - u8 data; - - data = xspi->read_fn(xspi->regs + XSPI_RXD_OFFSET); - if (xspi->rx_ptr) { - *xspi->rx_ptr++ = data; - } + xspi->rx_fn(xspi); sr = xspi->read_fn(xspi->regs + XSPI_SR_OFFSET); } @@ -337,6 +380,19 @@ struct spi_master *xilinx_spi_init(struct device *dev, struct resource *mem, xspi->read_fn = ioread32be; xspi->write_fn = iowrite32be; } + xspi->bits_per_word = pdata->bits_per_word; + if (xspi->bits_per_word == 8) { + xspi->tx_fn = xspi_tx8; + xspi->rx_fn = xspi_rx8; + } else if (xspi->bits_per_word == 16) { + xspi->tx_fn = xspi_tx16; + xspi->rx_fn = xspi_rx16; + } else if (xspi->bits_per_word == 32) { + xspi->tx_fn = xspi_tx32; + xspi->rx_fn = xspi_rx32; + } else + goto unmap_io; + /* SPI controller initializations */ xspi_init_hw(xspi); |