Current implementation only supports 8 bit word lengths, even though omap3 can handle anything between 4 and 32.
Update the spi interface to support changing the SPI word length, and implement it in omap3_spi driver to support the full range of possible word lengths. This implementation is backwards compatible by defaulting to the old behavior of 8 bit word lengths. Also, it required a change to the omap3_spi non static I/O functions, but since they are not used anywhere else, no collateral changes are required.
Cc: Tom Rini trini@ti.com Cc: Igor Grinberg grinberg@compulab.co.il Cc: Jagannadha Sutradharudu Teki jagannadh.teki@gmail.com Signed-off-by: Nikita Kiryanov nikita@compulab.co.il --- drivers/spi/omap3_spi.c | 78 ++++++++++++++++++++++++++++++++++++++----------- drivers/spi/omap3_spi.h | 11 ++++--- include/spi.h | 13 +++++++++ 3 files changed, 81 insertions(+), 21 deletions(-)
diff --git a/drivers/spi/omap3_spi.c b/drivers/spi/omap3_spi.c index 6bac245..add98e1 100644 --- a/drivers/spi/omap3_spi.c +++ b/drivers/spi/omap3_spi.c @@ -20,7 +20,7 @@ #include <asm/io.h> #include "omap3_spi.h"
-#define WORD_LEN 8 +#define SPI_DEFAULT_WORDLEN 8; #define SPI_WAIT_TIMEOUT 3000000;
static void spi_reset(struct omap3_spi_slave *ds) @@ -128,10 +128,32 @@ struct spi_slave *spi_setup_slave(unsigned int bus, unsigned int cs, ds->regs = regs; ds->freq = max_hz; ds->mode = mode; + ds->wordlen = SPI_DEFAULT_WORDLEN;
return &ds->slave; }
+int spi_set_wordlen(struct spi_slave *slave, unsigned int wordlen) +{ + struct omap3_spi_slave *ds; + int chconf; + + if (wordlen < 4 || wordlen > 32) { + printf("SPI error: unsupported wordlen %d\n", wordlen); + return -1; + } + + ds = to_omap3_spi(slave); + ds->wordlen = wordlen; + + chconf = readl(&ds->regs->channel[ds->slave.cs].chconf); + chconf &= ~OMAP3_MCSPI_CHCONF_WL_MASK; + chconf |= (wordlen - 1) << 7; + omap3_spi_write_chconf(ds, chconf); + + return 0; +} + void spi_free_slave(struct spi_slave *slave) { struct omap3_spi_slave *ds = to_omap3_spi(slave); @@ -185,7 +207,7 @@ int spi_claim_bus(struct spi_slave *slave)
/* wordlength */ conf &= ~OMAP3_MCSPI_CHCONF_WL_MASK; - conf |= (WORD_LEN - 1) << 7; + conf |= (ds->wordlen - 1) << 7;
/* set chipselect polarity; manage with FORCE */ if (!(ds->mode & SPI_CS_HIGH)) @@ -223,7 +245,7 @@ void spi_release_bus(struct spi_slave *slave) spi_reset(ds); }
-int omap3_spi_write(struct spi_slave *slave, unsigned int len, const u8 *txp, +int omap3_spi_write(struct spi_slave *slave, unsigned int len, const void *txp, unsigned long flags) { struct omap3_spi_slave *ds = to_omap3_spi(slave); @@ -250,7 +272,13 @@ int omap3_spi_write(struct spi_slave *slave, unsigned int len, const u8 *txp, } } /* Write the data */ - writel(txp[i], &ds->regs->channel[ds->slave.cs].tx); + unsigned int *tx = &ds->regs->channel[ds->slave.cs].tx; + if (ds->wordlen > 16) + writel(((u32 *)txp)[i], tx); + else if (ds->wordlen > 8) + writel(((u16 *)txp)[i], tx); + else + writel(((u8 *)txp)[i], tx); }
/* wait to finish of transfer */ @@ -268,7 +296,7 @@ int omap3_spi_write(struct spi_slave *slave, unsigned int len, const u8 *txp, return 0; }
-int omap3_spi_read(struct spi_slave *slave, unsigned int len, u8 *rxp, +int omap3_spi_read(struct spi_slave *slave, unsigned int len, void *rxp, unsigned long flags) { struct omap3_spi_slave *ds = to_omap3_spi(slave); @@ -302,7 +330,13 @@ int omap3_spi_read(struct spi_slave *slave, unsigned int len, u8 *rxp, omap3_spi_set_enable(ds,OMAP3_MCSPI_CHCTRL_DIS);
/* Read the data */ - rxp[i] = readl(&ds->regs->channel[ds->slave.cs].rx); + unsigned int *rx = &ds->regs->channel[ds->slave.cs].rx; + if (ds->wordlen > 16) + ((u32 *)rxp)[i] = readl(rx); + else if (ds->wordlen > 8) + ((u16 *)rxp)[i] = (u16)readl(rx); + else + ((u8 *)rxp)[i] = (u8)readl(rx); }
if (flags & SPI_XFER_END) { @@ -314,8 +348,8 @@ int omap3_spi_read(struct spi_slave *slave, unsigned int len, u8 *rxp, }
/*McSPI Transmit Receive Mode*/ -int omap3_spi_txrx(struct spi_slave *slave, - unsigned int len, const u8 *txp, u8 *rxp, unsigned long flags) +int omap3_spi_txrx(struct spi_slave *slave, unsigned int len, + const void *txp, void *rxp, unsigned long flags) { struct omap3_spi_slave *ds = to_omap3_spi(slave); int timeout = SPI_WAIT_TIMEOUT; @@ -344,7 +378,13 @@ int omap3_spi_txrx(struct spi_slave *slave, } } /* Write the data */ - writel(txp[i], &ds->regs->channel[ds->slave.cs].tx); + unsigned int *tx = &ds->regs->channel[ds->slave.cs].tx; + if (ds->wordlen > 16) + writel(((u32 *)txp)[i], tx); + else if (ds->wordlen > 8) + writel(((u16 *)txp)[i], tx); + else + writel(((u8 *)txp)[i], tx);
/*Read: wait for RX containing data (RXS == 1)*/ while (!(readl(&ds->regs->channel[ds->slave.cs].chstat) & @@ -356,7 +396,13 @@ int omap3_spi_txrx(struct spi_slave *slave, } } /* Read the data */ - rxp[i] = readl(&ds->regs->channel[ds->slave.cs].rx); + unsigned int *rx = &ds->regs->channel[ds->slave.cs].rx; + if (ds->wordlen > 16) + ((u32 *)rxp)[i] = readl(rx); + else if (ds->wordlen > 8) + ((u16 *)rxp)[i] = (u16)readl(rx); + else + ((u8 *)rxp)[i] = (u8)readl(rx); } /* Disable the channel */ omap3_spi_set_enable(ds,OMAP3_MCSPI_CHCTRL_DIS); @@ -375,14 +421,12 @@ int spi_xfer(struct spi_slave *slave, unsigned int bitlen, { struct omap3_spi_slave *ds = to_omap3_spi(slave); unsigned int len; - const u8 *txp = dout; - u8 *rxp = din; int ret = -1;
- if (bitlen % 8) + if (bitlen % ds->wordlen) return -1;
- len = bitlen / 8; + len = bitlen / ds->wordlen;
if (bitlen == 0) { /* only change CS */ int chconf = readl(&ds->regs->channel[ds->slave.cs].chconf); @@ -400,11 +444,11 @@ int spi_xfer(struct spi_slave *slave, unsigned int bitlen, ret = 0; } else { if (dout != NULL && din != NULL) - ret = omap3_spi_txrx(slave, len, txp, rxp, flags); + ret = omap3_spi_txrx(slave, len, dout, din, flags); else if (dout != NULL) - ret = omap3_spi_write(slave, len, txp, flags); + ret = omap3_spi_write(slave, len, dout, flags); else if (din != NULL) - ret = omap3_spi_read(slave, len, rxp, flags); + ret = omap3_spi_read(slave, len, din, flags); } return ret; } diff --git a/drivers/spi/omap3_spi.h b/drivers/spi/omap3_spi.h index 01537b6..aeddb53 100644 --- a/drivers/spi/omap3_spi.h +++ b/drivers/spi/omap3_spi.h @@ -92,6 +92,7 @@ struct omap3_spi_slave { struct mcspi *regs; unsigned int freq; unsigned int mode; + unsigned int wordlen; };
static inline struct omap3_spi_slave *to_omap3_spi(struct spi_slave *slave) @@ -99,11 +100,13 @@ static inline struct omap3_spi_slave *to_omap3_spi(struct spi_slave *slave) return container_of(slave, struct omap3_spi_slave, slave); }
-int omap3_spi_txrx(struct spi_slave *slave, unsigned int len, const u8 *txp, - u8 *rxp, unsigned long flags); -int omap3_spi_write(struct spi_slave *slave, unsigned int len, const u8 *txp, +int omap3_spi_set_wordlen(struct spi_slave *slave, unsigned int wordlen); + +int omap3_spi_txrx(struct spi_slave *slave, unsigned int len, const void *txp, + void *rxp, unsigned long flags); +int omap3_spi_write(struct spi_slave *slave, unsigned int len, const void *txp, unsigned long flags); -int omap3_spi_read(struct spi_slave *slave, unsigned int len, u8 *rxp, +int omap3_spi_read(struct spi_slave *slave, unsigned int len, void *rxp, unsigned long flags);
#endif /* _OMAP3_SPI_H_ */ diff --git a/include/spi.h b/include/spi.h index c0dab57..ae318ff 100644 --- a/include/spi.h +++ b/include/spi.h @@ -149,6 +149,19 @@ int spi_claim_bus(struct spi_slave *slave); void spi_release_bus(struct spi_slave *slave);
/*----------------------------------------------------------------------- + * Set the word length for SPI transactions + * + * Set the word length (number of bits per word) for SPI transactions. + * This setting is persistent until changed. + * + * slave: The SPI slave + * wordlen: The number of bits in a word + * + * Returns: 0 on success, -1 on failure. + */ +int spi_set_wordlen(struct spi_slave *slave, unsigned int wordlen); + +/*----------------------------------------------------------------------- * SPI transfer * * This writes "bitlen" bits out the SPI MOSI port and simultaneously clocks