From: ajoy akdas75@yahoo.in
Added posted writes (read after writes) to effect the change immediately for channel confiuration and channel enable register
Disable the channel to purge receieve data in TX_ONLY mode transfer otherwise rx data will get affected by the next immediate RX_ONLY mode transfer
Wait for the EOT bit to be set after last byte has been loaded to TX shift register in the the TX_ONLY mode.This ensures TX data has been completely shifted out
Disable the channel in RX_ONLY mode before reading the last data from RXX register to prevent the SPI slave to transmit next word
Signed-off-by: Ajoy Kumar Das akdas75@yahoo.in Cc: Tom Rini trini@ti.com Cc: jacopo mondi j.mondi@voltaelectronics.com --- drivers/spi/omap3_spi.c | 84 +++++++++++++++++++++++++++-------------------- drivers/spi/omap3_spi.h | 1 + 2 files changed, 49 insertions(+), 36 deletions(-)
diff --git a/drivers/spi/omap3_spi.c b/drivers/spi/omap3_spi.c index 6791a7e..dd4ae7c 100644 --- a/drivers/spi/omap3_spi.c +++ b/drivers/spi/omap3_spi.c @@ -57,6 +57,20 @@ static void spi_reset(struct omap3_spi_slave *ds) writel(OMAP3_MCSPI_WAKEUPENABLE_WKEN, &ds->regs->wakeupenable); }
+static void omap3_spi_write_chconf(struct omap3_spi_slave *ds, int val) +{ + writel(val, &ds->regs->channel[ds->slave.cs].chconf); + /* Flash post writes to make immediate effect */ + readl(&ds->regs->channel[ds->slave.cs].chconf); +} + +static void omap3_spi_set_enable(struct omap3_spi_slave *ds, int enable) +{ + writel(enable, &ds->regs->channel[ds->slave.cs].chctrl); + /* Flash post writes to make immediate effect */ + readl(&ds->regs->channel[ds->slave.cs].chctrl); +} + void spi_init() { /* do nothing */ @@ -211,8 +225,8 @@ int spi_claim_bus(struct spi_slave *slave)
/* Transmit & receive mode */ conf &= ~OMAP3_MCSPI_CHCONF_TRM_MASK; - - writel(conf, &ds->regs->channel[ds->slave.cs].chconf); + + omap3_spi_write_chconf(ds,conf);
return 0; } @@ -233,14 +247,13 @@ int omap3_spi_write(struct spi_slave *slave, unsigned int len, const u8 *txp, int timeout = SPI_WAIT_TIMEOUT; int chconf = readl(&ds->regs->channel[ds->slave.cs].chconf);
- if (flags & SPI_XFER_BEGIN) - writel(OMAP3_MCSPI_CHCTRL_EN, - &ds->regs->channel[ds->slave.cs].chctrl); + /* Enable the channel */ + omap3_spi_set_enable(ds,OMAP3_MCSPI_CHCTRL_EN);
chconf &= ~OMAP3_MCSPI_CHCONF_TRM_MASK; chconf |= OMAP3_MCSPI_CHCONF_TRM_TX_ONLY; chconf |= OMAP3_MCSPI_CHCONF_FORCE; - writel(chconf, &ds->regs->channel[ds->slave.cs].chconf); + omap3_spi_write_chconf(ds,chconf);
for (i = 0; i < len; i++) { /* wait till TX register is empty (TXS == 1) */ @@ -256,15 +269,17 @@ int omap3_spi_write(struct spi_slave *slave, unsigned int len, const u8 *txp, writel(txp[i], &ds->regs->channel[ds->slave.cs].tx); }
+ /* wait to finish of transfer */ + while (!(readl(&ds->regs->channel[ds->slave.cs].chstat) & + OMAP3_MCSPI_CHSTAT_EOT)); + + /* Disable the channel otherwise the next immediate RX will get affected */ + omap3_spi_set_enable(ds,OMAP3_MCSPI_CHCTRL_DIS); + if (flags & SPI_XFER_END) { - /* wait to finish of transfer */ - while (!(readl(&ds->regs->channel[ds->slave.cs].chstat) & - OMAP3_MCSPI_CHSTAT_EOT));
chconf &= ~OMAP3_MCSPI_CHCONF_FORCE; - writel(chconf, &ds->regs->channel[ds->slave.cs].chconf); - - writel(0, &ds->regs->channel[ds->slave.cs].chctrl); + omap3_spi_write_chconf(ds,chconf); } return 0; } @@ -277,15 +292,14 @@ int omap3_spi_read(struct spi_slave *slave, unsigned int len, u8 *rxp, int timeout = SPI_WAIT_TIMEOUT; int chconf = readl(&ds->regs->channel[ds->slave.cs].chconf);
- if (flags & SPI_XFER_BEGIN) - writel(OMAP3_MCSPI_CHCTRL_EN, - &ds->regs->channel[ds->slave.cs].chctrl); + /* Enable the channel */ + omap3_spi_set_enable(ds,OMAP3_MCSPI_CHCTRL_EN);
chconf &= ~OMAP3_MCSPI_CHCONF_TRM_MASK; chconf |= OMAP3_MCSPI_CHCONF_TRM_RX_ONLY; chconf |= OMAP3_MCSPI_CHCONF_FORCE; - writel(chconf, &ds->regs->channel[ds->slave.cs].chconf); - + omap3_spi_write_chconf(ds,chconf); + writel(0, &ds->regs->channel[ds->slave.cs].tx);
for (i = 0; i < len; i++) { @@ -298,15 +312,18 @@ int omap3_spi_read(struct spi_slave *slave, unsigned int len, u8 *rxp, return -1; } } + + /* Disable the channel to prevent furher receiving */ + if(i == (len - 1)) + omap3_spi_set_enable(ds,OMAP3_MCSPI_CHCTRL_DIS); + /* Read the data */ rxp[i] = readl(&ds->regs->channel[ds->slave.cs].rx); }
if (flags & SPI_XFER_END) { chconf &= ~OMAP3_MCSPI_CHCONF_FORCE; - writel(chconf, &ds->regs->channel[ds->slave.cs].chconf); - - writel(0, &ds->regs->channel[ds->slave.cs].chctrl); + omap3_spi_write_chconf(ds,chconf); }
return 0; @@ -323,15 +340,13 @@ int omap3_spi_txrx(struct spi_slave *slave, int i=0;
/*Enable SPI channel*/ - if (flags & SPI_XFER_BEGIN) - writel(OMAP3_MCSPI_CHCTRL_EN, - &ds->regs->channel[ds->slave.cs].chctrl); - + omap3_spi_set_enable(ds,OMAP3_MCSPI_CHCTRL_EN); + /*set TRANSMIT-RECEIVE Mode*/ chconf &= ~OMAP3_MCSPI_CHCONF_TRM_MASK; chconf |= OMAP3_MCSPI_CHCONF_FORCE; - writel(chconf, &ds->regs->channel[ds->slave.cs].chconf); - + omap3_spi_write_chconf(ds,chconf); + /*Shift in and out 1 byte at time*/ for (i=0; i < len; i++){ /* Write: wait for TX empty (TXS == 1)*/ @@ -359,13 +374,13 @@ int omap3_spi_txrx(struct spi_slave *slave, /* Read the data */ rxp[i] = readl(&ds->regs->channel[ds->slave.cs].rx); } + /* Disable the channel */ + omap3_spi_set_enable(ds,OMAP3_MCSPI_CHCTRL_DIS);
/*if transfer must be terminated disable the channel*/ if (flags & SPI_XFER_END) { chconf &= ~OMAP3_MCSPI_CHCONF_FORCE; - writel(chconf, &ds->regs->channel[ds->slave.cs].chconf); - - writel(0, &ds->regs->channel[ds->slave.cs].chctrl); + omap3_spi_write_chconf(ds,chconf); }
return 0; @@ -389,17 +404,14 @@ int spi_xfer(struct spi_slave *slave, unsigned int bitlen, int chconf = readl(&ds->regs->channel[ds->slave.cs].chconf);
if (flags & SPI_XFER_BEGIN) { - writel(OMAP3_MCSPI_CHCTRL_EN, - &ds->regs->channel[ds->slave.cs].chctrl); + omap3_spi_set_enable(ds,OMAP3_MCSPI_CHCTRL_EN); chconf |= OMAP3_MCSPI_CHCONF_FORCE; - writel(chconf, - &ds->regs->channel[ds->slave.cs].chconf); + omap3_spi_write_chconf(ds,chconf); } if (flags & SPI_XFER_END) { chconf &= ~OMAP3_MCSPI_CHCONF_FORCE; - writel(chconf, - &ds->regs->channel[ds->slave.cs].chconf); - writel(0, &ds->regs->channel[ds->slave.cs].chctrl); + omap3_spi_write_chconf(ds,chconf); + omap3_spi_set_enable(ds,OMAP3_MCSPI_CHCTRL_DIS); } ret = 0; } else { diff --git a/drivers/spi/omap3_spi.h b/drivers/spi/omap3_spi.h index bffa43c..5e00208 100644 --- a/drivers/spi/omap3_spi.h +++ b/drivers/spi/omap3_spi.h @@ -99,6 +99,7 @@ struct mcspi { #define OMAP3_MCSPI_CHSTAT_EOT (1 << 2)
#define OMAP3_MCSPI_CHCTRL_EN (1 << 0) +#define OMAP3_MCSPI_CHCTRL_DIS (0 << 0)
#define OMAP3_MCSPI_WAKEUPENABLE_WKEN (1 << 0)