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path: root/drivers/spi/omap3_spi.c
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Diffstat (limited to 'drivers/spi/omap3_spi.c')
-rw-r--r--drivers/spi/omap3_spi.c76
1 files changed, 44 insertions, 32 deletions
diff --git a/drivers/spi/omap3_spi.c b/drivers/spi/omap3_spi.c
index 6791a7e..344d5b8 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 */
@@ -212,7 +226,7 @@ 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;
}
@@ -277,14 +292,13 @@ 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);
@@ -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;
@@ -323,14 +340,12 @@ 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++){
@@ -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 {
generated by cgit v1.1 at 2024-12-19 02:52:38 +0000