spi: omap3: add support for more word lengths
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: Jagannadha Sutradharudu Teki <jagannadh.teki@gmail.com>
Cc: Igor Grinberg <grinberg@compulab.co.il>
Signed-off-by: Nikita Kiryanov <nikita@compulab.co.il>
diff --git a/drivers/spi/omap3_spi.c b/drivers/spi/omap3_spi.c
index 116276c..a3ad056 100644
--- a/drivers/spi/omap3_spi.c
+++ b/drivers/spi/omap3_spi.c
@@ -20,7 +20,6 @@
#include <asm/io.h>
#include "omap3_spi.h"
-#define WORD_LEN 8
#define SPI_WAIT_TIMEOUT 3000000
static void spi_reset(struct omap3_spi_slave *ds)
@@ -185,7 +184,7 @@
/* wordlength */
conf &= ~OMAP3_MCSPI_CHCONF_WL_MASK;
- conf |= (WORD_LEN - 1) << 7;
+ conf |= (ds->slave.wordlen - 1) << 7;
/* set chipselect polarity; manage with FORCE */
if (!(ds->mode & SPI_CS_HIGH))
@@ -223,7 +222,7 @@
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);
@@ -234,7 +233,8 @@
/* Enable the channel */
omap3_spi_set_enable(ds,OMAP3_MCSPI_CHCTRL_EN);
- chconf &= ~OMAP3_MCSPI_CHCONF_TRM_MASK;
+ chconf &= ~(OMAP3_MCSPI_CHCONF_TRM_MASK | OMAP3_MCSPI_CHCONF_WL_MASK);
+ chconf |= (ds->slave.wordlen - 1) << 7;
chconf |= OMAP3_MCSPI_CHCONF_TRM_TX_ONLY;
chconf |= OMAP3_MCSPI_CHCONF_FORCE;
omap3_spi_write_chconf(ds,chconf);
@@ -250,7 +250,13 @@
}
}
/* 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->slave.wordlen > 16)
+ writel(((u32 *)txp)[i], tx);
+ else if (ds->slave.wordlen > 8)
+ writel(((u16 *)txp)[i], tx);
+ else
+ writel(((u8 *)txp)[i], tx);
}
/* wait to finish of transfer */
@@ -268,7 +274,7 @@
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);
@@ -279,7 +285,8 @@
/* Enable the channel */
omap3_spi_set_enable(ds,OMAP3_MCSPI_CHCTRL_EN);
- chconf &= ~OMAP3_MCSPI_CHCONF_TRM_MASK;
+ chconf &= ~(OMAP3_MCSPI_CHCONF_TRM_MASK | OMAP3_MCSPI_CHCONF_WL_MASK);
+ chconf |= (ds->slave.wordlen - 1) << 7;
chconf |= OMAP3_MCSPI_CHCONF_TRM_RX_ONLY;
chconf |= OMAP3_MCSPI_CHCONF_FORCE;
omap3_spi_write_chconf(ds,chconf);
@@ -302,7 +309,13 @@
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->slave.wordlen > 16)
+ ((u32 *)rxp)[i] = readl(rx);
+ else if (ds->slave.wordlen > 8)
+ ((u16 *)rxp)[i] = (u16)readl(rx);
+ else
+ ((u8 *)rxp)[i] = (u8)readl(rx);
}
if (flags & SPI_XFER_END) {
@@ -314,8 +327,8 @@
}
/*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;
@@ -327,7 +340,8 @@
omap3_spi_set_enable(ds,OMAP3_MCSPI_CHCTRL_EN);
/*set TRANSMIT-RECEIVE Mode*/
- chconf &= ~OMAP3_MCSPI_CHCONF_TRM_MASK;
+ chconf &= ~(OMAP3_MCSPI_CHCONF_TRM_MASK | OMAP3_MCSPI_CHCONF_WL_MASK);
+ chconf |= (ds->slave.wordlen - 1) << 7;
chconf |= OMAP3_MCSPI_CHCONF_FORCE;
omap3_spi_write_chconf(ds,chconf);
@@ -344,7 +358,13 @@
}
}
/* 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->slave.wordlen > 16)
+ writel(((u32 *)txp)[i], tx);
+ else if (ds->slave.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 +376,13 @@
}
}
/* 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->slave.wordlen > 16)
+ ((u32 *)rxp)[i] = readl(rx);
+ else if (ds->slave.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 +401,17 @@
{
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 (ds->slave.wordlen < 4 || ds->slave.wordlen > 32) {
+ printf("omap3_spi: invalid wordlen %d\n", ds->slave.wordlen);
+ return -1;
+ }
+
+ if (bitlen % ds->slave.wordlen)
return -1;
- len = bitlen / 8;
+ len = bitlen / ds->slave.wordlen;
if (bitlen == 0) { /* only change CS */
int chconf = readl(&ds->regs->channel[ds->slave.cs].chconf);
@@ -400,11 +429,11 @@
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;
}