[U-Boot] [PATCH 1/3] spi: omap3: add support for more word lengths
Nikita Kiryanov
nikita at compulab.co.il
Wed Oct 9 16:46:03 CEST 2013
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 at ti.com>
Cc: Igor Grinberg <grinberg at compulab.co.il>
Cc: Jagannadha Sutradharudu Teki <jagannadh.teki at gmail.com>
Signed-off-by: Nikita Kiryanov <nikita at 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
--
1.8.1.2
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