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spi: omap3: add support for more word lengths

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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>
master
Nikita Kiryanov 11 years ago committed by Anatolij Gustschin
parent 54a759c880
commit 5753d09b10
4 changed files with 82 additions and 24 deletions
Show all changes Ignore whitespace when comparing lines Ignore changes in amount of whitespace Ignore changes in whitespace at EOL
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  1. 69
      drivers/spi/omap3_spi.c
  2. 8
      drivers/spi/omap3_spi.h
  3. 13
      drivers/spi/spi.c
  4. 16
      include/spi.h

69
drivers/spi/omap3_spi.c
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@ -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 @@ int spi_claim_bus(struct spi_slave *slave)
/* 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 @@ 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);
@ -234,7 +233,8 @@ int omap3_spi_write(struct spi_slave *slave, unsigned int len, const u8 *txp,
/* 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 @@ 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->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 @@ 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);
@ -279,7 +285,8 @@ int omap3_spi_read(struct spi_slave *slave, unsigned int len, u8 *rxp,
/* 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 @@ 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->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 @@ 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;
@ -327,7 +340,8 @@ int omap3_spi_txrx(struct spi_slave *slave,
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 @@ 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->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 @@ 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->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 @@ 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 (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 @@ 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;
}

8
drivers/spi/omap3_spi.h
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@ -99,11 +99,11 @@ 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_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_ */

13
drivers/spi/spi.c
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@ -8,6 +8,18 @@
#include <malloc.h>
#include <spi.h>
int spi_set_wordlen(struct spi_slave *slave, unsigned int wordlen)
{
if (wordlen == 0 || wordlen > 32) {
printf("spi: invalid wordlen %d\n", wordlen);
return -1;
}
slave->wordlen = wordlen;
return 0;
}
void *spi_do_alloc_slave(int offset, int size, unsigned int bus,
unsigned int cs)
{
@ -20,6 +32,7 @@ void *spi_do_alloc_slave(int offset, int size, unsigned int bus,
slave = (struct spi_slave *)(ptr + offset);
slave->bus = bus;
slave->cs = cs;
slave->wordlen = SPI_DEFAULT_WORDLEN;
}
return ptr;

16
include/spi.h
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@ -33,6 +33,8 @@
/* Header byte that marks the start of the message */
#define SPI_PREAMBLE_END_BYTE 0xec
#define SPI_DEFAULT_WORDLEN 8
/**
* struct spi_slave - Representation of a SPI slave
*
@ -40,6 +42,7 @@
*
* @bus: ID of the bus that the slave is attached to.
* @cs: ID of the chip select connected to the slave.
* @wordlen: Size of SPI word in number of bits
* @max_write_size: If non-zero, the maximum number of bytes which can
* be written at once, excluding command bytes.
* @memory_map: Address of read-only SPI flash access.
@ -47,6 +50,7 @@
struct spi_slave {
unsigned int bus;
unsigned int cs;
unsigned int wordlen;
unsigned int max_write_size;
void *memory_map;
};
@ -153,6 +157,18 @@ 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.
*
* @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

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