[PATCH v3 1/2]spi: DUAL and QUAD support
wangyuhang
wangyuhang2014 at gmail.com
Sun Aug 11 06:15:17 EDT 2013
fix the previous patch some mistake below:
1. DT in slave node, use "spi-tx-nbits = <1/2/4>" in place of using
"spi-tx-dual, spi-tx-quad" directly, same to rx. So correct the
previous way to get the property in @of_register_spi_devices().
2. Change the value of transfer bit macro(SPI_NBITS_SINGLE, SPI_NBITS_DUAL
SPI_NBITS_QUAD) to 0x01, 0x02 and 0x04 to match the actual wires.
3. Add the following check
(1)keep the tx_nbits and rx_nbits in spi_transfer is not beyond the
single, dual and quad.
(2)keep tx_nbits and rx_nbits are contained by @spi_device->mode
example: if @spi_device->mode = DUAL, then tx/rx_nbits can not be set
to QUAD(SPI_NBITS_QUAD)
(3)if "@spi_device->mode & SPI_3WIRE", then tx/rx_nbits should be in
single(SPI_NBITS_SINGLE)
Signed-off-by: wangyuhang <wangyuhang2014 at gmail.com>
---
drivers/spi/spi.c | 96 +++++++++++++++++++++++++++++++++++++++++++++++
include/linux/spi/spi.h | 22 ++++++++++-
2 files changed, 116 insertions(+), 2 deletions(-)
diff --git a/drivers/spi/spi.c b/drivers/spi/spi.c
index 004b10f..78f257a 100644
--- a/drivers/spi/spi.c
+++ b/drivers/spi/spi.c
@@ -869,6 +869,51 @@ static void of_register_spi_devices(struct spi_master *master)
if (of_find_property(nc, "spi-3wire", NULL))
spi->mode |= SPI_3WIRE;
+ /* Device DUAL/QUAD mode */
+ prop = of_get_property(nc, "spi-tx-nbits", &len);
+ if (!prop || len < sizeof(*prop)) {
+ dev_err(&master->dev, "%s has no 'spi-tx-nbits' property\n",
+ nc->full_name);
+ spi_dev_put(spi);
+ continue;
+ }
+ switch(be32_to_cpup(prop)) {
+ case SPI_NBITS_SINGLE:
+ break;
+ case SPI_NBITS_DUAL:
+ spi->mode |= SPI_TX_DUAL;
+ break;
+ case SPI_NBITS_QUAD:
+ spi->mode |= SPI_TX_QUAD;
+ break;
+ default:
+ dev_err(&master->dev, "spi-tx-nbits value is not supported\n");
+ spi_dev_put(spi);
+ continue;
+ }
+
+ prop = of_get_property(nc, "spi-rx-nbits", &len);
+ if (!prop || len < sizeof(*prop)) {
+ dev_err(&master->dev, "%s has no 'spi-rx-nbits' property\n",
+ nc->full_name);
+ spi_dev_put(spi);
+ continue;
+ }
+ switch(be32_to_cpup(prop)) {
+ case SPI_NBITS_SINGLE:
+ break;
+ case SPI_NBITS_DUAL:
+ spi->mode |= SPI_RX_DUAL;
+ break;
+ case SPI_NBITS_QUAD:
+ spi->mode |= SPI_RX_QUAD;
+ break;
+ default:
+ dev_err(&master->dev, "spi-rx-nbits value is not supported\n");
+ spi_dev_put(spi);
+ continue;
+ }
+
/* Device speed */
prop = of_get_property(nc, "spi-max-frequency", &len);
if (!prop || len < sizeof(*prop)) {
@@ -1313,6 +1358,19 @@ int spi_setup(struct spi_device *spi)
unsigned bad_bits;
int status = 0;
+ /* check mode to prevent that DUAL and QUAD set at the same time
+ */
+ if (((spi->mode & SPI_TX_DUAL) && (spi->mode & SPI_TX_QUAD)) ||
+ ((spi->mode & SPI_RX_DUAL) && (spi->mode & SPI_RX_QUAD))) {
+ dev_err(&spi->dev,
+ "setup: can not select dual and quad at the same time\n");
+ return -EINVAL;
+ }
+ /* if it is SPI_3WIRE mode, DUAL and QUAD should be forbidden
+ */
+ if ((spi->mode & SPI_3WIRE) && (spi->mode &
+ (SPI_TX_DUAL | SPI_TX_QUAD | SPI_RX_DUAL | SPI_RX_QUAD)))
+ return -EINVAL;
/* help drivers fail *cleanly* when they need options
* that aren't supported with their current master
*/
@@ -1370,12 +1428,50 @@ static int __spi_async(struct spi_device *spi, struct spi_message *message)
/**
* Set transfer bits_per_word and max speed as spi device default if
* it is not set for this transfer.
+ * Set transfer tx_nbits and rx_nbits as single transfer default
+ * (SPI_NBITS_SINGLE) if it is not set for this transfer.
*/
list_for_each_entry(xfer, &message->transfers, transfer_list) {
if (!xfer->bits_per_word)
xfer->bits_per_word = spi->bits_per_word;
if (!xfer->speed_hz)
xfer->speed_hz = spi->max_speed_hz;
+ if (xfer->tx_buf && !xfer->tx_nbits)
+ xfer->tx_nbits = SPI_NBITS_SINGLE;
+ if (xfer->rx_buf && !xfer->rx_nbits)
+ xfer->rx_nbits = SPI_NBITS_SINGLE;
+ /* check transfer tx/rx_nbits:
+ * 1. keep the value is not out of single, dual and quad
+ * 2. keep tx/rx_nbits is contained by mode in spi_device
+ * 3. if SPI_3WIRE, tx/rx_nbits should be in single
+ */
+ if (xfer->tx_nbits != SPI_NBITS_SINGLE &&
+ xfer->tx_nbits != SPI_NBITS_DUAL &&
+ xfer->tx_nbits != SPI_NBITS_QUAD)
+ return -EINVAL;
+ if ((xfer->tx_nbits == SPI_NBITS_DUAL) &&
+ !(spi->mode & (SPI_TX_DUAL | SPI_TX_QUAD)))
+ return -EINVAL;
+ if ((xfer->tx_nbits == SPI_NBITS_QUAD) &&
+ !(spi->mode & SPI_TX_QUAD))
+ return -EINVAL;
+ if ((spi->mode & SPI_3WIRE) &&
+ (xfer->tx_nbits != SPI_NBITS_SINGLE))
+ return -EINVAL;
+ /* check transfer rx_nbits */
+ if (xfer->rx_nbits != SPI_NBITS_SINGLE &&
+ xfer->rx_nbits != SPI_NBITS_DUAL &&
+ xfer->rx_nbits != SPI_NBITS_QUAD)
+ return -EINVAL;
+ if ((xfer->rx_nbits == SPI_NBITS_DUAL) &&
+ !(spi->mode & (SPI_RX_DUAL | SPI_RX_QUAD)))
+ return -EINVAL;
+ if ((xfer->rx_nbits == SPI_NBITS_QUAD) &&
+ !(spi->mode & SPI_RX_QUAD))
+ return -EINVAL;
+ if ((spi->mode & SPI_3WIRE) &&
+ (xfer->rx_nbits != SPI_NBITS_SINGLE))
+ return -EINVAL;
}
message->spi = spi;
diff --git a/include/linux/spi/spi.h b/include/linux/spi/spi.h
index 38c2b92..3dc0a86 100644
--- a/include/linux/spi/spi.h
+++ b/include/linux/spi/spi.h
@@ -74,7 +74,7 @@ struct spi_device {
struct spi_master *master;
u32 max_speed_hz;
u8 chip_select;
- u8 mode;
+ u16 mode;
#define SPI_CPHA 0x01 /* clock phase */
#define SPI_CPOL 0x02 /* clock polarity */
#define SPI_MODE_0 (0|0) /* (original MicroWire) */
@@ -87,6 +87,10 @@ struct spi_device {
#define SPI_LOOP 0x20 /* loopback mode */
#define SPI_NO_CS 0x40 /* 1 dev/bus, no chipselect */
#define SPI_READY 0x80 /* slave pulls low to pause */
+#define SPI_TX_DUAL 0x100 /* transmit with 2 wires */
+#define SPI_TX_QUAD 0x200 /* transmit with 4 wires */
+#define SPI_RX_DUAL 0x400 /* receive with 2 wires */
+#define SPI_RX_QUAD 0x800 /* receive with 4 wires */
u8 bits_per_word;
int irq;
void *controller_state;
@@ -437,6 +441,10 @@ extern struct spi_master *spi_busnum_to_master(u16 busnum);
* @rx_buf: data to be read (dma-safe memory), or NULL
* @tx_dma: DMA address of tx_buf, if @spi_message.is_dma_mapped
* @rx_dma: DMA address of rx_buf, if @spi_message.is_dma_mapped
+ * @tx_nbits: number of bits used for writting. If 0 the default
+ * (SPI_NBITS_SINGLE) is used.
+ * @rx_nbits: number of bits used for reading. If 0 the default
+ * (SPI_NBITS_SINGLE) is used.
* @len: size of rx and tx buffers (in bytes)
* @speed_hz: Select a speed other than the device default for this
* transfer. If 0 the default (from @spi_device) is used.
@@ -491,6 +499,11 @@ extern struct spi_master *spi_busnum_to_master(u16 busnum);
* by the results of previous messages and where the whole transaction
* ends when the chipselect goes intactive.
*
+ * When SPI can transfer in 1x,2x or 4x. It can get this tranfer information
+ * from device through @tx_nbits and @rx_nbits. In Bi-direction, these
+ * two should both be set. User can set transfer mode with SPI_NBITS_SINGLE(1x)
+ * SPI_NBITS_DUAL(2x) and SPI_NBITS_QUAD(4x) to support these three transfer.
+ *
* The code that submits an spi_message (and its spi_transfers)
* to the lower layers is responsible for managing its memory.
* Zero-initialize every field you don't set up explicitly, to
@@ -511,6 +524,11 @@ struct spi_transfer {
dma_addr_t rx_dma;
unsigned cs_change:1;
+ u8 tx_nbits;
+ u8 rx_nbits;
+#define SPI_NBITS_SINGLE 0x01 /* 1bit transfer */
+#define SPI_NBITS_DUAL 0x02 /* 2bits transfer */
+#define SPI_NBITS_QUAD 0x04 /* 4bits transfer */
u8 bits_per_word;
u16 delay_usecs;
u32 speed_hz;
@@ -858,7 +876,7 @@ struct spi_board_info {
/* mode becomes spi_device.mode, and is essential for chips
* where the default of SPI_CS_HIGH = 0 is wrong.
*/
- u8 mode;
+ u16 mode;
/* ... may need additional spi_device chip config data here.
* avoid stuff protocol drivers can set; but include stuff
--
1.7.9.5
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