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Subject[PATCH v2 2/4] spi: spidev: Add support for Dual/Quad SPI Transfers
Date
From: Geert Uytterhoeven <geert+renesas@linux-m68k.org>

Add support for Dual/Quad SPI Transfers to the spidev API.
As this uses SPI mode bits that don't fit in a single byte, two new
ioctls (SPI_IOC_RD_MODE32 and SPI_IOC_WR_MODE32) are introduced.

Signed-off-by: Geert Uytterhoeven <geert+renesas@linux-m68k.org>
---
v2:
- Introduce SPI_IOC_{RD,WR}_MODE32 to avoid breaking backwards
compatibility,
- Split off the spidev_test changes in a separate patch
- Update documentation.

Documentation/spi/spidev | 6 ++++++
drivers/spi/spidev.c | 19 +++++++++++++++----
include/uapi/linux/spi/spidev.h | 14 ++++++++++++--
3 files changed, 33 insertions(+), 6 deletions(-)

diff --git a/Documentation/spi/spidev b/Documentation/spi/spidev
index ed2da5e5b28a..3d14035b1766 100644
--- a/Documentation/spi/spidev
+++ b/Documentation/spi/spidev
@@ -85,6 +85,12 @@ settings for data transfer parameters:
SPI_MODE_0..SPI_MODE_3; or if you prefer you can combine SPI_CPOL
(clock polarity, idle high iff this is set) or SPI_CPHA (clock phase,
sample on trailing edge iff this is set) flags.
+ Note that this request is limited to SPI mode flags that fit in a
+ single byte.
+
+ SPI_IOC_RD_MODE32, SPI_IOC_WR_MODE32 ... pass a pointer to a uin32_t
+ which will return (RD) or assign (WR) the full SPI transfer mode,
+ not limited to the bits that fit in one byte.

SPI_IOC_RD_LSB_FIRST, SPI_IOC_WR_LSB_FIRST ... pass a pointer to a byte
which will return (RD) or assign (WR) the bit justification used to
diff --git a/drivers/spi/spidev.c b/drivers/spi/spidev.c
index 2abc0f5a82be..e3bc23bb5883 100644
--- a/drivers/spi/spidev.c
+++ b/drivers/spi/spidev.c
@@ -73,7 +73,8 @@ static DECLARE_BITMAP(minors, N_SPI_MINORS);
*/
#define SPI_MODE_MASK (SPI_CPHA | SPI_CPOL | SPI_CS_HIGH \
| SPI_LSB_FIRST | SPI_3WIRE | SPI_LOOP \
- | SPI_NO_CS | SPI_READY)
+ | SPI_NO_CS | SPI_READY | SPI_TX_DUAL \
+ | SPI_TX_QUAD | SPI_RX_DUAL | SPI_RX_QUAD)

struct spidev_data {
dev_t devt;
@@ -265,6 +266,8 @@ static int spidev_message(struct spidev_data *spidev,
buf += k_tmp->len;

k_tmp->cs_change = !!u_tmp->cs_change;
+ k_tmp->tx_nbits = u_tmp->tx_nbits;
+ k_tmp->rx_nbits = u_tmp->rx_nbits;
k_tmp->bits_per_word = u_tmp->bits_per_word;
k_tmp->delay_usecs = u_tmp->delay_usecs;
k_tmp->speed_hz = u_tmp->speed_hz;
@@ -359,6 +362,10 @@ spidev_ioctl(struct file *filp, unsigned int cmd, unsigned long arg)
retval = __put_user(spi->mode & SPI_MODE_MASK,
(__u8 __user *)arg);
break;
+ case SPI_IOC_RD_MODE32:
+ retval = __put_user(spi->mode & SPI_MODE_MASK,
+ (__u32 __user *)arg);
+ break;
case SPI_IOC_RD_LSB_FIRST:
retval = __put_user((spi->mode & SPI_LSB_FIRST) ? 1 : 0,
(__u8 __user *)arg);
@@ -372,7 +379,11 @@ spidev_ioctl(struct file *filp, unsigned int cmd, unsigned long arg)

/* write requests */
case SPI_IOC_WR_MODE:
- retval = __get_user(tmp, (u8 __user *)arg);
+ case SPI_IOC_WR_MODE32:
+ if (cmd == SPI_IOC_WR_MODE)
+ retval = __get_user(tmp, (u8 __user *)arg);
+ else
+ retval = __get_user(tmp, (u32 __user *)arg);
if (retval == 0) {
u32 save = spi->mode;

@@ -382,12 +393,12 @@ spidev_ioctl(struct file *filp, unsigned int cmd, unsigned long arg)
}

tmp |= spi->mode & ~SPI_MODE_MASK;
- spi->mode = (u8)tmp;
+ spi->mode = (u16)tmp;
retval = spi_setup(spi);
if (retval < 0)
spi->mode = save;
else
- dev_dbg(&spi->dev, "spi mode %02x\n", tmp);
+ dev_dbg(&spi->dev, "spi mode %x\n", tmp);
}
break;
case SPI_IOC_WR_LSB_FIRST:
diff --git a/include/uapi/linux/spi/spidev.h b/include/uapi/linux/spi/spidev.h
index 52d9ed01855f..dd5f21e75805 100644
--- a/include/uapi/linux/spi/spidev.h
+++ b/include/uapi/linux/spi/spidev.h
@@ -42,6 +42,10 @@
#define SPI_LOOP 0x20
#define SPI_NO_CS 0x40
#define SPI_READY 0x80
+#define SPI_TX_DUAL 0x100
+#define SPI_TX_QUAD 0x200
+#define SPI_RX_DUAL 0x400
+#define SPI_RX_QUAD 0x800

/*---------------------------------------------------------------------------*/

@@ -92,7 +96,9 @@ struct spi_ioc_transfer {
__u16 delay_usecs;
__u8 bits_per_word;
__u8 cs_change;
- __u32 pad;
+ __u8 tx_nbits;
+ __u8 rx_nbits;
+ __u16 pad;

/* If the contents of 'struct spi_ioc_transfer' ever change
* incompatibly, then the ioctl number (currently 0) must change;
@@ -110,7 +116,7 @@ struct spi_ioc_transfer {
#define SPI_IOC_MESSAGE(N) _IOW(SPI_IOC_MAGIC, 0, char[SPI_MSGSIZE(N)])


-/* Read / Write of SPI mode (SPI_MODE_0..SPI_MODE_3) */
+/* Read / Write of SPI mode (SPI_MODE_0..SPI_MODE_3) (limited to 8 bits) */
#define SPI_IOC_RD_MODE _IOR(SPI_IOC_MAGIC, 1, __u8)
#define SPI_IOC_WR_MODE _IOW(SPI_IOC_MAGIC, 1, __u8)

@@ -126,6 +132,10 @@ struct spi_ioc_transfer {
#define SPI_IOC_RD_MAX_SPEED_HZ _IOR(SPI_IOC_MAGIC, 4, __u32)
#define SPI_IOC_WR_MAX_SPEED_HZ _IOW(SPI_IOC_MAGIC, 4, __u32)

+/* Read / Write of the SPI mode field */
+#define SPI_IOC_RD_MODE32 _IOR(SPI_IOC_MAGIC, 5, __u32)
+#define SPI_IOC_WR_MODE32 _IOW(SPI_IOC_MAGIC, 5, __u32)
+


#endif /* SPIDEV_H */
--
1.7.9.5


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