This change moves all the SPI mode bits into a separate 'spi.h' header in
uapi. This is meant to re-use these definitions inside the kernel as well
as export them to userspace (via uapi).
The SPI mode definitions have usually been duplicated between between
'include/linux/spi/spi.h' and 'include/uapi/linux/spi/spidev.h', so
whenever adding a new entry, this would need to be put in both headers.
They've been moved from 'include/linux/spi/spi.h', since that seems a bit
more complete; the bits have descriptions and there is the SPI_MODE_X_MASK.
For now, this change does a simple move; no conversions to BIT() macros are
being done at this point. This can be done later, as that requires also
another header inclusion (the 'const.h' header).
The change as-is makes this 'spi.h' header more standalone.
Signed-off-by: Alexandru Ardelean <[email protected]>
---
Personally, I am not sure whether to convert the bitfield tos _BITUL()
macros or not. I feel that not-having these macros makes this uapi spi.h
header more standalone.
If there's a strong insistence to use those _BITUL() macros, I'll do it.
I'm hesitant now, because it requires that this spi.h includes the
'const.h' header.
Changelog v2 -> v3:
* https://lore.kernel.org/linux-spi/[email protected]/
* dropped 'spi: convert to BIT() all spi_device flags '
added 'spi: uapi: unify SPI modes into a single spi.h header'
include/linux/spi/spi.h | 22 +--------------
include/uapi/linux/spi/spi.h | 47 +++++++++++++++++++++++++++++++++
include/uapi/linux/spi/spidev.h | 30 +--------------------
3 files changed, 49 insertions(+), 50 deletions(-)
create mode 100644 include/uapi/linux/spi/spi.h
diff --git a/include/linux/spi/spi.h b/include/linux/spi/spi.h
index aa09fdc8042d..a4fedb33d34b 100644
--- a/include/linux/spi/spi.h
+++ b/include/linux/spi/spi.h
@@ -14,6 +14,7 @@
#include <linux/scatterlist.h>
#include <linux/gpio/consumer.h>
#include <linux/ptp_clock_kernel.h>
+#include <uapi/linux/spi/spi.h>
struct dma_chan;
struct property_entry;
@@ -165,27 +166,6 @@ struct spi_device {
u8 bits_per_word;
bool rt;
u32 mode;
-#define SPI_CPHA 0x01 /* clock phase */
-#define SPI_CPOL 0x02 /* clock polarity */
-#define SPI_MODE_0 (0|0) /* (original MicroWire) */
-#define SPI_MODE_1 (0|SPI_CPHA)
-#define SPI_MODE_2 (SPI_CPOL|0)
-#define SPI_MODE_3 (SPI_CPOL|SPI_CPHA)
-#define SPI_MODE_X_MASK (SPI_CPOL|SPI_CPHA)
-#define SPI_CS_HIGH 0x04 /* chipselect active high? */
-#define SPI_LSB_FIRST 0x08 /* per-word bits-on-wire */
-#define SPI_3WIRE 0x10 /* SI/SO signals shared */
-#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 */
-#define SPI_CS_WORD 0x1000 /* toggle cs after each word */
-#define SPI_TX_OCTAL 0x2000 /* transmit with 8 wires */
-#define SPI_RX_OCTAL 0x4000 /* receive with 8 wires */
-#define SPI_3WIRE_HIZ 0x8000 /* high impedance turnaround */
int irq;
void *controller_state;
void *controller_data;
diff --git a/include/uapi/linux/spi/spi.h b/include/uapi/linux/spi/spi.h
new file mode 100644
index 000000000000..ae028d64c779
--- /dev/null
+++ b/include/uapi/linux/spi/spi.h
@@ -0,0 +1,47 @@
+/* SPDX-License-Identifier: GPL-2.0+ WITH Linux-syscall-note */
+/*
+ * include/linux/spi/spi.h
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
+ */
+
+#ifndef _UAPI_SPI_H
+#define _UAPI_SPI_H
+
+#define SPI_CPHA 0x01 /* clock phase */
+#define SPI_CPOL 0x02 /* clock polarity */
+
+#define SPI_MODE_0 (0|0) /* (original MicroWire) */
+#define SPI_MODE_1 (0|SPI_CPHA)
+#define SPI_MODE_2 (SPI_CPOL|0)
+#define SPI_MODE_3 (SPI_CPOL|SPI_CPHA)
+#define SPI_MODE_X_MASK (SPI_CPOL|SPI_CPHA)
+
+#define SPI_CS_HIGH 0x04 /* chipselect active high? */
+#define SPI_LSB_FIRST 0x08 /* per-word bits-on-wire */
+#define SPI_3WIRE 0x10 /* SI/SO signals shared */
+#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 */
+#define SPI_CS_WORD 0x1000 /* toggle cs after each word */
+#define SPI_TX_OCTAL 0x2000 /* transmit with 8 wires */
+#define SPI_RX_OCTAL 0x4000 /* receive with 8 wires */
+#define SPI_3WIRE_HIZ 0x8000 /* high impedance turnaround */
+
+#endif /* _UAPI_SPI_H */
diff --git a/include/uapi/linux/spi/spidev.h b/include/uapi/linux/spi/spidev.h
index d56427c0b3e0..0c3da08f2aff 100644
--- a/include/uapi/linux/spi/spidev.h
+++ b/include/uapi/linux/spi/spidev.h
@@ -25,35 +25,7 @@
#include <linux/types.h>
#include <linux/ioctl.h>
-
-/* User space versions of kernel symbols for SPI clocking modes,
- * matching <linux/spi/spi.h>
- */
-
-#define SPI_CPHA 0x01
-#define SPI_CPOL 0x02
-
-#define SPI_MODE_0 (0|0)
-#define SPI_MODE_1 (0|SPI_CPHA)
-#define SPI_MODE_2 (SPI_CPOL|0)
-#define SPI_MODE_3 (SPI_CPOL|SPI_CPHA)
-
-#define SPI_CS_HIGH 0x04
-#define SPI_LSB_FIRST 0x08
-#define SPI_3WIRE 0x10
-#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
-#define SPI_CS_WORD 0x1000
-#define SPI_TX_OCTAL 0x2000
-#define SPI_RX_OCTAL 0x4000
-#define SPI_3WIRE_HIZ 0x8000
-
-/*---------------------------------------------------------------------------*/
+#include <linux/spi/spi.h>
/* IOCTL commands */
--
2.27.0
Following a change to the SPI framework, providing a value of zero for
'spi-rx-bus-width' and 'spi-tx-bus-width' is now possible and will
essentially mean than no RX or TX is allowed.
Signed-off-by: Alexandru Ardelean <[email protected]>
---
Documentation/devicetree/bindings/spi/spi-controller.yaml | 6 ++++--
1 file changed, 4 insertions(+), 2 deletions(-)
diff --git a/Documentation/devicetree/bindings/spi/spi-controller.yaml b/Documentation/devicetree/bindings/spi/spi-controller.yaml
index 1b56d5e40f1f..f1aaaf9b3709 100644
--- a/Documentation/devicetree/bindings/spi/spi-controller.yaml
+++ b/Documentation/devicetree/bindings/spi/spi-controller.yaml
@@ -125,8 +125,9 @@ patternProperties:
spi-rx-bus-width:
description:
Bus width to the SPI bus used for read transfers.
+ If 0 is provided, then no RX will be possible on this devices.
$ref: /schemas/types.yaml#/definitions/uint32
- enum: [1, 2, 4, 8]
+ enum: [0, 1, 2, 4, 8]
default: 1
spi-rx-delay-us:
@@ -136,8 +137,9 @@ patternProperties:
spi-tx-bus-width:
description:
Bus width to the SPI bus used for write transfers.
+ If 0 is provided, then no RX will be possible on this devices.
$ref: /schemas/types.yaml#/definitions/uint32
- enum: [1, 2, 4, 8]
+ enum: [0, 1, 2, 4, 8]
default: 1
spi-tx-delay-us:
--
2.27.0
On Fri, Nov 27, 2020 at 3:08 PM Alexandru Ardelean
<[email protected]> wrote:
>
> This change moves all the SPI mode bits into a separate 'spi.h' header in
> uapi. This is meant to re-use these definitions inside the kernel as well
> as export them to userspace (via uapi).
uapi -> UAPI (or uAPI) here and everywhere else where it makes sense.
> The SPI mode definitions have usually been duplicated between between
> 'include/linux/spi/spi.h' and 'include/uapi/linux/spi/spidev.h', so
> whenever adding a new entry, this would need to be put in both headers.
>
> They've been moved from 'include/linux/spi/spi.h', since that seems a bit
> more complete; the bits have descriptions and there is the SPI_MODE_X_MASK.
>
> For now, this change does a simple move; no conversions to BIT() macros are
> being done at this point. This can be done later, as that requires also
> another header inclusion (the 'const.h' header).
> The change as-is makes this 'spi.h' header more standalone.
>
> Signed-off-by: Alexandru Ardelean <[email protected]>
> ---
>
> Personally, I am not sure whether to convert the bitfield tos _BITUL()
> macros or not. I feel that not-having these macros makes this uapi spi.h
> header more standalone.
> If there's a strong insistence to use those _BITUL() macros, I'll do it.
> I'm hesitant now, because it requires that this spi.h includes the
> 'const.h' header.
_BITUL is a part of uAPI, why not to use it?
In general BIT() type of macros makes values easier to read and less
error prone (in big numbers it's easy to miss 0).
It's not a strong opinion, it's just the rationale behind how I see it.
> Changelog v2 -> v3:
> * https://lore.kernel.org/linux-spi/[email protected]/
> * dropped 'spi: convert to BIT() all spi_device flags '
> added 'spi: uapi: unify SPI modes into a single spi.h header'
>
> include/linux/spi/spi.h | 22 +--------------
> include/uapi/linux/spi/spi.h | 47 +++++++++++++++++++++++++++++++++
> include/uapi/linux/spi/spidev.h | 30 +--------------------
> 3 files changed, 49 insertions(+), 50 deletions(-)
> create mode 100644 include/uapi/linux/spi/spi.h
>
> diff --git a/include/linux/spi/spi.h b/include/linux/spi/spi.h
> index aa09fdc8042d..a4fedb33d34b 100644
> --- a/include/linux/spi/spi.h
> +++ b/include/linux/spi/spi.h
> @@ -14,6 +14,7 @@
> #include <linux/scatterlist.h>
> #include <linux/gpio/consumer.h>
> #include <linux/ptp_clock_kernel.h>
> +#include <uapi/linux/spi/spi.h>
>
> struct dma_chan;
> struct property_entry;
> @@ -165,27 +166,6 @@ struct spi_device {
> u8 bits_per_word;
> bool rt;
> u32 mode;
> -#define SPI_CPHA 0x01 /* clock phase */
> -#define SPI_CPOL 0x02 /* clock polarity */
> -#define SPI_MODE_0 (0|0) /* (original MicroWire) */
> -#define SPI_MODE_1 (0|SPI_CPHA)
> -#define SPI_MODE_2 (SPI_CPOL|0)
> -#define SPI_MODE_3 (SPI_CPOL|SPI_CPHA)
> -#define SPI_MODE_X_MASK (SPI_CPOL|SPI_CPHA)
> -#define SPI_CS_HIGH 0x04 /* chipselect active high? */
> -#define SPI_LSB_FIRST 0x08 /* per-word bits-on-wire */
> -#define SPI_3WIRE 0x10 /* SI/SO signals shared */
> -#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 */
> -#define SPI_CS_WORD 0x1000 /* toggle cs after each word */
> -#define SPI_TX_OCTAL 0x2000 /* transmit with 8 wires */
> -#define SPI_RX_OCTAL 0x4000 /* receive with 8 wires */
> -#define SPI_3WIRE_HIZ 0x8000 /* high impedance turnaround */
> int irq;
> void *controller_state;
> void *controller_data;
> diff --git a/include/uapi/linux/spi/spi.h b/include/uapi/linux/spi/spi.h
> new file mode 100644
> index 000000000000..ae028d64c779
> --- /dev/null
> +++ b/include/uapi/linux/spi/spi.h
> @@ -0,0 +1,47 @@
> +/* SPDX-License-Identifier: GPL-2.0+ WITH Linux-syscall-note */
> +/*
> + * include/linux/spi/spi.h
> + *
> + * This program is free software; you can redistribute it and/or modify
> + * it under the terms of the GNU General Public License as published by
> + * the Free Software Foundation; either version 2 of the License, or
> + * (at your option) any later version.
> + *
> + * This program is distributed in the hope that it will be useful,
> + * but WITHOUT ANY WARRANTY; without even the implied warranty of
> + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
> + * GNU General Public License for more details.
> + *
> + * You should have received a copy of the GNU General Public License
> + * along with this program; if not, write to the Free Software
> + * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
> + */
Do we still need this boilerplate license header?
> +
> +#ifndef _UAPI_SPI_H
> +#define _UAPI_SPI_H
> +
> +#define SPI_CPHA 0x01 /* clock phase */
> +#define SPI_CPOL 0x02 /* clock polarity */
> +
> +#define SPI_MODE_0 (0|0) /* (original MicroWire) */
> +#define SPI_MODE_1 (0|SPI_CPHA)
> +#define SPI_MODE_2 (SPI_CPOL|0)
> +#define SPI_MODE_3 (SPI_CPOL|SPI_CPHA)
> +#define SPI_MODE_X_MASK (SPI_CPOL|SPI_CPHA)
> +
> +#define SPI_CS_HIGH 0x04 /* chipselect active high? */
> +#define SPI_LSB_FIRST 0x08 /* per-word bits-on-wire */
> +#define SPI_3WIRE 0x10 /* SI/SO signals shared */
> +#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 */
> +#define SPI_CS_WORD 0x1000 /* toggle cs after each word */
> +#define SPI_TX_OCTAL 0x2000 /* transmit with 8 wires */
> +#define SPI_RX_OCTAL 0x4000 /* receive with 8 wires */
> +#define SPI_3WIRE_HIZ 0x8000 /* high impedance turnaround */
> +
> +#endif /* _UAPI_SPI_H */
> diff --git a/include/uapi/linux/spi/spidev.h b/include/uapi/linux/spi/spidev.h
> index d56427c0b3e0..0c3da08f2aff 100644
> --- a/include/uapi/linux/spi/spidev.h
> +++ b/include/uapi/linux/spi/spidev.h
> @@ -25,35 +25,7 @@
>
> #include <linux/types.h>
> #include <linux/ioctl.h>
> -
> -/* User space versions of kernel symbols for SPI clocking modes,
> - * matching <linux/spi/spi.h>
> - */
> -
> -#define SPI_CPHA 0x01
> -#define SPI_CPOL 0x02
> -
> -#define SPI_MODE_0 (0|0)
> -#define SPI_MODE_1 (0|SPI_CPHA)
> -#define SPI_MODE_2 (SPI_CPOL|0)
> -#define SPI_MODE_3 (SPI_CPOL|SPI_CPHA)
> -
> -#define SPI_CS_HIGH 0x04
> -#define SPI_LSB_FIRST 0x08
> -#define SPI_3WIRE 0x10
> -#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
> -#define SPI_CS_WORD 0x1000
> -#define SPI_TX_OCTAL 0x2000
> -#define SPI_RX_OCTAL 0x4000
> -#define SPI_3WIRE_HIZ 0x8000
> -
> -/*---------------------------------------------------------------------------*/
> +#include <linux/spi/spi.h>
>
> /* IOCTL commands */
>
> --
> 2.27.0
>
--
With Best Regards,
Andy Shevchenko
From: Dragos Bogdan <[email protected]>
Transmit/receive only is a valid SPI mode. For example, the MOSI/TX line
might be missing from an ADC while for a DAC the MISO/RX line may be
optional. This patch adds these two new modes: SPI_NO_TX and
SPI_NO_RX. This way, the drivers will be able to identify if any of
these two lines is missing and to adjust the transfers accordingly.
Signed-off-by: Dragos Bogdan <[email protected]>
Signed-off-by: Alexandru Ardelean <[email protected]>
---
drivers/spi/spi.c | 26 +++++++++++++++++++++-----
include/uapi/linux/spi/spi.h | 2 ++
2 files changed, 23 insertions(+), 5 deletions(-)
diff --git a/drivers/spi/spi.c b/drivers/spi/spi.c
index cd3c395b4e90..17d4004bd2c6 100644
--- a/drivers/spi/spi.c
+++ b/drivers/spi/spi.c
@@ -1941,6 +1941,9 @@ static int of_spi_parse_dt(struct spi_controller *ctlr, struct spi_device *spi,
/* Device DUAL/QUAD mode */
if (!of_property_read_u32(nc, "spi-tx-bus-width", &value)) {
switch (value) {
+ case 0:
+ spi->mode |= SPI_NO_TX;
+ break;
case 1:
break;
case 2:
@@ -1962,6 +1965,9 @@ static int of_spi_parse_dt(struct spi_controller *ctlr, struct spi_device *spi,
if (!of_property_read_u32(nc, "spi-rx-bus-width", &value)) {
switch (value) {
+ case 0:
+ spi->mode |= SPI_NO_RX;
+ break;
case 1:
break;
case 2:
@@ -3329,12 +3335,17 @@ int spi_setup(struct spi_device *spi)
unsigned bad_bits, ugly_bits;
int status;
- /* check mode to prevent that DUAL and QUAD set at the same time
+ /*
+ * check mode to prevent that any two of DUAL, QUAD and NO_MOSI/MISO
+ * are 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))) {
+ if ((hweight_long(spi->mode &
+ (SPI_TX_DUAL | SPI_TX_QUAD | SPI_NO_TX)) > 1) ||
+ (hweight_long(spi->mode &
+ (SPI_RX_DUAL | SPI_RX_QUAD | SPI_NO_RX)) > 1)) {
dev_err(&spi->dev,
- "setup: can not select dual and quad at the same time\n");
+ "setup: can not select any two of dual, quad and no-rx/tx "
+ "at the same time\n");
return -EINVAL;
}
/* if it is SPI_3WIRE mode, DUAL and QUAD should be forbidden
@@ -3348,7 +3359,8 @@ int spi_setup(struct spi_device *spi)
* SPI_CS_WORD has a fallback software implementation,
* so it is ignored here.
*/
- bad_bits = spi->mode & ~(spi->controller->mode_bits | SPI_CS_WORD);
+ bad_bits = spi->mode & ~(spi->controller->mode_bits | SPI_CS_WORD |
+ SPI_NO_TX | SPI_NO_RX);
/* nothing prevents from working with active-high CS in case if it
* is driven by GPIO.
*/
@@ -3609,6 +3621,8 @@ static int __spi_validate(struct spi_device *spi, struct spi_message *message)
* 2. check tx/rx_nbits match the mode in spi_device
*/
if (xfer->tx_buf) {
+ if (spi->mode & SPI_NO_TX)
+ return -EINVAL;
if (xfer->tx_nbits != SPI_NBITS_SINGLE &&
xfer->tx_nbits != SPI_NBITS_DUAL &&
xfer->tx_nbits != SPI_NBITS_QUAD)
@@ -3622,6 +3636,8 @@ static int __spi_validate(struct spi_device *spi, struct spi_message *message)
}
/* check transfer rx_nbits */
if (xfer->rx_buf) {
+ if (spi->mode & SPI_NO_RX)
+ return -EINVAL;
if (xfer->rx_nbits != SPI_NBITS_SINGLE &&
xfer->rx_nbits != SPI_NBITS_DUAL &&
xfer->rx_nbits != SPI_NBITS_QUAD)
diff --git a/include/uapi/linux/spi/spi.h b/include/uapi/linux/spi/spi.h
index ae028d64c779..b504e46a6f18 100644
--- a/include/uapi/linux/spi/spi.h
+++ b/include/uapi/linux/spi/spi.h
@@ -43,5 +43,7 @@
#define SPI_TX_OCTAL 0x2000 /* transmit with 8 wires */
#define SPI_RX_OCTAL 0x4000 /* receive with 8 wires */
#define SPI_3WIRE_HIZ 0x8000 /* high impedance turnaround */
+#define SPI_NO_TX 0x10000 /* no transmit wire */
+#define SPI_NO_RX 0x20000 /* no receive wire */
#endif /* _UAPI_SPI_H */
--
2.27.0
On Fri, Nov 27, 2020 at 3:08 PM Alexandru Ardelean
<[email protected]> wrote:
>
> Following a change to the SPI framework, providing a value of zero for
> 'spi-rx-bus-width' and 'spi-tx-bus-width' is now possible and will
> essentially mean than no RX or TX is allowed.
than -> that
I'm wondering if we have a possibility to strict this for controllers
that always duplex (I assume that schema works in a way that the
generic bindings is most relaxed in comparison to the device specific
ones in case of the same binding in question).
--
With Best Regards,
Andy Shevchenko
> -----Original Message-----
> From: Andy Shevchenko <[email protected]>
> Sent: Friday, November 27, 2020 4:13 PM
> To: Ardelean, Alexandru <[email protected]>
> Cc: linux-spi <[email protected]>; devicetree
> <[email protected]>; Linux Kernel Mailing List <linux-
> [email protected]>; Rob Herring <[email protected]>; Mark Brown
> <[email protected]>; Bogdan, Dragos <[email protected]>
> Subject: Re: [PATCH v3 1/3] spi: uapi: unify SPI modes into a single spi.h header
>
> On Fri, Nov 27, 2020 at 3:08 PM Alexandru Ardelean
> <[email protected]> wrote:
> >
> > This change moves all the SPI mode bits into a separate 'spi.h' header
> > in uapi. This is meant to re-use these definitions inside the kernel
> > as well as export them to userspace (via uapi).
>
> uapi -> UAPI (or uAPI) here and everywhere else where it makes sense.
>
> > The SPI mode definitions have usually been duplicated between between
> > 'include/linux/spi/spi.h' and 'include/uapi/linux/spi/spidev.h', so
> > whenever adding a new entry, this would need to be put in both headers.
> >
> > They've been moved from 'include/linux/spi/spi.h', since that seems a
> > bit more complete; the bits have descriptions and there is the
> SPI_MODE_X_MASK.
> >
> > For now, this change does a simple move; no conversions to BIT()
> > macros are being done at this point. This can be done later, as that
> > requires also another header inclusion (the 'const.h' header).
> > The change as-is makes this 'spi.h' header more standalone.
> >
> > Signed-off-by: Alexandru Ardelean <[email protected]>
> > ---
> >
> > Personally, I am not sure whether to convert the bitfield tos _BITUL()
> > macros or not. I feel that not-having these macros makes this uapi
> > spi.h header more standalone.
> > If there's a strong insistence to use those _BITUL() macros, I'll do it.
> > I'm hesitant now, because it requires that this spi.h includes the
> > 'const.h' header.
>
> _BITUL is a part of uAPI, why not to use it?
> In general BIT() type of macros makes values easier to read and less error prone
> (in big numbers it's easy to miss 0).
> It's not a strong opinion, it's just the rationale behind how I see it.
Yeah I understand.
I guess since this is a new header in UAPI, I can use the _BITUL macro.
Sometimes I look at some code and remember how some people tend to use some things.
Like, I would expect some people to maybe just copy this header as-is in some "libspi".
So, then: do we make it easier for those people or not?
But again, since this is a new header, the concern may be reduced by just using _BITUL() from the start.
I sometimes have these arguments with myself whenever going into API code.
Kernel code is easy: all the users of that code in the kernel, and we try not to bother too much with out-of-tree drivers. Those get impossible to care about.
>
> > Changelog v2 -> v3:
> > *
> > https://urldefense.com/v3/__https://lore.kernel.org/linux-spi/20201124
> > 102152.16548-1-
> [email protected]/__;!!A3Ni8CS0y2Y!oNpULNID
> > JsvU1BX8CZgZYoS90mW3rZ2dHrZOwTRS4ndZ-_rLq3eJt22Rj1RQafWyw1-3YA$
> > * dropped 'spi: convert to BIT() all spi_device flags '
> > added 'spi: uapi: unify SPI modes into a single spi.h header'
> >
> > include/linux/spi/spi.h | 22 +--------------
> > include/uapi/linux/spi/spi.h | 47 +++++++++++++++++++++++++++++++++
> > include/uapi/linux/spi/spidev.h | 30 +--------------------
> > 3 files changed, 49 insertions(+), 50 deletions(-) create mode
> > 100644 include/uapi/linux/spi/spi.h
> >
> > diff --git a/include/linux/spi/spi.h b/include/linux/spi/spi.h index
> > aa09fdc8042d..a4fedb33d34b 100644
> > --- a/include/linux/spi/spi.h
> > +++ b/include/linux/spi/spi.h
> > @@ -14,6 +14,7 @@
> > #include <linux/scatterlist.h>
> > #include <linux/gpio/consumer.h>
> > #include <linux/ptp_clock_kernel.h>
> > +#include <uapi/linux/spi/spi.h>
> >
> > struct dma_chan;
> > struct property_entry;
> > @@ -165,27 +166,6 @@ struct spi_device {
> > u8 bits_per_word;
> > bool rt;
> > u32 mode;
> > -#define SPI_CPHA 0x01 /* clock phase */
> > -#define SPI_CPOL 0x02 /* clock polarity */
> > -#define SPI_MODE_0 (0|0) /* (original MicroWire) */
> > -#define SPI_MODE_1 (0|SPI_CPHA)
> > -#define SPI_MODE_2 (SPI_CPOL|0)
> > -#define SPI_MODE_3 (SPI_CPOL|SPI_CPHA)
> > -#define SPI_MODE_X_MASK (SPI_CPOL|SPI_CPHA)
> > -#define SPI_CS_HIGH 0x04 /* chipselect active high? */
> > -#define SPI_LSB_FIRST 0x08 /* per-word bits-on-wire */
> > -#define SPI_3WIRE 0x10 /* SI/SO signals shared */
> > -#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 */
> > -#define SPI_CS_WORD 0x1000 /* toggle cs after each word */
> > -#define SPI_TX_OCTAL 0x2000 /* transmit with 8 wires */
> > -#define SPI_RX_OCTAL 0x4000 /* receive with 8 wires */
> > -#define SPI_3WIRE_HIZ 0x8000 /* high impedance turnaround
> */
> > int irq;
> > void *controller_state;
> > void *controller_data;
> > diff --git a/include/uapi/linux/spi/spi.h
> > b/include/uapi/linux/spi/spi.h new file mode 100644 index
> > 000000000000..ae028d64c779
> > --- /dev/null
> > +++ b/include/uapi/linux/spi/spi.h
> > @@ -0,0 +1,47 @@
> > +/* SPDX-License-Identifier: GPL-2.0+ WITH Linux-syscall-note */
> > +/*
> > + * include/linux/spi/spi.h
> > + *
> > + * This program is free software; you can redistribute it and/or
> > +modify
> > + * it under the terms of the GNU General Public License as published
> > +by
> > + * the Free Software Foundation; either version 2 of the License, or
> > + * (at your option) any later version.
> > + *
> > + * This program is distributed in the hope that it will be useful,
> > + * but WITHOUT ANY WARRANTY; without even the implied warranty of
> > + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
> > + * GNU General Public License for more details.
> > + *
> > + * You should have received a copy of the GNU General Public License
> > + * along with this program; if not, write to the Free Software
> > + * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
> > + */
>
> Do we still need this boilerplate license header?
I'll remove this.
I'm still a n00b with all this licensing stuff.
>
> > +
> > +#ifndef _UAPI_SPI_H
> > +#define _UAPI_SPI_H
> > +
> > +#define SPI_CPHA 0x01 /* clock phase */
> > +#define SPI_CPOL 0x02 /* clock polarity */
> > +
> > +#define SPI_MODE_0 (0|0) /* (original MicroWire) */
> > +#define SPI_MODE_1 (0|SPI_CPHA)
> > +#define SPI_MODE_2 (SPI_CPOL|0)
> > +#define SPI_MODE_3 (SPI_CPOL|SPI_CPHA)
> > +#define SPI_MODE_X_MASK (SPI_CPOL|SPI_CPHA)
> > +
> > +#define SPI_CS_HIGH 0x04 /* chipselect active high? */
> > +#define SPI_LSB_FIRST 0x08 /* per-word bits-on-wire */
> > +#define SPI_3WIRE 0x10 /* SI/SO signals shared */
> > +#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 */
> > +#define SPI_CS_WORD 0x1000 /* toggle cs after each word */
> > +#define SPI_TX_OCTAL 0x2000 /* transmit with 8 wires */
> > +#define SPI_RX_OCTAL 0x4000 /* receive with 8 wires */
> > +#define SPI_3WIRE_HIZ 0x8000 /* high impedance turnaround
> */
> > +
> > +#endif /* _UAPI_SPI_H */
> > diff --git a/include/uapi/linux/spi/spidev.h
> > b/include/uapi/linux/spi/spidev.h index d56427c0b3e0..0c3da08f2aff
> > 100644
> > --- a/include/uapi/linux/spi/spidev.h
> > +++ b/include/uapi/linux/spi/spidev.h
> > @@ -25,35 +25,7 @@
> >
> > #include <linux/types.h>
> > #include <linux/ioctl.h>
> > -
> > -/* User space versions of kernel symbols for SPI clocking modes,
> > - * matching <linux/spi/spi.h>
> > - */
> > -
> > -#define SPI_CPHA 0x01
> > -#define SPI_CPOL 0x02
> > -
> > -#define SPI_MODE_0 (0|0)
> > -#define SPI_MODE_1 (0|SPI_CPHA)
> > -#define SPI_MODE_2 (SPI_CPOL|0)
> > -#define SPI_MODE_3 (SPI_CPOL|SPI_CPHA)
> > -
> > -#define SPI_CS_HIGH 0x04
> > -#define SPI_LSB_FIRST 0x08
> > -#define SPI_3WIRE 0x10
> > -#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
> > -#define SPI_CS_WORD 0x1000
> > -#define SPI_TX_OCTAL 0x2000
> > -#define SPI_RX_OCTAL 0x4000
> > -#define SPI_3WIRE_HIZ 0x8000
> > -
> > -/*-------------------------------------------------------------------
> > --------*/
> > +#include <linux/spi/spi.h>
> >
> > /* IOCTL commands */
> >
> > --
> > 2.27.0
> >
>
>
> --
> With Best Regards,
> Andy Shevchenko
> -----Original Message-----
> From: Andy Shevchenko <[email protected]>
> Sent: Friday, November 27, 2020 4:26 PM
> To: Ardelean, Alexandru <[email protected]>
> Cc: linux-spi <[email protected]>; devicetree
> <[email protected]>; Linux Kernel Mailing List <linux-
> [email protected]>; Rob Herring <[email protected]>; Mark Brown
> <[email protected]>; Bogdan, Dragos <[email protected]>
> Subject: Re: [PATCH v3 3/3] spi: dt-bindings: document zero value for spi-{rx,tx}-
> bus-width properties
>
> On Fri, Nov 27, 2020 at 3:08 PM Alexandru Ardelean
> <[email protected]> wrote:
> >
> > Following a change to the SPI framework, providing a value of zero for
> > 'spi-rx-bus-width' and 'spi-tx-bus-width' is now possible and will
> > essentially mean than no RX or TX is allowed.
>
> than -> that
>
> I'm wondering if we have a possibility to strict this for controllers that always
> duplex (I assume that schema works in a way that the generic bindings is most
> relaxed in comparison to the device specific ones in case of the same binding in
> question).
No idea here.
>
> --
> With Best Regards,
> Andy Shevchenko