diff mbox series

[v4,1/3] spi: uapi: unify SPI modes into a single spi.h header

Message ID 20201203140531.74470-1-alexandru.ardelean@analog.com
State Superseded
Headers show
Series [v4,1/3] spi: uapi: unify SPI modes into a single spi.h header | expand

Commit Message

Alexandru Ardelean Dec. 3, 2020, 2:05 p.m. UTC 
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.

This change also does a conversion of these bitfields to _BITUL() macro.

Signed-off-by: Alexandru Ardelean <alexandru.ardelean@analog.com>
---

Changelog v3 -> v4:
* https://lore.kernel.org/linux-spi/20201127130834.136348-1-alexandru.ardelean@analog.com/
* uapi -> uAPI in comment
* removed extra license text in 'uapi/linux/spi/spi.h'
* using _BITUL() macro

 include/linux/spi/spi.h         | 23 ++---------------------
 include/uapi/linux/spi/spi.h    | 31 +++++++++++++++++++++++++++++++
 include/uapi/linux/spi/spidev.h | 30 +-----------------------------
 3 files changed, 34 insertions(+), 50 deletions(-)
 create mode 100644 include/uapi/linux/spi/spi.h

Comments

Andy Shevchenko Dec. 3, 2020, 2:10 p.m. UTC | #1 
On Thu, Dec 3, 2020 at 4:00 PM Alexandru Ardelean
<alexandru.ardelean@analog.com> wrote:
> From: Dragos Bogdan <dragos.bogdan@analog.com>
>
> 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.

...

> +       BUILD_BUG_ON(SPI_MODE_USER_MASK & SPI_MODE_KERNEL_MASK);

Please, use static_assert() as I have been pointed out. It may be
located outside of a function scope. You may attach it directly to the
definition of the KERNEL_MASK (I haven't tried yet with header
though).

...

> +#define SPI_NO_TX      BIT(31)         /* no transmit wire */
> +#define SPI_NO_RX      BIT(30)         /* no receive wire */
> +#define SPI_MODE_KERNEL_MASK   (SPI_NO_TX | SPI_NO_RX)

This needs a comment to explain what's going on with the flags (split).
Andy Shevchenko Dec. 3, 2020, 2:27 p.m. UTC | #2 
On Thu, Dec 3, 2020 at 4:10 PM Andy Shevchenko
<andy.shevchenko@gmail.com> wrote:
> On Thu, Dec 3, 2020 at 4:00 PM Alexandru Ardelean
> <alexandru.ardelean@analog.com> wrote:

> > +#define SPI_NO_TX      BIT(31)         /* no transmit wire */
> > +#define SPI_NO_RX      BIT(30)         /* no receive wire */
> > +#define SPI_MODE_KERNEL_MASK   (SPI_NO_TX | SPI_NO_RX)
>
> This needs a comment to explain what's going on with the flags (split).

...and to be consistent with proposal in uAPI:

#define SPI_MODE_KERNEL_MASK   (~(BIT(30) - 1))
diff mbox series

Patch

diff --git a/include/linux/spi/spi.h b/include/linux/spi/spi.h
index aa09fdc8042d..a08c3f37e202 100644
--- a/include/linux/spi/spi.h
+++ b/include/linux/spi/spi.h
@@ -15,6 +15,8 @@ 
 #include <linux/gpio/consumer.h>
 #include <linux/ptp_clock_kernel.h>
 
+#include <uapi/linux/spi/spi.h>
+
 struct dma_chan;
 struct property_entry;
 struct spi_controller;
@@ -165,27 +167,6 @@  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..703b586f35df
--- /dev/null
+++ b/include/uapi/linux/spi/spi.h
@@ -0,0 +1,31 @@ 
+/* SPDX-License-Identifier: GPL-2.0+ WITH Linux-syscall-note */
+#ifndef _UAPI_SPI_H
+#define _UAPI_SPI_H
+
+#include <linux/const.h>
+
+#define	SPI_CPHA		_BITUL(0)	/* clock phase */
+#define	SPI_CPOL		_BITUL(1)	/* 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		_BITUL(2)	/* chipselect active high? */
+#define	SPI_LSB_FIRST		_BITUL(3)	/* per-word bits-on-wire */
+#define	SPI_3WIRE		_BITUL(4)	/* SI/SO signals shared */
+#define	SPI_LOOP		_BITUL(5)	/* loopback mode */
+#define	SPI_NO_CS		_BITUL(6)	/* 1 dev/bus, no chipselect */
+#define	SPI_READY		_BITUL(7)	/* slave pulls low to pause */
+#define	SPI_TX_DUAL		_BITUL(8)	/* transmit with 2 wires */
+#define	SPI_TX_QUAD		_BITUL(9)	/* transmit with 4 wires */
+#define	SPI_RX_DUAL		_BITUL(10)	/* receive with 2 wires */
+#define	SPI_RX_QUAD		_BITUL(11)	/* receive with 4 wires */
+#define	SPI_CS_WORD		_BITUL(12)	/* toggle cs after each word */
+#define	SPI_TX_OCTAL		_BITUL(13)	/* transmit with 8 wires */
+#define	SPI_RX_OCTAL		_BITUL(14)	/* receive with 8 wires */
+#define	SPI_3WIRE_HIZ		_BITUL(15)	/* 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 */