From 7d0771970c51e736758525dd71fb82dd036b823a Mon Sep 17 00:00:00 2001 From: David Brownell Date: Wed, 17 Jun 2009 16:26:03 -0700 Subject: spi: move common spi_setup() functionality into core Start moving some spi_setup() functionality into the SPI core from the various spi_master controller drivers: - Make that function stop being an inline; - Move two common idioms from drivers into that new function: * Default bits_per_word to 8 if that field isn't set * Issue a standardized dev_dbg() message This is a net minor source code shrink, and supports enhancments found in some follow-up patches. Signed-off-by: David Brownell Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- include/linux/spi/spi.h | 25 +------------------------ 1 file changed, 1 insertion(+), 24 deletions(-) (limited to 'include/linux/spi/spi.h') diff --git a/include/linux/spi/spi.h b/include/linux/spi/spi.h index a0faa18f7b1b..0db5d64fc5e8 100644 --- a/include/linux/spi/spi.h +++ b/include/linux/spi/spi.h @@ -523,30 +523,7 @@ static inline void spi_message_free(struct spi_message *m) kfree(m); } -/** - * spi_setup - setup SPI mode and clock rate - * @spi: the device whose settings are being modified - * Context: can sleep, and no requests are queued to the device - * - * SPI protocol drivers may need to update the transfer mode if the - * device doesn't work with its default. They may likewise need - * to update clock rates or word sizes from initial values. This function - * changes those settings, and must be called from a context that can sleep. - * Except for SPI_CS_HIGH, which takes effect immediately, the changes take - * effect the next time the device is selected and data is transferred to - * or from it. When this function returns, the spi device is deselected. - * - * Note that this call will fail if the protocol driver specifies an option - * that the underlying controller or its driver does not support. For - * example, not all hardware supports wire transfers using nine bit words, - * LSB-first wire encoding, or active-high chipselects. - */ -static inline int -spi_setup(struct spi_device *spi) -{ - return spi->master->setup(spi); -} - +extern int spi_setup(struct spi_device *spi); /** * spi_async - asynchronous SPI transfer -- cgit v1.2.3 From e7db06b5d5afcef15c4c3e61c3a7441ed7ad1407 Mon Sep 17 00:00:00 2001 From: David Brownell Date: Wed, 17 Jun 2009 16:26:04 -0700 Subject: spi: move more spi_setup() functionality into core Move some common spi_setup() error checks into the SPI framework from the spi_master controller drivers: - Add a new "mode_bits" field to spi_master - Use that in spi_setup to validate the spi->mode value being requested. Setting this new field is now mandatory for any controller supporting more than vanilla SPI_MODE_0. - Update all spi_master drivers to: * Initialize that field * Remove current spi_setup() checks using that value. This is a net minor code shrink. Signed-off-by: David Brownell Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- include/linux/spi/spi.h | 3 +++ 1 file changed, 3 insertions(+) (limited to 'include/linux/spi/spi.h') diff --git a/include/linux/spi/spi.h b/include/linux/spi/spi.h index 0db5d64fc5e8..9c4cd27f4685 100644 --- a/include/linux/spi/spi.h +++ b/include/linux/spi/spi.h @@ -245,6 +245,9 @@ struct spi_master { */ u16 dma_alignment; + /* spi_device.mode flags understood by this controller driver */ + u16 mode_bits; + /* Setup mode and clock, etc (spi driver may call many times). * * IMPORTANT: this may be called when transfers to another -- cgit v1.2.3 From b55f627feeb9d48fdbde3835e18afbc76712e49b Mon Sep 17 00:00:00 2001 From: David Brownell Date: Tue, 30 Jun 2009 11:41:26 -0700 Subject: spi: new spi->mode bits Add two new spi_device.mode bits to accomodate more protocol options, and pass them through to usermode drivers: * SPI_NO_CS ... a second 3-wire variant, where the chipselect line is removed instead of a data line; transfers are still full duplex. This obviously has STRONG protocol implications since the chipselect transitions can't be used to synchronize state transitions with the SPI master. * SPI_READY ... defines open drain signal that's pulled low to pause the clock. This defines a 5-wire variant (normal 4-wire SPI plus READY) and two 4-wire variants (READY plus each of the 3-wire flavors). Such hardware flow control can be a big win. There are ADC converters and flash chips that expose READY signals, but not many host controllers support it today. The spi_bitbang code should be changed to use SPI_NO_CS instead of its current nonportable hack. That's a mode most hardware can easily support (unlike SPI_READY). Signed-off-by: David Brownell Cc: "Paulraj, Sandeep" Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- include/linux/spi/spi.h | 2 ++ 1 file changed, 2 insertions(+) (limited to 'include/linux/spi/spi.h') diff --git a/include/linux/spi/spi.h b/include/linux/spi/spi.h index 9c4cd27f4685..743c933ac4e7 100644 --- a/include/linux/spi/spi.h +++ b/include/linux/spi/spi.h @@ -80,6 +80,8 @@ struct spi_device { #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 */ u8 bits_per_word; int irq; void *controller_state; -- cgit v1.2.3 From 70d6027ff2bc8bab180273b77e7ab3e8a62cca51 Mon Sep 17 00:00:00 2001 From: David Brownell Date: Tue, 30 Jun 2009 11:41:27 -0700 Subject: spi: add spi_master flag word Add a new spi_master.flags word listing constraints relevant to that controller. Define the first constraint bit: a half duplex restriction. Include that constraint in the OMAP1 MicroWire controller driver. Have the mmc_spi host be the first customer of this flag. Its coding relies heavily on full duplex transfers, so it must fail when the underlying controller driver won't perform them. (The spi_write_then_read routine could use it too: use the temporarily-withdrawn full-duplex speedup unless this flag is set, in which case the existing code applies. Similarly, any spi_master implementing only SPI_3WIRE should set the flag.) Signed-off-by: David Brownell Cc: Marek Szyprowski Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- include/linux/spi/spi.h | 4 ++++ 1 file changed, 4 insertions(+) (limited to 'include/linux/spi/spi.h') diff --git a/include/linux/spi/spi.h b/include/linux/spi/spi.h index 743c933ac4e7..c47c4b4da97e 100644 --- a/include/linux/spi/spi.h +++ b/include/linux/spi/spi.h @@ -250,6 +250,10 @@ struct spi_master { /* spi_device.mode flags understood by this controller driver */ u16 mode_bits; + /* other constraints relevant to this driver */ + u16 flags; +#define SPI_MASTER_HALF_DUPLEX BIT(0) /* can't do full duplex */ + /* Setup mode and clock, etc (spi driver may call many times). * * IMPORTANT: this may be called when transfers to another -- cgit v1.2.3