From 4cff33f94fefcce1b3c01a9d1da6bb85fe3cbdfa Mon Sep 17 00:00:00 2001 From: Imre Deak Date: Fri, 17 Feb 2006 10:02:18 -0800 Subject: [PATCH] SPI: per-transfer overrides for wordsize and clocking Some protocols (like one for some bitmap displays) require different clock speed or word size settings for each transfer in an SPI message. This adds those parameters to struct spi_transfer. They are to be used when they are nonzero; otherwise the defaults from spi_device are to be used. The patch also adds a setup_transfer callback to spi_bitbang, uses it for messages that use those overrides, and implements it so that the pure bitbanging code can help resolve any questions about how it should work. Signed-off-by: Imre Deak Signed-off-by: David Brownell Signed-off-by: Greg Kroah-Hartman --- drivers/spi/spi_bitbang.c | 77 ++++++++++++++++++++++++++++++++++++++--------- 1 file changed, 63 insertions(+), 14 deletions(-) (limited to 'drivers/spi/spi_bitbang.c') diff --git a/drivers/spi/spi_bitbang.c b/drivers/spi/spi_bitbang.c index f037e559326..0525c99118c 100644 --- a/drivers/spi/spi_bitbang.c +++ b/drivers/spi/spi_bitbang.c @@ -138,6 +138,43 @@ static unsigned bitbang_txrx_32( return t->len - count; } +static int +bitbang_transfer_setup(struct spi_device *spi, struct spi_transfer *t) +{ + struct spi_bitbang_cs *cs = spi->controller_state; + u8 bits_per_word; + u32 hz; + + if (t) { + bits_per_word = t->bits_per_word; + hz = t->speed_hz; + } else { + bits_per_word = 0; + hz = 0; + } + + /* spi_transfer level calls that work per-word */ + if (!bits_per_word) + bits_per_word = spi->bits_per_word; + if (bits_per_word <= 8) + cs->txrx_bufs = bitbang_txrx_8; + else if (bits_per_word <= 16) + cs->txrx_bufs = bitbang_txrx_16; + else if (bits_per_word <= 32) + cs->txrx_bufs = bitbang_txrx_32; + else + return -EINVAL; + + /* nsecs = (clock period)/2 */ + if (!hz) + hz = spi->max_speed_hz; + cs->nsecs = (1000000000/2) / hz; + if (cs->nsecs > MAX_UDELAY_MS * 1000) + return -EINVAL; + + return 0; +} + /** * spi_bitbang_setup - default setup for per-word I/O loops */ @@ -145,6 +182,7 @@ int spi_bitbang_setup(struct spi_device *spi) { struct spi_bitbang_cs *cs = spi->controller_state; struct spi_bitbang *bitbang; + int retval; if (!spi->max_speed_hz) return -EINVAL; @@ -160,25 +198,14 @@ int spi_bitbang_setup(struct spi_device *spi) if (!spi->bits_per_word) spi->bits_per_word = 8; - /* spi_transfer level calls that work per-word */ - if (spi->bits_per_word <= 8) - cs->txrx_bufs = bitbang_txrx_8; - else if (spi->bits_per_word <= 16) - cs->txrx_bufs = bitbang_txrx_16; - else if (spi->bits_per_word <= 32) - cs->txrx_bufs = bitbang_txrx_32; - else - return -EINVAL; - /* per-word shift register access, in hardware or bitbanging */ cs->txrx_word = bitbang->txrx_word[spi->mode & (SPI_CPOL|SPI_CPHA)]; if (!cs->txrx_word) return -EINVAL; - /* nsecs = (clock period)/2 */ - cs->nsecs = (1000000000/2) / (spi->max_speed_hz); - if (cs->nsecs > MAX_UDELAY_MS * 1000) - return -EINVAL; + retval = bitbang_transfer_setup(spi, NULL); + if (retval < 0) + return retval; dev_dbg(&spi->dev, "%s, mode %d, %u bits/w, %u nsec\n", __FUNCTION__, spi->mode & (SPI_CPOL | SPI_CPHA), @@ -246,6 +273,8 @@ static void bitbang_work(void *_bitbang) unsigned tmp; unsigned cs_change; int status; + int (*setup_transfer)(struct spi_device *, + struct spi_transfer *); m = container_of(bitbang->queue.next, struct spi_message, queue); @@ -262,6 +291,7 @@ static void bitbang_work(void *_bitbang) tmp = 0; cs_change = 1; status = 0; + setup_transfer = NULL; list_for_each_entry (t, &m->transfers, transfer_list) { if (bitbang->shutdown) { @@ -269,6 +299,20 @@ static void bitbang_work(void *_bitbang) break; } + /* override or restore speed and wordsize */ + if (t->speed_hz || t->bits_per_word) { + setup_transfer = bitbang->setup_transfer; + if (!setup_transfer) { + status = -ENOPROTOOPT; + break; + } + } + if (setup_transfer) { + status = setup_transfer(spi, t); + if (status < 0) + break; + } + /* set up default clock polarity, and activate chip; * this implicitly updates clock and spi modes as * previously recorded for this device via setup(). @@ -325,6 +369,10 @@ static void bitbang_work(void *_bitbang) m->status = status; m->complete(m->context); + /* restore speed and wordsize */ + if (setup_transfer) + setup_transfer(spi, NULL); + /* normally deactivate chipselect ... unless no error and * cs_change has hinted that the next message will probably * be for this chip too. @@ -406,6 +454,7 @@ int spi_bitbang_start(struct spi_bitbang *bitbang) bitbang->use_dma = 0; bitbang->txrx_bufs = spi_bitbang_bufs; if (!bitbang->master->setup) { + bitbang->setup_transfer = bitbang_transfer_setup; bitbang->master->setup = spi_bitbang_setup; bitbang->master->cleanup = spi_bitbang_cleanup; } -- cgit v1.2.3 From ff9f4771b5f017ee0f57629488b6cd7a6ef3d19b Mon Sep 17 00:00:00 2001 From: Kumar Gala Date: Sun, 2 Apr 2006 16:06:35 -0500 Subject: [PATCH] SPI: Renamed bitbang_transfer_setup to spi_bitbang_setup_transfer and export it Renamed bitbang_transfer_setup to follow convention of other exported symbols from spi-bitbang. Exported spi_bitbang_setup_transfer to allow users of spi-bitbang to use the function in their own setup_transfer. Signed-off-by: Kumar Gala Cc: David Brownell Signed-off-by: Greg Kroah-Hartman --- drivers/spi/spi_bitbang.c | 10 ++++++---- 1 file changed, 6 insertions(+), 4 deletions(-) (limited to 'drivers/spi/spi_bitbang.c') diff --git a/drivers/spi/spi_bitbang.c b/drivers/spi/spi_bitbang.c index 0525c99118c..6c3da64d609 100644 --- a/drivers/spi/spi_bitbang.c +++ b/drivers/spi/spi_bitbang.c @@ -138,8 +138,7 @@ static unsigned bitbang_txrx_32( return t->len - count; } -static int -bitbang_transfer_setup(struct spi_device *spi, struct spi_transfer *t) +int spi_bitbang_setup_transfer(struct spi_device *spi, struct spi_transfer *t) { struct spi_bitbang_cs *cs = spi->controller_state; u8 bits_per_word; @@ -174,6 +173,7 @@ bitbang_transfer_setup(struct spi_device *spi, struct spi_transfer *t) return 0; } +EXPORT_SYMBOL_GPL(spi_bitbang_setup_transfer); /** * spi_bitbang_setup - default setup for per-word I/O loops @@ -203,7 +203,7 @@ int spi_bitbang_setup(struct spi_device *spi) if (!cs->txrx_word) return -EINVAL; - retval = bitbang_transfer_setup(spi, NULL); + retval = spi_bitbang_setup_transfer(spi, NULL); if (retval < 0) return retval; @@ -454,7 +454,9 @@ int spi_bitbang_start(struct spi_bitbang *bitbang) bitbang->use_dma = 0; bitbang->txrx_bufs = spi_bitbang_bufs; if (!bitbang->master->setup) { - bitbang->setup_transfer = bitbang_transfer_setup; + if (!bitbang->setup_transfer) + bitbang->setup_transfer = + spi_bitbang_setup_transfer; bitbang->master->setup = spi_bitbang_setup; bitbang->master->cleanup = spi_bitbang_cleanup; } -- cgit v1.2.3 From ccf77cc4af5b048e20cfd9327fcc286cb69c34cc Mon Sep 17 00:00:00 2001 From: David Brownell Date: Mon, 3 Apr 2006 15:46:22 -0700 Subject: [PATCH] SPI: devices can require LSB-first encodings Add spi_device hook for LSB-first word encoding, and update all the (in-tree) controller drivers to reject such devices. Eventually, some controller drivers will be updated to support lsb-first encodings on the wire; no current drivers need this. Signed-off-by: David Brownell Signed-off-by: Greg Kroah-Hartman --- drivers/spi/spi_bitbang.c | 11 ++++++++++- 1 file changed, 10 insertions(+), 1 deletion(-) (limited to 'drivers/spi/spi_bitbang.c') diff --git a/drivers/spi/spi_bitbang.c b/drivers/spi/spi_bitbang.c index 6c3da64d609..0f7f5c64391 100644 --- a/drivers/spi/spi_bitbang.c +++ b/drivers/spi/spi_bitbang.c @@ -187,13 +187,22 @@ int spi_bitbang_setup(struct spi_device *spi) if (!spi->max_speed_hz) return -EINVAL; + bitbang = spi_master_get_devdata(spi->master); + + /* REVISIT: some systems will want to support devices using lsb-first + * bit encodings on the wire. In pure software that would be trivial, + * just bitbang_txrx_le_cphaX() routines shifting the other way, and + * some hardware controllers also have this support. + */ + if ((spi->mode & SPI_LSB_FIRST) != 0) + return -EINVAL; + if (!cs) { cs = kzalloc(sizeof *cs, SLAB_KERNEL); if (!cs) return -ENOMEM; spi->controller_state = cs; } - bitbang = spi_master_get_devdata(spi->master); if (!spi->bits_per_word) spi->bits_per_word = 8; -- cgit v1.2.3 From 1e316d7566b63767aa18902235c719e9e95465d0 Mon Sep 17 00:00:00 2001 From: David Brownell Date: Thu, 6 Apr 2006 22:25:56 -0700 Subject: [PATCH] SPI: spi_bitbang: clocking fixes This fixes two problems triggered by the MMC stack updating clocks: - SPI masters driver should accept a max clock speed of zero; that's one convention for marking idle devices. (Presumably that helps controllers that don't autogate clocks to "off" when not in use.) - There are more than 1000 nanoseconds per millisecond; setting the clock down to 125 KHz now works properly. Showing once again that Zero (http://en.wikipedia.org/wiki/Zero) is still an inexhaustible number of bugs. Signed-off-by: David Brownell Signed-off-by: Greg Kroah-Hartman --- drivers/spi/spi_bitbang.c | 24 ++++++++++++++---------- 1 file changed, 14 insertions(+), 10 deletions(-) (limited to 'drivers/spi/spi_bitbang.c') diff --git a/drivers/spi/spi_bitbang.c b/drivers/spi/spi_bitbang.c index 0f7f5c64391..dd2f950b21a 100644 --- a/drivers/spi/spi_bitbang.c +++ b/drivers/spi/spi_bitbang.c @@ -167,9 +167,11 @@ int spi_bitbang_setup_transfer(struct spi_device *spi, struct spi_transfer *t) /* nsecs = (clock period)/2 */ if (!hz) hz = spi->max_speed_hz; - cs->nsecs = (1000000000/2) / hz; - if (cs->nsecs > MAX_UDELAY_MS * 1000) - return -EINVAL; + if (hz) { + cs->nsecs = (1000000000/2) / hz; + if (cs->nsecs > (MAX_UDELAY_MS * 1000 * 1000)) + return -EINVAL; + } return 0; } @@ -184,9 +186,6 @@ int spi_bitbang_setup(struct spi_device *spi) struct spi_bitbang *bitbang; int retval; - if (!spi->max_speed_hz) - return -EINVAL; - bitbang = spi_master_get_devdata(spi->master); /* REVISIT: some systems will want to support devices using lsb-first @@ -216,7 +215,7 @@ int spi_bitbang_setup(struct spi_device *spi) if (retval < 0) return retval; - dev_dbg(&spi->dev, "%s, mode %d, %u bits/w, %u nsec\n", + dev_dbg(&spi->dev, "%s, mode %d, %u bits/w, %u nsec/bit\n", __FUNCTION__, spi->mode & (SPI_CPOL | SPI_CPHA), spi->bits_per_word, 2 * cs->nsecs); @@ -405,6 +404,7 @@ int spi_bitbang_transfer(struct spi_device *spi, struct spi_message *m) { struct spi_bitbang *bitbang; unsigned long flags; + int status = 0; m->actual_length = 0; m->status = -EINPROGRESS; @@ -414,11 +414,15 @@ int spi_bitbang_transfer(struct spi_device *spi, struct spi_message *m) return -ESHUTDOWN; spin_lock_irqsave(&bitbang->lock, flags); - list_add_tail(&m->queue, &bitbang->queue); - queue_work(bitbang->workqueue, &bitbang->work); + if (!spi->max_speed_hz) + status = -ENETDOWN; + else { + list_add_tail(&m->queue, &bitbang->queue); + queue_work(bitbang->workqueue, &bitbang->work); + } spin_unlock_irqrestore(&bitbang->lock, flags); - return 0; + return status; } EXPORT_SYMBOL_GPL(spi_bitbang_transfer); -- cgit v1.2.3