From e6f3f7e4dc76eb8d8a546dc66621a02c5c84f4ac Mon Sep 17 00:00:00 2001 From: Noralf Trønnes Date: Fri, 12 Apr 2019 11:41:30 +0200 Subject: spi: Add spi_is_bpw_supported() MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit This let SPI clients check if the controller supports a particular word width. drivers/gpu/drm/tinydrm/mipi-dbi.c will use this to determine if the controller supports 16-bit for RGB565 pixels. If it doesn't it will swap the bytes before transfer on little endian machines. Signed-off-by: Noralf Trønnes Signed-off-by: Mark Brown --- include/linux/spi/spi.h | 20 ++++++++++++++++++++ 1 file changed, 20 insertions(+) (limited to 'include/linux/spi/spi.h') diff --git a/include/linux/spi/spi.h b/include/linux/spi/spi.h index 662b336aa2e4..b30e3d13a5ac 100644 --- a/include/linux/spi/spi.h +++ b/include/linux/spi/spi.h @@ -983,6 +983,26 @@ spi_max_transfer_size(struct spi_device *spi) return min(tr_max, msg_max); } +/** + * spi_is_bpw_supported - Check if bits per word is supported + * @spi: SPI device + * @bpw: Bits per word + * + * This function checks to see if the SPI controller supports @bpw. + * + * Returns: + * True if @bpw is supported, false otherwise. + */ +static inline bool spi_is_bpw_supported(struct spi_device *spi, u32 bpw) +{ + u32 bpw_mask = spi->master->bits_per_word_mask; + + if (bpw == 8 || (bpw <= 32 && bpw_mask & SPI_BPW_MASK(bpw))) + return true; + + return false; +} + /*---------------------------------------------------------------------------*/ /* SPI transfer replacement methods which make use of spi_res */ -- cgit v1.2.3 From 0ff2de8bb163551ec4230a5a6f3c40c1f6adec4f Mon Sep 17 00:00:00 2001 From: Martin Sperl Date: Sat, 23 Feb 2019 08:49:48 +0000 Subject: spi: core: allow defining time that cs is deasserted For some SPI devices that support speed_hz > 1MHz the default 10 us delay when cs_change = 1 is typically way to long and may result in poor spi bus utilization. This patch makes it possible to control the delay at micro or nano second resolution on a per spi_transfer basis. It even allows an "as fast as possible" mode with: xfer.cs_change_delay_unit = SPI_DELAY_UNIT_NSECS; xfer.cs_change_delay = 0; The delay code is shared between delay_usecs and cs_change_delay for consistency and reuse, so in the future this change_delay_unit could also apply to delay_usec as well. Note that on slower SOCs/CPU actually reaching ns deasserts on cs is not realistic as the gpio overhead alone (without any delays added ) may already leave cs deasserted for more than 1us - at least on a raspberry pi. But at the very least this way we can keep it as short as possible. Signed-off-by: Martin Sperl Signed-off-by: Mark Brown --- drivers/spi/spi.c | 59 ++++++++++++++++++++++++++++++++++++++++--------- include/linux/spi/spi.h | 7 ++++++ 2 files changed, 56 insertions(+), 10 deletions(-) (limited to 'include/linux/spi/spi.h') diff --git a/drivers/spi/spi.c b/drivers/spi/spi.c index 5e75944ad5d1..7e8ffe3fdc00 100644 --- a/drivers/spi/spi.c +++ b/drivers/spi/spi.c @@ -1090,6 +1090,52 @@ static int spi_transfer_wait(struct spi_controller *ctlr, return 0; } +static void _spi_transfer_delay_ns(u32 ns) +{ + if (!ns) + return; + if (ns <= 1000) { + ndelay(ns); + } else { + u32 us = DIV_ROUND_UP(ns, 1000); + + if (us <= 10) + udelay(us); + else + usleep_range(us, us + DIV_ROUND_UP(us, 10)); + } +} + +static void _spi_transfer_cs_change_delay(struct spi_message *msg, + struct spi_transfer *xfer) +{ + u32 delay = xfer->cs_change_delay; + u32 unit = xfer->cs_change_delay_unit; + + /* return early on "fast" mode - for everything but USECS */ + if (!delay && unit != SPI_DELAY_UNIT_USECS) + return; + + switch (unit) { + case SPI_DELAY_UNIT_USECS: + /* for compatibility use default of 10us */ + if (!delay) + delay = 10000; + else + delay *= 1000; + break; + case SPI_DELAY_UNIT_NSECS: /* nothing to do here */ + break; + default: + dev_err_once(&msg->spi->dev, + "Use of unsupported delay unit %i, using default of 10us\n", + xfer->cs_change_delay_unit); + delay = 10000; + } + /* now sleep for the requested amount of time */ + _spi_transfer_delay_ns(delay); +} + /* * spi_transfer_one_message - Default implementation of transfer_one_message() * @@ -1148,14 +1194,8 @@ static int spi_transfer_one_message(struct spi_controller *ctlr, if (msg->status != -EINPROGRESS) goto out; - if (xfer->delay_usecs) { - u16 us = xfer->delay_usecs; - - if (us <= 10) - udelay(us); - else - usleep_range(us, us + DIV_ROUND_UP(us, 10)); - } + if (xfer->delay_usecs) + _spi_transfer_delay_ns(xfer->delay_usecs * 1000); if (xfer->cs_change) { if (list_is_last(&xfer->transfer_list, @@ -1163,7 +1203,7 @@ static int spi_transfer_one_message(struct spi_controller *ctlr, keep_cs = true; } else { spi_set_cs(msg->spi, false); - udelay(10); + _spi_transfer_cs_change_delay(msg, xfer); spi_set_cs(msg->spi, true); } } @@ -3757,4 +3797,3 @@ err0: * include needing to have boardinfo data structures be much more public. */ postcore_initcall(spi_init); - diff --git a/include/linux/spi/spi.h b/include/linux/spi/spi.h index 053abd22ad31..023beb9e9e4b 100644 --- a/include/linux/spi/spi.h +++ b/include/linux/spi/spi.h @@ -735,6 +735,9 @@ extern void spi_res_release(struct spi_controller *ctlr, * @bits_per_word: select a bits_per_word other than the device default * for this transfer. If 0 the default (from @spi_device) is used. * @cs_change: affects chipselect after this transfer completes + * @cs_change_delay: delay between cs deassert and assert when + * @cs_change is set and @spi_transfer is not the last in @spi_message + * @cs_change_delay_unit: unit of cs_change_delay * @delay_usecs: microseconds to delay after this transfer before * (optionally) changing the chipselect status, then starting * the next transfer or completing this @spi_message. @@ -824,6 +827,10 @@ struct spi_transfer { u8 bits_per_word; u8 word_delay_usecs; u16 delay_usecs; + u16 cs_change_delay; + u8 cs_change_delay_unit; +#define SPI_DELAY_UNIT_USECS 0 +#define SPI_DELAY_UNIT_NSECS 1 u32 speed_hz; u16 word_delay; -- cgit v1.2.3 From d5864e5bed96db7230da45463d6ae7af5b3b4399 Mon Sep 17 00:00:00 2001 From: Martin Sperl Date: Sat, 23 Feb 2019 08:49:50 +0000 Subject: spi: core: allow defining time that cs is deasserted as a multiple of SCK Support setting a delay between cs assert and deassert as a multiple of spi clock length. Signed-off-by: Martin Sperl Signed-off-by: Mark Brown --- drivers/spi/spi.c | 8 ++++++++ include/linux/spi/spi.h | 1 + 2 files changed, 9 insertions(+) (limited to 'include/linux/spi/spi.h') diff --git a/drivers/spi/spi.c b/drivers/spi/spi.c index 7e8ffe3fdc00..cfa3c3decb8a 100644 --- a/drivers/spi/spi.c +++ b/drivers/spi/spi.c @@ -1111,6 +1111,7 @@ static void _spi_transfer_cs_change_delay(struct spi_message *msg, { u32 delay = xfer->cs_change_delay; u32 unit = xfer->cs_change_delay_unit; + u32 hz; /* return early on "fast" mode - for everything but USECS */ if (!delay && unit != SPI_DELAY_UNIT_USECS) @@ -1126,6 +1127,13 @@ static void _spi_transfer_cs_change_delay(struct spi_message *msg, break; case SPI_DELAY_UNIT_NSECS: /* nothing to do here */ break; + case SPI_DELAY_UNIT_SCK: + /* if there is no effective speed know, then approximate + * by underestimating with half the requested hz + */ + hz = xfer->effective_speed_hz ?: xfer->speed_hz / 2; + delay *= DIV_ROUND_UP(1000000000, hz); + break; default: dev_err_once(&msg->spi->dev, "Use of unsupported delay unit %i, using default of 10us\n", diff --git a/include/linux/spi/spi.h b/include/linux/spi/spi.h index 023beb9e9e4b..e552a036cb4d 100644 --- a/include/linux/spi/spi.h +++ b/include/linux/spi/spi.h @@ -831,6 +831,7 @@ struct spi_transfer { u8 cs_change_delay_unit; #define SPI_DELAY_UNIT_USECS 0 #define SPI_DELAY_UNIT_NSECS 1 +#define SPI_DELAY_UNIT_SCK 2 u32 speed_hz; u16 word_delay; -- cgit v1.2.3 From 5d7e2b5ed5858fe739d4cb8ad22dcce7bd9dbe7b Mon Sep 17 00:00:00 2001 From: Martin Sperl Date: Sat, 23 Feb 2019 08:49:49 +0000 Subject: spi: core: allow reporting the effectivly used speed_hz for a transfer Provide a means for the spi bus driver to report the effectively used spi clock frequency used for each spi_transfer. Signed-off-by: Martin Sperl Signed-off-by: Mark Brown --- drivers/spi/spi.c | 1 + include/linux/spi/spi.h | 5 +++++ 2 files changed, 6 insertions(+) (limited to 'include/linux/spi/spi.h') diff --git a/drivers/spi/spi.c b/drivers/spi/spi.c index cfa3c3decb8a..e9bf0c23da50 100644 --- a/drivers/spi/spi.c +++ b/drivers/spi/spi.c @@ -3126,6 +3126,7 @@ static int __spi_validate(struct spi_device *spi, struct spi_message *message) */ message->frame_length = 0; list_for_each_entry(xfer, &message->transfers, transfer_list) { + xfer->effective_speed_hz = 0; message->frame_length += xfer->len; if (!xfer->bits_per_word) xfer->bits_per_word = spi->bits_per_word; diff --git a/include/linux/spi/spi.h b/include/linux/spi/spi.h index f55b20254612..d0c5ba746e01 100644 --- a/include/linux/spi/spi.h +++ b/include/linux/spi/spi.h @@ -745,6 +745,9 @@ extern void spi_res_release(struct spi_controller *ctlr, * (set by bits_per_word) transmission. * @word_delay: clock cycles to inter word delay after each word size * (set by bits_per_word) transmission. + * @effective_speed_hz: the effective SCK-speed that was used to + * transfer this transfer. Set to 0 if the spi bus driver does + * not support it. * @transfer_list: transfers are sequenced through @spi_message.transfers * @tx_sg: Scatterlist for transmit, currently not for client use * @rx_sg: Scatterlist for receive, currently not for client use @@ -835,6 +838,8 @@ struct spi_transfer { u32 speed_hz; u16 word_delay; + u32 effective_speed_hz; + struct list_head transfer_list; }; -- cgit v1.2.3 From 36f34737ff48f66c8a19b8788311e4b40d4adf80 Mon Sep 17 00:00:00 2001 From: Andy Shevchenko Date: Sat, 15 Jun 2019 20:47:37 +0300 Subject: spi: Add a prototype for exported spi_set_cs_timing() MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Compiler is not happy about spi_set_cs_timing() prototype. drivers/spi/spi.c:3016:6: warning: no previous prototype for ‘spi_set_cs_timing’ [-Wmissing-prototypes] void spi_set_cs_timing(struct spi_device *spi, u8 setup, u8 hold, ^~~~~~~~~~~~~~~~~ Let's add it to the header. Signed-off-by: Andy Shevchenko Signed-off-by: Mark Brown --- 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 d0c5ba746e01..0ec11f2911af 100644 --- a/include/linux/spi/spi.h +++ b/include/linux/spi/spi.h @@ -980,6 +980,8 @@ static inline void spi_message_free(struct spi_message *m) kfree(m); } +extern void spi_set_cs_timing(struct spi_device *spi, u8 setup, u8 hold, u8 inactive_dly); + extern int spi_setup(struct spi_device *spi); extern int spi_async(struct spi_device *spi, struct spi_message *message); extern int spi_async_locked(struct spi_device *spi, -- cgit v1.2.3