[PATCH v4 00/19] spi: introduce `struct spi_delay` data-type

[PATCH v4 00/19] spi: introduce `struct spi_delay` data-type

[Alexandru Ardelean]

Initially, I started this patchset thinking: "we need a new delay for
something-something" (in case someone is curios, we needed a CS-hold-time
when CS is asserted, because the CS wakes a chip from sleep-mode).

Then I added the delay, and felt a bit dirty-inside about adding a new one
(just like that), and decided to look at maybe cleaning things up a bit,
and a few days/weeks later, I got here.

It's based on top of Jonathan's `iio/togreg` branch which also includes the
ADIS driver library changes for `cs_change_delay`.

The current v4 tries to be a complete change as possible about converting
all delays to the `struct delay` data-type; at least in the scope of the
SPI subsystem. Many external users of the SPI subsystem use the
`delay_usecs` field to specify delays for transfers; which is why this
field is still kept temporarily for backwards compatibility until all other
delays are switched to `delay`.

Thanks
Alex

Changelog v3 -> v4:
* re-unify all `spi_delay` changes into a single big series spanning SPI &
  IIO subsystems; patches are based on top of IIO, so patch
  `drivers/iio/imu/adis.c` does not apply on top of SPI/for-next tree

Changelog v2 -> v3:
* squash patches 3 & 4 into a single patch; otherwise the kernel is in
  broken state between those 2 patches

Changelog v1 -> v2:
* split away from the RFC patchset, which aims to be a broader explanation
  for this changeset; parts of v1 are not 100% defined yet, and may require
  some discussion and refinement.


Alexandru Ardelean (19):
  spi: move `cs_change_delay` backwards compat logic outside switch
  spi: introduce spi_delay struct as "value + unit" &  spi_delay_exec()
  spi: make `cs_change_delay` the first user of the `spi_delay` logic
  spi: sprd: convert transfer word delay to spi_delay struct
  spi: orion: use new `word_delay` field for SPI transfers
  spi: spidev: use new `word_delay` field for spi transfers
  spi: core,atmel: convert `word_delay_usecs` -> `word_delay` for
    spi_device
  spi: introduce `delay` field for `spi_transfer` +
    spi_transfer_delay_exec()
  spi: use new `spi_transfer_delay_exec` helper where straightforward
  spi: tegra114: use `spi_transfer_delay_exec` helper
  spi: tegra20-sflash: use to new `spi_transfer_delay_exec`
  spi: spi-loopback-test: use new `delay` field
  spi: spidev: use new `delay` field for spi transfers
  spi: tegra114: change format for `spi_set_cs_timing()` function
  spi: implement SW control for CS times
  spi: spi-fsl-espi: convert transfer delay to `spi_delay` format
  spi: spi-falcon: extend warning to `delay` as well
  spi: bcm63xx: extend error condition to `delay` as well
  spi: spi-axi: extend support for the `delay` field

 drivers/iio/imu/adis.c           |  24 ++---
 drivers/spi/spi-atmel.c          |  29 +++++-
 drivers/spi/spi-axi-spi-engine.c |  16 +++-
 drivers/spi/spi-bcm63xx-hsspi.c  |   3 +-
 drivers/spi/spi-bcm63xx.c        |   2 +-
 drivers/spi/spi-cavium.c         |   3 +-
 drivers/spi/spi-falcon.c         |   2 +-
 drivers/spi/spi-fsl-dspi.c       |   3 +-
 drivers/spi/spi-fsl-espi.c       |  19 +++-
 drivers/spi/spi-fsl-spi.c        |   3 +-
 drivers/spi/spi-loopback-test.c  |  12 ++-
 drivers/spi/spi-mpc512x-psc.c    |   3 +-
 drivers/spi/spi-mpc52xx-psc.c    |   3 +-
 drivers/spi/spi-omap-100k.c      |   3 +-
 drivers/spi/spi-orion.c          |   6 +-
 drivers/spi/spi-pl022.c          |  25 +++--
 drivers/spi/spi-sc18is602.c      |   3 +-
 drivers/spi/spi-sh-hspi.c        |   3 +-
 drivers/spi/spi-sprd.c           |  15 ++-
 drivers/spi/spi-tegra114.c       |  39 ++++----
 drivers/spi/spi-tegra20-sflash.c |   5 +-
 drivers/spi/spi-topcliff-pch.c   |   7 +-
 drivers/spi/spi-txx9.c           |   3 +-
 drivers/spi/spi-xcomm.c          |   3 +-
 drivers/spi/spi.c                | 158 +++++++++++++++++++++++++------
 drivers/spi/spidev.c             |   6 +-
 include/linux/spi/spi.h          |  66 +++++++++----
 27 files changed, 323 insertions(+), 141 deletions(-)

-- 
2.20.1

[PATCH v4 01/19] spi: move `cs_change_delay` backwards compat logic outside switch

[Alexandru Ardelean]

The `cs_change_delay` backwards compatibility value could be moved outside
of the switch statement.
The only reason to do it, is to make the next patches easier to diff.

Signed-off-by: Alexandru Ardelean <alexandru.ardelean@analog.com>
---
 drivers/spi/spi.c | 11 +++++------
 1 file changed, 5 insertions(+), 6 deletions(-)

diff --git a/drivers/spi/spi.c b/drivers/spi/spi.c
index 75ac046cae52..c90e02e6d62f 100644
--- a/drivers/spi/spi.c
+++ b/drivers/spi/spi.c
@@ -1114,16 +1114,15 @@ static void _spi_transfer_cs_change_delay(struct spi_message *msg,
 	u32 hz;
 
 	/* return early on "fast" mode - for everything but USECS */
-	if (!delay && unit != SPI_DELAY_UNIT_USECS)
+	if (!delay) {
+		if (unit == SPI_DELAY_UNIT_USECS)
+			_spi_transfer_delay_ns(10000);
 		return;
+	}
 
 	switch (unit) {
 	case SPI_DELAY_UNIT_USECS:
-		/* for compatibility use default of 10us */
-		if (!delay)
-			delay = 10000;
-		else
-			delay *= 1000;
+		delay *= 1000;
 		break;
 	case SPI_DELAY_UNIT_NSECS: /* nothing to do here */
 		break;
-- 
2.20.1

[PATCH v4 02/19] spi: introduce spi_delay struct as "value + unit" & spi_delay_exec()

[Alexandru Ardelean]

There are plenty of delays that have been introduced in SPI core. Most of
them are in micro-seconds, some need to be in nano-seconds, and some in
clock-cycles.

For some of these delays (related to transfers & CS timing) it may make
sense to have a `spi_delay` struct that abstracts these a bit.

The important element of these delays [for unification] seems to be the
`unit` of the delay.
It looks like micro-seconds is good enough for most people, but every-once
in a while, some delays seem to require other units of measurement.

This change adds the `spi_delay` struct & a `spi_delay_exec()` function
that processes a `spi_delay` object/struct to execute the delay.
It's a copy of the `cs_change_delay` mechanism, but without the default
for 10 uS.

The clock-cycle delay unit is a bit special, as it needs to be bound to an
`spi_transfer` object to execute.

Signed-off-by: Alexandru Ardelean <alexandru.ardelean@analog.com>
---
 drivers/spi/spi.c       | 51 +++++++++++++++++++++++++++++++++++++++++
 include/linux/spi/spi.h | 18 ++++++++++++---
 2 files changed, 66 insertions(+), 3 deletions(-)

diff --git a/drivers/spi/spi.c b/drivers/spi/spi.c
index c90e02e6d62f..1883de8ffa82 100644
--- a/drivers/spi/spi.c
+++ b/drivers/spi/spi.c
@@ -1106,6 +1106,57 @@ static void _spi_transfer_delay_ns(u32 ns)
 	}
 }
 
+static int _spi_delay_to_ns(struct spi_delay *_delay, struct spi_transfer *xfer)
+{
+	u32 delay = _delay->value;
+	u32 unit = _delay->unit;
+	u32 hz;
+
+	if (!delay)
+		return 0;
+
+	switch (unit) {
+	case SPI_DELAY_UNIT_USECS:
+		delay *= 1000;
+		break;
+	case SPI_DELAY_UNIT_NSECS: /* nothing to do here */
+		break;
+	case SPI_DELAY_UNIT_SCK:
+		/* clock cycles need to be obtained from spi_transfer */
+		if (!xfer)
+			return -EINVAL;
+		/* 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;
+		if (!hz)
+			return -EINVAL;
+		delay *= DIV_ROUND_UP(1000000000, hz);
+		break;
+	default:
+		return -EINVAL;
+	}
+
+	return delay;
+}
+
+int spi_delay_exec(struct spi_delay *_delay, struct spi_transfer *xfer)
+{
+	int delay;
+
+	if (!_delay)
+		return -EINVAL;
+
+	delay = _spi_delay_to_ns(_delay, xfer);
+	if (delay < 0)
+		return delay;
+
+	_spi_transfer_delay_ns(delay);
+
+	return 0;
+}
+EXPORT_SYMBOL_GPL(spi_delay_exec);
+
 static void _spi_transfer_cs_change_delay(struct spi_message *msg,
 					  struct spi_transfer *xfer)
 {
diff --git a/include/linux/spi/spi.h b/include/linux/spi/spi.h
index af4f265d0f67..c18cfa7cda35 100644
--- a/include/linux/spi/spi.h
+++ b/include/linux/spi/spi.h
@@ -89,6 +89,21 @@ void spi_statistics_add_transfer_stats(struct spi_statistics *stats,
 #define SPI_STATISTICS_INCREMENT_FIELD(stats, field)	\
 	SPI_STATISTICS_ADD_TO_FIELD(stats, field, 1)
 
+/**
+ * struct spi_delay - SPI delay information
+ * @value: Value for the delay
+ * @unit: Unit for the delay
+ */
+struct spi_delay {
+#define SPI_DELAY_UNIT_USECS	0
+#define SPI_DELAY_UNIT_NSECS	1
+#define SPI_DELAY_UNIT_SCK	2
+	u16	value;
+	u8	unit;
+};
+
+extern int spi_delay_exec(struct spi_delay *_delay, struct spi_transfer *xfer);
+
 /**
  * struct spi_device - Controller side proxy for an SPI slave device
  * @dev: Driver model representation of the device.
@@ -834,9 +849,6 @@ struct spi_transfer {
 	u16		delay_usecs;
 	u16		cs_change_delay;
 	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;
 
-- 
2.20.1

[PATCH v4 03/19] spi: make `cs_change_delay` the first user of the `spi_delay` logic

[Alexandru Ardelean]

Since the logic for `spi_delay` struct + `spi_delay_exec()` has been copied
from the `cs_change_delay` logic, it's natural to make this delay, the
first user.

The `cs_change_delay` logic requires that the default remain 10 uS, in case
it is unspecified/unconfigured. So, there is some special handling needed
to do that.

The ADIS library is one of the few users of the new `cs_change_delay`
parameter for an spi_transfer.

The introduction of the `spi_delay` struct, requires that the users of of
`cs_change_delay` get an update. This change also updates the ADIS library.

Signed-off-by: Alexandru Ardelean <alexandru.ardelean@analog.com>
---
 drivers/iio/imu/adis.c  | 24 ++++++++++++------------
 drivers/spi/spi.c       | 28 +++++++---------------------
 include/linux/spi/spi.h |  4 +---
 3 files changed, 20 insertions(+), 36 deletions(-)

diff --git a/drivers/iio/imu/adis.c b/drivers/iio/imu/adis.c
index 1631c255deab..2cd2cc2316c6 100644
--- a/drivers/iio/imu/adis.c
+++ b/drivers/iio/imu/adis.c
@@ -39,24 +39,24 @@ int adis_write_reg(struct adis *adis, unsigned int reg,
 			.len = 2,
 			.cs_change = 1,
 			.delay_usecs = adis->data->write_delay,
-			.cs_change_delay = adis->data->cs_change_delay,
-			.cs_change_delay_unit = SPI_DELAY_UNIT_USECS,
+			.cs_change_delay.value = adis->data->cs_change_delay,
+			.cs_change_delay.unit = SPI_DELAY_UNIT_USECS,
 		}, {
 			.tx_buf = adis->tx + 2,
 			.bits_per_word = 8,
 			.len = 2,
 			.cs_change = 1,
 			.delay_usecs = adis->data->write_delay,
-			.cs_change_delay = adis->data->cs_change_delay,
-			.cs_change_delay_unit = SPI_DELAY_UNIT_USECS,
+			.cs_change_delay.value = adis->data->cs_change_delay,
+			.cs_change_delay.unit = SPI_DELAY_UNIT_USECS,
 		}, {
 			.tx_buf = adis->tx + 4,
 			.bits_per_word = 8,
 			.len = 2,
 			.cs_change = 1,
 			.delay_usecs = adis->data->write_delay,
-			.cs_change_delay = adis->data->cs_change_delay,
-			.cs_change_delay_unit = SPI_DELAY_UNIT_USECS,
+			.cs_change_delay.value = adis->data->cs_change_delay,
+			.cs_change_delay.unit = SPI_DELAY_UNIT_USECS,
 		}, {
 			.tx_buf = adis->tx + 6,
 			.bits_per_word = 8,
@@ -139,16 +139,16 @@ int adis_read_reg(struct adis *adis, unsigned int reg,
 			.len = 2,
 			.cs_change = 1,
 			.delay_usecs = adis->data->write_delay,
-			.cs_change_delay = adis->data->cs_change_delay,
-			.cs_change_delay_unit = SPI_DELAY_UNIT_USECS,
+			.cs_change_delay.value = adis->data->cs_change_delay,
+			.cs_change_delay.unit = SPI_DELAY_UNIT_USECS,
 		}, {
 			.tx_buf = adis->tx + 2,
 			.bits_per_word = 8,
 			.len = 2,
 			.cs_change = 1,
 			.delay_usecs = adis->data->read_delay,
-			.cs_change_delay = adis->data->cs_change_delay,
-			.cs_change_delay_unit = SPI_DELAY_UNIT_USECS,
+			.cs_change_delay.value = adis->data->cs_change_delay,
+			.cs_change_delay.unit = SPI_DELAY_UNIT_USECS,
 		}, {
 			.tx_buf = adis->tx + 4,
 			.rx_buf = adis->rx,
@@ -156,8 +156,8 @@ int adis_read_reg(struct adis *adis, unsigned int reg,
 			.len = 2,
 			.cs_change = 1,
 			.delay_usecs = adis->data->read_delay,
-			.cs_change_delay = adis->data->cs_change_delay,
-			.cs_change_delay_unit = SPI_DELAY_UNIT_USECS,
+			.cs_change_delay.value = adis->data->cs_change_delay,
+			.cs_change_delay.unit = SPI_DELAY_UNIT_USECS,
 		}, {
 			.rx_buf = adis->rx + 2,
 			.bits_per_word = 8,
diff --git a/drivers/spi/spi.c b/drivers/spi/spi.c
index 1883de8ffa82..d0bf0ffca042 100644
--- a/drivers/spi/spi.c
+++ b/drivers/spi/spi.c
@@ -1160,9 +1160,9 @@ EXPORT_SYMBOL_GPL(spi_delay_exec);
 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;
-	u32 hz;
+	u32 delay = xfer->cs_change_delay.value;
+	u32 unit = xfer->cs_change_delay.unit;
+	int ret;
 
 	/* return early on "fast" mode - for everything but USECS */
 	if (!delay) {
@@ -1171,27 +1171,13 @@ static void _spi_transfer_cs_change_delay(struct spi_message *msg,
 		return;
 	}
 
-	switch (unit) {
-	case SPI_DELAY_UNIT_USECS:
-		delay *= 1000;
-		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:
+	ret = spi_delay_exec(&xfer->cs_change_delay, xfer);
+	if (ret) {
 		dev_err_once(&msg->spi->dev,
 			     "Use of unsupported delay unit %i, using default of 10us\n",
-			     xfer->cs_change_delay_unit);
-		delay = 10000;
+			     unit);
+		_spi_transfer_delay_ns(10000);
 	}
-	/* now sleep for the requested amount of time */
-	_spi_transfer_delay_ns(delay);
 }
 
 /*
diff --git a/include/linux/spi/spi.h b/include/linux/spi/spi.h
index c18cfa7cda35..9ded3f44d58e 100644
--- a/include/linux/spi/spi.h
+++ b/include/linux/spi/spi.h
@@ -754,7 +754,6 @@ extern void spi_res_release(struct spi_controller *ctlr,
  * @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.
@@ -847,8 +846,7 @@ struct spi_transfer {
 	u8		bits_per_word;
 	u8		word_delay_usecs;
 	u16		delay_usecs;
-	u16		cs_change_delay;
-	u8		cs_change_delay_unit;
+	struct spi_delay	cs_change_delay;
 	u32		speed_hz;
 	u16		word_delay;
 
-- 
2.20.1

[PATCH v4 04/19] spi: sprd: convert transfer word delay to spi_delay struct

[Alexandru Ardelean]

The Spreadtrum SPI driver is the only user of the `word_delay` field in
the `spi_transfer` struct.

This change converts the field to use the `spi_delay` struct. This also
enforces the users to specify the delay unit to be `SPI_DELAY_UNIT_SCK`.

Signed-off-by: Alexandru Ardelean <alexandru.ardelean@analog.com>
---
 drivers/spi/spi-sprd.c  | 15 ++++++++++++---
 include/linux/spi/spi.h |  4 ++--
 2 files changed, 14 insertions(+), 5 deletions(-)

diff --git a/drivers/spi/spi-sprd.c b/drivers/spi/spi-sprd.c
index 1b7eebb72c07..7e72e8facff7 100644
--- a/drivers/spi/spi-sprd.c
+++ b/drivers/spi/spi-sprd.c
@@ -669,11 +669,15 @@ static void sprd_spi_set_speed(struct sprd_spi *ss, u32 speed_hz)
 	writel_relaxed(clk_div, ss->base + SPRD_SPI_CLKD);
 }
 
-static void sprd_spi_init_hw(struct sprd_spi *ss, struct spi_transfer *t)
+static int sprd_spi_init_hw(struct sprd_spi *ss, struct spi_transfer *t)
 {
+	struct spi_delay *d = &t->word_delay;
 	u16 word_delay, interval;
 	u32 val;
 
+	if (d->unit != SPI_DELAY_UNIT_SCK)
+		return -EINVAL;
+
 	val = readl_relaxed(ss->base + SPRD_SPI_CTL7);
 	val &= ~(SPRD_SPI_SCK_REV | SPRD_SPI_NG_TX | SPRD_SPI_NG_RX);
 	/* Set default chip selection, clock phase and clock polarity */
@@ -686,7 +690,7 @@ static void sprd_spi_init_hw(struct sprd_spi *ss, struct spi_transfer *t)
 	 * formula as below per datasheet:
 	 * interval time (source clock cycles) = interval * 4 + 10.
 	 */
-	word_delay = clamp_t(u16, t->word_delay, SPRD_SPI_MIN_DELAY_CYCLE,
+	word_delay = clamp_t(u16, d->value, SPRD_SPI_MIN_DELAY_CYCLE,
 			     SPRD_SPI_MAX_DELAY_CYCLE);
 	interval = DIV_ROUND_UP(word_delay - 10, 4);
 	ss->word_delay = interval * 4 + 10;
@@ -711,6 +715,8 @@ static void sprd_spi_init_hw(struct sprd_spi *ss, struct spi_transfer *t)
 		val &= ~SPRD_SPI_DATA_LINE2_EN;
 
 	writel_relaxed(val, ss->base + SPRD_SPI_CTL7);
+
+	return 0;
 }
 
 static int sprd_spi_setup_transfer(struct spi_device *sdev,
@@ -719,13 +725,16 @@ static int sprd_spi_setup_transfer(struct spi_device *sdev,
 	struct sprd_spi *ss = spi_controller_get_devdata(sdev->controller);
 	u8 bits_per_word = t->bits_per_word;
 	u32 val, mode = 0;
+	int ret;
 
 	ss->len = t->len;
 	ss->tx_buf = t->tx_buf;
 	ss->rx_buf = t->rx_buf;
 
 	ss->hw_mode = sdev->mode;
-	sprd_spi_init_hw(ss, t);
+	ret = sprd_spi_init_hw(ss, t);
+	if (ret)
+		return ret;
 
 	/* Set tansfer speed and valid bits */
 	sprd_spi_set_speed(ss, t->speed_hz);
diff --git a/include/linux/spi/spi.h b/include/linux/spi/spi.h
index 9ded3f44d58e..16397b210e0c 100644
--- a/include/linux/spi/spi.h
+++ b/include/linux/spi/spi.h
@@ -759,7 +759,7 @@ extern void spi_res_release(struct spi_controller *ctlr,
  *	the next transfer or completing this @spi_message.
  * @word_delay_usecs: microseconds to inter word delay after each word size
  *	(set by bits_per_word) transmission.
- * @word_delay: clock cycles to inter word delay after each word size
+ * @word_delay: inter word delay to be introduced 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
@@ -847,8 +847,8 @@ struct spi_transfer {
 	u8		word_delay_usecs;
 	u16		delay_usecs;
 	struct spi_delay	cs_change_delay;
+	struct spi_delay	word_delay;
 	u32		speed_hz;
-	u16		word_delay;
 
 	u32		effective_speed_hz;
 
-- 
2.20.1

[PATCH v4 05/19] spi: orion: use new `word_delay` field for SPI transfers

[Alexandru Ardelean]

The `word_delay` field had it's type changed to `struct spi_delay`.
This allows users to specify nano-second or clock-cycle delays (if needed).

Converting to use `word_delay` is straightforward: it just uses the new
`spi_delay_exec()` routine, that handles the `unit` part.

Signed-off-by: Alexandru Ardelean <alexandru.ardelean@analog.com>
---
 drivers/spi/spi-orion.c | 6 ++----
 1 file changed, 2 insertions(+), 4 deletions(-)

diff --git a/drivers/spi/spi-orion.c b/drivers/spi/spi-orion.c
index 6643ccdc2508..756c37e32dfe 100644
--- a/drivers/spi/spi-orion.c
+++ b/drivers/spi/spi-orion.c
@@ -467,8 +467,7 @@ orion_spi_write_read(struct spi_device *spi, struct spi_transfer *xfer)
 			if (orion_spi_write_read_8bit(spi, &tx, &rx) < 0)
 				goto out;
 			count--;
-			if (xfer->word_delay_usecs)
-				udelay(xfer->word_delay_usecs);
+			spi_delay_exec(&xfer->word_delay, xfer);
 		} while (count);
 	} else if (word_len == 16) {
 		const u16 *tx = xfer->tx_buf;
@@ -478,8 +477,7 @@ orion_spi_write_read(struct spi_device *spi, struct spi_transfer *xfer)
 			if (orion_spi_write_read_16bit(spi, &tx, &rx) < 0)
 				goto out;
 			count -= 2;
-			if (xfer->word_delay_usecs)
-				udelay(xfer->word_delay_usecs);
+			spi_delay_exec(&xfer->word_delay, xfer);
 		} while (count);
 	}
 
-- 
2.20.1

[PATCH v4 06/19] spi: spidev: use new `word_delay` field for spi transfers

[Alexandru Ardelean]

The `word_delay` field had it's type changed to `struct spi_delay`.
This allows users to specify nano-second or clock-cycle delays (if needed).

Converting to use `word_delay` is straightforward: it's just assigning the
value to `word_delay.value` and hard-coding the `word_delay.unit` to
`SPI_DELAY_UNIT_USECS`

This keeps the uapi for spidev un-changed. Changing it can be part of
another changeset and discussion.

Signed-off-by: Alexandru Ardelean <alexandru.ardelean@analog.com>
---
 drivers/spi/spidev.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/drivers/spi/spidev.c b/drivers/spi/spidev.c
index 255786f2e844..495319c2fa11 100644
--- a/drivers/spi/spidev.c
+++ b/drivers/spi/spidev.c
@@ -267,7 +267,8 @@ static int spidev_message(struct spidev_data *spidev,
 		k_tmp->bits_per_word = u_tmp->bits_per_word;
 		k_tmp->delay_usecs = u_tmp->delay_usecs;
 		k_tmp->speed_hz = u_tmp->speed_hz;
-		k_tmp->word_delay_usecs = u_tmp->word_delay_usecs;
+		k_tmp->word_delay.value = u_tmp->word_delay_usecs;
+		k_tmp->word_delay.unit = SPI_DELAY_UNIT_USECS;
 		if (!k_tmp->speed_hz)
 			k_tmp->speed_hz = spidev->speed_hz;
 #ifdef VERBOSE
-- 
2.20.1

[PATCH v4 07/19] spi: core,atmel: convert `word_delay_usecs` -> `word_delay` for spi_device

[Alexandru Ardelean]

This change does a conversion from the `word_delay_usecs` -> `word_delay`
for the `spi_device` struct.

This allows users to specify inter-word delays in other unit types
(nano-seconds or clock cycles), depending on how users want.

The Atmel SPI driver is the only current user of the `word_delay_usecs`
field (from the `spi_device` struct).
So, it needed a slight conversion to use the `word_delay` as an `spi_delay`
struct.

In SPI core, the only required mechanism is to update the `word_delay`
information per `spi_transfer`. This requires a bit more logic than before,
because it needs that both delays be converted to a common unit
(nano-seconds) for comparison.

Signed-off-by: Alexandru Ardelean <alexandru.ardelean@analog.com>
---
 drivers/spi/spi-atmel.c | 26 ++++++++++++++++++++++++--
 drivers/spi/spi.c       | 24 ++++++++++++++++++++++--
 include/linux/spi/spi.h |  7 ++-----
 3 files changed, 48 insertions(+), 9 deletions(-)

diff --git a/drivers/spi/spi-atmel.c b/drivers/spi/spi-atmel.c
index f00b367523cd..f04b92791515 100644
--- a/drivers/spi/spi-atmel.c
+++ b/drivers/spi/spi-atmel.c
@@ -1172,12 +1172,31 @@ atmel_spi_pdc_interrupt(int irq, void *dev_id)
 	return ret;
 }
 
+static int atmel_word_delay_csr(struct spi_device *spi, struct atmel_spi *as)
+{
+	struct spi_delay *delay = &spi->word_delay;
+	u32 value = delay->value;
+
+	switch (delay->unit) {
+	case SPI_DELAY_UNIT_NSECS:
+		value /= 1000;
+		break;
+	case SPI_DELAY_UNIT_USECS:
+		break;
+	default:
+		return -EINVAL;
+	}
+
+	return (as->spi_clk / 1000000 * value) >> 5;
+}
+
 static int atmel_spi_setup(struct spi_device *spi)
 {
 	struct atmel_spi	*as;
 	struct atmel_spi_device	*asd;
 	u32			csr;
 	unsigned int		bits = spi->bits_per_word;
+	int			word_delay_csr;
 
 	as = spi_master_get_devdata(spi->master);
 
@@ -1201,11 +1220,14 @@ static int atmel_spi_setup(struct spi_device *spi)
 	 */
 	csr |= SPI_BF(DLYBS, 0);
 
+	word_delay_csr = atmel_word_delay_csr(spi, as);
+	if (word_delay_csr < 0)
+		return word_delay_csr;
+
 	/* DLYBCT adds delays between words.  This is useful for slow devices
 	 * that need a bit of time to setup the next transfer.
 	 */
-	csr |= SPI_BF(DLYBCT,
-			(as->spi_clk / 1000000 * spi->word_delay_usecs) >> 5);
+	csr |= SPI_BF(DLYBCT, word_delay_csr);
 
 	asd = spi->controller_state;
 	if (!asd) {
diff --git a/drivers/spi/spi.c b/drivers/spi/spi.c
index d0bf0ffca042..ba8731b77753 100644
--- a/drivers/spi/spi.c
+++ b/drivers/spi/spi.c
@@ -3159,6 +3159,26 @@ void spi_set_cs_timing(struct spi_device *spi, u8 setup, u8 hold,
 }
 EXPORT_SYMBOL_GPL(spi_set_cs_timing);
 
+static int _spi_xfer_word_delay_update(struct spi_transfer *xfer,
+				       struct spi_device *spi)
+{
+	int delay1, delay2;
+
+	delay1 = _spi_delay_to_ns(&xfer->word_delay, xfer);
+	if (delay1 < 0)
+		return delay1;
+
+	delay2 = _spi_delay_to_ns(&spi->word_delay, xfer);
+	if (delay2 < 0)
+		return delay2;
+
+	if (delay1 < delay2)
+		memcpy(&xfer->word_delay, &spi->word_delay,
+		       sizeof(xfer->word_delay));
+
+	return 0;
+}
+
 static int __spi_validate(struct spi_device *spi, struct spi_message *message)
 {
 	struct spi_controller *ctlr = spi->controller;
@@ -3294,8 +3314,8 @@ static int __spi_validate(struct spi_device *spi, struct spi_message *message)
 				return -EINVAL;
 		}
 
-		if (xfer->word_delay_usecs < spi->word_delay_usecs)
-			xfer->word_delay_usecs = spi->word_delay_usecs;
+		if (_spi_xfer_word_delay_update(xfer, spi))
+			return -EINVAL;
 	}
 
 	message->status = -EINPROGRESS;
diff --git a/include/linux/spi/spi.h b/include/linux/spi/spi.h
index 16397b210e0c..e7ec0be16a82 100644
--- a/include/linux/spi/spi.h
+++ b/include/linux/spi/spi.h
@@ -138,7 +138,7 @@ extern int spi_delay_exec(struct spi_delay *_delay, struct spi_transfer *xfer);
  *	the spi_master.
  * @cs_gpiod: gpio descriptor of the chipselect line (optional, NULL when
  *	not using a GPIO line)
- * @word_delay_usecs: microsecond delay to be inserted between consecutive
+ * @word_delay: delay to be inserted between consecutive
  *	words of a transfer
  *
  * @statistics: statistics for the spi_device
@@ -188,7 +188,7 @@ struct spi_device {
 	const char		*driver_override;
 	int			cs_gpio;	/* LEGACY: chip select gpio */
 	struct gpio_desc	*cs_gpiod;	/* chip select gpio desc */
-	uint8_t			word_delay_usecs; /* inter-word delay */
+	struct spi_delay	word_delay; /* inter-word delay */
 
 	/* the statistics */
 	struct spi_statistics	statistics;
@@ -757,8 +757,6 @@ extern void spi_res_release(struct spi_controller *ctlr,
  * @delay_usecs: microseconds to delay after this transfer before
  *	(optionally) changing the chipselect status, then starting
  *	the next transfer or completing this @spi_message.
- * @word_delay_usecs: microseconds to inter word delay after each word size
- *	(set by bits_per_word) transmission.
  * @word_delay: inter word delay to be introduced after each word size
  *	(set by bits_per_word) transmission.
  * @effective_speed_hz: the effective SCK-speed that was used to
@@ -844,7 +842,6 @@ struct spi_transfer {
 #define	SPI_NBITS_DUAL		0x02 /* 2bits transfer */
 #define	SPI_NBITS_QUAD		0x04 /* 4bits transfer */
 	u8		bits_per_word;
-	u8		word_delay_usecs;
 	u16		delay_usecs;
 	struct spi_delay	cs_change_delay;
 	struct spi_delay	word_delay;
-- 
2.20.1

[PATCH v4 08/19] spi: introduce `delay` field for `spi_transfer` + spi_transfer_delay_exec()

[Alexandru Ardelean]

The change introduces the `delay` field to the `spi_transfer` struct as an
`struct spi_delay` type.
This intends to eventually replace `delay_usecs`.

But, since there are many users of `delay_usecs`, this needs some
intermediate work.
A helper called `spi_transfer_delay_exec()` is also added, which maintains
backwards compatibility with `delay_usecs`, by assigning the value to
`delay` if non-zero.
This should maintain backwards compatibility with current users of
`udelay_usecs`.

Signed-off-by: Alexandru Ardelean <alexandru.ardelean@analog.com>
---
 drivers/spi/spi.c       |  6 +++---
 include/linux/spi/spi.h | 18 ++++++++++++++++++
 2 files changed, 21 insertions(+), 3 deletions(-)

diff --git a/drivers/spi/spi.c b/drivers/spi/spi.c
index ba8731b77753..489eb64d9ee0 100644
--- a/drivers/spi/spi.c
+++ b/drivers/spi/spi.c
@@ -1238,8 +1238,7 @@ static int spi_transfer_one_message(struct spi_controller *ctlr,
 		if (msg->status != -EINPROGRESS)
 			goto out;
 
-		if (xfer->delay_usecs)
-			_spi_transfer_delay_ns(xfer->delay_usecs * 1000);
+		spi_transfer_delay_exec(xfer);
 
 		if (xfer->cs_change) {
 			if (list_is_last(&xfer->transfer_list,
@@ -2904,10 +2903,11 @@ struct spi_replaced_transfers *spi_replace_transfers(
 		/* add to list */
 		list_add(&xfer->transfer_list, rxfer->replaced_after);
 
-		/* clear cs_change and delay_usecs for all but the last */
+		/* clear cs_change and delay for all but the last */
 		if (i) {
 			xfer->cs_change = false;
 			xfer->delay_usecs = 0;
+			xfer->delay.value = 0;
 		}
 	}
 
diff --git a/include/linux/spi/spi.h b/include/linux/spi/spi.h
index e7ec0be16a82..2cee9ac35737 100644
--- a/include/linux/spi/spi.h
+++ b/include/linux/spi/spi.h
@@ -754,6 +754,9 @@ extern void spi_res_release(struct spi_controller *ctlr,
  * @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
+ * @delay: delay to be introduced after this transfer before
+ *	(optionally) changing the chipselect status, then starting
+ *	the next transfer or completing this @spi_message.
  * @delay_usecs: microseconds to delay after this transfer before
  *	(optionally) changing the chipselect status, then starting
  *	the next transfer or completing this @spi_message.
@@ -843,6 +846,7 @@ struct spi_transfer {
 #define	SPI_NBITS_QUAD		0x04 /* 4bits transfer */
 	u8		bits_per_word;
 	u16		delay_usecs;
+	struct spi_delay	delay;
 	struct spi_delay	cs_change_delay;
 	struct spi_delay	word_delay;
 	u32		speed_hz;
@@ -942,6 +946,20 @@ spi_transfer_del(struct spi_transfer *t)
 	list_del(&t->transfer_list);
 }
 
+static inline int
+spi_transfer_delay_exec(struct spi_transfer *t)
+{
+	struct spi_delay d;
+
+	if (t->delay_usecs) {
+		d.value = t->delay_usecs;
+		d.unit = SPI_DELAY_UNIT_USECS;
+		return spi_delay_exec(&d, NULL);
+	}
+
+	return spi_delay_exec(&t->delay, t);
+}
+
 /**
  * spi_message_init_with_transfers - Initialize spi_message and append transfers
  * @m: spi_message to be initialized
-- 
2.20.1

[PATCH v4 09/19] spi: use new `spi_transfer_delay_exec` helper where straightforward

[Alexandru Ardelean]

For many places in the spi drivers, using the new `spi_transfer_delay`
helper is straightforward.
It's just replacing:
```
  if (t->delay_usecs)
     udelay(t->delay_usecs);
```
with `spi_transfer_delay(t)` which handles both `delay_usecs` and the new
`delay` field.

This change replaces in all places (in the spi drivers)  where this change
is simple.

Signed-off-by: Alexandru Ardelean <alexandru.ardelean@analog.com>
---
 drivers/spi/spi-atmel.c         |  3 +--
 drivers/spi/spi-bcm63xx-hsspi.c |  3 +--
 drivers/spi/spi-cavium.c        |  3 +--
 drivers/spi/spi-fsl-dspi.c      |  3 +--
 drivers/spi/spi-fsl-espi.c      |  3 +--
 drivers/spi/spi-fsl-spi.c       |  3 +--
 drivers/spi/spi-mpc512x-psc.c   |  3 +--
 drivers/spi/spi-mpc52xx-psc.c   |  3 +--
 drivers/spi/spi-omap-100k.c     |  3 +--
 drivers/spi/spi-pl022.c         | 25 +++++++++++--------------
 drivers/spi/spi-sc18is602.c     |  3 +--
 drivers/spi/spi-sh-hspi.c       |  3 +--
 drivers/spi/spi-topcliff-pch.c  |  7 +------
 drivers/spi/spi-txx9.c          |  3 +--
 drivers/spi/spi-xcomm.c         |  3 +--
 15 files changed, 25 insertions(+), 46 deletions(-)

diff --git a/drivers/spi/spi-atmel.c b/drivers/spi/spi-atmel.c
index f04b92791515..2f7388e53b82 100644
--- a/drivers/spi/spi-atmel.c
+++ b/drivers/spi/spi-atmel.c
@@ -1389,8 +1389,7 @@ static int atmel_spi_one_transfer(struct spi_master *master,
 		&& as->use_pdc)
 		atmel_spi_dma_unmap_xfer(master, xfer);
 
-	if (xfer->delay_usecs)
-		udelay(xfer->delay_usecs);
+	spi_transfer_delay_exec(xfer);
 
 	if (xfer->cs_change) {
 		if (list_is_last(&xfer->transfer_list,
diff --git a/drivers/spi/spi-bcm63xx-hsspi.c b/drivers/spi/spi-bcm63xx-hsspi.c
index 9a06ffdb73b8..949b59b6449f 100644
--- a/drivers/spi/spi-bcm63xx-hsspi.c
+++ b/drivers/spi/spi-bcm63xx-hsspi.c
@@ -291,8 +291,7 @@ static int bcm63xx_hsspi_transfer_one(struct spi_master *master,
 
 		msg->actual_length += t->len;
 
-		if (t->delay_usecs)
-			udelay(t->delay_usecs);
+		spi_transfer_delay_exec(t);
 
 		if (t->cs_change)
 			bcm63xx_hsspi_set_cs(bs, spi->chip_select, false);
diff --git a/drivers/spi/spi-cavium.c b/drivers/spi/spi-cavium.c
index 5aaf21582cb5..6854c3ce423b 100644
--- a/drivers/spi/spi-cavium.c
+++ b/drivers/spi/spi-cavium.c
@@ -119,8 +119,7 @@ static int octeon_spi_do_transfer(struct octeon_spi *p,
 			*rx_buf++ = (u8)v;
 		}
 
-	if (xfer->delay_usecs)
-		udelay(xfer->delay_usecs);
+	spi_transfer_delay_exec(xfer);
 
 	return xfer->len;
 }
diff --git a/drivers/spi/spi-fsl-dspi.c b/drivers/spi/spi-fsl-dspi.c
index 53335ccc98f6..736071e2b9d8 100644
--- a/drivers/spi/spi-fsl-dspi.c
+++ b/drivers/spi/spi-fsl-dspi.c
@@ -752,8 +752,7 @@ static int dspi_transfer_one_message(struct spi_master *master,
 			dspi->waitflags = 0;
 		}
 
-		if (transfer->delay_usecs)
-			udelay(transfer->delay_usecs);
+		spi_transfer_delay_exec(transfer);
 	}
 
 out:
diff --git a/drivers/spi/spi-fsl-espi.c b/drivers/spi/spi-fsl-espi.c
index f20326714b9d..732bf3195917 100644
--- a/drivers/spi/spi-fsl-espi.c
+++ b/drivers/spi/spi-fsl-espi.c
@@ -427,8 +427,7 @@ static int fsl_espi_trans(struct spi_message *m, struct spi_transfer *trans)
 
 	ret = fsl_espi_bufs(spi, trans);
 
-	if (trans->delay_usecs)
-		udelay(trans->delay_usecs);
+	spi_transfer_delay_exec(trans);
 
 	return ret;
 }
diff --git a/drivers/spi/spi-fsl-spi.c b/drivers/spi/spi-fsl-spi.c
index 1d9b33aa1a3b..139ab57aec99 100644
--- a/drivers/spi/spi-fsl-spi.c
+++ b/drivers/spi/spi-fsl-spi.c
@@ -417,8 +417,7 @@ static int fsl_spi_do_one_msg(struct spi_master *master,
 		}
 		m->actual_length += t->len;
 
-		if (t->delay_usecs)
-			udelay(t->delay_usecs);
+		spi_transfer_delay_exec(t);
 
 		if (cs_change) {
 			ndelay(nsecs);
diff --git a/drivers/spi/spi-mpc512x-psc.c b/drivers/spi/spi-mpc512x-psc.c
index a337b842ae8c..ea1b07953d38 100644
--- a/drivers/spi/spi-mpc512x-psc.c
+++ b/drivers/spi/spi-mpc512x-psc.c
@@ -311,8 +311,7 @@ static int mpc512x_psc_spi_msg_xfer(struct spi_master *master,
 			break;
 		m->actual_length += t->len;
 
-		if (t->delay_usecs)
-			udelay(t->delay_usecs);
+		spi_transfer_delay_exec(t);
 
 		if (cs_change)
 			mpc512x_psc_spi_deactivate_cs(spi);
diff --git a/drivers/spi/spi-mpc52xx-psc.c b/drivers/spi/spi-mpc52xx-psc.c
index c7e478b9b586..17935e71b02f 100644
--- a/drivers/spi/spi-mpc52xx-psc.c
+++ b/drivers/spi/spi-mpc52xx-psc.c
@@ -234,8 +234,7 @@ static void mpc52xx_psc_spi_work(struct work_struct *work)
 				break;
 			m->actual_length += t->len;
 
-			if (t->delay_usecs)
-				udelay(t->delay_usecs);
+			spi_transfer_delay_exec(t);
 
 			if (cs_change)
 				mpc52xx_psc_spi_deactivate_cs(spi);
diff --git a/drivers/spi/spi-omap-100k.c b/drivers/spi/spi-omap-100k.c
index b955ca8796d2..89608eb55f1f 100644
--- a/drivers/spi/spi-omap-100k.c
+++ b/drivers/spi/spi-omap-100k.c
@@ -321,8 +321,7 @@ static int omap1_spi100k_transfer_one_message(struct spi_master *master,
 			}
 		}
 
-		if (t->delay_usecs)
-			udelay(t->delay_usecs);
+		spi_transfer_delay_exec(t);
 
 		/* ignore the "leave it on after last xfer" hint */
 
diff --git a/drivers/spi/spi-pl022.c b/drivers/spi/spi-pl022.c
index 7fedea67159c..3024c30e7f2e 100644
--- a/drivers/spi/spi-pl022.c
+++ b/drivers/spi/spi-pl022.c
@@ -485,12 +485,11 @@ static void giveback(struct pl022 *pl022)
 					struct spi_transfer, transfer_list);
 
 	/* Delay if requested before any change in chip select */
-	if (last_transfer->delay_usecs)
-		/*
-		 * FIXME: This runs in interrupt context.
-		 * Is this really smart?
-		 */
-		udelay(last_transfer->delay_usecs);
+	/*
+	 * FIXME: This runs in interrupt context.
+	 * Is this really smart?
+	 */
+	spi_transfer_delay_exec(last_transfer);
 
 	if (!last_transfer->cs_change) {
 		struct spi_message *next_msg;
@@ -1401,12 +1400,11 @@ static void pump_transfers(unsigned long data)
 		previous = list_entry(transfer->transfer_list.prev,
 					struct spi_transfer,
 					transfer_list);
-		if (previous->delay_usecs)
-			/*
-			 * FIXME: This runs in interrupt context.
-			 * Is this really smart?
-			 */
-			udelay(previous->delay_usecs);
+		/*
+		 * FIXME: This runs in interrupt context.
+		 * Is this really smart?
+		 */
+		spi_transfer_delay_exec(previous);
 
 		/* Reselect chip select only if cs_change was requested */
 		if (previous->cs_change)
@@ -1520,8 +1518,7 @@ static void do_polling_transfer(struct pl022 *pl022)
 			previous =
 			    list_entry(transfer->transfer_list.prev,
 				       struct spi_transfer, transfer_list);
-			if (previous->delay_usecs)
-				udelay(previous->delay_usecs);
+			spi_transfer_delay_exec(previous);
 			if (previous->cs_change)
 				pl022_cs_control(pl022, SSP_CHIP_SELECT);
 		} else {
diff --git a/drivers/spi/spi-sc18is602.c b/drivers/spi/spi-sc18is602.c
index 11acddc83304..5497eeb3bf3e 100644
--- a/drivers/spi/spi-sc18is602.c
+++ b/drivers/spi/spi-sc18is602.c
@@ -211,8 +211,7 @@ static int sc18is602_transfer_one(struct spi_master *master,
 		}
 		status = 0;
 
-		if (t->delay_usecs)
-			udelay(t->delay_usecs);
+		spi_transfer_delay_exec(t);
 	}
 	m->status = status;
 	spi_finalize_current_message(master);
diff --git a/drivers/spi/spi-sh-hspi.c b/drivers/spi/spi-sh-hspi.c
index 7f73f91d412a..a62034e2a7cb 100644
--- a/drivers/spi/spi-sh-hspi.c
+++ b/drivers/spi/spi-sh-hspi.c
@@ -190,8 +190,7 @@ static int hspi_transfer_one_message(struct spi_controller *ctlr,
 
 		msg->actual_length += t->len;
 
-		if (t->delay_usecs)
-			udelay(t->delay_usecs);
+		spi_transfer_delay_exec(t);
 
 		if (cs_change) {
 			ndelay(nsecs);
diff --git a/drivers/spi/spi-topcliff-pch.c b/drivers/spi/spi-topcliff-pch.c
index f88cbb94ce12..223353fa2d8a 100644
--- a/drivers/spi/spi-topcliff-pch.c
+++ b/drivers/spi/spi-topcliff-pch.c
@@ -1229,12 +1229,7 @@ static void pch_spi_process_messages(struct work_struct *pwork)
 			"%s:data->current_msg->actual_length=%d\n",
 			__func__, data->current_msg->actual_length);
 
-		/* check for delay */
-		if (data->cur_trans->delay_usecs) {
-			dev_dbg(&data->master->dev, "%s:delay in usec=%d\n",
-				__func__, data->cur_trans->delay_usecs);
-			udelay(data->cur_trans->delay_usecs);
-		}
+		spi_transfer_delay_exec(data->cur_trans);
 
 		spin_lock(&data->lock);
 
diff --git a/drivers/spi/spi-txx9.c b/drivers/spi/spi-txx9.c
index 51759d3fd45f..83daaa597acc 100644
--- a/drivers/spi/spi-txx9.c
+++ b/drivers/spi/spi-txx9.c
@@ -248,8 +248,7 @@ static void txx9spi_work_one(struct txx9spi *c, struct spi_message *m)
 			len -= count * wsize;
 		}
 		m->actual_length += t->len;
-		if (t->delay_usecs)
-			udelay(t->delay_usecs);
+		spi_transfer_delay_exec(t);
 
 		if (!cs_change)
 			continue;
diff --git a/drivers/spi/spi-xcomm.c b/drivers/spi/spi-xcomm.c
index a3496c46cc1b..1d9b3f03d986 100644
--- a/drivers/spi/spi-xcomm.c
+++ b/drivers/spi/spi-xcomm.c
@@ -188,8 +188,7 @@ static int spi_xcomm_transfer_one(struct spi_master *master,
 		}
 		status = 0;
 
-		if (t->delay_usecs)
-			udelay(t->delay_usecs);
+		spi_transfer_delay_exec(t);
 
 		is_first = false;
 	}
-- 
2.20.1

[PATCH v4 10/19] spi: tegra114: use `spi_transfer_delay_exec` helper

[Alexandru Ardelean]

The tegra114 driver has a weird/separate `tegra_spi_transfer_delay()`
function that does 2 delays: one mdelay() and one udelay().

This was introduced via commit f4fade12d506e14867a2b0a5e2f7aaf227297d8b
("spi/tegra114: Correct support for cs_change").

There doesn't seem to be a mention in that commit message to suggest a
specific need/use-case for having the 2 delay calls.
For the most part, udelay() should be sufficient.

This change replaces it with the new `spi_transfer_delay_exec()`, which
should do the same thing.

Signed-off-by: Alexandru Ardelean <alexandru.ardelean@analog.com>
---
 drivers/spi/spi-tegra114.c | 17 +++--------------
 1 file changed, 3 insertions(+), 14 deletions(-)

diff --git a/drivers/spi/spi-tegra114.c b/drivers/spi/spi-tegra114.c
index 39374c2edcf3..8133dc49d34f 100644
--- a/drivers/spi/spi-tegra114.c
+++ b/drivers/spi/spi-tegra114.c
@@ -984,17 +984,6 @@ static int tegra_spi_setup(struct spi_device *spi)
 	return 0;
 }
 
-static void tegra_spi_transfer_delay(int delay)
-{
-	if (!delay)
-		return;
-
-	if (delay >= 1000)
-		mdelay(delay / 1000);
-
-	udelay(delay % 1000);
-}
-
 static void tegra_spi_transfer_end(struct spi_device *spi)
 {
 	struct tegra_spi_data *tspi = spi_master_get_devdata(spi->master);
@@ -1098,7 +1087,7 @@ static int tegra_spi_transfer_one_message(struct spi_master *master,
 complete_xfer:
 		if (ret < 0 || skip) {
 			tegra_spi_transfer_end(spi);
-			tegra_spi_transfer_delay(xfer->delay_usecs);
+			spi_transfer_delay_exec(xfer);
 			goto exit;
 		} else if (list_is_last(&xfer->transfer_list,
 					&msg->transfers)) {
@@ -1106,11 +1095,11 @@ static int tegra_spi_transfer_one_message(struct spi_master *master,
 				tspi->cs_control = spi;
 			else {
 				tegra_spi_transfer_end(spi);
-				tegra_spi_transfer_delay(xfer->delay_usecs);
+				spi_transfer_delay_exec(xfer);
 			}
 		} else if (xfer->cs_change) {
 			tegra_spi_transfer_end(spi);
-			tegra_spi_transfer_delay(xfer->delay_usecs);
+			spi_transfer_delay_exec(xfer);
 		}
 
 	}
-- 
2.20.1

[PATCH v4 11/19] spi: tegra20-sflash: use to new `spi_transfer_delay_exec`

[Alexandru Ardelean]

This conversion to the spi_transfer_delay_exec() helper is not
straightforward, as it seems that when a delay is present, the controller
issues a command, and then a delay is followed.

This change adds support for the new `delay` field which is of type
`spi_delay` and keeps backwards compatibility with the old `delay_usecs`
field.

Signed-off-by: Alexandru Ardelean <alexandru.ardelean@analog.com>
---
 drivers/spi/spi-tegra20-sflash.c | 5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)

diff --git a/drivers/spi/spi-tegra20-sflash.c b/drivers/spi/spi-tegra20-sflash.c
index cd714a4f52c6..ff1933e55830 100644
--- a/drivers/spi/spi-tegra20-sflash.c
+++ b/drivers/spi/spi-tegra20-sflash.c
@@ -341,10 +341,11 @@ static int tegra_sflash_transfer_one_message(struct spi_master *master,
 			goto exit;
 		}
 		msg->actual_length += xfer->len;
-		if (xfer->cs_change && xfer->delay_usecs) {
+		if (xfer->cs_change &&
+		    (xfer->delay_usecs || xfer->delay.value)) {
 			tegra_sflash_writel(tsd, tsd->def_command_reg,
 					SPI_COMMAND);
-			udelay(xfer->delay_usecs);
+			spi_transfer_delay_exec(xfer);
 		}
 	}
 	ret = 0;
-- 
2.20.1

[PATCH v4 12/19] spi: spi-loopback-test: use new `delay` field

[Alexandru Ardelean]

This change replaces the use of the `delay_usecs` field with the new
`delay` field. The code/test still uses micro-seconds, but they are now
configured and used via the `struct spi_delay` format of the `delay` field.

Signed-off-by: Alexandru Ardelean <alexandru.ardelean@analog.com>
---
 drivers/spi/spi-loopback-test.c | 12 +++++++++---
 1 file changed, 9 insertions(+), 3 deletions(-)

diff --git a/drivers/spi/spi-loopback-test.c b/drivers/spi/spi-loopback-test.c
index 6f18d4952767..b6d79cd156fb 100644
--- a/drivers/spi/spi-loopback-test.c
+++ b/drivers/spi/spi-loopback-test.c
@@ -298,12 +298,18 @@ static struct spi_test spi_tests[] = {
 			{
 				.tx_buf = TX(0),
 				.rx_buf = RX(0),
-				.delay_usecs = 1000,
+				.delay = {
+					.value = 1000,
+					.unit = SPI_DELAY_UNIT_USECS,
+				},
 			},
 			{
 				.tx_buf = TX(0),
 				.rx_buf = RX(0),
-				.delay_usecs = 1000,
+				.delay = {
+					.value = 1000,
+					.unit = SPI_DELAY_UNIT_USECS,
+				},
 			},
 		},
 	},
@@ -537,7 +543,7 @@ static int spi_test_check_elapsed_time(struct spi_device *spi,
 		unsigned long long nbits = (unsigned long long)BITS_PER_BYTE *
 					   xfer->len;
 
-		delay_usecs += xfer->delay_usecs;
+		delay_usecs += xfer->delay.value;
 		if (!xfer->speed_hz)
 			continue;
 		estimated_time += div_u64(nbits * NSEC_PER_SEC, xfer->speed_hz);
-- 
2.20.1

[PATCH v4 13/19] spi: spidev: use new `delay` field for spi transfers

[Alexandru Ardelean]

The `delay` field has type `struct spi_delay`.
This allows users to specify nano-second or clock-cycle delays (if needed).

Converting to use `delay` is straightforward: it's just assigning the
value to `delay.value` and hard-coding the `delay.unit` to
`SPI_DELAY_UNIT_USECS`.

This keeps the uapi for spidev un-changed. Changing it can be part of
another changeset and discussion.

Signed-off-by: Alexandru Ardelean <alexandru.ardelean@analog.com>
---
 drivers/spi/spidev.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/drivers/spi/spidev.c b/drivers/spi/spidev.c
index 495319c2fa11..6b6afd27f4a1 100644
--- a/drivers/spi/spidev.c
+++ b/drivers/spi/spidev.c
@@ -265,7 +265,8 @@ static int spidev_message(struct spidev_data *spidev,
 		k_tmp->tx_nbits = u_tmp->tx_nbits;
 		k_tmp->rx_nbits = u_tmp->rx_nbits;
 		k_tmp->bits_per_word = u_tmp->bits_per_word;
-		k_tmp->delay_usecs = u_tmp->delay_usecs;
+		k_tmp->delay.value = u_tmp->delay_usecs;
+		k_tmp->delay.unit = SPI_DELAY_UNIT_USECS;
 		k_tmp->speed_hz = u_tmp->speed_hz;
 		k_tmp->word_delay.value = u_tmp->word_delay_usecs;
 		k_tmp->word_delay.unit = SPI_DELAY_UNIT_USECS;
-- 
2.20.1

[PATCH v4 14/19] spi: tegra114: change format for `spi_set_cs_timing()` function

[Alexandru Ardelean]

The initial version of `spi_set_cs_timing()` was implemented with
consideration only for clock-cycles as delay.

For cases like `CS setup` time, it's sometimes needed that micro-seconds
(or nano-seconds) are required, or sometimes even longer delays, for cases
where the device needs a little longer to start transferring that after CS
is asserted.

Signed-off-by: Alexandru Ardelean <alexandru.ardelean@analog.com>
---
 drivers/spi/spi-tegra114.c | 22 ++++++++++++++++++++--
 drivers/spi/spi.c          | 16 ++++++++++------
 include/linux/spi/spi.h    |  9 ++++++---
 3 files changed, 36 insertions(+), 11 deletions(-)

diff --git a/drivers/spi/spi-tegra114.c b/drivers/spi/spi-tegra114.c
index 8133dc49d34f..e6a450d9b4f0 100644
--- a/drivers/spi/spi-tegra114.c
+++ b/drivers/spi/spi-tegra114.c
@@ -723,15 +723,31 @@ static void tegra_spi_deinit_dma_param(struct tegra_spi_data *tspi,
 	dma_release_channel(dma_chan);
 }
 
-static void tegra_spi_set_hw_cs_timing(struct spi_device *spi, u8 setup_dly,
-				       u8 hold_dly, u8 inactive_dly)
+static int tegra_spi_set_hw_cs_timing(struct spi_device *spi,
+				      struct spi_delay *setup,
+				      struct spi_delay *hold,
+				      struct spi_delay *inactive)
 {
 	struct tegra_spi_data *tspi = spi_master_get_devdata(spi->master);
+	u8 setup_dly, hold_dly, inactive_dly;
 	u32 setup_hold;
 	u32 spi_cs_timing;
 	u32 inactive_cycles;
 	u8 cs_state;
 
+	if ((setup && setup->unit != SPI_DELAY_UNIT_SCK) ||
+	    (hold && hold->unit != SPI_DELAY_UNIT_SCK) ||
+	    (inactive && inactive->unit != SPI_DELAY_UNIT_SCK)) {
+		dev_err(&spi->dev,
+			"Invalid delay unit %d, should be SPI_DELAY_UNIT_SCK\n",
+			SPI_DELAY_UNIT_SCK);
+		return -EINVAL;
+	}
+
+	setup_dly = setup ? setup->value : 0;
+	hold_dly = hold ? hold->value : 0;
+	inactive_dly = inactive ? inactive->value : 0;
+
 	setup_dly = min_t(u8, setup_dly, MAX_SETUP_HOLD_CYCLES);
 	hold_dly = min_t(u8, hold_dly, MAX_SETUP_HOLD_CYCLES);
 	if (setup_dly && hold_dly) {
@@ -758,6 +774,8 @@ static void tegra_spi_set_hw_cs_timing(struct spi_device *spi, u8 setup_dly,
 		tspi->spi_cs_timing2 = spi_cs_timing;
 		tegra_spi_writel(tspi, spi_cs_timing, SPI_CS_TIMING2);
 	}
+
+	return 0;
 }
 
 static u32 tegra_spi_setup_transfer_one(struct spi_device *spi,
diff --git a/drivers/spi/spi.c b/drivers/spi/spi.c
index 489eb64d9ee0..122af2264bfe 100644
--- a/drivers/spi/spi.c
+++ b/drivers/spi/spi.c
@@ -3147,15 +3147,19 @@ EXPORT_SYMBOL_GPL(spi_setup);
 /**
  * spi_set_cs_timing - configure CS setup, hold, and inactive delays
  * @spi: the device that requires specific CS timing configuration
- * @setup: CS setup time in terms of clock count
- * @hold: CS hold time in terms of clock count
- * @inactive_dly: CS inactive delay between transfers in terms of clock count
+ * @setup: CS setup time specified via @spi_delay
+ * @hold: CS hold time specified via @spi_delay
+ * @inactive: CS inactive delay between transfers specified via @spi_delay
+ *
+ * Return: zero on success, else a negative error code.
  */
-void spi_set_cs_timing(struct spi_device *spi, u8 setup, u8 hold,
-		       u8 inactive_dly)
+int spi_set_cs_timing(struct spi_device *spi, struct spi_delay *setup,
+		      struct spi_delay *hold, struct spi_delay *inactive)
 {
 	if (spi->controller->set_cs_timing)
-		spi->controller->set_cs_timing(spi, setup, hold, inactive_dly);
+		return spi->controller->set_cs_timing(spi, setup, hold,
+						      inactive);
+	return -ENOTSUPP;
 }
 EXPORT_SYMBOL_GPL(spi_set_cs_timing);
 
diff --git a/include/linux/spi/spi.h b/include/linux/spi/spi.h
index 2cee9ac35737..592e50aae998 100644
--- a/include/linux/spi/spi.h
+++ b/include/linux/spi/spi.h
@@ -517,8 +517,8 @@ struct spi_controller {
 	 * to configure specific CS timing through spi_set_cs_timing() after
 	 * spi_setup().
 	 */
-	void (*set_cs_timing)(struct spi_device *spi, u8 setup_clk_cycles,
-			      u8 hold_clk_cycles, u8 inactive_clk_cycles);
+	int (*set_cs_timing)(struct spi_device *spi, struct spi_delay *setup,
+			     struct spi_delay *hold, struct spi_delay *inactive);
 
 	/* bidirectional bulk transfers
 	 *
@@ -1007,7 +1007,10 @@ 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_set_cs_timing(struct spi_device *spi,
+			     struct spi_delay *setup,
+			     struct spi_delay *hold,
+			     struct spi_delay *inactive);
 
 extern int spi_setup(struct spi_device *spi);
 extern int spi_async(struct spi_device *spi, struct spi_message *message);
-- 
2.20.1

[PATCH v4 15/19] spi: implement SW control for CS times

[Alexandru Ardelean]

This change implements CS control for setup, hold & inactive delays.

The `cs_setup` delay is completely new, and can help with cases where
asserting the CS, also brings the device out of power-sleep, where there
needs to be a longer (than usual), before transferring data.

The `cs_hold` time can overlap with the `delay` (or `delay_usecs`) from an
SPI transfer. The main difference is that `cs_hold` implies that CS will be
de-asserted.

The `cs_inactive` delay does not have a clear use-case yet. It has been
implemented mostly because the `spi_set_cs_timing()` function implements
it. To some degree, this could overlap or replace `cs_change_delay`, but
this will require more consideration/investigation in the future.

All these delays have been added to the `spi_controller` struct, as they
would typically be configured by calling `spi_set_cs_timing()` after an
`spi_setup()` call.

Software-mode for CS control, implies that the `set_cs_timing()` hook has
not been provided for the `spi_controller` object.

Signed-off-by: Alexandru Ardelean <alexandru.ardelean@analog.com>
---
 drivers/spi/spi.c       | 45 ++++++++++++++++++++++++++++++++++++++++-
 include/linux/spi/spi.h |  5 +++++
 2 files changed, 49 insertions(+), 1 deletion(-)

diff --git a/drivers/spi/spi.c b/drivers/spi/spi.c
index 122af2264bfe..61ef286f954a 100644
--- a/drivers/spi/spi.c
+++ b/drivers/spi/spi.c
@@ -775,6 +775,15 @@ int spi_register_board_info(struct spi_board_info const *info, unsigned n)
 
 static void spi_set_cs(struct spi_device *spi, bool enable)
 {
+	bool enable1 = enable;
+
+	if (!spi->controller->set_cs_timing) {
+		if (enable1)
+			spi_delay_exec(&spi->controller->cs_setup, NULL);
+		else
+			spi_delay_exec(&spi->controller->cs_hold, NULL);
+	}
+
 	if (spi->mode & SPI_CS_HIGH)
 		enable = !enable;
 
@@ -800,6 +809,11 @@ static void spi_set_cs(struct spi_device *spi, bool enable)
 	} else if (spi->controller->set_cs) {
 		spi->controller->set_cs(spi, !enable);
 	}
+
+	if (!spi->controller->set_cs_timing) {
+		if (!enable1)
+			spi_delay_exec(&spi->controller->cs_inactive, NULL);
+	}
 }
 
 #ifdef CONFIG_HAS_DMA
@@ -3156,10 +3170,39 @@ EXPORT_SYMBOL_GPL(spi_setup);
 int spi_set_cs_timing(struct spi_device *spi, struct spi_delay *setup,
 		      struct spi_delay *hold, struct spi_delay *inactive)
 {
+	size_t len;
+
 	if (spi->controller->set_cs_timing)
 		return spi->controller->set_cs_timing(spi, setup, hold,
 						      inactive);
-	return -ENOTSUPP;
+
+	if ((setup && setup->unit == SPI_DELAY_UNIT_SCK) ||
+	    (hold && hold->unit == SPI_DELAY_UNIT_SCK) ||
+	    (inactive && inactive->unit == SPI_DELAY_UNIT_SCK)) {
+		dev_err(&spi->dev,
+			"Clock-cycle delays for CS not supported in SW mode\n");
+		return -ENOTSUPP;
+	}
+
+	len = sizeof(struct spi_delay);
+
+	/* copy delays to controller */
+	if (setup)
+		memcpy(&spi->controller->cs_setup, setup, len);
+	else
+		memset(&spi->controller->cs_setup, 0, len);
+
+	if (hold)
+		memcpy(&spi->controller->cs_hold, hold, len);
+	else
+		memset(&spi->controller->cs_hold, 0, len);
+
+	if (inactive)
+		memcpy(&spi->controller->cs_inactive, inactive, len);
+	else
+		memset(&spi->controller->cs_inactive, 0, len);
+
+	return 0;
 }
 EXPORT_SYMBOL_GPL(spi_set_cs_timing);
 
diff --git a/include/linux/spi/spi.h b/include/linux/spi/spi.h
index 592e50aae998..66031c8d0093 100644
--- a/include/linux/spi/spi.h
+++ b/include/linux/spi/spi.h
@@ -602,6 +602,11 @@ struct spi_controller {
 	/* Optimized handlers for SPI memory-like operations. */
 	const struct spi_controller_mem_ops *mem_ops;
 
+	/* CS delays */
+	struct spi_delay	cs_setup;
+	struct spi_delay	cs_hold;
+	struct spi_delay	cs_inactive;
+
 	/* gpio chip select */
 	int			*cs_gpios;
 	struct gpio_desc	**cs_gpiods;
-- 
2.20.1

[PATCH v4 16/19] spi: spi-fsl-espi: convert transfer delay to `spi_delay` format

[Alexandru Ardelean]

The way the max delay is computed for this controller, it looks like it is
searching for the max delay from an SPI message a using that.

No idea if this is valid. But this change should support both `delay_usecs`
and the new `delay` data which is of `spi_delay` type.

Signed-off-by: Alexandru Ardelean <alexandru.ardelean@analog.com>
---
 drivers/spi/spi-fsl-espi.c | 16 +++++++++++++---
 drivers/spi/spi.c          |  9 +++++----
 include/linux/spi/spi.h    |  1 +
 3 files changed, 19 insertions(+), 7 deletions(-)

diff --git a/drivers/spi/spi-fsl-espi.c b/drivers/spi/spi-fsl-espi.c
index 732bf3195917..e60581283a24 100644
--- a/drivers/spi/spi-fsl-espi.c
+++ b/drivers/spi/spi-fsl-espi.c
@@ -436,6 +436,7 @@ static int fsl_espi_do_one_msg(struct spi_master *master,
 			       struct spi_message *m)
 {
 	unsigned int delay_usecs = 0, rx_nbits = 0;
+	unsigned int delay_nsecs = 0, delay_nsecs1 = 0;
 	struct spi_transfer *t, trans = {};
 	int ret;
 
@@ -444,8 +445,16 @@ static int fsl_espi_do_one_msg(struct spi_master *master,
 		goto out;
 
 	list_for_each_entry(t, &m->transfers, transfer_list) {
-		if (t->delay_usecs > delay_usecs)
-			delay_usecs = t->delay_usecs;
+		if (t->delay_usecs) {
+			if (t->delay_usecs > delay_usecs) {
+				delay_usecs = t->delay_usecs;
+				delay_nsecs = delay_usecs * 1000;
+			}
+		} else {
+			delay_nsecs1 = spi_delay_to_ns(&t->delay, t);
+			if (delay_nsecs1 > delay_nsecs)
+				delay_nsecs = delay_nsecs1;
+		}
 		if (t->rx_nbits > rx_nbits)
 			rx_nbits = t->rx_nbits;
 	}
@@ -456,7 +465,8 @@ static int fsl_espi_do_one_msg(struct spi_master *master,
 	trans.len = m->frame_length;
 	trans.speed_hz = t->speed_hz;
 	trans.bits_per_word = t->bits_per_word;
-	trans.delay_usecs = delay_usecs;
+	trans.delay.value = delay_nsecs;
+	trans.delay.unit = SPI_DELAY_UNIT_NSECS;
 	trans.rx_nbits = rx_nbits;
 
 	if (trans.len)
diff --git a/drivers/spi/spi.c b/drivers/spi/spi.c
index 61ef286f954a..1f0b55c9e2e8 100644
--- a/drivers/spi/spi.c
+++ b/drivers/spi/spi.c
@@ -1120,7 +1120,7 @@ static void _spi_transfer_delay_ns(u32 ns)
 	}
 }
 
-static int _spi_delay_to_ns(struct spi_delay *_delay, struct spi_transfer *xfer)
+int spi_delay_to_ns(struct spi_delay *_delay, struct spi_transfer *xfer)
 {
 	u32 delay = _delay->value;
 	u32 unit = _delay->unit;
@@ -1153,6 +1153,7 @@ static int _spi_delay_to_ns(struct spi_delay *_delay, struct spi_transfer *xfer)
 
 	return delay;
 }
+EXPORT_SYMBOL_GPL(spi_delay_to_ns);
 
 int spi_delay_exec(struct spi_delay *_delay, struct spi_transfer *xfer)
 {
@@ -1161,7 +1162,7 @@ int spi_delay_exec(struct spi_delay *_delay, struct spi_transfer *xfer)
 	if (!_delay)
 		return -EINVAL;
 
-	delay = _spi_delay_to_ns(_delay, xfer);
+	delay = spi_delay_to_ns(_delay, xfer);
 	if (delay < 0)
 		return delay;
 
@@ -3211,11 +3212,11 @@ static int _spi_xfer_word_delay_update(struct spi_transfer *xfer,
 {
 	int delay1, delay2;
 
-	delay1 = _spi_delay_to_ns(&xfer->word_delay, xfer);
+	delay1 = spi_delay_to_ns(&xfer->word_delay, xfer);
 	if (delay1 < 0)
 		return delay1;
 
-	delay2 = _spi_delay_to_ns(&spi->word_delay, xfer);
+	delay2 = spi_delay_to_ns(&spi->word_delay, xfer);
 	if (delay2 < 0)
 		return delay2;
 
diff --git a/include/linux/spi/spi.h b/include/linux/spi/spi.h
index 66031c8d0093..3bc5912fca36 100644
--- a/include/linux/spi/spi.h
+++ b/include/linux/spi/spi.h
@@ -102,6 +102,7 @@ struct spi_delay {
 	u8	unit;
 };
 
+extern int spi_delay_to_ns(struct spi_delay *_delay, struct spi_transfer *xfer);
 extern int spi_delay_exec(struct spi_delay *_delay, struct spi_transfer *xfer);
 
 /**
-- 
2.20.1

[PATCH v4 17/19] spi: spi-falcon: extend warning to `delay` as well

[Alexandru Ardelean]

The WARN_ON macro prints a warning in syslog if `delay_usecs` is non-zero.
However, with the new intermediate `delay`, the warning should also be
printed.

Signed-off-by: Alexandru Ardelean <alexandru.ardelean@analog.com>
---
 drivers/spi/spi-falcon.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/spi/spi-falcon.c b/drivers/spi/spi-falcon.c
index 00f46c816a56..d3336a63f462 100644
--- a/drivers/spi/spi-falcon.c
+++ b/drivers/spi/spi-falcon.c
@@ -377,7 +377,7 @@ static int falcon_sflash_xfer_one(struct spi_master *master,
 
 		m->actual_length += t->len;
 
-		WARN_ON(t->delay_usecs || t->cs_change);
+		WARN_ON(t->delay_usecs || t->delay.value || t->cs_change);
 		spi_flags = 0;
 	}
 
-- 
2.20.1

[PATCH v4 18/19] spi: bcm63xx: extend error condition to `delay` as well

[Alexandru Ardelean]

The driver errors out if `delay_usecs` is non-zero. This error condition
should be extended to the new `delay` field, to account for when it will be
used.

Signed-off-by: Alexandru Ardelean <alexandru.ardelean@analog.com>
---
 drivers/spi/spi-bcm63xx.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/spi/spi-bcm63xx.c b/drivers/spi/spi-bcm63xx.c
index df1c94a131e6..4e582acda709 100644
--- a/drivers/spi/spi-bcm63xx.c
+++ b/drivers/spi/spi-bcm63xx.c
@@ -368,7 +368,7 @@ static int bcm63xx_spi_transfer_one(struct spi_master *master,
 		}
 
 		/* CS will be deasserted directly after transfer */
-		if (t->delay_usecs) {
+		if (t->delay_usecs || t->delay.value) {
 			dev_err(&spi->dev, "unable to keep CS asserted after transfer\n");
 			status = -EINVAL;
 			goto exit;
-- 
2.20.1

[PATCH v4 19/19] spi: spi-axi: extend support for the `delay` field

[Alexandru Ardelean]

The AXI SPI engine driver uses the `delay_usecs` field from `spi_transfer`
to configure delays, which the controller will execute.
This change extends the logic to also include the `delay` value, in case it
is used (instead if `delay_usecs`).

Signed-off-by: Alexandru Ardelean <alexandru.ardelean@analog.com>
---
 drivers/spi/spi-axi-spi-engine.c | 16 +++++++++++++---
 1 file changed, 13 insertions(+), 3 deletions(-)

diff --git a/drivers/spi/spi-axi-spi-engine.c b/drivers/spi/spi-axi-spi-engine.c
index 3b1833e6c7ad..111d3b83285f 100644
--- a/drivers/spi/spi-axi-spi-engine.c
+++ b/drivers/spi/spi-axi-spi-engine.c
@@ -163,10 +163,21 @@ static void spi_engine_gen_xfer(struct spi_engine_program *p, bool dry,
 }
 
 static void spi_engine_gen_sleep(struct spi_engine_program *p, bool dry,
-	struct spi_engine *spi_engine, unsigned int clk_div, unsigned int delay)
+	struct spi_engine *spi_engine, unsigned int clk_div,
+	struct spi_transfer *xfer)
 {
 	unsigned int spi_clk = clk_get_rate(spi_engine->ref_clk);
 	unsigned int t;
+	int delay;
+
+	if (xfer->delay_usecs) {
+		delay = xfer->delay_usecs;
+	} else {
+		delay = spi_delay_to_ns(&xfer->delay, xfer);
+		if (delay < 0)
+			return;
+		delay /= 1000;
+	}
 
 	if (delay == 0)
 		return;
@@ -218,8 +229,7 @@ static int spi_engine_compile_message(struct spi_engine *spi_engine,
 			spi_engine_gen_cs(p, dry, spi, true);
 
 		spi_engine_gen_xfer(p, dry, xfer);
-		spi_engine_gen_sleep(p, dry, spi_engine, clk_div,
-			xfer->delay_usecs);
+		spi_engine_gen_sleep(p, dry, spi_engine, clk_div, xfer);
 
 		cs_change = xfer->cs_change;
 		if (list_is_last(&xfer->transfer_list, &msg->transfers))
-- 
2.20.1

Re: [PATCH v4 04/19] spi: sprd: convert transfer word delay to spi_delay struct

[Mark Brown]

[-- Attachment #1.1: Type: text/plain, Size: 238 bytes --]

On Thu, Sep 26, 2019 at 01:51:32PM +0300, Alexandru Ardelean wrote:
> The Spreadtrum SPI driver is the only user of the `word_delay` field in
> the `spi_transfer` struct.

This doesn't apply against current code, please check and resend.

[-- Attachment #1.2: signature.asc --]
[-- Type: application/pgp-signature, Size: 488 bytes --]

[-- Attachment #2: Type: text/plain, Size: 176 bytes --]

_______________________________________________
linux-arm-kernel mailing list
linux-arm-kernel@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/linux-arm-kernel

Applied "spi: spi-axi: extend support for the `delay` field" to the spi tree

[Mark Brown]

The patch

   spi: spi-axi: extend support for the `delay` field

has been applied to the spi tree at

   https://git.kernel.org/pub/scm/linux/kernel/git/broonie/spi.git for-5.5

All being well this means that it will be integrated into the linux-next
tree (usually sometime in the next 24 hours) and sent to Linus during
the next merge window (or sooner if it is a bug fix), however if
problems are discovered then the patch may be dropped or reverted.  

You may get further e-mails resulting from automated or manual testing
and review of the tree, please engage with people reporting problems and
send followup patches addressing any issues that are reported if needed.

If any updates are required or you are submitting further changes they
should be sent as incremental updates against current git, existing
patches will not be replaced.

Please add any relevant lists and maintainers to the CCs when replying
to this mail.

Thanks,
Mark

>From acc7720de3cb9721ac07f68309dd6d7aae8e9a7a Mon Sep 17 00:00:00 2001
From: Alexandru Ardelean <alexandru.ardelean@analog.com>
Date: Thu, 26 Sep 2019 13:51:47 +0300
Subject: [PATCH] spi: spi-axi: extend support for the `delay` field

The AXI SPI engine driver uses the `delay_usecs` field from `spi_transfer`
to configure delays, which the controller will execute.
This change extends the logic to also include the `delay` value, in case it
is used (instead if `delay_usecs`).

Signed-off-by: Alexandru Ardelean <alexandru.ardelean@analog.com>
Link: https://lore.kernel.org/r/20190926105147.7839-20-alexandru.ardelean@analog.com
Signed-off-by: Mark Brown <broonie@kernel.org>
---
 drivers/spi/spi-axi-spi-engine.c | 16 +++++++++++++---
 1 file changed, 13 insertions(+), 3 deletions(-)

diff --git a/drivers/spi/spi-axi-spi-engine.c b/drivers/spi/spi-axi-spi-engine.c
index 74842f6019ed..eb9b78a90dcf 100644
--- a/drivers/spi/spi-axi-spi-engine.c
+++ b/drivers/spi/spi-axi-spi-engine.c
@@ -163,10 +163,21 @@ static void spi_engine_gen_xfer(struct spi_engine_program *p, bool dry,
 }
 
 static void spi_engine_gen_sleep(struct spi_engine_program *p, bool dry,
-	struct spi_engine *spi_engine, unsigned int clk_div, unsigned int delay)
+	struct spi_engine *spi_engine, unsigned int clk_div,
+	struct spi_transfer *xfer)
 {
 	unsigned int spi_clk = clk_get_rate(spi_engine->ref_clk);
 	unsigned int t;
+	int delay;
+
+	if (xfer->delay_usecs) {
+		delay = xfer->delay_usecs;
+	} else {
+		delay = spi_delay_to_ns(&xfer->delay, xfer);
+		if (delay < 0)
+			return;
+		delay /= 1000;
+	}
 
 	if (delay == 0)
 		return;
@@ -218,8 +229,7 @@ static int spi_engine_compile_message(struct spi_engine *spi_engine,
 			spi_engine_gen_cs(p, dry, spi, true);
 
 		spi_engine_gen_xfer(p, dry, xfer);
-		spi_engine_gen_sleep(p, dry, spi_engine, clk_div,
-			xfer->delay_usecs);
+		spi_engine_gen_sleep(p, dry, spi_engine, clk_div, xfer);
 
 		cs_change = xfer->cs_change;
 		if (list_is_last(&xfer->transfer_list, &msg->transfers))
-- 
2.20.1

Applied "spi: bcm63xx: extend error condition to `delay` as well" to the spi tree

[Mark Brown]

The patch

   spi: bcm63xx: extend error condition to `delay` as well

has been applied to the spi tree at

   https://git.kernel.org/pub/scm/linux/kernel/git/broonie/spi.git for-5.5

All being well this means that it will be integrated into the linux-next
tree (usually sometime in the next 24 hours) and sent to Linus during
the next merge window (or sooner if it is a bug fix), however if
problems are discovered then the patch may be dropped or reverted.  

You may get further e-mails resulting from automated or manual testing
and review of the tree, please engage with people reporting problems and
send followup patches addressing any issues that are reported if needed.

If any updates are required or you are submitting further changes they
should be sent as incremental updates against current git, existing
patches will not be replaced.

Please add any relevant lists and maintainers to the CCs when replying
to this mail.

Thanks,
Mark

>From c5751ba0f71e3afe62000a9505915093efa31bd6 Mon Sep 17 00:00:00 2001
From: Alexandru Ardelean <alexandru.ardelean@analog.com>
Date: Thu, 26 Sep 2019 13:51:46 +0300
Subject: [PATCH] spi: bcm63xx: extend error condition to `delay` as well

The driver errors out if `delay_usecs` is non-zero. This error condition
should be extended to the new `delay` field, to account for when it will be
used.

Signed-off-by: Alexandru Ardelean <alexandru.ardelean@analog.com>
Link: https://lore.kernel.org/r/20190926105147.7839-19-alexandru.ardelean@analog.com
Signed-off-by: Mark Brown <broonie@kernel.org>
---
 drivers/spi/spi-bcm63xx.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/spi/spi-bcm63xx.c b/drivers/spi/spi-bcm63xx.c
index fdd7eaa0b8ed..0f1b10a4ef0c 100644
--- a/drivers/spi/spi-bcm63xx.c
+++ b/drivers/spi/spi-bcm63xx.c
@@ -368,7 +368,7 @@ static int bcm63xx_spi_transfer_one(struct spi_master *master,
 		}
 
 		/* CS will be deasserted directly after transfer */
-		if (t->delay_usecs) {
+		if (t->delay_usecs || t->delay.value) {
 			dev_err(&spi->dev, "unable to keep CS asserted after transfer\n");
 			status = -EINVAL;
 			goto exit;
-- 
2.20.1

Applied "spi: spi-fsl-espi: convert transfer delay to `spi_delay` format" to the spi tree

[Mark Brown]

The patch

   spi: spi-fsl-espi: convert transfer delay to `spi_delay` format

has been applied to the spi tree at

   https://git.kernel.org/pub/scm/linux/kernel/git/broonie/spi.git for-5.5

All being well this means that it will be integrated into the linux-next
tree (usually sometime in the next 24 hours) and sent to Linus during
the next merge window (or sooner if it is a bug fix), however if
problems are discovered then the patch may be dropped or reverted.  

You may get further e-mails resulting from automated or manual testing
and review of the tree, please engage with people reporting problems and
send followup patches addressing any issues that are reported if needed.

If any updates are required or you are submitting further changes they
should be sent as incremental updates against current git, existing
patches will not be replaced.

Please add any relevant lists and maintainers to the CCs when replying
to this mail.

Thanks,
Mark

>From 3984d39b0e41ac4de8b4530ae3911ccf52ed4bbf Mon Sep 17 00:00:00 2001
From: Alexandru Ardelean <alexandru.ardelean@analog.com>
Date: Thu, 26 Sep 2019 13:51:44 +0300
Subject: [PATCH] spi: spi-fsl-espi: convert transfer delay to `spi_delay`
 format

The way the max delay is computed for this controller, it looks like it is
searching for the max delay from an SPI message a using that.

No idea if this is valid. But this change should support both `delay_usecs`
and the new `delay` data which is of `spi_delay` type.

Signed-off-by: Alexandru Ardelean <alexandru.ardelean@analog.com>
Link: https://lore.kernel.org/r/20190926105147.7839-17-alexandru.ardelean@analog.com
Signed-off-by: Mark Brown <broonie@kernel.org>
---
 drivers/spi/spi-fsl-espi.c | 16 +++++++++++++---
 drivers/spi/spi.c          |  9 +++++----
 include/linux/spi/spi.h    |  1 +
 3 files changed, 19 insertions(+), 7 deletions(-)

diff --git a/drivers/spi/spi-fsl-espi.c b/drivers/spi/spi-fsl-espi.c
index f20326714b9d..f72daf66f3f3 100644
--- a/drivers/spi/spi-fsl-espi.c
+++ b/drivers/spi/spi-fsl-espi.c
@@ -437,6 +437,7 @@ static int fsl_espi_do_one_msg(struct spi_master *master,
 			       struct spi_message *m)
 {
 	unsigned int delay_usecs = 0, rx_nbits = 0;
+	unsigned int delay_nsecs = 0, delay_nsecs1 = 0;
 	struct spi_transfer *t, trans = {};
 	int ret;
 
@@ -445,8 +446,16 @@ static int fsl_espi_do_one_msg(struct spi_master *master,
 		goto out;
 
 	list_for_each_entry(t, &m->transfers, transfer_list) {
-		if (t->delay_usecs > delay_usecs)
-			delay_usecs = t->delay_usecs;
+		if (t->delay_usecs) {
+			if (t->delay_usecs > delay_usecs) {
+				delay_usecs = t->delay_usecs;
+				delay_nsecs = delay_usecs * 1000;
+			}
+		} else {
+			delay_nsecs1 = spi_delay_to_ns(&t->delay, t);
+			if (delay_nsecs1 > delay_nsecs)
+				delay_nsecs = delay_nsecs1;
+		}
 		if (t->rx_nbits > rx_nbits)
 			rx_nbits = t->rx_nbits;
 	}
@@ -457,7 +466,8 @@ static int fsl_espi_do_one_msg(struct spi_master *master,
 	trans.len = m->frame_length;
 	trans.speed_hz = t->speed_hz;
 	trans.bits_per_word = t->bits_per_word;
-	trans.delay_usecs = delay_usecs;
+	trans.delay.value = delay_nsecs;
+	trans.delay.unit = SPI_DELAY_UNIT_NSECS;
 	trans.rx_nbits = rx_nbits;
 
 	if (trans.len)
diff --git a/drivers/spi/spi.c b/drivers/spi/spi.c
index 21628b0728f1..5414a10afd65 100644
--- a/drivers/spi/spi.c
+++ b/drivers/spi/spi.c
@@ -1120,7 +1120,7 @@ static void _spi_transfer_delay_ns(u32 ns)
 	}
 }
 
-static int _spi_delay_to_ns(struct spi_delay *_delay, struct spi_transfer *xfer)
+int spi_delay_to_ns(struct spi_delay *_delay, struct spi_transfer *xfer)
 {
 	u32 delay = _delay->value;
 	u32 unit = _delay->unit;
@@ -1153,6 +1153,7 @@ static int _spi_delay_to_ns(struct spi_delay *_delay, struct spi_transfer *xfer)
 
 	return delay;
 }
+EXPORT_SYMBOL_GPL(spi_delay_to_ns);
 
 int spi_delay_exec(struct spi_delay *_delay, struct spi_transfer *xfer)
 {
@@ -1161,7 +1162,7 @@ int spi_delay_exec(struct spi_delay *_delay, struct spi_transfer *xfer)
 	if (!_delay)
 		return -EINVAL;
 
-	delay = _spi_delay_to_ns(_delay, xfer);
+	delay = spi_delay_to_ns(_delay, xfer);
 	if (delay < 0)
 		return delay;
 
@@ -3333,11 +3334,11 @@ static int _spi_xfer_word_delay_update(struct spi_transfer *xfer,
 {
 	int delay1, delay2;
 
-	delay1 = _spi_delay_to_ns(&xfer->word_delay, xfer);
+	delay1 = spi_delay_to_ns(&xfer->word_delay, xfer);
 	if (delay1 < 0)
 		return delay1;
 
-	delay2 = _spi_delay_to_ns(&spi->word_delay, xfer);
+	delay2 = spi_delay_to_ns(&spi->word_delay, xfer);
 	if (delay2 < 0)
 		return delay2;
 
diff --git a/include/linux/spi/spi.h b/include/linux/spi/spi.h
index cfd87b18f077..c40d6af2bf07 100644
--- a/include/linux/spi/spi.h
+++ b/include/linux/spi/spi.h
@@ -103,6 +103,7 @@ struct spi_delay {
 	u8	unit;
 };
 
+extern int spi_delay_to_ns(struct spi_delay *_delay, struct spi_transfer *xfer);
 extern int spi_delay_exec(struct spi_delay *_delay, struct spi_transfer *xfer);
 
 /**
-- 
2.20.1

Applied "spi: spi-falcon: extend warning to `delay` as well" to the spi tree

[Mark Brown]

The patch

   spi: spi-falcon: extend warning to `delay` as well

has been applied to the spi tree at

   https://git.kernel.org/pub/scm/linux/kernel/git/broonie/spi.git for-5.5

All being well this means that it will be integrated into the linux-next
tree (usually sometime in the next 24 hours) and sent to Linus during
the next merge window (or sooner if it is a bug fix), however if
problems are discovered then the patch may be dropped or reverted.  

You may get further e-mails resulting from automated or manual testing
and review of the tree, please engage with people reporting problems and
send followup patches addressing any issues that are reported if needed.

If any updates are required or you are submitting further changes they
should be sent as incremental updates against current git, existing
patches will not be replaced.

Please add any relevant lists and maintainers to the CCs when replying
to this mail.

Thanks,
Mark

>From 3e2405f01f4a1e744f2bea28aa105d7f2257c893 Mon Sep 17 00:00:00 2001
From: Alexandru Ardelean <alexandru.ardelean@analog.com>
Date: Thu, 26 Sep 2019 13:51:45 +0300
Subject: [PATCH] spi: spi-falcon: extend warning to `delay` as well

The WARN_ON macro prints a warning in syslog if `delay_usecs` is non-zero.
However, with the new intermediate `delay`, the warning should also be
printed.

Signed-off-by: Alexandru Ardelean <alexandru.ardelean@analog.com>
Link: https://lore.kernel.org/r/20190926105147.7839-18-alexandru.ardelean@analog.com
Signed-off-by: Mark Brown <broonie@kernel.org>
---
 drivers/spi/spi-falcon.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/spi/spi-falcon.c b/drivers/spi/spi-falcon.c
index 00f46c816a56..d3336a63f462 100644
--- a/drivers/spi/spi-falcon.c
+++ b/drivers/spi/spi-falcon.c
@@ -377,7 +377,7 @@ static int falcon_sflash_xfer_one(struct spi_master *master,
 
 		m->actual_length += t->len;
 
-		WARN_ON(t->delay_usecs || t->cs_change);
+		WARN_ON(t->delay_usecs || t->delay.value || t->cs_change);
 		spi_flags = 0;
 	}
 
-- 
2.20.1

Applied "spi: implement SW control for CS times" to the spi tree

[Mark Brown]

The patch

   spi: implement SW control for CS times

has been applied to the spi tree at

   https://git.kernel.org/pub/scm/linux/kernel/git/broonie/spi.git for-5.5

All being well this means that it will be integrated into the linux-next
tree (usually sometime in the next 24 hours) and sent to Linus during
the next merge window (or sooner if it is a bug fix), however if
problems are discovered then the patch may be dropped or reverted.  

You may get further e-mails resulting from automated or manual testing
and review of the tree, please engage with people reporting problems and
send followup patches addressing any issues that are reported if needed.

If any updates are required or you are submitting further changes they
should be sent as incremental updates against current git, existing
patches will not be replaced.

Please add any relevant lists and maintainers to the CCs when replying
to this mail.

Thanks,
Mark

>From 25093bdeb6bcae728e12e3795261dbd3677060a9 Mon Sep 17 00:00:00 2001
From: Alexandru Ardelean <alexandru.ardelean@analog.com>
Date: Thu, 26 Sep 2019 13:51:43 +0300
Subject: [PATCH] spi: implement SW control for CS times

This change implements CS control for setup, hold & inactive delays.

The `cs_setup` delay is completely new, and can help with cases where
asserting the CS, also brings the device out of power-sleep, where there
needs to be a longer (than usual), before transferring data.

The `cs_hold` time can overlap with the `delay` (or `delay_usecs`) from an
SPI transfer. The main difference is that `cs_hold` implies that CS will be
de-asserted.

The `cs_inactive` delay does not have a clear use-case yet. It has been
implemented mostly because the `spi_set_cs_timing()` function implements
it. To some degree, this could overlap or replace `cs_change_delay`, but
this will require more consideration/investigation in the future.

All these delays have been added to the `spi_controller` struct, as they
would typically be configured by calling `spi_set_cs_timing()` after an
`spi_setup()` call.

Software-mode for CS control, implies that the `set_cs_timing()` hook has
not been provided for the `spi_controller` object.

Signed-off-by: Alexandru Ardelean <alexandru.ardelean@analog.com>
Link: https://lore.kernel.org/r/20190926105147.7839-16-alexandru.ardelean@analog.com
Signed-off-by: Mark Brown <broonie@kernel.org>
---
 drivers/spi/spi.c       | 45 ++++++++++++++++++++++++++++++++++++++++-
 include/linux/spi/spi.h |  5 +++++
 2 files changed, 49 insertions(+), 1 deletion(-)

diff --git a/drivers/spi/spi.c b/drivers/spi/spi.c
index 6beeb363515c..21628b0728f1 100644
--- a/drivers/spi/spi.c
+++ b/drivers/spi/spi.c
@@ -775,6 +775,15 @@ int spi_register_board_info(struct spi_board_info const *info, unsigned n)
 
 static void spi_set_cs(struct spi_device *spi, bool enable)
 {
+	bool enable1 = enable;
+
+	if (!spi->controller->set_cs_timing) {
+		if (enable1)
+			spi_delay_exec(&spi->controller->cs_setup, NULL);
+		else
+			spi_delay_exec(&spi->controller->cs_hold, NULL);
+	}
+
 	if (spi->mode & SPI_CS_HIGH)
 		enable = !enable;
 
@@ -800,6 +809,11 @@ static void spi_set_cs(struct spi_device *spi, bool enable)
 	} else if (spi->controller->set_cs) {
 		spi->controller->set_cs(spi, !enable);
 	}
+
+	if (!spi->controller->set_cs_timing) {
+		if (!enable1)
+			spi_delay_exec(&spi->controller->cs_inactive, NULL);
+	}
 }
 
 #ifdef CONFIG_HAS_DMA
@@ -3278,10 +3292,39 @@ EXPORT_SYMBOL_GPL(spi_setup);
 int spi_set_cs_timing(struct spi_device *spi, struct spi_delay *setup,
 		      struct spi_delay *hold, struct spi_delay *inactive)
 {
+	size_t len;
+
 	if (spi->controller->set_cs_timing)
 		return spi->controller->set_cs_timing(spi, setup, hold,
 						      inactive);
-	return -ENOTSUPP;
+
+	if ((setup && setup->unit == SPI_DELAY_UNIT_SCK) ||
+	    (hold && hold->unit == SPI_DELAY_UNIT_SCK) ||
+	    (inactive && inactive->unit == SPI_DELAY_UNIT_SCK)) {
+		dev_err(&spi->dev,
+			"Clock-cycle delays for CS not supported in SW mode\n");
+		return -ENOTSUPP;
+	}
+
+	len = sizeof(struct spi_delay);
+
+	/* copy delays to controller */
+	if (setup)
+		memcpy(&spi->controller->cs_setup, setup, len);
+	else
+		memset(&spi->controller->cs_setup, 0, len);
+
+	if (hold)
+		memcpy(&spi->controller->cs_hold, hold, len);
+	else
+		memset(&spi->controller->cs_hold, 0, len);
+
+	if (inactive)
+		memcpy(&spi->controller->cs_inactive, inactive, len);
+	else
+		memset(&spi->controller->cs_inactive, 0, len);
+
+	return 0;
 }
 EXPORT_SYMBOL_GPL(spi_set_cs_timing);
 
diff --git a/include/linux/spi/spi.h b/include/linux/spi/spi.h
index f9b4ba2db08d..cfd87b18f077 100644
--- a/include/linux/spi/spi.h
+++ b/include/linux/spi/spi.h
@@ -609,6 +609,11 @@ struct spi_controller {
 	/* Optimized handlers for SPI memory-like operations. */
 	const struct spi_controller_mem_ops *mem_ops;
 
+	/* CS delays */
+	struct spi_delay	cs_setup;
+	struct spi_delay	cs_hold;
+	struct spi_delay	cs_inactive;
+
 	/* gpio chip select */
 	int			*cs_gpios;
 	struct gpio_desc	**cs_gpiods;
-- 
2.20.1

Applied "spi: spi-loopback-test: use new `delay` field" to the spi tree

[Mark Brown]

The patch

   spi: spi-loopback-test: use new `delay` field

has been applied to the spi tree at

   https://git.kernel.org/pub/scm/linux/kernel/git/broonie/spi.git for-5.5

All being well this means that it will be integrated into the linux-next
tree (usually sometime in the next 24 hours) and sent to Linus during
the next merge window (or sooner if it is a bug fix), however if
problems are discovered then the patch may be dropped or reverted.  

You may get further e-mails resulting from automated or manual testing
and review of the tree, please engage with people reporting problems and
send followup patches addressing any issues that are reported if needed.

If any updates are required or you are submitting further changes they
should be sent as incremental updates against current git, existing
patches will not be replaced.

Please add any relevant lists and maintainers to the CCs when replying
to this mail.

Thanks,
Mark

>From 867bd8868bbd16e17bbd26c5959abc3118902218 Mon Sep 17 00:00:00 2001
From: Alexandru Ardelean <alexandru.ardelean@analog.com>
Date: Thu, 26 Sep 2019 13:51:40 +0300
Subject: [PATCH] spi: spi-loopback-test: use new `delay` field

This change replaces the use of the `delay_usecs` field with the new
`delay` field. The code/test still uses micro-seconds, but they are now
configured and used via the `struct spi_delay` format of the `delay` field.

Signed-off-by: Alexandru Ardelean <alexandru.ardelean@analog.com>
Link: https://lore.kernel.org/r/20190926105147.7839-13-alexandru.ardelean@analog.com
Signed-off-by: Mark Brown <broonie@kernel.org>
---
 drivers/spi/spi-loopback-test.c | 12 +++++++++---
 1 file changed, 9 insertions(+), 3 deletions(-)

diff --git a/drivers/spi/spi-loopback-test.c b/drivers/spi/spi-loopback-test.c
index 6f18d4952767..b6d79cd156fb 100644
--- a/drivers/spi/spi-loopback-test.c
+++ b/drivers/spi/spi-loopback-test.c
@@ -298,12 +298,18 @@ static struct spi_test spi_tests[] = {
 			{
 				.tx_buf = TX(0),
 				.rx_buf = RX(0),
-				.delay_usecs = 1000,
+				.delay = {
+					.value = 1000,
+					.unit = SPI_DELAY_UNIT_USECS,
+				},
 			},
 			{
 				.tx_buf = TX(0),
 				.rx_buf = RX(0),
-				.delay_usecs = 1000,
+				.delay = {
+					.value = 1000,
+					.unit = SPI_DELAY_UNIT_USECS,
+				},
 			},
 		},
 	},
@@ -537,7 +543,7 @@ static int spi_test_check_elapsed_time(struct spi_device *spi,
 		unsigned long long nbits = (unsigned long long)BITS_PER_BYTE *
 					   xfer->len;
 
-		delay_usecs += xfer->delay_usecs;
+		delay_usecs += xfer->delay.value;
 		if (!xfer->speed_hz)
 			continue;
 		estimated_time += div_u64(nbits * NSEC_PER_SEC, xfer->speed_hz);
-- 
2.20.1

Applied "spi: tegra114: change format for `spi_set_cs_timing()` function" to the spi tree

[Mark Brown]

The patch

   spi: tegra114: change format for `spi_set_cs_timing()` function

has been applied to the spi tree at

   https://git.kernel.org/pub/scm/linux/kernel/git/broonie/spi.git for-5.5

All being well this means that it will be integrated into the linux-next
tree (usually sometime in the next 24 hours) and sent to Linus during
the next merge window (or sooner if it is a bug fix), however if
problems are discovered then the patch may be dropped or reverted.  

You may get further e-mails resulting from automated or manual testing
and review of the tree, please engage with people reporting problems and
send followup patches addressing any issues that are reported if needed.

If any updates are required or you are submitting further changes they
should be sent as incremental updates against current git, existing
patches will not be replaced.

Please add any relevant lists and maintainers to the CCs when replying
to this mail.

Thanks,
Mark

>From 8105936684681195d9073880b06a123b2e316811 Mon Sep 17 00:00:00 2001
From: Alexandru Ardelean <alexandru.ardelean@analog.com>
Date: Thu, 26 Sep 2019 13:51:42 +0300
Subject: [PATCH] spi: tegra114: change format for `spi_set_cs_timing()`
 function

The initial version of `spi_set_cs_timing()` was implemented with
consideration only for clock-cycles as delay.

For cases like `CS setup` time, it's sometimes needed that micro-seconds
(or nano-seconds) are required, or sometimes even longer delays, for cases
where the device needs a little longer to start transferring that after CS
is asserted.

Signed-off-by: Alexandru Ardelean <alexandru.ardelean@analog.com>
Link: https://lore.kernel.org/r/20190926105147.7839-15-alexandru.ardelean@analog.com
Signed-off-by: Mark Brown <broonie@kernel.org>
---
 drivers/spi/spi-tegra114.c | 22 ++++++++++++++++++++--
 drivers/spi/spi.c          | 16 ++++++++++------
 include/linux/spi/spi.h    |  9 ++++++---
 3 files changed, 36 insertions(+), 11 deletions(-)

diff --git a/drivers/spi/spi-tegra114.c b/drivers/spi/spi-tegra114.c
index 8133dc49d34f..e6a450d9b4f0 100644
--- a/drivers/spi/spi-tegra114.c
+++ b/drivers/spi/spi-tegra114.c
@@ -723,15 +723,31 @@ static void tegra_spi_deinit_dma_param(struct tegra_spi_data *tspi,
 	dma_release_channel(dma_chan);
 }
 
-static void tegra_spi_set_hw_cs_timing(struct spi_device *spi, u8 setup_dly,
-				       u8 hold_dly, u8 inactive_dly)
+static int tegra_spi_set_hw_cs_timing(struct spi_device *spi,
+				      struct spi_delay *setup,
+				      struct spi_delay *hold,
+				      struct spi_delay *inactive)
 {
 	struct tegra_spi_data *tspi = spi_master_get_devdata(spi->master);
+	u8 setup_dly, hold_dly, inactive_dly;
 	u32 setup_hold;
 	u32 spi_cs_timing;
 	u32 inactive_cycles;
 	u8 cs_state;
 
+	if ((setup && setup->unit != SPI_DELAY_UNIT_SCK) ||
+	    (hold && hold->unit != SPI_DELAY_UNIT_SCK) ||
+	    (inactive && inactive->unit != SPI_DELAY_UNIT_SCK)) {
+		dev_err(&spi->dev,
+			"Invalid delay unit %d, should be SPI_DELAY_UNIT_SCK\n",
+			SPI_DELAY_UNIT_SCK);
+		return -EINVAL;
+	}
+
+	setup_dly = setup ? setup->value : 0;
+	hold_dly = hold ? hold->value : 0;
+	inactive_dly = inactive ? inactive->value : 0;
+
 	setup_dly = min_t(u8, setup_dly, MAX_SETUP_HOLD_CYCLES);
 	hold_dly = min_t(u8, hold_dly, MAX_SETUP_HOLD_CYCLES);
 	if (setup_dly && hold_dly) {
@@ -758,6 +774,8 @@ static void tegra_spi_set_hw_cs_timing(struct spi_device *spi, u8 setup_dly,
 		tspi->spi_cs_timing2 = spi_cs_timing;
 		tegra_spi_writel(tspi, spi_cs_timing, SPI_CS_TIMING2);
 	}
+
+	return 0;
 }
 
 static u32 tegra_spi_setup_transfer_one(struct spi_device *spi,
diff --git a/drivers/spi/spi.c b/drivers/spi/spi.c
index 2e448078a117..6beeb363515c 100644
--- a/drivers/spi/spi.c
+++ b/drivers/spi/spi.c
@@ -3269,15 +3269,19 @@ EXPORT_SYMBOL_GPL(spi_setup);
 /**
  * spi_set_cs_timing - configure CS setup, hold, and inactive delays
  * @spi: the device that requires specific CS timing configuration
- * @setup: CS setup time in terms of clock count
- * @hold: CS hold time in terms of clock count
- * @inactive_dly: CS inactive delay between transfers in terms of clock count
+ * @setup: CS setup time specified via @spi_delay
+ * @hold: CS hold time specified via @spi_delay
+ * @inactive: CS inactive delay between transfers specified via @spi_delay
+ *
+ * Return: zero on success, else a negative error code.
  */
-void spi_set_cs_timing(struct spi_device *spi, u8 setup, u8 hold,
-		       u8 inactive_dly)
+int spi_set_cs_timing(struct spi_device *spi, struct spi_delay *setup,
+		      struct spi_delay *hold, struct spi_delay *inactive)
 {
 	if (spi->controller->set_cs_timing)
-		spi->controller->set_cs_timing(spi, setup, hold, inactive_dly);
+		return spi->controller->set_cs_timing(spi, setup, hold,
+						      inactive);
+	return -ENOTSUPP;
 }
 EXPORT_SYMBOL_GPL(spi_set_cs_timing);
 
diff --git a/include/linux/spi/spi.h b/include/linux/spi/spi.h
index fe5b85df2c79..f9b4ba2db08d 100644
--- a/include/linux/spi/spi.h
+++ b/include/linux/spi/spi.h
@@ -524,8 +524,8 @@ struct spi_controller {
 	 * to configure specific CS timing through spi_set_cs_timing() after
 	 * spi_setup().
 	 */
-	void (*set_cs_timing)(struct spi_device *spi, u8 setup_clk_cycles,
-			      u8 hold_clk_cycles, u8 inactive_clk_cycles);
+	int (*set_cs_timing)(struct spi_device *spi, struct spi_delay *setup,
+			     struct spi_delay *hold, struct spi_delay *inactive);
 
 	/* bidirectional bulk transfers
 	 *
@@ -1068,7 +1068,10 @@ 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_set_cs_timing(struct spi_device *spi,
+			     struct spi_delay *setup,
+			     struct spi_delay *hold,
+			     struct spi_delay *inactive);
 
 extern int spi_setup(struct spi_device *spi);
 extern int spi_async(struct spi_device *spi, struct spi_message *message);
-- 
2.20.1

Applied "spi: spidev: use new `delay` field for spi transfers" to the spi tree

[Mark Brown]

The patch

   spi: spidev: use new `delay` field for spi transfers

has been applied to the spi tree at

   https://git.kernel.org/pub/scm/linux/kernel/git/broonie/spi.git for-5.5

All being well this means that it will be integrated into the linux-next
tree (usually sometime in the next 24 hours) and sent to Linus during
the next merge window (or sooner if it is a bug fix), however if
problems are discovered then the patch may be dropped or reverted.  

You may get further e-mails resulting from automated or manual testing
and review of the tree, please engage with people reporting problems and
send followup patches addressing any issues that are reported if needed.

If any updates are required or you are submitting further changes they
should be sent as incremental updates against current git, existing
patches will not be replaced.

Please add any relevant lists and maintainers to the CCs when replying
to this mail.

Thanks,
Mark

>From 8e319dd5f1ebbc1fffa9e550b2a643cbce7515b1 Mon Sep 17 00:00:00 2001
From: Alexandru Ardelean <alexandru.ardelean@analog.com>
Date: Thu, 26 Sep 2019 13:51:41 +0300
Subject: [PATCH] spi: spidev: use new `delay` field for spi transfers

The `delay` field has type `struct spi_delay`.
This allows users to specify nano-second or clock-cycle delays (if needed).

Converting to use `delay` is straightforward: it's just assigning the
value to `delay.value` and hard-coding the `delay.unit` to
`SPI_DELAY_UNIT_USECS`.

This keeps the uapi for spidev un-changed. Changing it can be part of
another changeset and discussion.

Signed-off-by: Alexandru Ardelean <alexandru.ardelean@analog.com>
Link: https://lore.kernel.org/r/20190926105147.7839-14-alexandru.ardelean@analog.com
Signed-off-by: Mark Brown <broonie@kernel.org>
---
 drivers/spi/spidev.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/drivers/spi/spidev.c b/drivers/spi/spidev.c
index d63235dcb231..1e217e3e9486 100644
--- a/drivers/spi/spidev.c
+++ b/drivers/spi/spidev.c
@@ -265,7 +265,8 @@ static int spidev_message(struct spidev_data *spidev,
 		k_tmp->tx_nbits = u_tmp->tx_nbits;
 		k_tmp->rx_nbits = u_tmp->rx_nbits;
 		k_tmp->bits_per_word = u_tmp->bits_per_word;
-		k_tmp->delay_usecs = u_tmp->delay_usecs;
+		k_tmp->delay.value = u_tmp->delay_usecs;
+		k_tmp->delay.unit = SPI_DELAY_UNIT_USECS;
 		k_tmp->speed_hz = u_tmp->speed_hz;
 		k_tmp->word_delay.value = u_tmp->word_delay_usecs;
 		k_tmp->word_delay.unit = SPI_DELAY_UNIT_USECS;
-- 
2.20.1

Applied "spi: tegra20-sflash: use to new `spi_transfer_delay_exec`" to the spi tree

[Mark Brown]

The patch

   spi: tegra20-sflash: use to new `spi_transfer_delay_exec`

has been applied to the spi tree at

   https://git.kernel.org/pub/scm/linux/kernel/git/broonie/spi.git for-5.5

All being well this means that it will be integrated into the linux-next
tree (usually sometime in the next 24 hours) and sent to Linus during
the next merge window (or sooner if it is a bug fix), however if
problems are discovered then the patch may be dropped or reverted.  

You may get further e-mails resulting from automated or manual testing
and review of the tree, please engage with people reporting problems and
send followup patches addressing any issues that are reported if needed.

If any updates are required or you are submitting further changes they
should be sent as incremental updates against current git, existing
patches will not be replaced.

Please add any relevant lists and maintainers to the CCs when replying
to this mail.

Thanks,
Mark

>From b883d5eda6c49a807e925b257bf9687d5c351004 Mon Sep 17 00:00:00 2001
From: Alexandru Ardelean <alexandru.ardelean@analog.com>
Date: Thu, 26 Sep 2019 13:51:39 +0300
Subject: [PATCH] spi: tegra20-sflash: use to new `spi_transfer_delay_exec`

This conversion to the spi_transfer_delay_exec() helper is not
straightforward, as it seems that when a delay is present, the controller
issues a command, and then a delay is followed.

This change adds support for the new `delay` field which is of type
`spi_delay` and keeps backwards compatibility with the old `delay_usecs`
field.

Signed-off-by: Alexandru Ardelean <alexandru.ardelean@analog.com>
Link: https://lore.kernel.org/r/20190926105147.7839-12-alexandru.ardelean@analog.com
Signed-off-by: Mark Brown <broonie@kernel.org>
---
 drivers/spi/spi-tegra20-sflash.c | 5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)

diff --git a/drivers/spi/spi-tegra20-sflash.c b/drivers/spi/spi-tegra20-sflash.c
index a841a7250d14..514429379206 100644
--- a/drivers/spi/spi-tegra20-sflash.c
+++ b/drivers/spi/spi-tegra20-sflash.c
@@ -341,10 +341,11 @@ static int tegra_sflash_transfer_one_message(struct spi_master *master,
 			goto exit;
 		}
 		msg->actual_length += xfer->len;
-		if (xfer->cs_change && xfer->delay_usecs) {
+		if (xfer->cs_change &&
+		    (xfer->delay_usecs || xfer->delay.value)) {
 			tegra_sflash_writel(tsd, tsd->def_command_reg,
 					SPI_COMMAND);
-			udelay(xfer->delay_usecs);
+			spi_transfer_delay_exec(xfer);
 		}
 	}
 	ret = 0;
-- 
2.20.1

Applied "spi: tegra114: use `spi_transfer_delay_exec` helper" to the spi tree

[Mark Brown]

The patch

   spi: tegra114: use `spi_transfer_delay_exec` helper

has been applied to the spi tree at

   https://git.kernel.org/pub/scm/linux/kernel/git/broonie/spi.git for-5.5

All being well this means that it will be integrated into the linux-next
tree (usually sometime in the next 24 hours) and sent to Linus during
the next merge window (or sooner if it is a bug fix), however if
problems are discovered then the patch may be dropped or reverted.  

You may get further e-mails resulting from automated or manual testing
and review of the tree, please engage with people reporting problems and
send followup patches addressing any issues that are reported if needed.

If any updates are required or you are submitting further changes they
should be sent as incremental updates against current git, existing
patches will not be replaced.

Please add any relevant lists and maintainers to the CCs when replying
to this mail.

Thanks,
Mark

>From cd13152bce34cd71f560a7c4a8f66096f2445984 Mon Sep 17 00:00:00 2001
From: Alexandru Ardelean <alexandru.ardelean@analog.com>
Date: Thu, 26 Sep 2019 13:51:38 +0300
Subject: [PATCH] spi: tegra114: use `spi_transfer_delay_exec` helper

The tegra114 driver has a weird/separate `tegra_spi_transfer_delay()`
function that does 2 delays: one mdelay() and one udelay().

This was introduced via commit f4fade12d506e14867a2b0a5e2f7aaf227297d8b
("spi/tegra114: Correct support for cs_change").

There doesn't seem to be a mention in that commit message to suggest a
specific need/use-case for having the 2 delay calls.
For the most part, udelay() should be sufficient.

This change replaces it with the new `spi_transfer_delay_exec()`, which
should do the same thing.

Signed-off-by: Alexandru Ardelean <alexandru.ardelean@analog.com>
Link: https://lore.kernel.org/r/20190926105147.7839-11-alexandru.ardelean@analog.com
Signed-off-by: Mark Brown <broonie@kernel.org>
---
 drivers/spi/spi-tegra114.c | 17 +++--------------
 1 file changed, 3 insertions(+), 14 deletions(-)

diff --git a/drivers/spi/spi-tegra114.c b/drivers/spi/spi-tegra114.c
index 39374c2edcf3..8133dc49d34f 100644
--- a/drivers/spi/spi-tegra114.c
+++ b/drivers/spi/spi-tegra114.c
@@ -984,17 +984,6 @@ static int tegra_spi_setup(struct spi_device *spi)
 	return 0;
 }
 
-static void tegra_spi_transfer_delay(int delay)
-{
-	if (!delay)
-		return;
-
-	if (delay >= 1000)
-		mdelay(delay / 1000);
-
-	udelay(delay % 1000);
-}
-
 static void tegra_spi_transfer_end(struct spi_device *spi)
 {
 	struct tegra_spi_data *tspi = spi_master_get_devdata(spi->master);
@@ -1098,7 +1087,7 @@ static int tegra_spi_transfer_one_message(struct spi_master *master,
 complete_xfer:
 		if (ret < 0 || skip) {
 			tegra_spi_transfer_end(spi);
-			tegra_spi_transfer_delay(xfer->delay_usecs);
+			spi_transfer_delay_exec(xfer);
 			goto exit;
 		} else if (list_is_last(&xfer->transfer_list,
 					&msg->transfers)) {
@@ -1106,11 +1095,11 @@ static int tegra_spi_transfer_one_message(struct spi_master *master,
 				tspi->cs_control = spi;
 			else {
 				tegra_spi_transfer_end(spi);
-				tegra_spi_transfer_delay(xfer->delay_usecs);
+				spi_transfer_delay_exec(xfer);
 			}
 		} else if (xfer->cs_change) {
 			tegra_spi_transfer_end(spi);
-			tegra_spi_transfer_delay(xfer->delay_usecs);
+			spi_transfer_delay_exec(xfer);
 		}
 
 	}
-- 
2.20.1

Applied "spi: introduce `delay` field for `spi_transfer` + spi_transfer_delay_exec()" to the spi tree

[Mark Brown]

The patch

   spi: introduce `delay` field for `spi_transfer` + spi_transfer_delay_exec()

has been applied to the spi tree at

   https://git.kernel.org/pub/scm/linux/kernel/git/broonie/spi.git for-5.5

All being well this means that it will be integrated into the linux-next
tree (usually sometime in the next 24 hours) and sent to Linus during
the next merge window (or sooner if it is a bug fix), however if
problems are discovered then the patch may be dropped or reverted.  

You may get further e-mails resulting from automated or manual testing
and review of the tree, please engage with people reporting problems and
send followup patches addressing any issues that are reported if needed.

If any updates are required or you are submitting further changes they
should be sent as incremental updates against current git, existing
patches will not be replaced.

Please add any relevant lists and maintainers to the CCs when replying
to this mail.

Thanks,
Mark

>From bebcfd272df648542c458d28fbd6a8f9428b5310 Mon Sep 17 00:00:00 2001
From: Alexandru Ardelean <alexandru.ardelean@analog.com>
Date: Thu, 26 Sep 2019 13:51:36 +0300
Subject: [PATCH] spi: introduce `delay` field for `spi_transfer` +
 spi_transfer_delay_exec()

The change introduces the `delay` field to the `spi_transfer` struct as an
`struct spi_delay` type.
This intends to eventually replace `delay_usecs`.

But, since there are many users of `delay_usecs`, this needs some
intermediate work.
A helper called `spi_transfer_delay_exec()` is also added, which maintains
backwards compatibility with `delay_usecs`, by assigning the value to
`delay` if non-zero.
This should maintain backwards compatibility with current users of
`udelay_usecs`.

Signed-off-by: Alexandru Ardelean <alexandru.ardelean@analog.com>
Link: https://lore.kernel.org/r/20190926105147.7839-9-alexandru.ardelean@analog.com
Signed-off-by: Mark Brown <broonie@kernel.org>
---
 drivers/spi/spi.c       |  6 +++---
 include/linux/spi/spi.h | 18 ++++++++++++++++++
 2 files changed, 21 insertions(+), 3 deletions(-)

diff --git a/drivers/spi/spi.c b/drivers/spi/spi.c
index 307e440dd92d..2e448078a117 100644
--- a/drivers/spi/spi.c
+++ b/drivers/spi/spi.c
@@ -1248,8 +1248,7 @@ static int spi_transfer_one_message(struct spi_controller *ctlr,
 		if (msg->status != -EINPROGRESS)
 			goto out;
 
-		if (xfer->delay_usecs)
-			_spi_transfer_delay_ns(xfer->delay_usecs * 1000);
+		spi_transfer_delay_exec(xfer);
 
 		if (xfer->cs_change) {
 			if (list_is_last(&xfer->transfer_list,
@@ -3026,10 +3025,11 @@ struct spi_replaced_transfers *spi_replace_transfers(
 		/* add to list */
 		list_add(&xfer->transfer_list, rxfer->replaced_after);
 
-		/* clear cs_change and delay_usecs for all but the last */
+		/* clear cs_change and delay for all but the last */
 		if (i) {
 			xfer->cs_change = false;
 			xfer->delay_usecs = 0;
+			xfer->delay.value = 0;
 		}
 	}
 
diff --git a/include/linux/spi/spi.h b/include/linux/spi/spi.h
index ebeb272aeb0f..fe5b85df2c79 100644
--- a/include/linux/spi/spi.h
+++ b/include/linux/spi/spi.h
@@ -778,6 +778,9 @@ extern void spi_res_release(struct spi_controller *ctlr,
  * @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
+ * @delay: delay to be introduced after this transfer before
+ *	(optionally) changing the chipselect status, then starting
+ *	the next transfer or completing this @spi_message.
  * @delay_usecs: microseconds to delay after this transfer before
  *	(optionally) changing the chipselect status, then starting
  *	the next transfer or completing this @spi_message.
@@ -896,6 +899,7 @@ struct spi_transfer {
 #define	SPI_NBITS_QUAD		0x04 /* 4bits transfer */
 	u8		bits_per_word;
 	u16		delay_usecs;
+	struct spi_delay	delay;
 	struct spi_delay	cs_change_delay;
 	struct spi_delay	word_delay;
 	u32		speed_hz;
@@ -1003,6 +1007,20 @@ spi_transfer_del(struct spi_transfer *t)
 	list_del(&t->transfer_list);
 }
 
+static inline int
+spi_transfer_delay_exec(struct spi_transfer *t)
+{
+	struct spi_delay d;
+
+	if (t->delay_usecs) {
+		d.value = t->delay_usecs;
+		d.unit = SPI_DELAY_UNIT_USECS;
+		return spi_delay_exec(&d, NULL);
+	}
+
+	return spi_delay_exec(&t->delay, t);
+}
+
 /**
  * spi_message_init_with_transfers - Initialize spi_message and append transfers
  * @m: spi_message to be initialized
-- 
2.20.1

Applied "spi: orion: use new `word_delay` field for SPI transfers" to the spi tree

[Mark Brown]

The patch

   spi: orion: use new `word_delay` field for SPI transfers

has been applied to the spi tree at

   https://git.kernel.org/pub/scm/linux/kernel/git/broonie/spi.git for-5.5

All being well this means that it will be integrated into the linux-next
tree (usually sometime in the next 24 hours) and sent to Linus during
the next merge window (or sooner if it is a bug fix), however if
problems are discovered then the patch may be dropped or reverted.  

You may get further e-mails resulting from automated or manual testing
and review of the tree, please engage with people reporting problems and
send followup patches addressing any issues that are reported if needed.

If any updates are required or you are submitting further changes they
should be sent as incremental updates against current git, existing
patches will not be replaced.

Please add any relevant lists and maintainers to the CCs when replying
to this mail.

Thanks,
Mark

>From 21e26062052c60d31640e614b792473fca787f9f Mon Sep 17 00:00:00 2001
From: Alexandru Ardelean <alexandru.ardelean@analog.com>
Date: Thu, 26 Sep 2019 13:51:33 +0300
Subject: [PATCH] spi: orion: use new `word_delay` field for SPI transfers

The `word_delay` field had it's type changed to `struct spi_delay`.
This allows users to specify nano-second or clock-cycle delays (if needed).

Converting to use `word_delay` is straightforward: it just uses the new
`spi_delay_exec()` routine, that handles the `unit` part.

Signed-off-by: Alexandru Ardelean <alexandru.ardelean@analog.com>
Link: https://lore.kernel.org/r/20190926105147.7839-6-alexandru.ardelean@analog.com
Signed-off-by: Mark Brown <broonie@kernel.org>
---
 drivers/spi/spi-orion.c | 6 ++----
 1 file changed, 2 insertions(+), 4 deletions(-)

diff --git a/drivers/spi/spi-orion.c b/drivers/spi/spi-orion.c
index 81c991c4ddbf..c7266ef295fd 100644
--- a/drivers/spi/spi-orion.c
+++ b/drivers/spi/spi-orion.c
@@ -467,8 +467,7 @@ orion_spi_write_read(struct spi_device *spi, struct spi_transfer *xfer)
 			if (orion_spi_write_read_8bit(spi, &tx, &rx) < 0)
 				goto out;
 			count--;
-			if (xfer->word_delay_usecs)
-				udelay(xfer->word_delay_usecs);
+			spi_delay_exec(&xfer->word_delay, xfer);
 		} while (count);
 	} else if (word_len == 16) {
 		const u16 *tx = xfer->tx_buf;
@@ -478,8 +477,7 @@ orion_spi_write_read(struct spi_device *spi, struct spi_transfer *xfer)
 			if (orion_spi_write_read_16bit(spi, &tx, &rx) < 0)
 				goto out;
 			count -= 2;
-			if (xfer->word_delay_usecs)
-				udelay(xfer->word_delay_usecs);
+			spi_delay_exec(&xfer->word_delay, xfer);
 		} while (count);
 	}
 
-- 
2.20.1

Applied "spi: spidev: use new `word_delay` field for spi transfers" to the spi tree

[Mark Brown]

The patch

   spi: spidev: use new `word_delay` field for spi transfers

has been applied to the spi tree at

   https://git.kernel.org/pub/scm/linux/kernel/git/broonie/spi.git for-5.5

All being well this means that it will be integrated into the linux-next
tree (usually sometime in the next 24 hours) and sent to Linus during
the next merge window (or sooner if it is a bug fix), however if
problems are discovered then the patch may be dropped or reverted.  

You may get further e-mails resulting from automated or manual testing
and review of the tree, please engage with people reporting problems and
send followup patches addressing any issues that are reported if needed.

If any updates are required or you are submitting further changes they
should be sent as incremental updates against current git, existing
patches will not be replaced.

Please add any relevant lists and maintainers to the CCs when replying
to this mail.

Thanks,
Mark

>From ec3fa72fa8404128771a095d5a56b738752ba9ff Mon Sep 17 00:00:00 2001
From: Alexandru Ardelean <alexandru.ardelean@analog.com>
Date: Thu, 26 Sep 2019 13:51:34 +0300
Subject: [PATCH] spi: spidev: use new `word_delay` field for spi transfers

The `word_delay` field had it's type changed to `struct spi_delay`.
This allows users to specify nano-second or clock-cycle delays (if needed).

Converting to use `word_delay` is straightforward: it's just assigning the
value to `word_delay.value` and hard-coding the `word_delay.unit` to
`SPI_DELAY_UNIT_USECS`

This keeps the uapi for spidev un-changed. Changing it can be part of
another changeset and discussion.

Signed-off-by: Alexandru Ardelean <alexandru.ardelean@analog.com>
Link: https://lore.kernel.org/r/20190926105147.7839-7-alexandru.ardelean@analog.com
Signed-off-by: Mark Brown <broonie@kernel.org>
---
 drivers/spi/spidev.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/drivers/spi/spidev.c b/drivers/spi/spidev.c
index 3ea9d8a3e6e8..d63235dcb231 100644
--- a/drivers/spi/spidev.c
+++ b/drivers/spi/spidev.c
@@ -267,7 +267,8 @@ static int spidev_message(struct spidev_data *spidev,
 		k_tmp->bits_per_word = u_tmp->bits_per_word;
 		k_tmp->delay_usecs = u_tmp->delay_usecs;
 		k_tmp->speed_hz = u_tmp->speed_hz;
-		k_tmp->word_delay_usecs = u_tmp->word_delay_usecs;
+		k_tmp->word_delay.value = u_tmp->word_delay_usecs;
+		k_tmp->word_delay.unit = SPI_DELAY_UNIT_USECS;
 		if (!k_tmp->speed_hz)
 			k_tmp->speed_hz = spidev->speed_hz;
 #ifdef VERBOSE
-- 
2.20.1

Applied "spi: core,atmel: convert `word_delay_usecs` -> `word_delay` for spi_device" to the spi tree

[Mark Brown]

The patch

   spi: core,atmel: convert `word_delay_usecs` -> `word_delay` for spi_device

has been applied to the spi tree at

   https://git.kernel.org/pub/scm/linux/kernel/git/broonie/spi.git for-5.5

All being well this means that it will be integrated into the linux-next
tree (usually sometime in the next 24 hours) and sent to Linus during
the next merge window (or sooner if it is a bug fix), however if
problems are discovered then the patch may be dropped or reverted.  

You may get further e-mails resulting from automated or manual testing
and review of the tree, please engage with people reporting problems and
send followup patches addressing any issues that are reported if needed.

If any updates are required or you are submitting further changes they
should be sent as incremental updates against current git, existing
patches will not be replaced.

Please add any relevant lists and maintainers to the CCs when replying
to this mail.

Thanks,
Mark

>From 6c613f68aabf33385c01e949204ac5ed30887161 Mon Sep 17 00:00:00 2001
From: Alexandru Ardelean <alexandru.ardelean@analog.com>
Date: Thu, 26 Sep 2019 13:51:35 +0300
Subject: [PATCH] spi: core,atmel: convert `word_delay_usecs` -> `word_delay`
 for spi_device

This change does a conversion from the `word_delay_usecs` -> `word_delay`
for the `spi_device` struct.

This allows users to specify inter-word delays in other unit types
(nano-seconds or clock cycles), depending on how users want.

The Atmel SPI driver is the only current user of the `word_delay_usecs`
field (from the `spi_device` struct).
So, it needed a slight conversion to use the `word_delay` as an `spi_delay`
struct.

In SPI core, the only required mechanism is to update the `word_delay`
information per `spi_transfer`. This requires a bit more logic than before,
because it needs that both delays be converted to a common unit
(nano-seconds) for comparison.

Signed-off-by: Alexandru Ardelean <alexandru.ardelean@analog.com>
Link: https://lore.kernel.org/r/20190926105147.7839-8-alexandru.ardelean@analog.com
Signed-off-by: Mark Brown <broonie@kernel.org>
---
 drivers/spi/spi-atmel.c | 26 ++++++++++++++++++++++++--
 drivers/spi/spi.c       | 24 ++++++++++++++++++++++--
 include/linux/spi/spi.h |  7 ++-----
 3 files changed, 48 insertions(+), 9 deletions(-)

diff --git a/drivers/spi/spi-atmel.c b/drivers/spi/spi-atmel.c
index 3ed5e663da6f..1471b049f99a 100644
--- a/drivers/spi/spi-atmel.c
+++ b/drivers/spi/spi-atmel.c
@@ -1149,12 +1149,31 @@ atmel_spi_pdc_interrupt(int irq, void *dev_id)
 	return ret;
 }
 
+static int atmel_word_delay_csr(struct spi_device *spi, struct atmel_spi *as)
+{
+	struct spi_delay *delay = &spi->word_delay;
+	u32 value = delay->value;
+
+	switch (delay->unit) {
+	case SPI_DELAY_UNIT_NSECS:
+		value /= 1000;
+		break;
+	case SPI_DELAY_UNIT_USECS:
+		break;
+	default:
+		return -EINVAL;
+	}
+
+	return (as->spi_clk / 1000000 * value) >> 5;
+}
+
 static int atmel_spi_setup(struct spi_device *spi)
 {
 	struct atmel_spi	*as;
 	struct atmel_spi_device	*asd;
 	u32			csr;
 	unsigned int		bits = spi->bits_per_word;
+	int			word_delay_csr;
 
 	as = spi_master_get_devdata(spi->master);
 
@@ -1178,11 +1197,14 @@ static int atmel_spi_setup(struct spi_device *spi)
 	 */
 	csr |= SPI_BF(DLYBS, 0);
 
+	word_delay_csr = atmel_word_delay_csr(spi, as);
+	if (word_delay_csr < 0)
+		return word_delay_csr;
+
 	/* DLYBCT adds delays between words.  This is useful for slow devices
 	 * that need a bit of time to setup the next transfer.
 	 */
-	csr |= SPI_BF(DLYBCT,
-			(as->spi_clk / 1000000 * spi->word_delay_usecs) >> 5);
+	csr |= SPI_BF(DLYBCT, word_delay_csr);
 
 	asd = spi->controller_state;
 	if (!asd) {
diff --git a/drivers/spi/spi.c b/drivers/spi/spi.c
index b69c14082c52..307e440dd92d 100644
--- a/drivers/spi/spi.c
+++ b/drivers/spi/spi.c
@@ -3281,6 +3281,26 @@ void spi_set_cs_timing(struct spi_device *spi, u8 setup, u8 hold,
 }
 EXPORT_SYMBOL_GPL(spi_set_cs_timing);
 
+static int _spi_xfer_word_delay_update(struct spi_transfer *xfer,
+				       struct spi_device *spi)
+{
+	int delay1, delay2;
+
+	delay1 = _spi_delay_to_ns(&xfer->word_delay, xfer);
+	if (delay1 < 0)
+		return delay1;
+
+	delay2 = _spi_delay_to_ns(&spi->word_delay, xfer);
+	if (delay2 < 0)
+		return delay2;
+
+	if (delay1 < delay2)
+		memcpy(&xfer->word_delay, &spi->word_delay,
+		       sizeof(xfer->word_delay));
+
+	return 0;
+}
+
 static int __spi_validate(struct spi_device *spi, struct spi_message *message)
 {
 	struct spi_controller *ctlr = spi->controller;
@@ -3416,8 +3436,8 @@ static int __spi_validate(struct spi_device *spi, struct spi_message *message)
 				return -EINVAL;
 		}
 
-		if (xfer->word_delay_usecs < spi->word_delay_usecs)
-			xfer->word_delay_usecs = spi->word_delay_usecs;
+		if (_spi_xfer_word_delay_update(xfer, spi))
+			return -EINVAL;
 	}
 
 	message->status = -EINPROGRESS;
diff --git a/include/linux/spi/spi.h b/include/linux/spi/spi.h
index 6cb67ad53ffa..ebeb272aeb0f 100644
--- a/include/linux/spi/spi.h
+++ b/include/linux/spi/spi.h
@@ -139,7 +139,7 @@ extern int spi_delay_exec(struct spi_delay *_delay, struct spi_transfer *xfer);
  *	the spi_master.
  * @cs_gpiod: gpio descriptor of the chipselect line (optional, NULL when
  *	not using a GPIO line)
- * @word_delay_usecs: microsecond delay to be inserted between consecutive
+ * @word_delay: delay to be inserted between consecutive
  *	words of a transfer
  *
  * @statistics: statistics for the spi_device
@@ -189,7 +189,7 @@ struct spi_device {
 	const char		*driver_override;
 	int			cs_gpio;	/* LEGACY: chip select gpio */
 	struct gpio_desc	*cs_gpiod;	/* chip select gpio desc */
-	uint8_t			word_delay_usecs; /* inter-word delay */
+	struct spi_delay	word_delay; /* inter-word delay */
 
 	/* the statistics */
 	struct spi_statistics	statistics;
@@ -781,8 +781,6 @@ extern void spi_res_release(struct spi_controller *ctlr,
  * @delay_usecs: microseconds to delay after this transfer before
  *	(optionally) changing the chipselect status, then starting
  *	the next transfer or completing this @spi_message.
- * @word_delay_usecs: microseconds to inter word delay after each word size
- *	(set by bits_per_word) transmission.
  * @word_delay: inter word delay to be introduced after each word size
  *	(set by bits_per_word) transmission.
  * @effective_speed_hz: the effective SCK-speed that was used to
@@ -897,7 +895,6 @@ struct spi_transfer {
 #define	SPI_NBITS_DUAL		0x02 /* 2bits transfer */
 #define	SPI_NBITS_QUAD		0x04 /* 4bits transfer */
 	u8		bits_per_word;
-	u8		word_delay_usecs;
 	u16		delay_usecs;
 	struct spi_delay	cs_change_delay;
 	struct spi_delay	word_delay;
-- 
2.20.1

Applied "spi: sprd: convert transfer word delay to spi_delay struct" to the spi tree

[Mark Brown]

The patch

   spi: sprd: convert transfer word delay to spi_delay struct

has been applied to the spi tree at

   https://git.kernel.org/pub/scm/linux/kernel/git/broonie/spi.git 

All being well this means that it will be integrated into the linux-next
tree (usually sometime in the next 24 hours) and sent to Linus during
the next merge window (or sooner if it is a bug fix), however if
problems are discovered then the patch may be dropped or reverted.  

You may get further e-mails resulting from automated or manual testing
and review of the tree, please engage with people reporting problems and
send followup patches addressing any issues that are reported if needed.

If any updates are required or you are submitting further changes they
should be sent as incremental updates against current git, existing
patches will not be replaced.

Please add any relevant lists and maintainers to the CCs when replying
to this mail.

Thanks,
Mark

>From 84593a131c3af21d686d05c4b4432290a415d399 Mon Sep 17 00:00:00 2001
From: Alexandru Ardelean <alexandru.ardelean@analog.com>
Date: Thu, 26 Sep 2019 13:51:32 +0300
Subject: [PATCH] spi: sprd: convert transfer word delay to spi_delay struct

The Spreadtrum SPI driver is the only user of the `word_delay` field in
the `spi_transfer` struct.

This change converts the field to use the `spi_delay` struct. This also
enforces the users to specify the delay unit to be `SPI_DELAY_UNIT_SCK`.

Signed-off-by: Alexandru Ardelean <alexandru.ardelean@analog.com>
Link: https://lore.kernel.org/r/20190926105147.7839-5-alexandru.ardelean@analog.com
Signed-off-by: Mark Brown <broonie@kernel.org>
---
 drivers/spi/spi-sprd.c  | 15 ++++++++++++---
 include/linux/spi/spi.h |  4 ++--
 2 files changed, 14 insertions(+), 5 deletions(-)

diff --git a/drivers/spi/spi-sprd.c b/drivers/spi/spi-sprd.c
index 8c9021b7f7a9..2ee1feb41681 100644
--- a/drivers/spi/spi-sprd.c
+++ b/drivers/spi/spi-sprd.c
@@ -669,11 +669,15 @@ static void sprd_spi_set_speed(struct sprd_spi *ss, u32 speed_hz)
 	writel_relaxed(clk_div, ss->base + SPRD_SPI_CLKD);
 }
 
-static void sprd_spi_init_hw(struct sprd_spi *ss, struct spi_transfer *t)
+static int sprd_spi_init_hw(struct sprd_spi *ss, struct spi_transfer *t)
 {
+	struct spi_delay *d = &t->word_delay;
 	u16 word_delay, interval;
 	u32 val;
 
+	if (d->unit != SPI_DELAY_UNIT_SCK)
+		return -EINVAL;
+
 	val = readl_relaxed(ss->base + SPRD_SPI_CTL7);
 	val &= ~(SPRD_SPI_SCK_REV | SPRD_SPI_NG_TX | SPRD_SPI_NG_RX);
 	/* Set default chip selection, clock phase and clock polarity */
@@ -686,7 +690,7 @@ static void sprd_spi_init_hw(struct sprd_spi *ss, struct spi_transfer *t)
 	 * formula as below per datasheet:
 	 * interval time (source clock cycles) = interval * 4 + 10.
 	 */
-	word_delay = clamp_t(u16, t->word_delay, SPRD_SPI_MIN_DELAY_CYCLE,
+	word_delay = clamp_t(u16, d->value, SPRD_SPI_MIN_DELAY_CYCLE,
 			     SPRD_SPI_MAX_DELAY_CYCLE);
 	interval = DIV_ROUND_UP(word_delay - 10, 4);
 	ss->word_delay = interval * 4 + 10;
@@ -711,6 +715,8 @@ static void sprd_spi_init_hw(struct sprd_spi *ss, struct spi_transfer *t)
 		val &= ~SPRD_SPI_DATA_LINE2_EN;
 
 	writel_relaxed(val, ss->base + SPRD_SPI_CTL7);
+
+	return 0;
 }
 
 static int sprd_spi_setup_transfer(struct spi_device *sdev,
@@ -719,13 +725,16 @@ static int sprd_spi_setup_transfer(struct spi_device *sdev,
 	struct sprd_spi *ss = spi_controller_get_devdata(sdev->controller);
 	u8 bits_per_word = t->bits_per_word;
 	u32 val, mode = 0;
+	int ret;
 
 	ss->len = t->len;
 	ss->tx_buf = t->tx_buf;
 	ss->rx_buf = t->rx_buf;
 
 	ss->hw_mode = sdev->mode;
-	sprd_spi_init_hw(ss, t);
+	ret = sprd_spi_init_hw(ss, t);
+	if (ret)
+		return ret;
 
 	/* Set tansfer speed and valid bits */
 	sprd_spi_set_speed(ss, t->speed_hz);
diff --git a/include/linux/spi/spi.h b/include/linux/spi/spi.h
index 7670be934643..6cb67ad53ffa 100644
--- a/include/linux/spi/spi.h
+++ b/include/linux/spi/spi.h
@@ -783,7 +783,7 @@ extern void spi_res_release(struct spi_controller *ctlr,
  *	the next transfer or completing this @spi_message.
  * @word_delay_usecs: microseconds to inter word delay after each word size
  *	(set by bits_per_word) transmission.
- * @word_delay: clock cycles to inter word delay after each word size
+ * @word_delay: inter word delay to be introduced 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
@@ -900,8 +900,8 @@ struct spi_transfer {
 	u8		word_delay_usecs;
 	u16		delay_usecs;
 	struct spi_delay	cs_change_delay;
+	struct spi_delay	word_delay;
 	u32		speed_hz;
-	u16		word_delay;
 
 	u32		effective_speed_hz;
 
-- 
2.20.1

Applied "spi: make `cs_change_delay` the first user of the `spi_delay` logic" to the spi tree

[Mark Brown]

The patch

   spi: make `cs_change_delay` the first user of the `spi_delay` logic

has been applied to the spi tree at

   https://git.kernel.org/pub/scm/linux/kernel/git/broonie/spi.git for-5.5

All being well this means that it will be integrated into the linux-next
tree (usually sometime in the next 24 hours) and sent to Linus during
the next merge window (or sooner if it is a bug fix), however if
problems are discovered then the patch may be dropped or reverted.  

You may get further e-mails resulting from automated or manual testing
and review of the tree, please engage with people reporting problems and
send followup patches addressing any issues that are reported if needed.

If any updates are required or you are submitting further changes they
should be sent as incremental updates against current git, existing
patches will not be replaced.

Please add any relevant lists and maintainers to the CCs when replying
to this mail.

Thanks,
Mark

>From 329f0dac4cad9fa4b1439a88180d91bcb5c4eaf8 Mon Sep 17 00:00:00 2001
From: Alexandru Ardelean <alexandru.ardelean@analog.com>
Date: Thu, 26 Sep 2019 13:51:31 +0300
Subject: [PATCH] spi: make `cs_change_delay` the first user of the `spi_delay`
 logic

Since the logic for `spi_delay` struct + `spi_delay_exec()` has been copied
from the `cs_change_delay` logic, it's natural to make this delay, the
first user.

The `cs_change_delay` logic requires that the default remain 10 uS, in case
it is unspecified/unconfigured. So, there is some special handling needed
to do that.

The ADIS library is one of the few users of the new `cs_change_delay`
parameter for an spi_transfer.

The introduction of the `spi_delay` struct, requires that the users of of
`cs_change_delay` get an update. This change also updates the ADIS library.

Signed-off-by: Alexandru Ardelean <alexandru.ardelean@analog.com>
Link: https://lore.kernel.org/r/20190926105147.7839-4-alexandru.ardelean@analog.com
Signed-off-by: Mark Brown <broonie@kernel.org>
---
 drivers/iio/imu/adis.c  | 24 ++++++++++++------------
 drivers/spi/spi.c       | 28 +++++++---------------------
 include/linux/spi/spi.h |  4 +---
 3 files changed, 20 insertions(+), 36 deletions(-)

diff --git a/drivers/iio/imu/adis.c b/drivers/iio/imu/adis.c
index 1631c255deab..2cd2cc2316c6 100644
--- a/drivers/iio/imu/adis.c
+++ b/drivers/iio/imu/adis.c
@@ -39,24 +39,24 @@ int adis_write_reg(struct adis *adis, unsigned int reg,
 			.len = 2,
 			.cs_change = 1,
 			.delay_usecs = adis->data->write_delay,
-			.cs_change_delay = adis->data->cs_change_delay,
-			.cs_change_delay_unit = SPI_DELAY_UNIT_USECS,
+			.cs_change_delay.value = adis->data->cs_change_delay,
+			.cs_change_delay.unit = SPI_DELAY_UNIT_USECS,
 		}, {
 			.tx_buf = adis->tx + 2,
 			.bits_per_word = 8,
 			.len = 2,
 			.cs_change = 1,
 			.delay_usecs = adis->data->write_delay,
-			.cs_change_delay = adis->data->cs_change_delay,
-			.cs_change_delay_unit = SPI_DELAY_UNIT_USECS,
+			.cs_change_delay.value = adis->data->cs_change_delay,
+			.cs_change_delay.unit = SPI_DELAY_UNIT_USECS,
 		}, {
 			.tx_buf = adis->tx + 4,
 			.bits_per_word = 8,
 			.len = 2,
 			.cs_change = 1,
 			.delay_usecs = adis->data->write_delay,
-			.cs_change_delay = adis->data->cs_change_delay,
-			.cs_change_delay_unit = SPI_DELAY_UNIT_USECS,
+			.cs_change_delay.value = adis->data->cs_change_delay,
+			.cs_change_delay.unit = SPI_DELAY_UNIT_USECS,
 		}, {
 			.tx_buf = adis->tx + 6,
 			.bits_per_word = 8,
@@ -139,16 +139,16 @@ int adis_read_reg(struct adis *adis, unsigned int reg,
 			.len = 2,
 			.cs_change = 1,
 			.delay_usecs = adis->data->write_delay,
-			.cs_change_delay = adis->data->cs_change_delay,
-			.cs_change_delay_unit = SPI_DELAY_UNIT_USECS,
+			.cs_change_delay.value = adis->data->cs_change_delay,
+			.cs_change_delay.unit = SPI_DELAY_UNIT_USECS,
 		}, {
 			.tx_buf = adis->tx + 2,
 			.bits_per_word = 8,
 			.len = 2,
 			.cs_change = 1,
 			.delay_usecs = adis->data->read_delay,
-			.cs_change_delay = adis->data->cs_change_delay,
-			.cs_change_delay_unit = SPI_DELAY_UNIT_USECS,
+			.cs_change_delay.value = adis->data->cs_change_delay,
+			.cs_change_delay.unit = SPI_DELAY_UNIT_USECS,
 		}, {
 			.tx_buf = adis->tx + 4,
 			.rx_buf = adis->rx,
@@ -156,8 +156,8 @@ int adis_read_reg(struct adis *adis, unsigned int reg,
 			.len = 2,
 			.cs_change = 1,
 			.delay_usecs = adis->data->read_delay,
-			.cs_change_delay = adis->data->cs_change_delay,
-			.cs_change_delay_unit = SPI_DELAY_UNIT_USECS,
+			.cs_change_delay.value = adis->data->cs_change_delay,
+			.cs_change_delay.unit = SPI_DELAY_UNIT_USECS,
 		}, {
 			.rx_buf = adis->rx + 2,
 			.bits_per_word = 8,
diff --git a/drivers/spi/spi.c b/drivers/spi/spi.c
index 7499a4efbaba..b69c14082c52 100644
--- a/drivers/spi/spi.c
+++ b/drivers/spi/spi.c
@@ -1160,9 +1160,9 @@ EXPORT_SYMBOL_GPL(spi_delay_exec);
 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;
-	u32 hz;
+	u32 delay = xfer->cs_change_delay.value;
+	u32 unit = xfer->cs_change_delay.unit;
+	int ret;
 
 	/* return early on "fast" mode - for everything but USECS */
 	if (!delay) {
@@ -1171,27 +1171,13 @@ static void _spi_transfer_cs_change_delay(struct spi_message *msg,
 		return;
 	}
 
-	switch (unit) {
-	case SPI_DELAY_UNIT_USECS:
-		delay *= 1000;
-		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:
+	ret = spi_delay_exec(&xfer->cs_change_delay, xfer);
+	if (ret) {
 		dev_err_once(&msg->spi->dev,
 			     "Use of unsupported delay unit %i, using default of 10us\n",
-			     xfer->cs_change_delay_unit);
-		delay = 10000;
+			     unit);
+		_spi_transfer_delay_ns(10000);
 	}
-	/* now sleep for the requested amount of time */
-	_spi_transfer_delay_ns(delay);
 }
 
 /*
diff --git a/include/linux/spi/spi.h b/include/linux/spi/spi.h
index 8f643de3197b..7670be934643 100644
--- a/include/linux/spi/spi.h
+++ b/include/linux/spi/spi.h
@@ -778,7 +778,6 @@ extern void spi_res_release(struct spi_controller *ctlr,
  * @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.
@@ -900,8 +899,7 @@ struct spi_transfer {
 	u8		bits_per_word;
 	u8		word_delay_usecs;
 	u16		delay_usecs;
-	u16		cs_change_delay;
-	u8		cs_change_delay_unit;
+	struct spi_delay	cs_change_delay;
 	u32		speed_hz;
 	u16		word_delay;
 
-- 
2.20.1

Applied "spi: move `cs_change_delay` backwards compat logic outside switch" to the spi tree

[Mark Brown]

The patch

   spi: move `cs_change_delay` backwards compat logic outside switch

has been applied to the spi tree at

   https://git.kernel.org/pub/scm/linux/kernel/git/broonie/spi.git for-5.5

All being well this means that it will be integrated into the linux-next
tree (usually sometime in the next 24 hours) and sent to Linus during
the next merge window (or sooner if it is a bug fix), however if
problems are discovered then the patch may be dropped or reverted.  

You may get further e-mails resulting from automated or manual testing
and review of the tree, please engage with people reporting problems and
send followup patches addressing any issues that are reported if needed.

If any updates are required or you are submitting further changes they
should be sent as incremental updates against current git, existing
patches will not be replaced.

Please add any relevant lists and maintainers to the CCs when replying
to this mail.

Thanks,
Mark

>From 6b3f236a998550dba91a46a22feb1cc02f39fb06 Mon Sep 17 00:00:00 2001
From: Alexandru Ardelean <alexandru.ardelean@analog.com>
Date: Thu, 26 Sep 2019 13:51:29 +0300
Subject: [PATCH] spi: move `cs_change_delay` backwards compat logic outside
 switch

The `cs_change_delay` backwards compatibility value could be moved outside
of the switch statement.
The only reason to do it, is to make the next patches easier to diff.

Signed-off-by: Alexandru Ardelean <alexandru.ardelean@analog.com>
Link: https://lore.kernel.org/r/20190926105147.7839-2-alexandru.ardelean@analog.com
Signed-off-by: Mark Brown <broonie@kernel.org>
---
 drivers/spi/spi.c | 11 +++++------
 1 file changed, 5 insertions(+), 6 deletions(-)

diff --git a/drivers/spi/spi.c b/drivers/spi/spi.c
index 9bb36c32cbf9..7ba981cdb86b 100644
--- a/drivers/spi/spi.c
+++ b/drivers/spi/spi.c
@@ -1114,16 +1114,15 @@ static void _spi_transfer_cs_change_delay(struct spi_message *msg,
 	u32 hz;
 
 	/* return early on "fast" mode - for everything but USECS */
-	if (!delay && unit != SPI_DELAY_UNIT_USECS)
+	if (!delay) {
+		if (unit == SPI_DELAY_UNIT_USECS)
+			_spi_transfer_delay_ns(10000);
 		return;
+	}
 
 	switch (unit) {
 	case SPI_DELAY_UNIT_USECS:
-		/* for compatibility use default of 10us */
-		if (!delay)
-			delay = 10000;
-		else
-			delay *= 1000;
+		delay *= 1000;
 		break;
 	case SPI_DELAY_UNIT_NSECS: /* nothing to do here */
 		break;
-- 
2.20.1

Applied "spi: introduce spi_delay struct as "value + unit" & spi_delay_exec()" to the spi tree

[Mark Brown]

The patch

   spi: introduce spi_delay struct as "value + unit" & spi_delay_exec()

has been applied to the spi tree at

   https://git.kernel.org/pub/scm/linux/kernel/git/broonie/spi.git for-5.5

All being well this means that it will be integrated into the linux-next
tree (usually sometime in the next 24 hours) and sent to Linus during
the next merge window (or sooner if it is a bug fix), however if
problems are discovered then the patch may be dropped or reverted.  

You may get further e-mails resulting from automated or manual testing
and review of the tree, please engage with people reporting problems and
send followup patches addressing any issues that are reported if needed.

If any updates are required or you are submitting further changes they
should be sent as incremental updates against current git, existing
patches will not be replaced.

Please add any relevant lists and maintainers to the CCs when replying
to this mail.

Thanks,
Mark

>From b2c98153f45fc17b9fcb241000f2d131ddea6030 Mon Sep 17 00:00:00 2001
From: Alexandru Ardelean <alexandru.ardelean@analog.com>
Date: Thu, 26 Sep 2019 13:51:30 +0300
Subject: [PATCH] spi: introduce spi_delay struct as "value + unit" &
 spi_delay_exec()

There are plenty of delays that have been introduced in SPI core. Most of
them are in micro-seconds, some need to be in nano-seconds, and some in
clock-cycles.

For some of these delays (related to transfers & CS timing) it may make
sense to have a `spi_delay` struct that abstracts these a bit.

The important element of these delays [for unification] seems to be the
`unit` of the delay.
It looks like micro-seconds is good enough for most people, but every-once
in a while, some delays seem to require other units of measurement.

This change adds the `spi_delay` struct & a `spi_delay_exec()` function
that processes a `spi_delay` object/struct to execute the delay.
It's a copy of the `cs_change_delay` mechanism, but without the default
for 10 uS.

The clock-cycle delay unit is a bit special, as it needs to be bound to an
`spi_transfer` object to execute.

Signed-off-by: Alexandru Ardelean <alexandru.ardelean@analog.com>
Link: https://lore.kernel.org/r/20190926105147.7839-3-alexandru.ardelean@analog.com
Signed-off-by: Mark Brown <broonie@kernel.org>
---
 drivers/spi/spi.c       | 51 +++++++++++++++++++++++++++++++++++++++++
 include/linux/spi/spi.h | 18 ++++++++++++---
 2 files changed, 66 insertions(+), 3 deletions(-)

diff --git a/drivers/spi/spi.c b/drivers/spi/spi.c
index 7ba981cdb86b..7499a4efbaba 100644
--- a/drivers/spi/spi.c
+++ b/drivers/spi/spi.c
@@ -1106,6 +1106,57 @@ static void _spi_transfer_delay_ns(u32 ns)
 	}
 }
 
+static int _spi_delay_to_ns(struct spi_delay *_delay, struct spi_transfer *xfer)
+{
+	u32 delay = _delay->value;
+	u32 unit = _delay->unit;
+	u32 hz;
+
+	if (!delay)
+		return 0;
+
+	switch (unit) {
+	case SPI_DELAY_UNIT_USECS:
+		delay *= 1000;
+		break;
+	case SPI_DELAY_UNIT_NSECS: /* nothing to do here */
+		break;
+	case SPI_DELAY_UNIT_SCK:
+		/* clock cycles need to be obtained from spi_transfer */
+		if (!xfer)
+			return -EINVAL;
+		/* 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;
+		if (!hz)
+			return -EINVAL;
+		delay *= DIV_ROUND_UP(1000000000, hz);
+		break;
+	default:
+		return -EINVAL;
+	}
+
+	return delay;
+}
+
+int spi_delay_exec(struct spi_delay *_delay, struct spi_transfer *xfer)
+{
+	int delay;
+
+	if (!_delay)
+		return -EINVAL;
+
+	delay = _spi_delay_to_ns(_delay, xfer);
+	if (delay < 0)
+		return delay;
+
+	_spi_transfer_delay_ns(delay);
+
+	return 0;
+}
+EXPORT_SYMBOL_GPL(spi_delay_exec);
+
 static void _spi_transfer_cs_change_delay(struct spi_message *msg,
 					  struct spi_transfer *xfer)
 {
diff --git a/include/linux/spi/spi.h b/include/linux/spi/spi.h
index 27f6b046cf92..8f643de3197b 100644
--- a/include/linux/spi/spi.h
+++ b/include/linux/spi/spi.h
@@ -90,6 +90,21 @@ void spi_statistics_add_transfer_stats(struct spi_statistics *stats,
 #define SPI_STATISTICS_INCREMENT_FIELD(stats, field)	\
 	SPI_STATISTICS_ADD_TO_FIELD(stats, field, 1)
 
+/**
+ * struct spi_delay - SPI delay information
+ * @value: Value for the delay
+ * @unit: Unit for the delay
+ */
+struct spi_delay {
+#define SPI_DELAY_UNIT_USECS	0
+#define SPI_DELAY_UNIT_NSECS	1
+#define SPI_DELAY_UNIT_SCK	2
+	u16	value;
+	u8	unit;
+};
+
+extern int spi_delay_exec(struct spi_delay *_delay, struct spi_transfer *xfer);
+
 /**
  * struct spi_device - Controller side proxy for an SPI slave device
  * @dev: Driver model representation of the device.
@@ -887,9 +902,6 @@ struct spi_transfer {
 	u16		delay_usecs;
 	u16		cs_change_delay;
 	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;
 
-- 
2.20.1