Merge series "spi: finalize 'delay_usecs' removal/transition" from Alexandru Ardelean <aardelean@deviqon.com>:

A while back I started the introduction of the 'spi_delay' data type:
  https://lore.kernel.org/linux-spi/20190926105147.7839-1-alexandru.ardelean@analog.com/

Users of the 'delay_usecs' were removed from drivers.

Now it's time to remove the 'delay_usecs' from the SPI subsystem and use
only the 'delay' field.

This changeset adapts all SPI drivers to do without 'delay_usecs'.
Additionally, for greybus we need to adapt it to use the 'delay' in
nano-seconds and convert it to micro-seconds.

Alexandru Ardelean (10):
  spi: spi-axi-spi-engine: remove usage of delay_usecs
  spi: bcm63xx-spi: don't check 'delay_usecs' field
  spi: spi-bcm-qspi: replace 'delay_usecs' with 'delay.value' check
  spi: spi-sh: replace 'delay_usecs' with 'delay.value' in pr_debug
  spi: spi-tegra20-flash: don't check 'delay_usecs' field for spi
    transfer
  staging: greybus: spilib: use 'spi_delay_to_ns' for getting xfer delay
  spi: spi-falcon: remove check for 'delay_usecs'
  spi: fsl-espi: remove usage of 'delay_usecs' field
  spi: core: remove 'delay_usecs' field from spi_transfer
  spi: docs: update info about 'delay_usecs'

 Documentation/spi/spi-summary.rst |  7 +++++--
 drivers/spi/spi-axi-spi-engine.c  | 12 ++++--------
 drivers/spi/spi-bcm-qspi.c        |  2 +-
 drivers/spi/spi-bcm63xx.c         |  2 +-
 drivers/spi/spi-falcon.c          |  2 +-
 drivers/spi/spi-fsl-espi.c        | 17 +++++------------
 drivers/spi/spi-sh.c              |  4 ++--
 drivers/spi/spi-tegra20-sflash.c  |  3 +--
 drivers/spi/spi.c                 |  1 -
 drivers/staging/greybus/spilib.c  |  5 ++++-
 include/linux/spi/spi.h           | 12 ------------
 11 files changed, 24 insertions(+), 43 deletions(-)

--
2.29.2

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Documentation/spi/spi-summary.rst

@@ -411,8 +411,11 @@ any more such messages.
         duplex (one pointer is NULL) transfers;
 
       + optionally defining short delays after transfers ... using
-        the spi_transfer.delay_usecs setting (this delay can be the
-        only protocol effect, if the buffer length is zero);
+        the spi_transfer.delay.value setting (this delay can be the
+        only protocol effect, if the buffer length is zero) ...
+        when specifying this delay the default spi_transfer.delay.unit
+        is microseconds, however this can be adjusted to clock cycles
+        or nanoseconds if needed;
 
       + whether the chipselect becomes inactive after a transfer and
         any delay ... by using the spi_transfer.cs_change flag;

drivers/spi/spi-axi-spi-engine.c

@@ -170,14 +170,10 @@ static void spi_engine_gen_sleep(struct spi_engine_program *p, bool dry,
 	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;
-	}
+	delay = spi_delay_to_ns(&xfer->delay, xfer);
+	if (delay < 0)
+		return;
+	delay /= 1000;
 
 	if (delay == 0)
 		return;

drivers/spi/spi-bcm-qspi.c

@@ -671,7 +671,7 @@ static int update_qspi_trans_byte_count(struct bcm_qspi *qspi,
 	if (qt->byte >= qt->trans->len) {
 		/* we're at the end of the spi_transfer */
 		/* in TX mode, need to pause for a delay or CS change */
-		if (qt->trans->delay_usecs &&
+		if (qt->trans->delay.value &&
 		    (flags & TRANS_STATUS_BREAK_DELAY))
 			ret |= TRANS_STATUS_BREAK_DELAY;
 		if (qt->trans->cs_change &&

drivers/spi/spi-bcm63xx.c

@@ -369,7 +369,7 @@ static int bcm63xx_spi_transfer_one(struct spi_master *master,
 		}
 
 		/* CS will be deasserted directly after transfer */
-		if (t->delay_usecs || t->delay.value) {
+		if (t->delay.value) {
 			dev_err(&spi->dev, "unable to keep CS asserted after transfer\n");
 			status = -EINVAL;
 			goto exit;

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->delay.value || t->cs_change);
+		WARN_ON(t->delay.value || t->cs_change);
 		spi_flags = 0;
 	}
 

drivers/spi/spi-fsl-espi.c

@@ -435,8 +435,7 @@ static int fsl_espi_trans(struct spi_message *m, struct spi_transfer *trans)
 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;
+	unsigned int rx_nbits = 0, delay_nsecs = 0;
 	struct spi_transfer *t, trans = {};
 	int ret;
 
@@ -445,16 +444,10 @@ 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) {
-			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;
-		}
+		unsigned int delay = spi_delay_to_ns(&t->delay, t);
+
+		if (delay > delay_nsecs)
+			delay_nsecs = delay;
 		if (t->rx_nbits > rx_nbits)
 			rx_nbits = t->rx_nbits;
 	}

drivers/spi/spi-sh.c

@@ -290,8 +290,8 @@ static void spi_sh_work(struct work_struct *work)
 		list_for_each_entry(t, &mesg->transfers, transfer_list) {
 			pr_debug("tx_buf = %p, rx_buf = %p\n",
 					t->tx_buf, t->rx_buf);
-			pr_debug("len = %d, delay_usecs = %d\n",
-					t->len, t->delay_usecs);
+			pr_debug("len = %d, delay.value = %d\n",
+					t->len, t->delay.value);
 
 			if (t->tx_buf) {
 				ret = spi_sh_send(ss, mesg, t);

drivers/spi/spi-tegra20-sflash.c

@@ -341,8 +341,7 @@ 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 || xfer->delay.value)) {
+		if (xfer->cs_change && xfer->delay.value) {
 			tegra_sflash_writel(tsd, tsd->def_command_reg,
 					SPI_COMMAND);
 			spi_transfer_delay_exec(xfer);

drivers/spi/spi.c

@@ -3178,7 +3178,6 @@ struct spi_replaced_transfers *spi_replace_transfers(
 		/* clear cs_change and delay for all but the last */
 		if (i) {
 			xfer->cs_change = false;
-			xfer->delay_usecs = 0;
 			xfer->delay.value = 0;
 		}
 	}

drivers/staging/greybus/spilib.c

@@ -245,6 +245,7 @@ static struct gb_operation *gb_spi_operation_create(struct gb_spilib *spi,
 	/* Fill in the transfers array */
 	xfer = spi->first_xfer;
 	while (msg->state != GB_SPI_STATE_OP_DONE) {
+		int xfer_delay;
 		if (xfer == spi->last_xfer)
 			xfer_len = spi->last_xfer_size;
 		else
@@ -259,7 +260,9 @@ static struct gb_operation *gb_spi_operation_create(struct gb_spilib *spi,
 
 		gb_xfer->speed_hz = cpu_to_le32(xfer->speed_hz);
 		gb_xfer->len = cpu_to_le32(xfer_len);
-		gb_xfer->delay_usecs = cpu_to_le16(xfer->delay_usecs);
+		xfer_delay = spi_delay_to_ns(&xfer->delay, xfer) / 1000;
+		xfer_delay = clamp_t(u16, xfer_delay, 0, U16_MAX);
+		gb_xfer->delay_usecs = cpu_to_le16(xfer_delay);
 		gb_xfer->cs_change = xfer->cs_change;
 		gb_xfer->bits_per_word = xfer->bits_per_word;
 

include/linux/spi/spi.h

@@ -832,9 +832,6 @@ extern void spi_res_release(struct spi_controller *ctlr,
  * @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.
  * @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
@@ -946,7 +943,6 @@ struct spi_transfer {
 #define	SPI_NBITS_DUAL		0x02 /* 2bits 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;
@@ -1060,14 +1056,6 @@ spi_transfer_del(struct spi_transfer *t)
 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);
 }