Unverified Commit 329f0dac authored by Alexandru Ardelean's avatar Alexandru Ardelean Committed by Mark Brown
Browse files

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: default avatarAlexandru Ardelean <alexandru.ardelean@analog.com>
Link: https://lore.kernel.org/r/20190926105147.7839-4-alexandru.ardelean@analog.com


Signed-off-by: default avatarMark Brown <broonie@kernel.org>
parent b2c98153

drivers/iio/imu/adis.c

+12 −12
Original line number Diff line number Diff line
@@ -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,

drivers/spi/spi.c

+7 −21
Original line number Diff line number Diff line
@@ -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);

}



/*

include/linux/spi/spi.h

+1 −3
Original line number Diff line number Diff line
@@ -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;

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