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spi: make cs_change_delay the first user of the spi_delay logic

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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>
This commit is contained in:
Alexandru Ardelean 2019-09-26 13:51:31 +03:00 committed by Mark Brown
parent b2c98153f4
commit 329f0dac4c
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GPG Key ID: 24D68B725D5487D0
3 changed files with 20 additions and 36 deletions
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24
drivers/iio/imu/adis.c
View File

@ -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,

28
drivers/spi/spi.c
View File

@ -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);
}
/*

4
include/linux/spi/spi.h
View File

@ -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;