diff options
| author | Jan Kundrát <jan.kundrat@cesnet.cz> | 2019-03-07 15:29:42 +0100 |
|---|---|---|
| committer | Mark Brown <broonie@kernel.org> | 2019-03-18 12:18:28 +0000 |
| commit | 2ed6692e8ce924346c3aab5585b07005adb30625 (patch) | |
| tree | 9c77ba50e365714bc1d4e5cfd5dfee6382cc416b | |
| parent | 4e3891a55f671a4e641d2ef4e5ec0e27e56b20d9 (diff) | |
spi: spidev: Enable control of inter-word delays
Commit b7bb367afa4b added support for inserting delays in between
individual words within a single SPI transaction. This makes it
accessible from userspace.
WARNING: This delay is silently ignored unless the SPI controller
implements extra support for it. This is similar to how the in-kernel
users handle the other existing property, spi_transfer->word_delay.
Signed-off-by: Jan Kundrát <jan.kundrat@cesnet.cz>
Signed-off-by: Mark Brown <broonie@kernel.org>
| -rw-r--r-- | drivers/spi/spidev.c | 4 | ||||
| -rw-r--r-- | include/uapi/linux/spi/spidev.h | 6 |
2 files changed, 8 insertions, 2 deletions
diff --git a/drivers/spi/spidev.c b/drivers/spi/spidev.c index b0c76e2626ce..70966e10be7e 100644 --- a/drivers/spi/spidev.c +++ b/drivers/spi/spidev.c @@ -276,17 +276,19 @@ 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; if (!k_tmp->speed_hz) k_tmp->speed_hz = spidev->speed_hz; #ifdef VERBOSE dev_dbg(&spidev->spi->dev, - " xfer len %u %s%s%s%dbits %u usec %uHz\n", + " xfer len %u %s%s%s%dbits %u usec %u usec %uHz\n", u_tmp->len, u_tmp->rx_buf ? "rx " : "", u_tmp->tx_buf ? "tx " : "", u_tmp->cs_change ? "cs " : "", u_tmp->bits_per_word ? : spidev->spi->bits_per_word, u_tmp->delay_usecs, + u_tmp->word_delay_usecs, u_tmp->speed_hz ? : spidev->spi->max_speed_hz); #endif spi_message_add_tail(k_tmp, &msg); diff --git a/include/uapi/linux/spi/spidev.h b/include/uapi/linux/spi/spidev.h index c4253f0090d8..ee0f2460bff6 100644 --- a/include/uapi/linux/spi/spidev.h +++ b/include/uapi/linux/spi/spidev.h @@ -66,6 +66,9 @@ * @delay_usecs: If nonzero, how long to delay after the last bit transfer * before optionally deselecting the device before the next transfer. * @cs_change: True to deselect device before starting the next transfer. + * @word_delay_usecs: If nonzero, how long to wait between words within one + * transfer. This property needs explicit support in the SPI controller, + * otherwise it is silently ignored. * * This structure is mapped directly to the kernel spi_transfer structure; * the fields have the same meanings, except of course that the pointers @@ -100,7 +103,8 @@ struct spi_ioc_transfer { __u8 cs_change; __u8 tx_nbits; __u8 rx_nbits; - __u16 pad; + __u8 word_delay_usecs; + __u8 pad; /* If the contents of 'struct spi_ioc_transfer' ever change * incompatibly, then the ioctl number (currently 0) must change; |