spi: spidev: Enable control of inter-word delays
Commit b7bb367afa
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>
This commit is contained in:
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@ -276,17 +276,19 @@ static int spidev_message(struct spidev_data *spidev,
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k_tmp->bits_per_word = u_tmp->bits_per_word;
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k_tmp->delay_usecs = u_tmp->delay_usecs;
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k_tmp->speed_hz = u_tmp->speed_hz;
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k_tmp->word_delay_usecs = u_tmp->word_delay_usecs;
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if (!k_tmp->speed_hz)
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k_tmp->speed_hz = spidev->speed_hz;
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#ifdef VERBOSE
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dev_dbg(&spidev->spi->dev,
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" xfer len %u %s%s%s%dbits %u usec %uHz\n",
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" xfer len %u %s%s%s%dbits %u usec %u usec %uHz\n",
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u_tmp->len,
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u_tmp->rx_buf ? "rx " : "",
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u_tmp->tx_buf ? "tx " : "",
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u_tmp->cs_change ? "cs " : "",
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u_tmp->bits_per_word ? : spidev->spi->bits_per_word,
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u_tmp->delay_usecs,
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u_tmp->word_delay_usecs,
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u_tmp->speed_hz ? : spidev->spi->max_speed_hz);
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#endif
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spi_message_add_tail(k_tmp, &msg);
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@ -66,6 +66,9 @@
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* @delay_usecs: If nonzero, how long to delay after the last bit transfer
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* before optionally deselecting the device before the next transfer.
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* @cs_change: True to deselect device before starting the next transfer.
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* @word_delay_usecs: If nonzero, how long to wait between words within one
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* transfer. This property needs explicit support in the SPI controller,
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* otherwise it is silently ignored.
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*
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* This structure is mapped directly to the kernel spi_transfer structure;
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* the fields have the same meanings, except of course that the pointers
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@ -100,7 +103,8 @@ struct spi_ioc_transfer {
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__u8 cs_change;
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__u8 tx_nbits;
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__u8 rx_nbits;
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__u16 pad;
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__u8 word_delay_usecs;
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__u8 pad;
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/* If the contents of 'struct spi_ioc_transfer' ever change
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* incompatibly, then the ioctl number (currently 0) must change;
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