spi/bcm63xx: make spi subsystem aware of message size limits

The bcm63xx SPI controller does not allow manual control of the CS lines and will toggle it automatically before and after sending data, so we are limited to messages that fit in the FIFO buffer. Since the CS lines aren't available as GPIOs either, we will need to make slave drivers aware of this limitation so they can handle them accordingly.

---
 drivers/spi/spi-bcm63xx.c | 9 +++++++++
 1 file changed, 9 insertions(+)

index fee747030ee6..caa733ec405c 100644
@@ -428,6 +428,13 @@ static irqreturn_t bcm63xx_spi_interrupt(int irq, void *dev_id)
 	return IRQ_HANDLED;
 }
 
+static size_t bcm63xx_spi_max_length(struct spi_device *dev)
+{
+	struct bcm63xx_spi *bs = spi_master_get_devdata(spi->master);
+
+	return bs->fifo_size;
+}
+
 static const unsigned long bcm6348_spi_reg_offsets[] = {
 	[SPI_CMD]		= SPI_6348_CMD,
 	[SPI_INT_STATUS]	= SPI_6348_INT_STATUS,

@@ -541,6 +548,8 @@ static int bcm63xx_spi_probe(struct platform_device *pdev)
 	master->transfer_one_message = bcm63xx_spi_transfer_one;
 	master->mode_bits = MODEBITS;
 	master->bits_per_word_mask = SPI_BPW_MASK(8);
+	master->max_transfer_size = bcm63xx_spi_max_length;
+	master->max_message_size = bcm63xx_spi_max_length;
 	master->auto_runtime_pm = true;
 	bs->msg_type_shift = bs->reg_offsets[SPI_MSG_TYPE_SHIFT];
 	bs->msg_ctl_width = bs->reg_offsets[SPI_MSG_CTL_WIDTH];

2.11.0

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The patch

spi/bcm63xx: make spi subsystem aware of message size limits

has been applied to the spi tree at

git://git.kernel.org/pub/scm/linux/kernel/git/broonie/spi.git

All being well this means that it will be integrated into the linux-next tree (usually sometime in the next 24 hours) and sent to Linus during the next merge window (or sooner if it is a bug fix), however if problems are discovered then the patch may be dropped or reverted.

You may get further e-mails resulting from automated or manual testing and review of the tree, please engage with people reporting problems and send followup patches addressing any issues that are reported if needed.

If any updates are required or you are submitting further changes they should be sent as incremental updates against current git, existing patches will not be replaced.

Please add any relevant lists and maintainers to the CCs when replying to this mail.

Thanks,
Mark

From: Jonas Gorski <[email protected]>
Date: Mon, 20 Feb 2017 11:50:09 +0100
Subject: [PATCH] spi/bcm63xx: make spi subsystem aware of message size limits

The bcm63xx SPI controller does not allow manual control of the CS lines and will toggle it automatically before and after sending data, so we are limited to messages that fit in the FIFO buffer. Since the CS lines aren't available as GPIOs either, we will need to make slave drivers aware of this limitation so they can handle them accordingly.

---
 drivers/spi/spi-bcm63xx.c | 9 +++++++++
 1 file changed, 9 insertions(+)

index fee747030ee6..caa733ec405c 100644
@@ -428,6 +428,13 @@ static irqreturn_t bcm63xx_spi_interrupt(int irq, void *dev_id)
 	return IRQ_HANDLED;
 }
 
+static size_t bcm63xx_spi_max_length(struct spi_device *dev)
+{
+	struct bcm63xx_spi *bs = spi_master_get_devdata(spi->master);
+
+	return bs->fifo_size;
+}
+
 static const unsigned long bcm6348_spi_reg_offsets[] = {
 	[SPI_CMD]		= SPI_6348_CMD,
 	[SPI_INT_STATUS]	= SPI_6348_INT_STATUS,

@@ -541,6 +548,8 @@ static int bcm63xx_spi_probe(struct platform_device *pdev)
 	master->transfer_one_message = bcm63xx_spi_transfer_one;
 	master->mode_bits = MODEBITS;
 	master->bits_per_word_mask = SPI_BPW_MASK(8);
+	master->max_transfer_size = bcm63xx_spi_max_length;
+	master->max_message_size = bcm63xx_spi_max_length;
 	master->auto_runtime_pm = true;
 	bs->msg_type_shift = bs->reg_offsets[SPI_MSG_TYPE_SHIFT];
 	bs->msg_ctl_width = bs->reg_offsets[SPI_MSG_CTL_WIDTH];

2.11.0

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