spi: sunxi: expose maximum transfer size limit
The sun4i spi hardware can trasfer at most 63 bytes of data without DMA
support so report the limitation. Same for sun6i.
Signed-off-by: Michal Suchanek <hramrach@gmail.com>
Acked-by: Maxime Ripard <maxime.ripard@free-electrons.com>
Signed-off-by: Mark Brown <broonie@kernel.org>
diff --git a/drivers/spi/spi-sun4i.c b/drivers/spi/spi-sun4i.c
index 1ddd9e2..07ce7c9 100644
--- a/drivers/spi/spi-sun4i.c
+++ b/drivers/spi/spi-sun4i.c
@@ -167,6 +167,11 @@
sun4i_spi_write(sspi, SUN4I_CTL_REG, reg);
}
+static size_t sun4i_spi_max_transfer_size(struct spi_device *spi)
+{
+ return SUN4I_FIFO_DEPTH - 1;
+}
+
static int sun4i_spi_transfer_one(struct spi_master *master,
struct spi_device *spi,
struct spi_transfer *tfr)
@@ -394,6 +399,7 @@
master->bits_per_word_mask = SPI_BPW_MASK(8);
master->dev.of_node = pdev->dev.of_node;
master->auto_runtime_pm = true;
+ master->max_transfer_size = sun4i_spi_max_transfer_size;
sspi->hclk = devm_clk_get(&pdev->dev, "ahb");
if (IS_ERR(sspi->hclk)) {