This let SPI clients check if the controller supports a particular word
width. drivers/gpu/drm/tinydrm/mipi-dbi.c will use this to determine if
the controller supports 16-bit for RGB565 pixels. If it doesn't it will
swap the bytes before transfer on little endian machines.
Signed-off-by: Noralf Trønnes <nor...@tronnes.org>
---
include/linux/spi/spi.h | 20 ++++++++++++++++++++
1 file changed, 20 insertions(+)
diff --git a/include/linux/spi/spi.h b/include/linux/spi/spi.h
index 662b336aa2e4..b30e3d13a5ac 100644
--- a/include/linux/spi/spi.h
+++ b/include/linux/spi/spi.h
@@ -983,6 +983,26 @@ spi_max_transfer_size(struct spi_device *spi)
return min(tr_max, msg_max);
}
+/**
+ * spi_is_bpw_supported - Check if bits per word is supported
+ * @spi: SPI device
+ * @bpw: Bits per word
+ *
+ * This function checks to see if the SPI controller supports @bpw.
+ *
+ * Returns:
+ * True if @bpw is supported, false otherwise.
+ */
+static inline bool spi_is_bpw_supported(struct spi_device *spi, u32 bpw)
+{
+ u32 bpw_mask = spi->master->bits_per_word_mask;
+
+ if (bpw == 8 || (bpw <= 32 && bpw_mask & SPI_BPW_MASK(bpw)))
+ return true;
+
+ return false;
+}
+
/*---------------------------------------------------------------------------*/
/* SPI transfer replacement methods which make use of spi_res */
--
2.20.1
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