From d1a7718ee8dbcc488d3243d52e19c755123e0024 Mon Sep 17 00:00:00 2001 From: Jaewon Kim Date: Tue, 2 May 2023 15:28:11 +0900 Subject: spi: s3c64xx: change polling mode to optional Previously, Polling mode was supported as quirk for SOC without DMA. To provide more flexible support for polling mode, it changed to polling mode when the 'dmas' property is not present in the devicetree, rather than using a quirk. Signed-off-by: Jaewon Kim Date: Thu, 22 Jun 2023 11:06:32 +0200 Subject: spi: Create a helper to derive adaptive timeouts Big transfers might take a bit of time, too constraining timeouts might lead to false positives. In order to simplify the drivers work and with the goal of factorizing code in mind, let's add a helper that can be used by any spi controller driver to derive a relevant per-transfer timeout value. The logic is simple: we know how much time it would take to transfer a byte, we can easily derive the total theoretical amount of time involved for each transfer. We multiply it by two to have a bit of margin and enforce a minimum of 500ms. Suggested-by: Mark Brown Signed-off-by: Miquel Raynal Link: https://lore.kernel.org/r/Message-Id: <20230622090634.3411468-2-miquel.raynal@bootlin.com> Signed-off-by: Mark Brown --- include/linux/spi/spi.h | 17 +++++++++++++++++ 1 file changed, 17 insertions(+) (limited to 'include/linux') diff --git a/include/linux/spi/spi.h b/include/linux/spi/spi.h index cfe42f8cd7a4..32c94eae8926 100644 --- a/include/linux/spi/spi.h +++ b/include/linux/spi/spi.h @@ -1261,6 +1261,23 @@ static inline bool spi_is_bpw_supported(struct spi_device *spi, u32 bpw) return false; } +/** + * spi_controller_xfer_timeout - Compute a suitable timeout value + * @ctlr: SPI device + * @xfer: Transfer descriptor + * + * Compute a relevant timeout value for the given transfer. We derive the time + * that it would take on a single data line and take twice this amount of time + * with a minimum of 500ms to avoid false positives on loaded systems. + * + * Returns: Transfer timeout value in milliseconds. + */ +static inline unsigned int spi_controller_xfer_timeout(struct spi_controller *ctlr, + struct spi_transfer *xfer) +{ + return max(xfer->len * 8 * 2 / (xfer->speed_hz / 1000), 500U); +} + /*---------------------------------------------------------------------------*/ /* SPI transfer replacement methods which make use of spi_res */ -- cgit v1.2.3