| Message ID | 1423049510-32244-1-git-send-email-luis.henriques@canonical.com |
|---|---|
| State | New |
| Headers | show |
diff --git a/drivers/spi/spi-dw.c b/drivers/spi/spi-dw.c index 080e0a343675..32a3718cc5b4 100644 --- a/drivers/spi/spi-dw.c +++ b/drivers/spi/spi-dw.c @@ -622,13 +622,13 @@ static void spi_hw_init(struct dw_spi *dws) */ if (!dws->fifo_len) { u32 fifo; - for (fifo = 2; fifo <= 257; fifo++) { + for (fifo = 2; fifo <= 256; fifo++) { dw_writew(dws, DW_SPI_TXFLTR, fifo); if (fifo != dw_readw(dws, DW_SPI_TXFLTR)) break; } - dws->fifo_len = (fifo == 257) ? 0 : fifo; + dws->fifo_len = (fifo == 2) ? 0 : fifo - 1; dw_writew(dws, DW_SPI_TXFLTR, 0); } }
This is a note to let you know that I have just added a patch titled spi: dw: Fix detecting FIFO depth to the linux-3.16.y-queue branch of the 3.16.y-ckt extended stable tree which can be found at: http://kernel.ubuntu.com/git?p=ubuntu/linux.git;a=shortlog;h=refs/heads/linux-3.16.y-queue This patch is scheduled to be released in version 3.16.7-ckt6. If you, or anyone else, feels it should not be added to this tree, please reply to this email. For more information about the 3.16.y-ckt tree, see https://wiki.ubuntu.com/Kernel/Dev/ExtendedStable Thanks. -Luis ------ From dd3f32c29e5509c31e214f8e2aea596dee2200d3 Mon Sep 17 00:00:00 2001 From: Axel Lin <axel.lin@ingics.com> Date: Mon, 5 Jan 2015 09:32:56 +0800 Subject: spi: dw: Fix detecting FIFO depth commit d297933cc7fcfbaaf2d37570baac73287bf0357d upstream. Current code tries to find the highest valid fifo depth by checking the value it wrote to DW_SPI_TXFLTR. There are a few problems in current code: 1) There is an off-by-one in dws->fifo_len setting because it assumes the latest register write fails so the latest valid value should be fifo - 1. 2) We know the depth could be from 2 to 256 from HW spec, so it is not necessary to test fifo == 257. In the case fifo is 257, it means the latest valid setting is fifo = 256. So after the for loop iteration, we should check fifo == 2 case instead of fifo == 257 if detecting the FIFO depth fails. This patch fixes above issues. Signed-off-by: Axel Lin <axel.lin@ingics.com> Reviewed-and-tested-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com> Signed-off-by: Mark Brown <broonie@kernel.org> Signed-off-by: Luis Henriques <luis.henriques@canonical.com> --- drivers/spi/spi-dw.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) -- 2.1.4