This is a note to let you know that I've just added the patch titled
spi: imx: do not access registers while clocks disabled
to the 4.4-stable tree which can be found at: http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git%3Ba=su...
The filename of the patch is: spi-imx-do-not-access-registers-while-clocks-disabled.patch and it can be found in the queue-4.4 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree, please let stable@vger.kernel.org know about it.
From d593574aff0ab846136190b1729c151c736727ec Mon Sep 17 00:00:00 2001
From: Stefan Agner stefan@agner.ch Date: Sun, 7 Jan 2018 15:05:49 +0100 Subject: spi: imx: do not access registers while clocks disabled
From: Stefan Agner stefan@agner.ch
commit d593574aff0ab846136190b1729c151c736727ec upstream.
Since clocks are disabled except during message transfer clocks are also disabled when spi_imx_remove gets called. Accessing registers leads to a freeeze at least on a i.MX 6ULL. Enable clocks before disabling accessing the MXC_CSPICTRL register.
Fixes: 9e556dcc55774 ("spi: spi-imx: only enable the clocks when we start to transfer a message") Signed-off-by: Stefan Agner stefan@agner.ch Signed-off-by: Mark Brown broonie@kernel.org Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org
--- drivers/spi/spi-imx.c | 15 +++++++++++++-- 1 file changed, 13 insertions(+), 2 deletions(-)
--- a/drivers/spi/spi-imx.c +++ b/drivers/spi/spi-imx.c @@ -1228,12 +1228,23 @@ static int spi_imx_remove(struct platfor { struct spi_master *master = platform_get_drvdata(pdev); struct spi_imx_data *spi_imx = spi_master_get_devdata(master); + int ret;
spi_bitbang_stop(&spi_imx->bitbang);
+ ret = clk_enable(spi_imx->clk_per); + if (ret) + return ret; + + ret = clk_enable(spi_imx->clk_ipg); + if (ret) { + clk_disable(spi_imx->clk_per); + return ret; + } + writel(0, spi_imx->base + MXC_CSPICTRL); - clk_unprepare(spi_imx->clk_ipg); - clk_unprepare(spi_imx->clk_per); + clk_disable_unprepare(spi_imx->clk_ipg); + clk_disable_unprepare(spi_imx->clk_per); spi_imx_sdma_exit(spi_imx); spi_master_put(master);
Patches currently in stable-queue which might be from stefan@agner.ch are
queue-4.4/spi-imx-do-not-access-registers-while-clocks-disabled.patch