Patch "spi: imx: do not access registers while clocks disabled" has been added to the 4.15-stable tree

Patch "spi: imx: do not access registers while clocks disabled" has been added to the 4.15-stable tree

[gregkh]

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 4.15-stable tree which can be found at:
    http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:
     spi-imx-do-not-access-registers-while-clocks-disabled.patch
and it can be found in the queue-4.15 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
@@ -1668,12 +1668,23 @@ 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-4.15/spi-imx-do-not-access-registers-while-clocks-disabled.patch