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authorPeng Fan <van.freenix@gmail.com>2016-06-02 14:05:11 +0300
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2016-06-25 17:42:55 +0300
commitdeb319705e7eb60a870e24f75ff8d6452372e350 (patch)
tree0b0ab9a66dc65f7b20b34d44ed955c9b4c3a7818 /drivers/nvmem
parent7d8867d71fba7604e5d6417e5cbd68a6ffd85bb4 (diff)
downloadlinux-deb319705e7eb60a870e24f75ff8d6452372e350.tar.xz
nvmem: imx-ocotp: handling clock
Before access ocotp nvmem area, the clock should be enabled. Or, `hexdump nvmem` will hang the system. So, use such flow: " 1. clock_enable_prepare 2. read nvmem ocotp area 3. clock_disable_unprepare " Signed-off-by: Peng Fan <van.freenix@gmail.com> Cc: Srinivas Kandagatla <srinivas.kandagatla@linaro.org> Cc: Maxime Ripard <maxime.ripard@free-electrons.com> Cc: Shawn Guo <shawnguo@kernel.org> Signed-off-by: Srinivas Kandagatla <srinivas.kandagatla@linaro.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'drivers/nvmem')
-rw-r--r--drivers/nvmem/imx-ocotp.c15
1 files changed, 14 insertions, 1 deletions
diff --git a/drivers/nvmem/imx-ocotp.c b/drivers/nvmem/imx-ocotp.c
index 75e66ef5b0ec..a34039018f9b 100644
--- a/drivers/nvmem/imx-ocotp.c
+++ b/drivers/nvmem/imx-ocotp.c
@@ -15,6 +15,7 @@
* http://www.gnu.org/copyleft/gpl.html
*/
+#include <linux/clk.h>
#include <linux/device.h>
#include <linux/io.h>
#include <linux/module.h>
@@ -26,6 +27,7 @@
struct ocotp_priv {
struct device *dev;
+ struct clk *clk;
void __iomem *base;
unsigned int nregs;
};
@@ -36,7 +38,7 @@ static int imx_ocotp_read(void *context, unsigned int offset,
struct ocotp_priv *priv = context;
unsigned int count;
u32 *buf = val;
- int i;
+ int i, ret;
u32 index;
index = offset >> 2;
@@ -45,9 +47,16 @@ static int imx_ocotp_read(void *context, unsigned int offset,
if (count > (priv->nregs - index))
count = priv->nregs - index;
+ ret = clk_prepare_enable(priv->clk);
+ if (ret < 0) {
+ dev_err(priv->dev, "failed to prepare/enable ocotp clk\n");
+ return ret;
+ }
for (i = index; i < (index + count); i++)
*buf++ = readl(priv->base + 0x400 + i * 0x10);
+ clk_disable_unprepare(priv->clk);
+
return 0;
}
@@ -85,6 +94,10 @@ static int imx_ocotp_probe(struct platform_device *pdev)
if (IS_ERR(priv->base))
return PTR_ERR(priv->base);
+ priv->clk = devm_clk_get(&pdev->dev, NULL);
+ if (IS_ERR(priv->clk))
+ return PTR_ERR(priv->clk);
+
of_id = of_match_device(imx_ocotp_dt_ids, dev);
priv->nregs = (unsigned int)of_id->data;
imx_ocotp_nvmem_config.size = 4 * priv->nregs;