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Subject[PATCH 3/3] nvmem: imx-ocotp: handling clock
Date
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>
---
drivers/nvmem/imx-ocotp.c | 10 ++++++++++
1 file changed, 10 insertions(+)

diff --git a/drivers/nvmem/imx-ocotp.c b/drivers/nvmem/imx-ocotp.c
index d7796eb..55095c0 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>
@@ -27,6 +28,7 @@

struct ocotp_priv {
struct device *dev;
+ struct clk *clk;
void __iomem *base;
unsigned int nregs;
};
@@ -46,11 +48,15 @@ static int imx_ocotp_read(void *context, const void *reg, size_t reg_size,
if (count > (priv->nregs - index))
count = priv->nregs - index;

+ clk_prepare_enable(priv->clk);
+
for (i = index; i < (index + count); i++) {
*(u32 *)val = readl(priv->base + 0x400 + i * 0x10);
val += 4;
}

+ clk_disable_unprepare(priv->clk);
+
return 0;
}

@@ -112,6 +118,10 @@ 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_regmap_config.max_register = 4 * priv->nregs - 4;
--
1.8.4.5
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