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nvmem: imx-ocotp: handling clock

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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>
This commit is contained in:
Peng Fan 2016-06-02 12:05:11 +01:00 committed by Greg Kroah-Hartman
parent 7d8867d71f
commit deb319705e
1 changed files with 14 additions and 1 deletions
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15
drivers/nvmem/imx-ocotp.c
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@ -15,6 +15,7 @@
* http://www.gnu.org/copyleft/gpl.html * http://www.gnu.org/copyleft/gpl.html
*/ */
#include <linux/clk.h>
#include <linux/device.h> #include <linux/device.h>
#include <linux/io.h> #include <linux/io.h>
#include <linux/module.h> #include <linux/module.h>
@ -26,6 +27,7 @@
struct ocotp_priv { struct ocotp_priv {
struct device *dev; struct device *dev;
struct clk *clk;
void __iomem *base; void __iomem *base;
unsigned int nregs; unsigned int nregs;
}; };
@ -36,7 +38,7 @@ static int imx_ocotp_read(void *context, unsigned int offset,
struct ocotp_priv *priv = context; struct ocotp_priv *priv = context;
unsigned int count; unsigned int count;
u32 *buf = val; u32 *buf = val;
int i; int i, ret;
u32 index; u32 index;
index = offset >> 2; index = offset >> 2;
@ -45,9 +47,16 @@ static int imx_ocotp_read(void *context, unsigned int offset,
if (count > (priv->nregs - index)) if (count > (priv->nregs - index))
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++) for (i = index; i < (index + count); i++)
*buf++ = readl(priv->base + 0x400 + i * 0x10); *buf++ = readl(priv->base + 0x400 + i * 0x10);
clk_disable_unprepare(priv->clk);
return 0; return 0;
} }
@ -85,6 +94,10 @@ static int imx_ocotp_probe(struct platform_device *pdev)
if (IS_ERR(priv->base)) if (IS_ERR(priv->base))
return PTR_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); of_id = of_match_device(imx_ocotp_dt_ids, dev);
priv->nregs = (unsigned int)of_id->data; priv->nregs = (unsigned int)of_id->data;
imx_ocotp_nvmem_config.size = 4 * priv->nregs; imx_ocotp_nvmem_config.size = 4 * priv->nregs;