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@xxxxxxxxx> Cc: Srinivas Kandagatla <srinivas.kandagatla@xxxxxxxxxx> Cc: Maxime Ripard <maxime.ripard@xxxxxxxxxxxxxxxxxx> Cc: Shawn Guo <shawnguo@xxxxxxxxxx> --- V2: Follow Fabio's comments, check return value of clk_prepare_enable drivers/nvmem/imx-ocotp.c | 16 +++++++++++++++- 1 file changed, 15 insertions(+), 1 deletion(-) diff --git a/drivers/nvmem/imx-ocotp.c b/drivers/nvmem/imx-ocotp.c index d7796eb..3f1dd9f 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; }; @@ -37,7 +39,7 @@ static int imx_ocotp_read(void *context, const void *reg, size_t reg_size, struct ocotp_priv *priv = context; unsigned int offset = *(u32 *)reg; unsigned int count; - int i; + int i, ret; u32 index; index = offset >> 2; @@ -46,11 +48,19 @@ static int imx_ocotp_read(void *context, const void *reg, size_t reg_size, 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++) { *(u32 *)val = readl(priv->base + 0x400 + i * 0x10); val += 4; } + clk_disable_unprepare(priv->clk); + return 0; } @@ -112,6 +122,10 @@ 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; -- 2.6.6 -- To unsubscribe from this list: send the line "unsubscribe devicetree" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
