From mboxrd@z Thu Jan 1 00:00:00 1970 From: Peng Fan Subject: [PATCH V2 3/3] nvmem: imx-ocotp: handling clock Date: Thu, 21 Apr 2016 01:26:17 +0800 Message-ID: <1461173177-11930-3-git-send-email-van.freenix@gmail.com> References: <1461173177-11930-1-git-send-email-van.freenix@gmail.com> Return-path: In-Reply-To: <1461173177-11930-1-git-send-email-van.freenix@gmail.com> Sender: linux-kernel-owner@vger.kernel.org To: shawnguo@kernel.org, srinivas.kandagatla@linaro.org, maxime.ripard@free-electrons.com Cc: linux-arm-kernel@lists.infradead.org, devicetree@vger.kernel.org, linux-kernel@vger.kernel.org, van.freenix@gmail.com List-Id: devicetree@vger.kernel.org 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 Cc: Srinivas Kandagatla Cc: Maxime Ripard Cc: Shawn Guo --- 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 #include #include #include @@ -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