From mboxrd@z Thu Jan 1 00:00:00 1970 From: Zhangfei Gao Subject: [PATCH v3] i2c: designware: add reset interface Date: Fri, 23 Dec 2016 21:40:51 +0800 Message-ID: <1482500451-30137-1-git-send-email-zhangfei.gao@linaro.org> Return-path: Received: from mail-pf0-f180.google.com ([209.85.192.180]:33968 "EHLO mail-pf0-f180.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755223AbcLWNl0 (ORCPT ); Fri, 23 Dec 2016 08:41:26 -0500 Received: by mail-pf0-f180.google.com with SMTP id c4so44683225pfb.1 for ; Fri, 23 Dec 2016 05:41:26 -0800 (PST) Sender: linux-i2c-owner@vger.kernel.org List-Id: linux-i2c@vger.kernel.org To: Wolfram Sang , andriy.shevchenko@linux.intel.com, mika.westerberg@linux.intel.com, jarkko.nikula@linux.intel.com, p.zabel@pengutronix.de Cc: linux-arm-kernel@lists.infradead.org, linux-i2c@vger.kernel.org, Zhangfei Gao Some platforms like hi3660 need do reset first to allow accessing registers Signed-off-by: Zhangfei Gao Reviewed-by: Andy Shevchenko Tested-by: Ramiro Oliveira --- drivers/i2c/busses/i2c-designware-core.h | 1 + drivers/i2c/busses/i2c-designware-platdrv.c | 28 ++++++++++++++++++++++++---- 2 files changed, 25 insertions(+), 4 deletions(-) diff --git a/drivers/i2c/busses/i2c-designware-core.h b/drivers/i2c/busses/i2c-designware-core.h index 0d44d2a..94b14fa 100644 --- a/drivers/i2c/busses/i2c-designware-core.h +++ b/drivers/i2c/busses/i2c-designware-core.h @@ -80,6 +80,7 @@ struct dw_i2c_dev { void __iomem *base; struct completion cmd_complete; struct clk *clk; + struct reset_control *rst; u32 (*get_clk_rate_khz) (struct dw_i2c_dev *dev); struct dw_pci_controller *controller; int cmd_err; diff --git a/drivers/i2c/busses/i2c-designware-platdrv.c b/drivers/i2c/busses/i2c-designware-platdrv.c index 0b42a12..1fbe66f 100644 --- a/drivers/i2c/busses/i2c-designware-platdrv.c +++ b/drivers/i2c/busses/i2c-designware-platdrv.c @@ -38,6 +38,7 @@ #include #include #include +#include #include #include #include @@ -176,6 +177,14 @@ static int dw_i2c_plat_probe(struct platform_device *pdev) dev->irq = irq; platform_set_drvdata(pdev, dev); + dev->rst = devm_reset_control_get_optional_exclusive(&pdev->dev, NULL); + if (IS_ERR(dev->rst)) { + if (PTR_ERR(dev->rst) == -EPROBE_DEFER) + return -EPROBE_DEFER; + } else { + reset_control_deassert(dev->rst); + } + /* fast mode by default because of legacy reasons */ dev->clk_freq = 400000; @@ -207,12 +216,13 @@ static int dw_i2c_plat_probe(struct platform_device *pdev) && dev->clk_freq != 1000000 && dev->clk_freq != 3400000) { dev_err(&pdev->dev, "Only 100kHz, 400kHz, 1MHz and 3.4MHz supported"); - return -EINVAL; + r = -EINVAL; + goto exit_reset; } r = i2c_dw_eval_lock_support(dev); if (r) - return r; + goto exit_reset; dev->functionality = I2C_FUNC_I2C | @@ -270,10 +280,18 @@ static int dw_i2c_plat_probe(struct platform_device *pdev) } r = i2c_dw_probe(dev); - if (r && !dev->pm_runtime_disabled) - pm_runtime_disable(&pdev->dev); + if (r) + goto exit_probe; return r; + +exit_probe: + if (!dev->pm_runtime_disabled) + pm_runtime_disable(&pdev->dev); +exit_reset: + if (!IS_ERR_OR_NULL(dev->rst)) + reset_control_assert(dev->rst); + return r; } static int dw_i2c_plat_remove(struct platform_device *pdev) @@ -290,6 +308,8 @@ static int dw_i2c_plat_remove(struct platform_device *pdev) pm_runtime_put_sync(&pdev->dev); if (!dev->pm_runtime_disabled) pm_runtime_disable(&pdev->dev); + if (!IS_ERR_OR_NULL(dev->rst)) + reset_control_assert(dev->rst); return 0; } -- 2.7.4