From mboxrd@z Thu Jan 1 00:00:00 1970 From: Andy Shevchenko Subject: Re: [PATCH v2] i2c: designware: add reset interface Date: Thu, 15 Dec 2016 14:33:47 +0200 Message-ID: <1481805227.9552.15.camel@linux.intel.com> References: <1479789700-19532-1-git-send-email-zhangfei.gao@linaro.org> <1481792388-13781-1-git-send-email-zhangfei.gao@linaro.org> Mime-Version: 1.0 Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: 8bit Return-path: Received: from mga02.intel.com ([134.134.136.20]:41526 "EHLO mga02.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751520AbcLOMdv (ORCPT ); Thu, 15 Dec 2016 07:33:51 -0500 In-Reply-To: <1481792388-13781-1-git-send-email-zhangfei.gao@linaro.org> Sender: linux-i2c-owner@vger.kernel.org List-Id: linux-i2c@vger.kernel.org To: Zhangfei Gao , Wolfram Sang , mika.westerberg@linux.intel.com, jarkko.nikula@linux.intel.com Cc: linux-arm-kernel@lists.infradead.org, linux-i2c@vger.kernel.org On Thu, 2016-12-15 at 16:59 +0800, Zhangfei Gao wrote: > Some platforms like hi3660 need do reset first to allow accessing > registers Patch itself looks good, but would be nice to have it tested. Reviewed-by: Andy Shevchenko > > Signed-off-by: Zhangfei Gao > --- >  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..e9016ae 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(&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; >  } -- Andy Shevchenko Intel Finland Oy