From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753539AbbJUGeT (ORCPT ); Wed, 21 Oct 2015 02:34:19 -0400 Received: from lucky1.263xmail.com ([211.157.147.132]:56060 "EHLO lucky1.263xmail.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752150AbbJUGeR (ORCPT ); Wed, 21 Oct 2015 02:34:17 -0400 X-263anti-spam: KSV:0; X-MAIL-GRAY: 1 X-MAIL-DELIVERY: 0 X-KSVirus-check: 0 X-ABS-CHECKED: 4 X-ADDR-CHECKED: 0 X-RL-SENDER: shawn.lin@rock-chips.com X-FST-TO: linux-kernel@vger.kernel.org X-SENDER-IP: 58.22.7.114 X-LOGIN-NAME: shawn.lin@rock-chips.com X-UNIQUE-TAG: <2cfd74967080427abf6912ff2a192e36> X-ATTACHMENT-NUM: 0 X-DNS-TYPE: 0 Subject: Re: [PATCH v3 2/3] mmc: sdhci-of-arasan: add phy support for sdhci-of-arasan To: Kishon Vijay Abraham I , Ulf Hansson References: <1445324718-31407-1-git-send-email-shawn.lin@rock-chips.com> <56269126.1070807@ti.com> Cc: shawn.lin@rock-chips.com, Michal Simek , =?UTF-8?Q?S=c3=b6ren_Brinkmann?= , linux-mmc , "linux-kernel@vger.kernel.org" From: Shawn Lin Message-ID: <562731DE.90303@rock-chips.com> Date: Wed, 21 Oct 2015 14:34:06 +0800 User-Agent: Mozilla/5.0 (Windows NT 6.3; WOW64; rv:38.0) Gecko/20100101 Thunderbird/38.3.0 MIME-Version: 1.0 In-Reply-To: <56269126.1070807@ti.com> Content-Type: text/plain; charset=utf-8; format=flowed Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 2015/10/21 3:08, Kishon Vijay Abraham I wrote: > Hi, > > On Tuesday 20 October 2015 02:09 PM, Ulf Hansson wrote: >> + Kishon >> >> On 20 October 2015 at 09:05, Shawn Lin wrote: >>> This patch adds Generic PHY access for sdhci-of-arasan. Driver >>> can get PHY handler from dt-binding, and power-on/init the PHY. >>> Also we add pm ops for PHY here if CONFIG_PM_SLEEP is enabled. >>> Currently, it's just mandatory for arasan,sdhci-5.1. >>> >>> Signed-off-by: Shawn Lin >>> >>> Serise-changes: 3 >>> - remove phy_init/exit for suspend/resume >>> - adjust phy_int/power_on seq to make code more reasonable >>> - simplify suspend/resume_phy >>> >>> Serise-changes: 2 >>> - Keep phy as a mandatory requirement for arasan,sdhci-5.1 >>> >>> --- >>> >>> Changes in v2: None >>> >>> drivers/mmc/host/sdhci-of-arasan.c | 87 ++++++++++++++++++++++++++++++++++++++ >>> 1 file changed, 87 insertions(+) >>> >>> diff --git a/drivers/mmc/host/sdhci-of-arasan.c b/drivers/mmc/host/sdhci-of-arasan.c >>> index 75379cb..85bd0f9d 100644 >>> --- a/drivers/mmc/host/sdhci-of-arasan.c >>> +++ b/drivers/mmc/host/sdhci-of-arasan.c >>> @@ -21,6 +21,7 @@ >>> >>> #include >>> #include >>> +#include >>> #include "sdhci-pltfm.h" >>> >>> #define SDHCI_ARASAN_CLK_CTRL_OFFSET 0x2c >>> @@ -35,6 +36,7 @@ >>> */ >>> struct sdhci_arasan_data { >>> struct clk *clk_ahb; >>> + struct phy *phy; >>> }; >>> >>> static unsigned int sdhci_arasan_get_timeout_clock(struct sdhci_host *host) >>> @@ -70,6 +72,42 @@ static struct sdhci_pltfm_data sdhci_arasan_pdata = { >>> >>> #ifdef CONFIG_PM_SLEEP >>> /** >>> + * sdhci_arasan_suspend_phy - Suspend phy method for the driver >>> + * @phy: Handler of phy structure >>> + * Returns 0 on success and error value on error >>> + * >>> + * Put the phy in a deactive state. >>> + */ >>> +static int sdhci_arasan_suspend_phy(struct phy *phy) >>> +{ >>> + int ret = 0; >>> + >>> + ret = phy_power_off(phy); >>> + if (ret) >> >> This is an odd error handling, should you really do phy_power_on()? > > right, if phy_power_off fails, it means the phy is still powered on. > This will also get reference counting wrong in the phy core. > > Also phy_power_off can be invoked directly instead of having a separate > function to invoke it. Thanks for comments, Kisho. Then I will remove these two wrappers and call phy_power_off/on directly. >> >>> + phy_power_on(phy); >>> + >>> + return ret; >>> +} >>> + >>> +/** >>> + * sdhci_arasan_resume_phy - Resume phy method for the driver >>> + * @phy: Handler of phy structure >>> + * Returns 0 on success and error value on error >>> + * >>> + * Put the phy in a active state. >>> + */ >>> +static int sdhci_arasan_resume_phy(struct phy *phy) >>> +{ >>> + int ret = 0; >>> + >>> + ret = phy_power_on(phy); >>> + if (ret) >> >> Similar comment as above. > > use phy_power_on directly. >> >>> + phy_power_off(phy); >>> + >>> + return ret; >>> +} >>> + >>> +/** >>> * sdhci_arasan_suspend - Suspend method for the driver >>> * @dev: Address of the device structure >>> * Returns 0 on success and error value on error >>> @@ -88,6 +126,15 @@ static int sdhci_arasan_suspend(struct device *dev) >>> if (ret) >>> return ret; >>> >>> + if (!IS_ERR(sdhci_arasan->phy)) { > > you can make this an optional PHY and then you don't have to check error > every time you use PHY API's. >>> + ret = sdhci_arasan_suspend_phy(sdhci_arasan->phy); >>> + if (ret) { >>> + dev_err(dev, "Cannot suspend phy.\n"); >>> + sdhci_resume_host(host); >> >> This is an odd error handling, why do sdhci_resume_host()? > > right, this will result in multiple power_on's to be invoked. >> >>> + return ret; >>> + } >>> + } >>> + >>> clk_disable(pltfm_host->clk); >>> clk_disable(sdhci_arasan->clk_ahb); >>> >>> @@ -122,6 +169,16 @@ static int sdhci_arasan_resume(struct device *dev) >>> return ret; >>> } >>> >>> + if (!IS_ERR(sdhci_arasan->phy)) { > > same here. >>> + ret = sdhci_arasan_resume_phy(sdhci_arasan->phy); >>> + if (ret) { >>> + dev_err(dev, "Cannot resume phy.\n"); >>> + clk_disable(sdhci_arasan->clk_ahb); >>> + clk_disable(pltfm_host->clk); >>> + return ret; >> >> The error handling is starting to be a bit complex in >> sdhci_arasan_resume(), perhaps it's time to add some labels to make >> the code more readable? >> >>> + } >>> + } >>> + >>> return sdhci_resume_host(host); >>> } >>> #endif /* ! CONFIG_PM_SLEEP */ >>> @@ -166,6 +223,33 @@ static int sdhci_arasan_probe(struct platform_device *pdev) >>> goto clk_dis_ahb; >>> } >>> >>> + sdhci_arasan->phy = NULL; >> >> NULL isn't an error. You probably want something like: >> sdhci_arasan->phy = ERR_PTR(-ENODEV); >> >> Although, I just realize that the phy API works a bit differently than >> other APIs. More precisely, instead of returning an error while you >> provide a NULL pointer to the APIs, it will treat it as a NOOP and >> return a non-error code (at least according to the documentation). I >> don't know why the phy API is different, but to me I prefer to use the >> regular kernel style and thus, please adopt to my suggestion above. > > So with optional PHY's, the phy core API will return NULL, if it's not > able to get the PHY (i.e if the ERR is ENODEV). So there don't have to > be error checking in the driver before invoking PHY APIs. >> >>> + if (of_device_is_compatible(pdev->dev.of_node, >>> + "arasan,sdhci-5.1")) { >>> + sdhci_arasan->phy = devm_phy_get(&pdev->dev, >>> + "phy_arasan"); > > oh.. so it's not an optional PHY. I think then initializing phy to NULL > above is okay IMO. yes, it's mandatory in the case. > > Thanks > Kishon > > > -- Best Regards Shawn Lin