Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751497AbcCFORB (ORCPT ); Sun, 6 Mar 2016 09:17:01 -0500 Received: from lucky1.263xmail.com ([211.157.147.131]:35690 "EHLO lucky1.263xmail.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751282AbcCFOQx (ORCPT ); Sun, 6 Mar 2016 09:16:53 -0500 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: zhangfei.gao@linaro.org X-SENDER-IP: 220.200.58.26 X-LOGIN-NAME: shawn.lin@rock-chips.com X-UNIQUE-TAG: <595427a2ad900c75e935d89c42ef258b> X-ATTACHMENT-NUM: 0 X-DNS-TYPE: 0 Subject: Re: [PATCH 2/2] mmc: dw_mmc: add resets support to dw_mmc To: Guodong Xu , robh+dt@kernel.org, pawel.moll@arm.com, mark.rutland@arm.com, ijc+devicetree@hellion.org.uk, galak@codeaurora.org, jh80.chung@samsung.com, ulf.hansson@linaro.org, devicetree@vger.kernel.org, linux-kernel@vger.kernel.org, linux-mmc@vger.kernel.org References: <1457254062-22677-1-git-send-email-guodong.xu@linaro.org> <1457254062-22677-2-git-send-email-guodong.xu@linaro.org> Cc: shawn.lin@rock-chips.com, shawn.lin@kernel-upstream.org, Xinwei Kong , Zhangfei Gao From: Shawn Lin Message-ID: <56DC3BAD.8020107@rock-chips.com> Date: Sun, 6 Mar 2016 22:16:13 +0800 User-Agent: Mozilla/5.0 (Windows NT 6.3; WOW64; rv:38.0) Gecko/20100101 Thunderbird/38.6.0 MIME-Version: 1.0 In-Reply-To: <1457254062-22677-2-git-send-email-guodong.xu@linaro.org> Content-Type: text/plain; charset=gbk; format=flowed Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 3324 Lines: 111 On 2016/3/6 16:47, Guodong Xu wrote: > mmc registers may in abnormal state if mmc is used in bootloader, > eg. to support booting from eMMC. So we need reset mmc registers > when kernel boots up, instead of assuming mmc is in clean state. > > With this patch, user can add a 'resets' property into dw_mmc dts > node. When driver parse_dt and probe, it calls reset API to > deassert the 'reset' of dw_mmc host controller. When probe error or > remove, it calls reset API to assert it. > > Please also refer to Documentation/devicetree/bindings/reset/reset.txt > > Signed-off-by: Guodong Xu > Signed-off-by: Xinwei Kong > Signed-off-by: Zhangfei Gao Really should V2 and add the changelog. > --- > drivers/mmc/host/dw_mmc.c | 22 +++++++++++++++++++++- > 1 file changed, 21 insertions(+), 1 deletion(-) > > diff --git a/drivers/mmc/host/dw_mmc.c b/drivers/mmc/host/dw_mmc.c > index 242f9a0..281ea9c 100644 > --- a/drivers/mmc/host/dw_mmc.c > +++ b/drivers/mmc/host/dw_mmc.c > @@ -2878,6 +2878,14 @@ static struct dw_mci_board *dw_mci_parse_dt(struct dw_mci *host) > if (!pdata) > return ERR_PTR(-ENOMEM); > > + /* find reset controller when exist */ > + pdata->rstc = devm_reset_control_get_optional(dev, NULL); > + if (IS_ERR(pdata->rstc)) { > + if (PTR_ERR(pdata->rstc) == -EPROBE_DEFER) > + return ERR_PTR(-EPROBE_DEFER); > + pdata->rstc = NULL; maybe we can remove "pdata->rstc = NULL", and directly use IS_ERR(..) for the following "if (host->pdata->rstc != NULL)" statement > + } > + > /* find out number of slots supported */ > of_property_read_u32(np, "num-slots", &pdata->num_slots); > > @@ -2949,7 +2957,9 @@ int dw_mci_probe(struct dw_mci *host) > > if (!host->pdata) { > host->pdata = dw_mci_parse_dt(host); > - if (IS_ERR(host->pdata)) { > + if (PTR_ERR(host->pdata) == -EPROBE_DEFER) > + return -EPROBE_DEFER; please fix the coding style here. > + else if (IS_ERR(host->pdata)) { > dev_err(host->dev, "platform data not available\n"); > return -EINVAL; > } > @@ -3012,6 +3022,9 @@ int dw_mci_probe(struct dw_mci *host) > } > } > > + if (host->pdata->rstc != NULL) > + reset_control_deassert(host->pdata->rstc); > + sorry, I can't follow your intention here. Shouldn't it be something like "assert mmc -> may need delay -> deassert mmc". As your current code, nothing happend right? > setup_timer(&host->cmd11_timer, > dw_mci_cmd11_timer, (unsigned long)host); > > @@ -3164,6 +3177,9 @@ err_dmaunmap: > if (host->use_dma && host->dma_ops->exit) > host->dma_ops->exit(host); > > + if (host->pdata->rstc != NULL) > + reset_control_assert(host->pdata->rstc); > + > err_clk_ciu: > if (!IS_ERR(host->ciu_clk)) > clk_disable_unprepare(host->ciu_clk); > @@ -3196,11 +3212,15 @@ void dw_mci_remove(struct dw_mci *host) > if (host->use_dma && host->dma_ops->exit) > host->dma_ops->exit(host); > > + if (host->pdata->rstc != NULL) > + reset_control_assert(host->pdata->rstc); > + > if (!IS_ERR(host->ciu_clk)) > clk_disable_unprepare(host->ciu_clk); > > if (!IS_ERR(host->biu_clk)) > clk_disable_unprepare(host->biu_clk); > + > } unnecessary new line here. > EXPORT_SYMBOL(dw_mci_remove); > > -- Best Regards Shawn Lin