Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751398AbcCFIsX (ORCPT ); Sun, 6 Mar 2016 03:48:23 -0500 Received: from mail-pa0-f54.google.com ([209.85.220.54]:35766 "EHLO mail-pa0-f54.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751203AbcCFIsI (ORCPT ); Sun, 6 Mar 2016 03:48:08 -0500 From: Guodong Xu To: 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, shawn.lin@rock-chips.com, devicetree@vger.kernel.org, linux-kernel@vger.kernel.org, linux-mmc@vger.kernel.org Cc: Guodong Xu , Xinwei Kong , Zhangfei Gao Subject: [PATCH 2/2] mmc: dw_mmc: add resets support to dw_mmc Date: Sun, 6 Mar 2016 15:47:42 +0700 Message-Id: <1457254062-22677-2-git-send-email-guodong.xu@linaro.org> X-Mailer: git-send-email 1.9.1 In-Reply-To: <1457254062-22677-1-git-send-email-guodong.xu@linaro.org> References: <1457254062-22677-1-git-send-email-guodong.xu@linaro.org> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2682 Lines: 86 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 --- 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; + } + /* 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; + 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); + 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); + } EXPORT_SYMBOL(dw_mci_remove); -- 1.9.1