Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751306AbbHQFwl (ORCPT ); Mon, 17 Aug 2015 01:52:41 -0400 Received: from mail-ig0-f174.google.com ([209.85.213.174]:35453 "EHLO mail-ig0-f174.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750710AbbHQFwk (ORCPT ); Mon, 17 Aug 2015 01:52:40 -0400 MIME-Version: 1.0 In-Reply-To: <55D13F07.70309@samsung.com> References: <3d03bfe2c18789eefa038018467c9c63c94ae4a2.1439381423.git.hramrach@gmail.com> <55D13F07.70309@samsung.com> From: Michal Suchanek Date: Mon, 17 Aug 2015 07:52:00 +0200 Message-ID: Subject: Re: [PATCH 2/3] mmc: dw_mmc: simplify the SDMMC_CLKEN_LOW_PWR logic To: Jaehoon Chung Cc: linux-sunxi , Seungwon Jeon , Ulf Hansson , Maxime Ripard , =?UTF-8?Q?David_Lanzend=C3=B6rfer?= , Hans de Goede , Chen-Yu Tsai , Arnd Bergmann , linux-mmc , Linux Kernel Mailing List , "linux-arm-kernel@lists.infradead.org" Content-Type: text/plain; charset=UTF-8 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 3467 Lines: 95 Hello, On 17 August 2015 at 03:55, Jaehoon Chung wrote: > Hi, Michal. > > On 08/12/2015 09:23 PM, Michal Suchanek wrote: >> The driver has open-coded test for SDIO cards. Use the mmc core provided >> MMC_QUIRK_BROKEN_CLK_GATING flag instead. > > Did you use the clock-gating for SDIO cards? > Doesn't MMC_CAP_SDIO_IRQ bit set? Which case is broken? > Could you explain to me more? The core flag for disabling power saving is MMC_QUIRK_BROKEN_CLK_GATING. It may coincide with MMC_CAP_SDIO_IRQ but that's different flag for different purpose. MMC_QUIRK_BROKEN_CLK_GATING is currently set for all SDIO cards except for cards on a whitelist. I don't know any particular SDIO card that has problems when the clock is off and does not use an IRQ. Thanks Michal > > Best Regards, > Jaehoon Chung > >> >> As a bonus this may enable clock gating on SDIO cards that are known to >> work with it. >> >> Signed-off-by: Michal Suchanek >> --- >> drivers/mmc/host/dw_mmc.c | 33 +++++++++++++++------------------ >> 1 file changed, 15 insertions(+), 18 deletions(-) >> >> diff --git a/drivers/mmc/host/dw_mmc.c b/drivers/mmc/host/dw_mmc.c >> index 40e9d8e..3bc9fd7 100644 >> --- a/drivers/mmc/host/dw_mmc.c >> +++ b/drivers/mmc/host/dw_mmc.c >> @@ -1335,27 +1335,24 @@ static void dw_mci_init_card(struct mmc_host *mmc, struct mmc_card *card) >> * description of the CLKENA register we should disable low power mode >> * for SDIO cards if we need SDIO interrupts to work. >> */ >> - if (mmc->caps & MMC_CAP_SDIO_IRQ) { >> - const u32 clken_low_pwr = SDMMC_CLKEN_LOW_PWR << slot->id; >> - u32 clk_en_a_old; >> - u32 clk_en_a; >> + const u32 clken_low_pwr = SDMMC_CLKEN_LOW_PWR << slot->id; >> + u32 clk_en_a_old; >> + u32 clk_en_a; >> >> - clk_en_a_old = mci_readl(host, CLKENA); >> + clk_en_a_old = mci_readl(host, CLKENA); >> >> - if (card->type == MMC_TYPE_SDIO || >> - card->type == MMC_TYPE_SD_COMBO) { >> - set_bit(DW_MMC_CARD_NO_LOW_PWR, &slot->flags); >> - clk_en_a = clk_en_a_old & ~clken_low_pwr; >> - } else { >> - clear_bit(DW_MMC_CARD_NO_LOW_PWR, &slot->flags); >> - clk_en_a = clk_en_a_old | clken_low_pwr; >> - } >> + if (card->quirks & MMC_QUIRK_BROKEN_CLK_GATING) { >> + set_bit(DW_MMC_CARD_NO_LOW_PWR, &slot->flags); >> + clk_en_a = clk_en_a_old & ~clken_low_pwr; >> + } else { >> + clear_bit(DW_MMC_CARD_NO_LOW_PWR, &slot->flags); >> + clk_en_a = clk_en_a_old | clken_low_pwr; >> + } >> >> - if (clk_en_a != clk_en_a_old) { >> - mci_writel(host, CLKENA, clk_en_a); >> - mci_send_cmd(slot, SDMMC_CMD_UPD_CLK | >> - SDMMC_CMD_PRV_DAT_WAIT, 0); >> - } >> + if (clk_en_a != clk_en_a_old) { >> + mci_writel(host, CLKENA, clk_en_a); >> + mci_send_cmd(slot, SDMMC_CMD_UPD_CLK | >> + SDMMC_CMD_PRV_DAT_WAIT, 0); >> } >> } >> >> > -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/