From mboxrd@z Thu Jan 1 00:00:00 1970 From: Balaji T K Subject: Re: [PATCH v10 5/5] mmc: omap_hsmmc: Pin remux workaround to support SDIO interrupt on AM335x Date: Fri, 2 May 2014 20:00:58 +0530 Message-ID: <5363AC22.9030208@ti.com> References: <1398670860-30695-1-git-send-email-afenkart@gmail.com> <1398670860-30695-6-git-send-email-afenkart@gmail.com> Mime-Version: 1.0 Content-Type: text/plain; charset="ISO-8859-1"; format=flowed Content-Transfer-Encoding: 7bit Return-path: Received: from bear.ext.ti.com ([192.94.94.41]:36346 "EHLO bear.ext.ti.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751721AbaEBObK (ORCPT ); Fri, 2 May 2014 10:31:10 -0400 In-Reply-To: <1398670860-30695-6-git-send-email-afenkart@gmail.com> Sender: linux-mmc-owner@vger.kernel.org List-Id: linux-mmc@vger.kernel.org To: Andreas Fenkart Cc: Tony Lindgren , Chris Ball , Grant Likely , Felipe Balbi , zonque@gmail.com, galak@codeaurora.org, linux-doc@vger.kernel.org, linux-mmc@vger.kernel.org, linux-omap@vger.kernel.org On Monday 28 April 2014 01:11 PM, Andreas Fenkart wrote: > The am335x can't detect pending cirq in PM runtime suspend. > This patch reconfigures dat1 as a GPIO before going to suspend. > SDIO interrupts are detected with the GPIO, the GPIO will only wake > the module from suspend, SDIO irq detection will still happen through the > IP block. > > Idea of remuxing the pins by Tony Lindgren. Code contributions from > Tony Lindgren and Balaji T K > > Signed-off-by: Andreas Fenkart > Signed-off-by: Tony Lindgren Thanks Andreas for the patch series. Few comments ... > > diff --git a/Documentation/devicetree/bindings/mmc/ti-omap-hsmmc.txt b/Documentation/devicetree/bindings/mmc/ti-omap-hsmmc.txt > index ce80561..4767cd1 100644 > --- a/Documentation/devicetree/bindings/mmc/ti-omap-hsmmc.txt > +++ b/Documentation/devicetree/bindings/mmc/ti-omap-hsmmc.txt > @@ -56,3 +56,54 @@ Examples: > &edma 25>; > dma-names = "tx", "rx"; > }; > + > +[workaround for missing swakeup on am33xx] > + > +This SOC is missing the swakeup line, it will not detect SDIO irq > +while in suspend. > + > + ------ > + | PRCM | > + ------ > + ^ | > + swakeup | | fclk > + | v > + ------ ------- ----- > + | card | -- CIRQ --> | hsmmc | -- IRQ --> | CPU | > + ------ ------- ----- > + > +In suspend the fclk is off and the module is disfunctional. Even > +register reads will fail. A small logic in the host will request > +fclk restore, when an external event is detected. Once the clock > +is restored, the host detects the event normally. Since am33xx > +doesn't have this line it never wakes from suspend. > + > +The workaround is to reconfigure the dat1 line as a GPIO upon > +suspend. To make this work, we need to set 1) the named pinctrl > +states "default", "idle" and "gpio_dat1", 2) the gpio detecting > +sdio irq in suspend and 3) the compatibe section, see example below. > +The MMC driver will then toggle between gpio_dat1 and default during > +the runtime. If configuration is incomplete, a warning message is > +emitted "falling back to polling". Mind not every application > +needs SDIO irq, e.g. MMC cards Affected chips are am335x, > +probably others > + > + > + mmc1: mmc@48060100 { > + compatible = "ti,am33xx-hsmmc"; > + ... > + interrupts-extended = <&intc 64 &gpio2 28 0>; > + ... > + pinctrl-names = "default", "idle", "sleep", "gpio_dat1" > + pinctrl-0 = <&mmc1_pins>; > + pinctrl-1 = <&mmc1_idle>; > + pinctrl-2 = <&mmc1_sleep>; > + pinctrl-3 = <&mmc1_cirq_pin>; > + ... > + }; > + > + mmc1_cirq_pin: pinmux_cirq_pin { > + pinctrl-single,pins = < > + 0x0f8 0x3f /* GPIO2_28 */ > + >; > + }; > diff --git a/drivers/mmc/host/omap_hsmmc.c b/drivers/mmc/host/omap_hsmmc.c > index 9cc0d21..8661e1f 100644 > --- a/drivers/mmc/host/omap_hsmmc.c > +++ b/drivers/mmc/host/omap_hsmmc.c > @@ -213,7 +213,10 @@ struct omap_hsmmc_host { > #define AUTO_CMD23 (1 << 0) /* Auto CMD23 support */ > #define HSMMC_SDIO_IRQ_ENABLED (1 << 1) /* SDIO irq enabled */ > #define HSMMC_WAKE_IRQ_ENABLED (1 << 2) > +#define HSMMC_SWAKEUP_QUIRK (1 << 3) > struct omap_hsmmc_next next_data; > + struct pinctrl *pinctrl; > + struct pinctrl_state *gpio_pinmux; > struct omap_mmc_platform_data *pdata; > }; > > @@ -1744,8 +1747,28 @@ static int omap_hsmmc_configure_wake_irq(struct omap_hsmmc_host *host) > * and need to remux SDIO DAT1 to GPIO for wake-up from idle. > */ > if (host->pdata->controller_flags & OMAP_HSMMC_SWAKEUP_MISSING) { > - ret = -ENODEV; > - goto err; > + if (IS_ERR(host->dev->pins->default_state)) { > + dev_info(host->dev, "missing default pinctrl state\n"); > + ret = -EINVAL; > + goto err; > + } > + > + host->pinctrl = devm_pinctrl_get(host->dev); > + if (IS_ERR(host->pinctrl)) { > + dev_warn(host->dev, "no pinctrl handle\n"); > + ret = -ENODEV; > + goto err; > + } > + > + host->gpio_pinmux = pinctrl_lookup_state(host->pinctrl, > + "gpio_dat1"); > + if (IS_ERR(host->gpio_pinmux)) { > + dev_info(host->dev, "missing \"gpio_dat1\" pinctrl state\n"); > + ret = -ENODEV; > + goto err; > + } > + > + host->flags |= HSMMC_SWAKEUP_QUIRK; > } > > devres_remove_group(host->dev, NULL); > @@ -2438,7 +2461,10 @@ static int omap_hsmmc_runtime_suspend(struct device *dev) > goto abort; > } > > - pinctrl_pm_select_idle_state(dev); > + if (host->flags & HSMMC_SWAKEUP_QUIRK) > + pinctrl_select_state(host->pinctrl, host->gpio_pinmux); Why not combine "gpio_dat1" state and "idle", update documentation to have gpio remuxed in idle state for SoCs with swakeup quirk, Since I don't see any use case where both idle/gpio_pinmux are getting used. > + else > + pinctrl_pm_select_idle_state(dev); > > WARN_ON(host->flags & HSMMC_WAKE_IRQ_ENABLED); > enable_irq(host->wake_irq); >