diff options
| -rw-r--r-- | Documentation/devicetree/bindings/mmc/ti-omap-hsmmc.txt | 53 | ||||
| -rw-r--r-- | drivers/mmc/host/omap_hsmmc.c | 24 |
2 files changed, 74 insertions, 3 deletions
diff --git a/Documentation/devicetree/bindings/mmc/ti-omap-hsmmc.txt b/Documentation/devicetree/bindings/mmc/ti-omap-hsmmc.txt index 0233ba7951e5..76bf087bc889 100644 --- a/Documentation/devicetree/bindings/mmc/ti-omap-hsmmc.txt +++ b/Documentation/devicetree/bindings/mmc/ti-omap-hsmmc.txt @@ -57,3 +57,56 @@ 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 the named pinctrl states "default" and "idle". +Prepare idle to remux dat1 as a gpio, and default to remux it back as sdio +dat1. The MMC driver will then toggle between idle and default state during +runtime. + +In summary: +1. select matching 'compatible' section, see example below. +2. specify pinctrl states "default" and "idle", "sleep" is optional. +3. specify the gpio irq used for detecting sdio irq in suspend + +If configuration is incomplete, a warning message is emitted "falling back to +polling". Also check the "sdio irq mode" in /sys/kernel/debug/mmc0/regs. Mind +not every application needs SDIO irq, e.g. MMC cards. + + mmc1: mmc@48060100 { + compatible = "ti,am33xx-hsmmc"; + ... + pinctrl-names = "default", "idle", "sleep" + pinctrl-0 = <&mmc1_pins>; + pinctrl-1 = <&mmc1_idle>; + pinctrl-2 = <&mmc1_sleep>; + ... + interrupts-extended = <&intc 64 &gpio2 28 0>; + }; + + mmc1_idle : 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 5167e55c0849..965672663ef0 100644 --- a/drivers/mmc/host/omap_hsmmc.c +++ b/drivers/mmc/host/omap_hsmmc.c @@ -1754,15 +1754,33 @@ 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; - devm_free_irq(host->dev, host->wake_irq, host); - goto err; + struct pinctrl *p = devm_pinctrl_get(host->dev); + if (!p) { + ret = -ENODEV; + goto err_free_irq; + } + if (IS_ERR(pinctrl_lookup_state(p, PINCTRL_STATE_DEFAULT))) { + dev_info(host->dev, "missing default pinctrl state\n"); + devm_pinctrl_put(p); + ret = -EINVAL; + goto err_free_irq; + } + + if (IS_ERR(pinctrl_lookup_state(p, PINCTRL_STATE_IDLE))) { + dev_info(host->dev, "missing idle pinctrl state\n"); + devm_pinctrl_put(p); + ret = -EINVAL; + goto err_free_irq; + } + devm_pinctrl_put(p); } OMAP_HSMMC_WRITE(host->base, HCTL, OMAP_HSMMC_READ(host->base, HCTL) | IWE); return 0; +err_free_irq: + devm_free_irq(host->dev, host->wake_irq, host); err: dev_warn(host->dev, "no SDIO IRQ support, falling back to polling\n"); host->wake_irq = 0; |