mmc: tmio_mmc: Hotplug code regrouping

This patch regroups the code slightly, adds documentation and allows
the rtpm counter of MMC_CAP_NEEDS_POLL devices to reach 0 again.

Signed-off-by: Bastian Hecht <hechtb@gmail.com>
[g.liakhovetski@gmx.de: restore pm_runtime_get_noresume()]
Signed-off-by: Guennadi Liakhovetski <g.liakhovetski@gmx.de>
Signed-off-by: Chris Ball <cjb@laptop.org>

1 files changed, 21 insertions, 9 deletions

diff --git a/drivers/mmc/host/tmio_mmc_pio.c b/drivers/mmc/host/tmio_mmc_pio.c
index 4208b3958069..abad01b37cfb 100644
--- a/drivers/mmc/host/tmio_mmc_pio.c
+++ b/drivers/mmc/host/tmio_mmc_pio.c
@@ -800,8 +800,7 @@ static void tmio_mmc_set_ios(struct mmc_host *mmc, struct mmc_ios *ios)
         } else if (ios->power_mode != MMC_POWER_UP) {
                 if (host->set_pwr && ios->power_mode == MMC_POWER_OFF)
                         host->set_pwr(host->pdev, 0);
-                if ((pdata->flags & TMIO_MMC_HAS_COLD_CD) &&
-                    pdata->power) {
+                if (pdata->power) {
                         pdata->power = false;
                         pm_runtime_put(&host->pdev->dev);
                 }
@@ -915,6 +914,23 @@ int __devinit tmio_mmc_host_probe(struct tmio_mmc_host **host,
         if (ret < 0)
                 goto pm_disable;
 
+        /*
+         * There are 4 different scenarios for the card detection:
+         *  1) an external gpio irq handles the cd (best for power savings)
+         *  2) internal sdhi irq handles the cd
+         *  3) a worker thread polls the sdhi - indicated by MMC_CAP_NEEDS_POLL
+         *  4) the medium is non-removable - indicated by MMC_CAP_NONREMOVABLE
+         *
+         *  While we increment the rtpm counter for all scenarios when the mmc
+         *  core activates us by calling an appropriate set_ios(), we must
+         *  additionally ensure that in case 2) the tmio mmc hardware stays
+         *  powered on during runtime for the card detection to work.
+         */
+        if (!(pdata->flags & TMIO_MMC_HAS_COLD_CD
+                || mmc->caps & MMC_CAP_NEEDS_POLL
+                || mmc->caps & MMC_CAP_NONREMOVABLE))
+                pm_runtime_get_noresume(&pdev->dev);
+
         tmio_mmc_clk_stop(_host);
         tmio_mmc_reset(_host);
 
@@ -933,12 +949,6 @@ int __devinit tmio_mmc_host_probe(struct tmio_mmc_host **host,
         /* See if we also get DMA */
         tmio_mmc_request_dma(_host, pdata);
 
-        /* We have to keep the device powered for its card detection to work */
-        if (!(pdata->flags & TMIO_MMC_HAS_COLD_CD)) {
-                pdata->power = true;
-                pm_runtime_get_noresume(&pdev->dev);
-        }
-
         mmc_add_host(mmc);
 
         /* Unmask the IRQs we want to know about */
@@ -974,7 +984,9 @@ void tmio_mmc_host_remove(struct tmio_mmc_host *host)
          * the controller, the runtime PM is suspended and pdata->power == false,
          * so, our .runtime_resume() will not try to detect a card in the slot.
          */
-        if (host->pdata->flags & TMIO_MMC_HAS_COLD_CD)
+        if (host->pdata->flags & TMIO_MMC_HAS_COLD_CD
+                || host->mmc->caps & MMC_CAP_NEEDS_POLL
+                || host->mmc->caps & MMC_CAP_NONREMOVABLE)
                 pm_runtime_get_sync(&pdev->dev);
 
         mmc_remove_host(host->mmc);