mmc: host: renesas_sdhi_core: support selecting an optional mux

Some hardware designs route data or control signals through a mux to
support multiple devices on a single sdhi controller.

In particular SolidRun RZ/G2L/G2LC/V2L System on Module use a mux for
switching between soldered eMMC and an optional microSD on a carrier
board, e.g. for development or provisioning.

SD/SDIO/eMMC are not well suited for runtime switching between different
cards, however boot-time selection is possible and useful - in
particular considering dt overlays.

Add support for an optional SD/SDIO/eMMC mux defined in dt, and select
it during probe.

Similar functionality already exists in other places, e.g. i2c-omap.

Signed-off-by: Josua Mayer <josua@solid-run.com>
Reviewed-by: Wolfram Sang <wsa+renesas@sang-engineering.com>
Tested-by: Wolfram Sang <wsa+renesas@sang-engineering.com>
Reviewed-by: Geert Uytterhoeven <geert+renesas@glider.be>
Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>

diff --git a/drivers/mmc/host/renesas_sdhi_core.c b/drivers/mmc/host/renesas_sdhi_core.c
index 2a310a1457855bddbdeb641693a71ac57fccbb15..f9ec78d699f458d2338e4a71a95d21a332d0ea67 100644 (file)
--- a/drivers/mmc/host/renesas_sdhi_core.c
+++ b/drivers/mmc/host/renesas_sdhi_core.c
@@ -26,6 +26,7 @@
 #include <linux/mmc/mmc.h>
 #include <linux/mmc/slot-gpio.h>
 #include <linux/module.h>
+#include <linux/mux/consumer.h>
 #include <linux/pinctrl/consumer.h>
 #include <linux/pinctrl/pinctrl-state.h>
 #include <linux/platform_data/tmio.h>
@@ -1062,6 +1063,7 @@ int renesas_sdhi_probe(struct platform_device *pdev,
        struct regulator_dev *rdev;
        struct renesas_sdhi_dma *dma_priv;
        struct device *dev = &pdev->dev;
+       struct mux_state *mux_state;
        struct tmio_mmc_host *host;
        struct renesas_sdhi *priv;
        int num_irqs, irq, ret, i;
@@ -1116,6 +1118,10 @@ int renesas_sdhi_probe(struct platform_device *pdev,
                                                "state_uhs");
        }
 
+       mux_state = devm_mux_state_get_optional_selected(&pdev->dev, NULL);
+       if (IS_ERR(mux_state))
+               return PTR_ERR(mux_state);
+
        host = tmio_mmc_host_alloc(pdev, mmc_data);
        if (IS_ERR(host))
                return PTR_ERR(host);