From: Ludovic Barre <ludovic.ba...@st.com>

Some variants could require a reset.
STM32 sdmmc variant needs to reset hardware block
during the power cycle procedure (for re-initialization)

Signed-off-by: Ludovic Barre <ludovic.ba...@st.com>
---
 Documentation/devicetree/bindings/mmc/mmci.txt | 2 ++
 drivers/mmc/host/mmci.c                        | 9 +++++++++
 drivers/mmc/host/mmci.h                        | 4 ++++
 3 files changed, 15 insertions(+)

diff --git a/Documentation/devicetree/bindings/mmc/mmci.txt 
b/Documentation/devicetree/bindings/mmc/mmci.txt
index 03796cf..e952707 100644
--- a/Documentation/devicetree/bindings/mmc/mmci.txt
+++ b/Documentation/devicetree/bindings/mmc/mmci.txt
@@ -11,6 +11,8 @@ Required properties:
 - compatible             : contains "arm,pl18x", "arm,primecell".
 - vmmc-supply            : phandle to the regulator device tree node, mentioned
                            as the VCC/VDD supply in the eMMC/SD specs.
+depend of variant:
+- resets                 : phandle to internal reset line.
 
 Optional properties:
 - arm,primecell-periphid : contains the PrimeCell Peripheral ID, it overrides
diff --git a/drivers/mmc/host/mmci.c b/drivers/mmc/host/mmci.c
index 9c00804..87724e1 100644
--- a/drivers/mmc/host/mmci.c
+++ b/drivers/mmc/host/mmci.c
@@ -37,6 +37,7 @@
 #include <linux/pm_runtime.h>
 #include <linux/types.h>
 #include <linux/pinctrl/consumer.h>
+#include <linux/reset.h>
 
 #include <asm/div64.h>
 #include <asm/io.h>
@@ -1445,6 +1446,14 @@ static int mmci_probe(struct amba_device *dev,
 
        dev_dbg(mmc_dev(mmc), "clocking block at %u Hz\n", mmc->f_max);
 
+       if (variant->reset) {
+               host->rst = devm_reset_control_get_exclusive(&dev->dev, NULL);
+               if (IS_ERR(host->rst)) {
+                       ret = PTR_ERR(host->rst);
+                       goto clk_disable;
+               }
+       }
+
        /* Get regulators and the supported OCR mask */
        ret = mmc_regulator_get_supply(mmc);
        if (ret)
diff --git a/drivers/mmc/host/mmci.h b/drivers/mmc/host/mmci.h
index 30d3f53..2d7e901 100644
--- a/drivers/mmc/host/mmci.h
+++ b/drivers/mmc/host/mmci.h
@@ -284,6 +284,7 @@ struct mmci_host;
  *            register.
  * @opendrain: bitmask identifying the OPENDRAIN bit inside MMCIPOWER register
  * @mmci_dma: Pointer to platform-specific DMA callbacks.
+ * @reset: true if variant has need reset signal.
  * @validate_data: if hardware block has specific constraint on validate data
  * @set_clk_ios: if clock procedure of variant is specific
  * @set_pwr_ios: if power procedure of variant is specific
@@ -329,6 +330,7 @@ struct variant_data {
        u32                     start_err;
        u32                     opendrain;
        struct mmci_dma_ops     *mmci_dma;
+       bool                    reset;
        int (*validate_data)(struct mmci_host *host, struct mmc_data *data);
        void (*set_clkreg)(struct mmci_host *host, unsigned int desired);
        void (*set_pwrreg)(struct mmci_host *host, unsigned char power_mode,
@@ -345,6 +347,8 @@ struct mmci_host {
        struct clk              *clk;
        bool                    singleirq;
 
+       struct reset_control    *rst;
+
        spinlock_t              lock;
 
        unsigned int            mclk;
-- 
2.7.4

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