mmc: arasan: Add driver for Arasan SDHCI

Add a driver for Arasan's SDHCI controller core.

Signed-off-by: Soren Brinkmann <soren.brinkmann@xilinx.com>
Acked-by: Rob Herring <rob.herring@calxeda.com> [binding]
Acked-by: Michal Simek <monstr@monstr.eu>
Signed-off-by: Chris Ball <chris@printf.net>

5 files changed, 265 insertions, 0 deletions

diff --git a/Documentation/devicetree/bindings/mmc/arasan,sdhci.txt b/Documentation/devicetree/bindings/mmc/arasan,sdhci.txt
new file mode 100644
index 000000000000..98ee2abbe138
--- /dev/null
+++ b/Documentation/devicetree/bindings/mmc/arasan,sdhci.txt
@@ -0,0 +1,27 @@
+Device Tree Bindings for the Arasan SDHCI Controller
+
+  The bindings follow the mmc[1], clock[2] and interrupt[3] bindings. Only
+  deviations are documented here.
+
+  [1] Documentation/devicetree/bindings/mmc/mmc.txt
+  [2] Documentation/devicetree/bindings/clock/clock-bindings.txt
+  [3] Documentation/devicetree/bindings/interrupt-controller/interrupts.txt
+
+Required Properties:
+  - compatible: Compatibility string. Must be 'arasan,sdhci-8.9a'
+  - reg: From mmc bindings: Register location and length.
+  - clocks: From clock bindings: Handles to clock inputs.
+  - clock-names: From clock bindings: Tuple including "clk_xin" and "clk_ahb"
+  - interrupts: Interrupt specifier
+  - interrupt-parent: Phandle for the interrupt controller that services
+                      interrupts for this device.
+
+Example:
+        sdhci@e0100000 {
+                compatible = "arasan,sdhci-8.9a";
+                reg = <0xe0100000 0x1000>;
+                clock-names = "clk_xin", "clk_ahb";
+                clocks = <&clkc 21>, <&clkc 32>;
+                interrupt-parent = <&gic>;
+                interrupts = <0 24 4>;
+        } ;
diff --git a/MAINTAINERS b/MAINTAINERS
index 7cda615c8dd7..518bf717b02b 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -1371,6 +1371,7 @@ T:	git git://git.xilinx.com/linux-xlnx.git
 S:      Supported
 F:      arch/arm/mach-zynq/
 F:      drivers/cpuidle/cpuidle-zynq.c
+F:      drivers/mmc/host/sdhci-of-arasan.c
 
 ARM SMMU DRIVER
 M:      Will Deacon <will.deacon@arm.com>
diff --git a/drivers/mmc/host/Kconfig b/drivers/mmc/host/Kconfig
index 6da5a085f5f8..c79c1ea722c3 100644
--- a/drivers/mmc/host/Kconfig
+++ b/drivers/mmc/host/Kconfig
@@ -104,6 +104,18 @@ config MMC_SDHCI_PLTFM
 
           If unsure, say N.
 
+config MMC_SDHCI_OF_ARASAN
+        tristate "SDHCI OF support for the Arasan SDHCI controllers"
+        depends on MMC_SDHCI_PLTFM
+        depends on OF
+        help
+          This selects the Arasan Secure Digital Host Controller Interface
+          (SDHCI). This hardware is found e.g. in Xilinx' Zynq SoC.
+
+          If you have a controller with this interface, say Y or M here.
+
+          If unsure, say N.
+
 config MMC_SDHCI_OF_ESDHC
         tristate "SDHCI OF support for the Freescale eSDHC controller"
         depends on MMC_SDHCI_PLTFM
diff --git a/drivers/mmc/host/Makefile b/drivers/mmc/host/Makefile
index a69fd640698d..3483b6b6b880 100644
--- a/drivers/mmc/host/Makefile
+++ b/drivers/mmc/host/Makefile
@@ -59,6 +59,7 @@ obj-$(CONFIG_MMC_SDHCI_CNS3XXX)		+= sdhci-cns3xxx.o
 obj-$(CONFIG_MMC_SDHCI_ESDHC_IMX)       += sdhci-esdhc-imx.o
 obj-$(CONFIG_MMC_SDHCI_DOVE)            += sdhci-dove.o
 obj-$(CONFIG_MMC_SDHCI_TEGRA)           += sdhci-tegra.o
+obj-$(CONFIG_MMC_SDHCI_OF_ARASAN)       += sdhci-of-arasan.o
 obj-$(CONFIG_MMC_SDHCI_OF_ESDHC)        += sdhci-of-esdhc.o
 obj-$(CONFIG_MMC_SDHCI_OF_HLWD)         += sdhci-of-hlwd.o
 obj-$(CONFIG_MMC_SDHCI_BCM_KONA)        += sdhci-bcm-kona.o
diff --git a/drivers/mmc/host/sdhci-of-arasan.c b/drivers/mmc/host/sdhci-of-arasan.c
new file mode 100644
index 000000000000..f7c7cf62437d
--- /dev/null
+++ b/drivers/mmc/host/sdhci-of-arasan.c
@@ -0,0 +1,224 @@
+/*
+ * Arasan Secure Digital Host Controller Interface.
+ * Copyright (C) 2011 - 2012 Michal Simek <monstr@monstr.eu>
+ * Copyright (c) 2012 Wind River Systems, Inc.
+ * Copyright (C) 2013 Pengutronix e.K.
+ * Copyright (C) 2013 Xilinx Inc.
+ *
+ * Based on sdhci-of-esdhc.c
+ *
+ * Copyright (c) 2007 Freescale Semiconductor, Inc.
+ * Copyright (c) 2009 MontaVista Software, Inc.
+ *
+ * Authors: Xiaobo Xie <X.Xie@freescale.com>
+ *          Anton Vorontsov <avorontsov@ru.mvista.com>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or (at
+ * your option) any later version.
+ */
+
+#include <linux/module.h>
+#include "sdhci-pltfm.h"
+
+#define SDHCI_ARASAN_CLK_CTRL_OFFSET    0x2c
+
+#define CLK_CTRL_TIMEOUT_SHIFT          16
+#define CLK_CTRL_TIMEOUT_MASK           (0xf << CLK_CTRL_TIMEOUT_SHIFT)
+#define CLK_CTRL_TIMEOUT_MIN_EXP        13
+
+/**
+ * struct sdhci_arasan_data
+ * @clk_ahb:    Pointer to the AHB clock
+ */
+struct sdhci_arasan_data {
+        struct clk      *clk_ahb;
+};
+
+static unsigned int sdhci_arasan_get_timeout_clock(struct sdhci_host *host)
+{
+        u32 div;
+        unsigned long freq;
+        struct sdhci_pltfm_host *pltfm_host = sdhci_priv(host);
+
+        div = readl(host->ioaddr + SDHCI_ARASAN_CLK_CTRL_OFFSET);
+        div = (div & CLK_CTRL_TIMEOUT_MASK) >> CLK_CTRL_TIMEOUT_SHIFT;
+
+        freq = clk_get_rate(pltfm_host->clk);
+        freq /= 1 << (CLK_CTRL_TIMEOUT_MIN_EXP + div);
+
+        return freq;
+}
+
+static struct sdhci_ops sdhci_arasan_ops = {
+        .get_max_clock = sdhci_pltfm_clk_get_max_clock,
+        .get_timeout_clock = sdhci_arasan_get_timeout_clock,
+};
+
+static struct sdhci_pltfm_data sdhci_arasan_pdata = {
+        .ops = &sdhci_arasan_ops,
+};
+
+#ifdef CONFIG_PM_SLEEP
+/**
+ * sdhci_arasan_suspend - Suspend method for the driver
+ * @dev:        Address of the device structure
+ * Returns 0 on success and error value on error
+ *
+ * Put the device in a low power state.
+ */
+static int sdhci_arasan_suspend(struct device *dev)
+{
+        struct platform_device *pdev = to_platform_device(dev);
+        struct sdhci_host *host = platform_get_drvdata(pdev);
+        struct sdhci_pltfm_host *pltfm_host = sdhci_priv(host);
+        struct sdhci_arasan_data *sdhci_arasan = pltfm_host->priv;
+        int ret;
+
+        ret = sdhci_suspend_host(host);
+        if (ret)
+                return ret;
+
+        clk_disable(pltfm_host->clk);
+        clk_disable(sdhci_arasan->clk_ahb);
+
+        return 0;
+}
+
+/**
+ * sdhci_arasan_resume - Resume method for the driver
+ * @dev:        Address of the device structure
+ * Returns 0 on success and error value on error
+ *
+ * Resume operation after suspend
+ */
+static int sdhci_arasan_resume(struct device *dev)
+{
+        struct platform_device *pdev = to_platform_device(dev);
+        struct sdhci_host *host = platform_get_drvdata(pdev);
+        struct sdhci_pltfm_host *pltfm_host = sdhci_priv(host);
+        struct sdhci_arasan_data *sdhci_arasan = pltfm_host->priv;
+        int ret;
+
+        ret = clk_enable(sdhci_arasan->clk_ahb);
+        if (ret) {
+                dev_err(dev, "Cannot enable AHB clock.\n");
+                return ret;
+        }
+
+        ret = clk_enable(pltfm_host->clk);
+        if (ret) {
+                dev_err(dev, "Cannot enable SD clock.\n");
+                clk_disable(sdhci_arasan->clk_ahb);
+                return ret;
+        }
+
+        return sdhci_resume_host(host);
+}
+#endif /* ! CONFIG_PM_SLEEP */
+
+static SIMPLE_DEV_PM_OPS(sdhci_arasan_dev_pm_ops, sdhci_arasan_suspend,
+                         sdhci_arasan_resume);
+
+static int sdhci_arasan_probe(struct platform_device *pdev)
+{
+        int ret;
+        struct clk *clk_xin;
+        struct sdhci_host *host;
+        struct sdhci_pltfm_host *pltfm_host;
+        struct sdhci_arasan_data *sdhci_arasan;
+
+        sdhci_arasan = devm_kzalloc(&pdev->dev, sizeof(*sdhci_arasan),
+                        GFP_KERNEL);
+        if (!sdhci_arasan)
+                return -ENOMEM;
+
+        sdhci_arasan->clk_ahb = devm_clk_get(&pdev->dev, "clk_ahb");
+        if (IS_ERR(sdhci_arasan->clk_ahb)) {
+                dev_err(&pdev->dev, "clk_ahb clock not found.\n");
+                return PTR_ERR(sdhci_arasan->clk_ahb);
+        }
+
+        clk_xin = devm_clk_get(&pdev->dev, "clk_xin");
+        if (IS_ERR(clk_xin)) {
+                dev_err(&pdev->dev, "clk_xin clock not found.\n");
+                return PTR_ERR(clk_xin);
+        }
+
+        ret = clk_prepare_enable(sdhci_arasan->clk_ahb);
+        if (ret) {
+                dev_err(&pdev->dev, "Unable to enable AHB clock.\n");
+                return ret;
+        }
+
+        ret = clk_prepare_enable(clk_xin);
+        if (ret) {
+                dev_err(&pdev->dev, "Unable to enable SD clock.\n");
+                goto clk_dis_ahb;
+        }
+
+        host = sdhci_pltfm_init(pdev, &sdhci_arasan_pdata, 0);
+        if (IS_ERR(host)) {
+                ret = PTR_ERR(host);
+                dev_err(&pdev->dev, "platform init failed (%u)\n", ret);
+                goto clk_disable_all;
+        }
+
+        sdhci_get_of_property(pdev);
+        pltfm_host = sdhci_priv(host);
+        pltfm_host->priv = sdhci_arasan;
+        pltfm_host->clk = clk_xin;
+
+        ret = sdhci_add_host(host);
+        if (ret) {
+                dev_err(&pdev->dev, "platform register failed (%u)\n", ret);
+                goto err_pltfm_free;
+        }
+
+        return 0;
+
+err_pltfm_free:
+        sdhci_pltfm_free(pdev);
+clk_disable_all:
+        clk_disable_unprepare(clk_xin);
+clk_dis_ahb:
+        clk_disable_unprepare(sdhci_arasan->clk_ahb);
+
+        return ret;
+}
+
+static int sdhci_arasan_remove(struct platform_device *pdev)
+{
+        struct sdhci_host *host = platform_get_drvdata(pdev);
+        struct sdhci_pltfm_host *pltfm_host = sdhci_priv(host);
+        struct sdhci_arasan_data *sdhci_arasan = pltfm_host->priv;
+
+        clk_disable_unprepare(pltfm_host->clk);
+        clk_disable_unprepare(sdhci_arasan->clk_ahb);
+
+        return sdhci_pltfm_unregister(pdev);
+}
+
+static const struct of_device_id sdhci_arasan_of_match[] = {
+        { .compatible = "arasan,sdhci-8.9a" },
+        { }
+};
+MODULE_DEVICE_TABLE(of, sdhci_arasan_of_match);
+
+static struct platform_driver sdhci_arasan_driver = {
+        .driver = {
+                .name = "sdhci-arasan",
+                .owner = THIS_MODULE,
+                .of_match_table = sdhci_arasan_of_match,
+                .pm = &sdhci_arasan_dev_pm_ops,
+        },
+        .probe = sdhci_arasan_probe,
+        .remove = sdhci_arasan_remove,
+};
+
+module_platform_driver(sdhci_arasan_driver);
+
+MODULE_DESCRIPTION("Driver for the Arasan SDHCI Controller");
+MODULE_AUTHOR("Soeren Brinkmann <soren.brinkmann@xilinx.com>");
+MODULE_LICENSE("GPL");