mmc: arasan: Add driver for Arasan SDHCI

Add a driver for Arasan's SDHCI controller core.

Signed-off-by: Soren Brinkmann <[e-mail]>
Acked-by: Rob Herring <[e-mail]> [binding]
Acked-by: Michal Simek <[e-mail]>
Signed-off-by: Chris Ball <[e-mail]>

Documentation/devicetree/bindings/mmc/arasan,sdhci.txt

···
+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>;
+	} ;

MAINTAINERS

···
 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 <[e-mail]>

drivers/mmc/host/Kconfig

···
 
 	  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

drivers/mmc/host/Makefile

···
 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

drivers/mmc/host/sdhci-of-arasan.c

···
+/*
+ * Arasan Secure Digital Host Controller Interface.
+ * Copyright (C) 2011 - 2012 Michal Simek <[e-mail]>
+ * 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 <[e-mail]>
+ *	    Anton Vorontsov <[e-mail]>
+ *
+ * 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 <[e-mail]>");
+MODULE_LICENSE("GPL");