mmc: sdhci-st: Intial support for ST SDHCI controller

This platform driver adds initial support for the SDHCI host controller
found on STMicroelectronics SoCs.

It has been tested on STiH41x b2020 platforms currently.

Signed-off-by: Giuseppe Cavallaro <[e-mail]>
Signed-off-by: Peter Griffin <[e-mail]>
Acked-by: Lee Jones <[e-mail]>
Acked-by: Maxime Coquelin <[e-mail]>
Signed-off-by: Ulf Hansson <[e-mail]>

drivers/mmc/host/Kconfig

···
 	  be found on some embedded hardware such as UC-7112-LX.
 	  If you have a controller with this interface, say Y here.
 
+config MMC_SDHCI_ST
+	tristate "SDHCI support on STMicroelectronics SoC"
+	depends on ARCH_STI
+	depends on MMC_SDHCI_PLTFM
+	select MMC_SDHCI_IO_ACCESSORS
+	help
+	  This selects the Secure Digital Host Controller Interface in
+	  STMicroelectronics SoCs.
+
+	  If you have a controller with this interface, say Y or M here.
+	  If unsure, say N.
+
 config MMC_OMAP
 	tristate "TI OMAP Multimedia Card Interface support"
 	depends on ARCH_OMAP

drivers/mmc/host/Makefile

···
 obj-$(CONFIG_MMC_SDHCI_BCM_KONA)	+= sdhci-bcm-kona.o
 obj-$(CONFIG_MMC_SDHCI_BCM2835)		+= sdhci-bcm2835.o
 obj-$(CONFIG_MMC_SDHCI_MSM)		+= sdhci-msm.o
+obj-$(CONFIG_MMC_SDHCI_ST)		+= sdhci-st.o
 
 ifeq ($(CONFIG_CB710_DEBUG),y)
 	CFLAGS-cb710-mmc	+= -DDEBUG

drivers/mmc/host/sdhci-st.c

···
+/*
+ * Support for SDHCI on STMicroelectronics SoCs
+ *
+ * Copyright (C) 2014 STMicroelectronics Ltd
+ * Author: Giuseppe Cavallaro <[e-mail]>
+ * Contributors: Peter Griffin <[e-mail]>
+ *
+ * Based on sdhci-cns3xxx.c
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ */
+
+#include <linux/io.h>
+#include <linux/of.h>
+#include <linux/module.h>
+#include <linux/err.h>
+#include <linux/mmc/host.h>
+
+#include "sdhci-pltfm.h"
+
+static u32 sdhci_st_readl(struct sdhci_host *host, int reg)
+{
+	u32 ret;
+
+	switch (reg) {
+	case SDHCI_CAPABILITIES:
+		ret = readl_relaxed(host->ioaddr + reg);
+		/* Support 3.3V and 1.8V */
+		ret &= ~SDHCI_CAN_VDD_300;
+		break;
+	default:
+		ret = readl_relaxed(host->ioaddr + reg);
+	}
+	return ret;
+}
+
+static const struct sdhci_ops sdhci_st_ops = {
+	.get_max_clock = sdhci_pltfm_clk_get_max_clock,
+	.set_clock = sdhci_set_clock,
+	.set_bus_width = sdhci_set_bus_width,
+	.read_l = sdhci_st_readl,
+	.reset = sdhci_reset,
+};
+
+static const struct sdhci_pltfm_data sdhci_st_pdata = {
+	.ops = &sdhci_st_ops,
+	.quirks = SDHCI_QUIRK_NO_ENDATTR_IN_NOPDESC |
+	    SDHCI_QUIRK_CAP_CLOCK_BASE_BROKEN,
+};
+
+
+static int sdhci_st_probe(struct platform_device *pdev)
+{
+	struct sdhci_host *host;
+	struct sdhci_pltfm_host *pltfm_host;
+	struct clk *clk;
+	int ret = 0;
+	u16 host_version;
+
+	clk =  devm_clk_get(&pdev->dev, "mmc");
+	if (IS_ERR(clk)) {
+		dev_err(&pdev->dev, "Peripheral clk not found\n");
+		return PTR_ERR(clk);
+	}
+
+	host = sdhci_pltfm_init(pdev, &sdhci_st_pdata, 0);
+	if (IS_ERR(host)) {
+		dev_err(&pdev->dev, "Failed sdhci_pltfm_init\n");
+		return PTR_ERR(host);
+	}
+
+	ret = mmc_of_parse(host->mmc);
+
+	if (ret) {
+		dev_err(&pdev->dev, "Failed mmc_of_parse\n");
+		return ret;
+	}
+
+	clk_prepare_enable(clk);
+
+	pltfm_host = sdhci_priv(host);
+	pltfm_host->clk = clk;
+
+	ret = sdhci_add_host(host);
+	if (ret) {
+		dev_err(&pdev->dev, "Failed sdhci_add_host\n");
+		goto err_out;
+	}
+
+	platform_set_drvdata(pdev, host);
+
+	host_version = readw_relaxed((host->ioaddr + SDHCI_HOST_VERSION));
+
+	dev_info(&pdev->dev, "SDHCI ST Initialised: Host Version: 0x%x Vendor Version 0x%x\n",
+		((host_version & SDHCI_SPEC_VER_MASK) >> SDHCI_SPEC_VER_SHIFT),
+		((host_version & SDHCI_VENDOR_VER_MASK) >>
+		SDHCI_VENDOR_VER_SHIFT));
+
+	return 0;
+
+err_out:
+	clk_disable_unprepare(clk);
+	sdhci_pltfm_free(pdev);
+
+	return ret;
+}
+
+static int sdhci_st_remove(struct platform_device *pdev)
+{
+	struct sdhci_host *host = platform_get_drvdata(pdev);
+	struct sdhci_pltfm_host *pltfm_host = sdhci_priv(host);
+
+	clk_disable_unprepare(pltfm_host->clk);
+
+	return sdhci_pltfm_unregister(pdev);
+}
+
+#ifdef CONFIG_PM_SLEEP
+static int sdhci_st_suspend(struct device *dev)
+{
+	struct sdhci_host *host = dev_get_drvdata(dev);
+	struct sdhci_pltfm_host *pltfm_host = sdhci_priv(host);
+	int ret = sdhci_suspend_host(host);
+
+	if (ret)
+		goto out;
+
+	clk_disable_unprepare(pltfm_host->clk);
+out:
+	return ret;
+}
+
+static int sdhci_st_resume(struct device *dev)
+{
+	struct sdhci_host *host = dev_get_drvdata(dev);
+	struct sdhci_pltfm_host *pltfm_host = sdhci_priv(host);
+
+	clk_prepare_enable(pltfm_host->clk);
+
+	return sdhci_resume_host(host);
+}
+#endif
+
+static SIMPLE_DEV_PM_OPS(sdhci_st_pmops, sdhci_st_suspend, sdhci_st_resume);
+
+static const struct of_device_id st_sdhci_match[] = {
+	{ .compatible = "st,sdhci" },
+	{},
+};
+
+MODULE_DEVICE_TABLE(of, st_sdhci_match);
+
+static struct platform_driver sdhci_st_driver = {
+	.probe = sdhci_st_probe,
+	.remove = sdhci_st_remove,
+	.driver = {
+		   .name = "sdhci-st",
+		   .pm = &sdhci_st_pmops,
+		   .of_match_table = of_match_ptr(st_sdhci_match),
+		  },
+};
+
+module_platform_driver(sdhci_st_driver);
+
+MODULE_DESCRIPTION("SDHCI driver for STMicroelectronics SoCs");
+MODULE_AUTHOR("Giuseppe Cavallaro <[e-mail]>");
+MODULE_LICENSE("GPL v2");
+MODULE_ALIAS("platform:st-sdhci");