usb: host: ehci-st: Add EHCI support for ST STB devices

This patch adds the glue code required to ensure the on-chip EHCI
controller works on STi consumer electronics SoC's from STMicroelectronics.

It mainly manages the setting and enabling of the relevant clocks and manages
the reset / power signals to the IP block.

Signed-off-by: Peter Griffin <peter.griffin@linaro.org>
Reviewed-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

1 files changed, 375 insertions, 0 deletions

diff --git a/drivers/usb/host/ehci-st.c b/drivers/usb/host/ehci-st.c
new file mode 100644
index 000000000000..7e4bd39cf757
--- /dev/null
+++ b/drivers/usb/host/ehci-st.c
@@ -0,0 +1,375 @@
+/*
+ * ST EHCI driver
+ *
+ * Copyright (C) 2014 STMicroelectronics – All Rights Reserved
+ *
+ * Author: Peter Griffin <peter.griffin@linaro.org>
+ *
+ * Derived from ehci-platform.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.
+ */
+
+#include <linux/clk.h>
+#include <linux/dma-mapping.h>
+#include <linux/err.h>
+#include <linux/kernel.h>
+#include <linux/hrtimer.h>
+#include <linux/io.h>
+#include <linux/module.h>
+#include <linux/of.h>
+#include <linux/phy/phy.h>
+#include <linux/platform_device.h>
+#include <linux/reset.h>
+#include <linux/usb.h>
+#include <linux/usb/hcd.h>
+#include <linux/usb/ehci_pdriver.h>
+
+#include "ehci.h"
+
+#define USB_MAX_CLKS 3
+
+struct st_ehci_platform_priv {
+        struct clk *clks[USB_MAX_CLKS];
+        struct clk *clk48;
+        struct reset_control *rst;
+        struct reset_control *pwr;
+        struct phy *phy;
+};
+
+#define DRIVER_DESC "EHCI STMicroelectronics driver"
+
+#define hcd_to_ehci_priv(h) \
+        ((struct st_ehci_platform_priv *)hcd_to_ehci(h)->priv)
+
+static const char hcd_name[] = "ehci-st";
+
+#define EHCI_CAPS_SIZE 0x10
+#define AHB2STBUS_INSREG01 (EHCI_CAPS_SIZE + 0x84)
+
+static int st_ehci_platform_reset(struct usb_hcd *hcd)
+{
+        struct platform_device *pdev = to_platform_device(hcd->self.controller);
+        struct usb_ehci_pdata *pdata = dev_get_platdata(&pdev->dev);
+        struct ehci_hcd *ehci = hcd_to_ehci(hcd);
+        int retval;
+        u32 threshold;
+
+        /* Set EHCI packet buffer IN/OUT threshold to 128 bytes */
+        threshold = 128 | (128 << 16);
+        writel(threshold, hcd->regs + AHB2STBUS_INSREG01);
+
+        ehci->caps = hcd->regs + pdata->caps_offset;
+        retval = ehci_setup(hcd);
+        if (retval)
+                return retval;
+
+        return 0;
+}
+
+static int st_ehci_platform_power_on(struct platform_device *dev)
+{
+        struct usb_hcd *hcd = platform_get_drvdata(dev);
+        struct st_ehci_platform_priv *priv = hcd_to_ehci_priv(hcd);
+        int clk, ret;
+
+        ret = reset_control_deassert(priv->pwr);
+        if (ret)
+                return ret;
+
+        ret = reset_control_deassert(priv->rst);
+        if (ret)
+                goto err_assert_power;
+
+        /* some SoCs don't have a dedicated 48Mhz clock, but those that do
+           need the rate to be explicitly set */
+        if (priv->clk48) {
+                ret = clk_set_rate(priv->clk48, 48000000);
+                if (ret)
+                        goto err_assert_reset;
+        }
+
+        for (clk = 0; clk < USB_MAX_CLKS && priv->clks[clk]; clk++) {
+                ret = clk_prepare_enable(priv->clks[clk]);
+                if (ret)
+                        goto err_disable_clks;
+        }
+
+        ret = phy_init(priv->phy);
+        if (ret)
+                goto err_disable_clks;
+
+        ret = phy_power_on(priv->phy);
+        if (ret)
+                goto err_exit_phy;
+
+        return 0;
+
+err_exit_phy:
+        phy_exit(priv->phy);
+err_disable_clks:
+        while (--clk >= 0)
+                clk_disable_unprepare(priv->clks[clk]);
+err_assert_reset:
+        reset_control_assert(priv->rst);
+err_assert_power:
+        reset_control_assert(priv->pwr);
+
+        return ret;
+}
+
+static void st_ehci_platform_power_off(struct platform_device *dev)
+{
+        struct usb_hcd *hcd = platform_get_drvdata(dev);
+        struct st_ehci_platform_priv *priv = hcd_to_ehci_priv(hcd);
+        int clk;
+
+        reset_control_assert(priv->pwr);
+
+        reset_control_assert(priv->rst);
+
+        phy_power_off(priv->phy);
+
+        phy_exit(priv->phy);
+
+        for (clk = USB_MAX_CLKS - 1; clk >= 0; clk--)
+                if (priv->clks[clk])
+                        clk_disable_unprepare(priv->clks[clk]);
+
+}
+
+static struct hc_driver __read_mostly ehci_platform_hc_driver;
+
+static const struct ehci_driver_overrides platform_overrides __initconst = {
+        .reset =                st_ehci_platform_reset,
+        .extra_priv_size =      sizeof(struct st_ehci_platform_priv),
+};
+
+static struct usb_ehci_pdata ehci_platform_defaults = {
+        .power_on =             st_ehci_platform_power_on,
+        .power_suspend =        st_ehci_platform_power_off,
+        .power_off =            st_ehci_platform_power_off,
+};
+
+static int st_ehci_platform_probe(struct platform_device *dev)
+{
+        struct usb_hcd *hcd;
+        struct resource *res_mem;
+        struct usb_ehci_pdata *pdata = &ehci_platform_defaults;
+        struct st_ehci_platform_priv *priv;
+        struct ehci_hcd *ehci;
+        int err, irq, clk = 0;
+
+        if (usb_disabled())
+                return -ENODEV;
+
+        irq = platform_get_irq(dev, 0);
+        if (irq < 0) {
+                dev_err(&dev->dev, "no irq provided");
+                return irq;
+        }
+        res_mem = platform_get_resource(dev, IORESOURCE_MEM, 0);
+        if (!res_mem) {
+                dev_err(&dev->dev, "no memory resource provided");
+                return -ENXIO;
+        }
+
+        hcd = usb_create_hcd(&ehci_platform_hc_driver, &dev->dev,
+                             dev_name(&dev->dev));
+        if (!hcd)
+                return -ENOMEM;
+
+        platform_set_drvdata(dev, hcd);
+        dev->dev.platform_data = pdata;
+        priv = hcd_to_ehci_priv(hcd);
+        ehci = hcd_to_ehci(hcd);
+
+        priv->phy = devm_phy_get(&dev->dev, "usb");
+        if (IS_ERR(priv->phy)) {
+                err = PTR_ERR(priv->phy);
+                goto err_put_hcd;
+        }
+
+        for (clk = 0; clk < USB_MAX_CLKS; clk++) {
+                priv->clks[clk] = of_clk_get(dev->dev.of_node, clk);
+                if (IS_ERR(priv->clks[clk])) {
+                        err = PTR_ERR(priv->clks[clk]);
+                        if (err == -EPROBE_DEFER)
+                                goto err_put_clks;
+                        priv->clks[clk] = NULL;
+                        break;
+                }
+        }
+
+        /* some SoCs don't have a dedicated 48Mhz clock, but those that
+           do need the rate to be explicitly set */
+        priv->clk48 = devm_clk_get(&dev->dev, "clk48");
+        if (IS_ERR(priv->clk48)) {
+                dev_info(&dev->dev, "48MHz clk not found\n");
+                priv->clk48 = NULL;
+        }
+
+        priv->pwr = devm_reset_control_get_optional(&dev->dev, "power");
+        if (IS_ERR(priv->pwr)) {
+                err = PTR_ERR(priv->pwr);
+                if (err == -EPROBE_DEFER)
+                        goto err_put_clks;
+                priv->pwr = NULL;
+        }
+
+        priv->rst = devm_reset_control_get_optional(&dev->dev, "softreset");
+        if (IS_ERR(priv->rst)) {
+                err = PTR_ERR(priv->rst);
+                if (err == -EPROBE_DEFER)
+                        goto err_put_clks;
+                priv->rst = NULL;
+        }
+
+        if (pdata->power_on) {
+                err = pdata->power_on(dev);
+                if (err < 0)
+                        goto err_put_clks;
+        }
+
+        hcd->rsrc_start = res_mem->start;
+        hcd->rsrc_len = resource_size(res_mem);
+
+        hcd->regs = devm_ioremap_resource(&dev->dev, res_mem);
+        if (IS_ERR(hcd->regs)) {
+                err = PTR_ERR(hcd->regs);
+                goto err_put_clks;
+        }
+
+        err = usb_add_hcd(hcd, irq, IRQF_SHARED);
+        if (err)
+                goto err_put_clks;
+
+        device_wakeup_enable(hcd->self.controller);
+        platform_set_drvdata(dev, hcd);
+
+        return err;
+
+err_put_clks:
+        while (--clk >= 0)
+                clk_put(priv->clks[clk]);
+err_put_hcd:
+        if (pdata == &ehci_platform_defaults)
+                dev->dev.platform_data = NULL;
+
+        usb_put_hcd(hcd);
+
+        return err;
+}
+
+static int st_ehci_platform_remove(struct platform_device *dev)
+{
+        struct usb_hcd *hcd = platform_get_drvdata(dev);
+        struct usb_ehci_pdata *pdata = dev_get_platdata(&dev->dev);
+        struct st_ehci_platform_priv *priv = hcd_to_ehci_priv(hcd);
+        int clk;
+
+        usb_remove_hcd(hcd);
+
+        if (pdata->power_off)
+                pdata->power_off(dev);
+
+        for (clk = 0; clk < USB_MAX_CLKS && priv->clks[clk]; clk++)
+                clk_put(priv->clks[clk]);
+
+        usb_put_hcd(hcd);
+
+        if (pdata == &ehci_platform_defaults)
+                dev->dev.platform_data = NULL;
+
+        return 0;
+}
+
+#ifdef CONFIG_PM_SLEEP
+
+static int st_ehci_suspend(struct device *dev)
+{
+        struct usb_hcd *hcd = dev_get_drvdata(dev);
+        struct usb_ehci_pdata *pdata = dev_get_platdata(dev);
+        struct platform_device *pdev =
+                container_of(dev, struct platform_device, dev);
+        bool do_wakeup = device_may_wakeup(dev);
+        int ret;
+
+        ret = ehci_suspend(hcd, do_wakeup);
+        if (ret)
+                return ret;
+
+        if (pdata->power_suspend)
+                pdata->power_suspend(pdev);
+
+        pinctrl_pm_select_sleep_state(dev);
+
+        return ret;
+}
+
+static int st_ehci_resume(struct device *dev)
+{
+        struct usb_hcd *hcd = dev_get_drvdata(dev);
+        struct usb_ehci_pdata *pdata = dev_get_platdata(dev);
+        struct platform_device *pdev =
+                container_of(dev, struct platform_device, dev);
+        int err;
+
+        pinctrl_pm_select_default_state(dev);
+
+        if (pdata->power_on) {
+                err = pdata->power_on(pdev);
+                if (err < 0)
+                        return err;
+        }
+
+        ehci_resume(hcd, false);
+        return 0;
+}
+
+static SIMPLE_DEV_PM_OPS(st_ehci_pm_ops, st_ehci_suspend, st_ehci_resume);
+
+#endif /* CONFIG_PM_SLEEP */
+
+static const struct of_device_id st_ehci_ids[] = {
+        { .compatible = "st,st-ehci-300x", },
+        { /* sentinel */ }
+};
+MODULE_DEVICE_TABLE(of, st_ehci_ids);
+
+static struct platform_driver ehci_platform_driver = {
+        .probe          = st_ehci_platform_probe,
+        .remove         = st_ehci_platform_remove,
+        .shutdown       = usb_hcd_platform_shutdown,
+        .driver         = {
+                .name   = "st-ehci",
+#ifdef CONFIG_PM_SLEEP
+                .pm     = &st_ehci_pm_ops,
+#endif
+                .of_match_table = st_ehci_ids,
+        }
+};
+
+static int __init ehci_platform_init(void)
+{
+        if (usb_disabled())
+                return -ENODEV;
+
+        pr_info("%s: " DRIVER_DESC "\n", hcd_name);
+
+        ehci_init_driver(&ehci_platform_hc_driver, &platform_overrides);
+        return platform_driver_register(&ehci_platform_driver);
+}
+module_init(ehci_platform_init);
+
+static void __exit ehci_platform_cleanup(void)
+{
+        platform_driver_unregister(&ehci_platform_driver);
+}
+module_exit(ehci_platform_cleanup);
+
+MODULE_DESCRIPTION(DRIVER_DESC);
+MODULE_AUTHOR("Peter Griffin <peter.griffin@linaro.org>");
+MODULE_LICENSE("GPL");