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>

diff --git a/drivers/usb/host/ehci-st.c b/drivers/usb/host/ehci-st.c
new file mode 100644 (file)
index 0000000..7e4bd39
--- /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");