phy: bcm-ns-usb2: new driver for USB 2.0 PHY on Northstar

Northstar is a family of SoCs used in home routers. They have USB 2.0
and 3.0 controllers with PHYs that need to be properly initialized.
This driver provides PHY init support in a generic way and can be bound
with an EHCI controller driver.
There are (just a few) registers being defined in bcma header. It's
because DMU/CRU registers will be also needed in other drivers. We will
need them e.g. in PCIe controller/PHY driver and at some point probably
in clock driver for BCM53573 chipset. By using include/linux/bcma/ we
avoid code duplication.

Signed-off-by: Rafał Miłecki <zajec5@gmail.com>
Signed-off-by: Kishon Vijay Abraham I <kishon@ti.com>

3 files changed, 147 insertions, 0 deletions

diff --git a/drivers/phy/Kconfig b/drivers/phy/Kconfig
index f6ff76ec89dc..f2b458fc0c89 100644
--- a/drivers/phy/Kconfig
+++ b/drivers/phy/Kconfig
@@ -15,6 +15,15 @@ config GENERIC_PHY
           phy users can obtain reference to the PHY. All the users of this
           framework should select this config.
 
+config PHY_BCM_NS_USB2
+        tristate "Broadcom Northstar USB 2.0 PHY Driver"
+        depends on ARCH_BCM_IPROC || COMPILE_TEST
+        depends on HAS_IOMEM && OF
+        select GENERIC_PHY
+        help
+          Enable this to support Broadcom USB 2.0 PHY connected to the USB
+          controller on Northstar family.
+
 config PHY_BERLIN_USB
         tristate "Marvell Berlin USB PHY Driver"
         depends on ARCH_BERLIN && RESET_CONTROLLER && HAS_IOMEM && OF
diff --git a/drivers/phy/Makefile b/drivers/phy/Makefile
index f03fa1fdf322..0de09e13fdbc 100644
--- a/drivers/phy/Makefile
+++ b/drivers/phy/Makefile
@@ -3,6 +3,7 @@
 #
 
 obj-$(CONFIG_GENERIC_PHY)               += phy-core.o
+obj-$(CONFIG_PHY_BCM_NS_USB2)           += phy-bcm-ns-usb2.o
 obj-$(CONFIG_PHY_BERLIN_USB)            += phy-berlin-usb.o
 obj-$(CONFIG_PHY_BERLIN_SATA)           += phy-berlin-sata.o
 obj-$(CONFIG_PHY_DM816X_USB)            += phy-dm816x-usb.o
diff --git a/drivers/phy/phy-bcm-ns-usb2.c b/drivers/phy/phy-bcm-ns-usb2.c
new file mode 100644
index 000000000000..95ab6b2a0de5
--- /dev/null
+++ b/drivers/phy/phy-bcm-ns-usb2.c
@@ -0,0 +1,137 @@
+/*
+ * Broadcom Northstar USB 2.0 PHY Driver
+ *
+ * Copyright (C) 2016 Rafał Miłecki <zajec5@gmail.com>
+ *
+ * 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/bcma/bcma.h>
+#include <linux/clk.h>
+#include <linux/delay.h>
+#include <linux/err.h>
+#include <linux/module.h>
+#include <linux/of_address.h>
+#include <linux/of_platform.h>
+#include <linux/phy/phy.h>
+#include <linux/platform_device.h>
+#include <linux/slab.h>
+
+struct bcm_ns_usb2 {
+        struct device *dev;
+        struct clk *ref_clk;
+        struct phy *phy;
+        void __iomem *dmu;
+};
+
+static int bcm_ns_usb2_phy_init(struct phy *phy)
+{
+        struct bcm_ns_usb2 *usb2 = phy_get_drvdata(phy);
+        struct device *dev = usb2->dev;
+        void __iomem *dmu = usb2->dmu;
+        u32 ref_clk_rate, usb2ctl, usb_pll_ndiv, usb_pll_pdiv;
+        int err = 0;
+
+        err = clk_prepare_enable(usb2->ref_clk);
+        if (err < 0) {
+                dev_err(dev, "Failed to prepare ref clock: %d\n", err);
+                goto err_out;
+        }
+
+        ref_clk_rate = clk_get_rate(usb2->ref_clk);
+        if (!ref_clk_rate) {
+                dev_err(dev, "Failed to get ref clock rate\n");
+                err = -EINVAL;
+                goto err_clk_off;
+        }
+
+        usb2ctl = readl(dmu + BCMA_DMU_CRU_USB2_CONTROL);
+
+        if (usb2ctl & BCMA_DMU_CRU_USB2_CONTROL_USB_PLL_PDIV_MASK) {
+                usb_pll_pdiv = usb2ctl;
+                usb_pll_pdiv &= BCMA_DMU_CRU_USB2_CONTROL_USB_PLL_PDIV_MASK;
+                usb_pll_pdiv >>= BCMA_DMU_CRU_USB2_CONTROL_USB_PLL_PDIV_SHIFT;
+        } else {
+                usb_pll_pdiv = 1 << 3;
+        }
+
+        /* Calculate ndiv based on a solid 1920 MHz that is for USB2 PHY */
+        usb_pll_ndiv = (1920000000 * usb_pll_pdiv) / ref_clk_rate;
+
+        /* Unlock DMU PLL settings with some magic value */
+        writel(0x0000ea68, dmu + BCMA_DMU_CRU_CLKSET_KEY);
+
+        /* Write USB 2.0 PLL control setting */
+        usb2ctl &= ~BCMA_DMU_CRU_USB2_CONTROL_USB_PLL_NDIV_MASK;
+        usb2ctl |= usb_pll_ndiv << BCMA_DMU_CRU_USB2_CONTROL_USB_PLL_NDIV_SHIFT;
+        writel(usb2ctl, dmu + BCMA_DMU_CRU_USB2_CONTROL);
+
+        /* Lock DMU PLL settings */
+        writel(0x00000000, dmu + BCMA_DMU_CRU_CLKSET_KEY);
+
+err_clk_off:
+        clk_disable_unprepare(usb2->ref_clk);
+err_out:
+        return err;
+}
+
+static const struct phy_ops ops = {
+        .init           = bcm_ns_usb2_phy_init,
+        .owner          = THIS_MODULE,
+};
+
+static int bcm_ns_usb2_probe(struct platform_device *pdev)
+{
+        struct device *dev = &pdev->dev;
+        struct bcm_ns_usb2 *usb2;
+        struct resource *res;
+        struct phy_provider *phy_provider;
+
+        usb2 = devm_kzalloc(&pdev->dev, sizeof(*usb2), GFP_KERNEL);
+        if (!usb2)
+                return -ENOMEM;
+        usb2->dev = dev;
+
+        res = platform_get_resource_byname(pdev, IORESOURCE_MEM, "dmu");
+        usb2->dmu = devm_ioremap_resource(dev, res);
+        if (IS_ERR(usb2->dmu)) {
+                dev_err(dev, "Failed to map DMU regs\n");
+                return PTR_ERR(usb2->dmu);
+        }
+
+        usb2->ref_clk = devm_clk_get(dev, "phy-ref-clk");
+        if (IS_ERR(usb2->ref_clk)) {
+                dev_err(dev, "Clock not defined\n");
+                return PTR_ERR(usb2->ref_clk);
+        }
+
+        usb2->phy = devm_phy_create(dev, NULL, &ops);
+        if (IS_ERR(dev))
+                return PTR_ERR(dev);
+
+        phy_set_drvdata(usb2->phy, usb2);
+        platform_set_drvdata(pdev, usb2);
+
+        phy_provider = devm_of_phy_provider_register(dev, of_phy_simple_xlate);
+        return PTR_ERR_OR_ZERO(phy_provider);
+}
+
+static const struct of_device_id bcm_ns_usb2_id_table[] = {
+        { .compatible = "brcm,ns-usb2-phy", },
+        {},
+};
+MODULE_DEVICE_TABLE(of, bcm_ns_usb2_id_table);
+
+static struct platform_driver bcm_ns_usb2_driver = {
+        .probe          = bcm_ns_usb2_probe,
+        .driver = {
+                .name = "bcm_ns_usb2",
+                .of_match_table = bcm_ns_usb2_id_table,
+        },
+};
+module_platform_driver(bcm_ns_usb2_driver);
+
+MODULE_LICENSE("GPL v2");