PHY: Add driver for Pistachio USB2.0 PHY

Add a driver for the USB2.0 PHY found on the IMG Pistachio SoC.

Signed-off-by: Andrew Bresticker <abrestic@chromium.org>
Cc: Kishon Vijay Abraham I <kishon@ti.com>
Cc: devicetree@vger.kernel.org
Cc: linux-mips@linux-mips.org
Cc: linux-kernel@vger.kernel.org
Cc: James Hartley <james.hartley@imgtec.com>
Cc: Damien Horsley <Damien.Horsley@imgtec.com>
Patchwork: https://patchwork.linux-mips.org/patch/9728/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>

diff --git a/drivers/phy/Kconfig b/drivers/phy/Kconfig
index fc9b9f0..e840260 100644 (file)
--- a/drivers/phy/Kconfig
+++ b/drivers/phy/Kconfig
@@ -247,6 +247,13 @@ config PHY_EXYNOS5_USBDRD
          This driver provides PHY interface for USB 3.0 DRD controller
          present on Exynos5 SoC series.
 
+config PHY_PISTACHIO_USB
+       tristate "IMG Pistachio USB2.0 PHY driver"
+       depends on MACH_PISTACHIO
+       select GENERIC_PHY
+       help
+         Enable this to support the USB2.0 PHY on the IMG Pistachio SoC.
+
 config PHY_QCOM_APQ8064_SATA
        tristate "Qualcomm APQ8064 SATA SerDes/PHY driver"
        depends on ARCH_QCOM

diff --git a/drivers/phy/Makefile b/drivers/phy/Makefile
index f126251..75a37dc 100644 (file)
--- a/drivers/phy/Makefile
+++ b/drivers/phy/Makefile
@@ -40,3 +40,4 @@ obj-$(CONFIG_PHY_STIH41X_USB)         += phy-stih41x-usb.o
 obj-$(CONFIG_PHY_QCOM_UFS)     += phy-qcom-ufs.o
 obj-$(CONFIG_PHY_QCOM_UFS)     += phy-qcom-ufs-qmp-20nm.o
 obj-$(CONFIG_PHY_QCOM_UFS)     += phy-qcom-ufs-qmp-14nm.o
+obj-$(CONFIG_PHY_PISTACHIO_USB)                += phy-pistachio-usb.o

diff --git a/drivers/phy/phy-pistachio-usb.c b/drivers/phy/phy-pistachio-usb.c
new file mode 100644 (file)
index 0000000..c6db35e
--- /dev/null
+++ b/drivers/phy/phy-pistachio-usb.c
@@ -0,0 +1,206 @@
+/*
+ * IMG Pistachio USB PHY driver
+ *
+ * Copyright (C) 2015 Google, Inc.
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms and conditions of the GNU General Public License,
+ * version 2, as published by the Free Software Foundation.
+ */
+
+#include <linux/clk.h>
+#include <linux/delay.h>
+#include <linux/io.h>
+#include <linux/kernel.h>
+#include <linux/mfd/syscon.h>
+#include <linux/module.h>
+#include <linux/of.h>
+#include <linux/phy/phy.h>
+#include <linux/platform_device.h>
+#include <linux/regmap.h>
+
+#include <dt-bindings/phy/phy-pistachio-usb.h>
+
+#define USB_PHY_CONTROL1                               0x04
+#define USB_PHY_CONTROL1_FSEL_SHIFT                    2
+#define USB_PHY_CONTROL1_FSEL_MASK                     0x7
+
+#define USB_PHY_STRAP_CONTROL                          0x10
+#define USB_PHY_STRAP_CONTROL_REFCLK_SHIFT             4
+#define USB_PHY_STRAP_CONTROL_REFCLK_MASK              0x3
+
+#define USB_PHY_STATUS                                 0x14
+#define USB_PHY_STATUS_RX_PHY_CLK                      BIT(9)
+#define USB_PHY_STATUS_RX_UTMI_CLK                     BIT(8)
+#define USB_PHY_STATUS_VBUS_FAULT                      BIT(7)
+
+struct pistachio_usb_phy {
+       struct device *dev;
+       struct regmap *cr_top;
+       struct clk *phy_clk;
+       unsigned int refclk;
+};
+
+static const unsigned long fsel_rate_map[] = {
+       9600000,
+       10000000,
+       12000000,
+       19200000,
+       20000000,
+       24000000,
+       0,
+       50000000,
+};
+
+static int pistachio_usb_phy_power_on(struct phy *phy)
+{
+       struct pistachio_usb_phy *p_phy = phy_get_drvdata(phy);
+       unsigned long timeout, rate;
+       unsigned int i;
+       int ret;
+
+       ret = clk_prepare_enable(p_phy->phy_clk);
+       if (ret < 0) {
+               dev_err(p_phy->dev, "Failed to enable PHY clock: %d\n", ret);
+               return ret;
+       }
+
+       regmap_update_bits(p_phy->cr_top, USB_PHY_STRAP_CONTROL,
+                          USB_PHY_STRAP_CONTROL_REFCLK_MASK <<
+                          USB_PHY_STRAP_CONTROL_REFCLK_SHIFT,
+                          p_phy->refclk << USB_PHY_STRAP_CONTROL_REFCLK_SHIFT);
+
+       rate = clk_get_rate(p_phy->phy_clk);
+       if (p_phy->refclk == REFCLK_XO_CRYSTAL && rate != 12000000) {
+               dev_err(p_phy->dev, "Unsupported rate for XO crystal: %ld\n",
+                       rate);
+               ret = -EINVAL;
+               goto disable_clk;
+       }
+
+       for (i = 0; i < ARRAY_SIZE(fsel_rate_map); i++) {
+               if (rate == fsel_rate_map[i])
+                       break;
+       }
+       if (i == ARRAY_SIZE(fsel_rate_map)) {
+               dev_err(p_phy->dev, "Unsupported clock rate: %lu\n", rate);
+               ret = -EINVAL;
+               goto disable_clk;
+       }
+
+       regmap_update_bits(p_phy->cr_top, USB_PHY_CONTROL1,
+                          USB_PHY_CONTROL1_FSEL_MASK <<
+                          USB_PHY_CONTROL1_FSEL_SHIFT,
+                          i << USB_PHY_CONTROL1_FSEL_SHIFT);
+
+       timeout = jiffies + msecs_to_jiffies(200);
+       while (time_before(jiffies, timeout)) {
+               unsigned int val;
+
+               regmap_read(p_phy->cr_top, USB_PHY_STATUS, &val);
+               if (val & USB_PHY_STATUS_VBUS_FAULT) {
+                       dev_err(p_phy->dev, "VBUS fault detected\n");
+                       ret = -EIO;
+                       goto disable_clk;
+               }
+               if ((val & USB_PHY_STATUS_RX_PHY_CLK) &&
+                   (val & USB_PHY_STATUS_RX_UTMI_CLK))
+                       return 0;
+               usleep_range(1000, 1500);
+       }
+
+       dev_err(p_phy->dev, "Timed out waiting for PHY to power on\n");
+       ret = -ETIMEDOUT;
+
+disable_clk:
+       clk_disable_unprepare(p_phy->phy_clk);
+       return ret;
+}
+
+static int pistachio_usb_phy_power_off(struct phy *phy)
+{
+       struct pistachio_usb_phy *p_phy = phy_get_drvdata(phy);
+
+       clk_disable_unprepare(p_phy->phy_clk);
+
+       return 0;
+}
+
+static const struct phy_ops pistachio_usb_phy_ops = {
+       .power_on = pistachio_usb_phy_power_on,
+       .power_off = pistachio_usb_phy_power_off,
+       .owner = THIS_MODULE,
+};
+
+static int pistachio_usb_phy_probe(struct platform_device *pdev)
+{
+       struct pistachio_usb_phy *p_phy;
+       struct phy_provider *provider;
+       struct phy *phy;
+       int ret;
+
+       p_phy = devm_kzalloc(&pdev->dev, sizeof(*p_phy), GFP_KERNEL);
+       if (!p_phy)
+               return -ENOMEM;
+       p_phy->dev = &pdev->dev;
+       platform_set_drvdata(pdev, p_phy);
+
+       p_phy->cr_top = syscon_regmap_lookup_by_phandle(p_phy->dev->of_node,
+                                                       "img,cr-top");
+       if (IS_ERR(p_phy->cr_top)) {
+               dev_err(p_phy->dev, "Failed to get CR_TOP registers: %ld\n",
+                       PTR_ERR(p_phy->cr_top));
+               return PTR_ERR(p_phy->cr_top);
+       }
+
+       p_phy->phy_clk = devm_clk_get(p_phy->dev, "usb_phy");
+       if (IS_ERR(p_phy->phy_clk)) {
+               dev_err(p_phy->dev, "Failed to get usb_phy clock: %ld\n",
+                       PTR_ERR(p_phy->phy_clk));
+               return PTR_ERR(p_phy->phy_clk);
+       }
+
+       ret = of_property_read_u32(p_phy->dev->of_node, "img,refclk",
+                                  &p_phy->refclk);
+       if (ret < 0) {
+               dev_err(p_phy->dev, "No reference clock selector specified\n");
+               return ret;
+       }
+
+       phy = devm_phy_create(p_phy->dev, NULL, &pistachio_usb_phy_ops);
+       if (IS_ERR(phy)) {
+               dev_err(p_phy->dev, "Failed to create PHY: %ld\n",
+                       PTR_ERR(phy));
+               return PTR_ERR(phy);
+       }
+       phy_set_drvdata(phy, p_phy);
+
+       provider = devm_of_phy_provider_register(p_phy->dev,
+                                                of_phy_simple_xlate);
+       if (IS_ERR(provider)) {
+               dev_err(p_phy->dev, "Failed to register PHY provider: %ld\n",
+                       PTR_ERR(provider));
+               return PTR_ERR(provider);
+       }
+
+       return 0;
+}
+
+static const struct of_device_id pistachio_usb_phy_of_match[] = {
+       { .compatible = "img,pistachio-usb-phy", },
+       { },
+};
+MODULE_DEVICE_TABLE(of, pistachio_usb_phy_of_match);
+
+static struct platform_driver pistachio_usb_phy_driver = {
+       .probe          = pistachio_usb_phy_probe,
+       .driver         = {
+               .name   = "pistachio-usb-phy",
+               .of_match_table = pistachio_usb_phy_of_match,
+       },
+};
+module_platform_driver(pistachio_usb_phy_driver);
+
+MODULE_AUTHOR("Andrew Bresticker <abrestic@chromium.org>");
+MODULE_DESCRIPTION("IMG Pistachio USB2.0 PHY driver");
+MODULE_LICENSE("GPL v2");