[PATCH v5 5/6] usb: mux: add driver for Intel drcfg controlled port mux

From: Lu Baolu
Date: Fri Mar 18 2016 - 02:33:15 EST

Several Intel PCHs and SOCs have an internal mux that is used to
share one USB port between device controller and host controller.
The mux is handled through the Dual Role Configuration Register.

Signed-off-by: Heikki Krogerus <heikki.krogerus@xxxxxxxxxxxxxxx>
Signed-off-by: Lu Baolu <baolu.lu@xxxxxxxxxxxxxxx>
Signed-off-by: Wu Hao <hao.wu@xxxxxxxxx>
Reviewed-by: Felipe Balbi <balbi@xxxxxxxxxx>
---
MAINTAINERS | 1 +
drivers/usb/mux/Kconfig | 7 ++
drivers/usb/mux/Makefile | 1 +
drivers/usb/mux/intel-mux-drcfg.c | 159 ++++++++++++++++++++++++++++++++++++++
4 files changed, 168 insertions(+)
create mode 100644 drivers/usb/mux/intel-mux-drcfg.c

diff --git a/MAINTAINERS b/MAINTAINERS
index 99bc198..1d0f090 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -11406,6 +11406,7 @@ S: Supported
F: include/linux/usb/intel-mux.h
F: drivers/usb/mux/intel-mux.c
F: drivers/usb/mux/intel-mux-gpio.c
+F: drivers/usb/mux/intel-mux-drcfg.c

USB PRINTER DRIVER (usblp)
M: Pete Zaitcev <zaitcev@xxxxxxxxxx>
diff --git a/drivers/usb/mux/Kconfig b/drivers/usb/mux/Kconfig
index 2b197c1..975c5a0 100644
--- a/drivers/usb/mux/Kconfig
+++ b/drivers/usb/mux/Kconfig
@@ -18,4 +18,11 @@ config INTEL_MUX_GPIO
Say Y here to enable support for Intel dual role port mux
controlled by GPIOs.

+config INTEL_MUX_DRCFG
+ tristate "Intel dual role port mux controlled by register"
+ depends on X86
+ select INTEL_USB_MUX
+ help
+ Say Y here to enable support for Intel dual role port mux
+ controlled by the Dual Role Configuration Register.
endmenu
diff --git a/drivers/usb/mux/Makefile b/drivers/usb/mux/Makefile
index 66f765c..3179909 100644
--- a/drivers/usb/mux/Makefile
+++ b/drivers/usb/mux/Makefile
@@ -3,3 +3,4 @@
#
obj-$(CONFIG_INTEL_USB_MUX) += intel-mux.o
obj-$(CONFIG_INTEL_MUX_GPIO) += intel-mux-gpio.o
+obj-$(CONFIG_INTEL_MUX_DRCFG) += intel-mux-drcfg.o
diff --git a/drivers/usb/mux/intel-mux-drcfg.c b/drivers/usb/mux/intel-mux-drcfg.c
new file mode 100644
index 0000000..4b6c2d1
--- /dev/null
+++ b/drivers/usb/mux/intel-mux-drcfg.c
@@ -0,0 +1,159 @@
+/**
+ * intel-mux-drcfg.c - Driver for Intel USB mux via register
+ *
+ * Copyright (C) 2016 Intel Corporation
+ * Author: Heikki Krogerus <heikki.krogerus@xxxxxxxxxxxxxxx>
+ * Author: Lu Baolu <baolu.lu@xxxxxxxxxxxxxxx>
+ *
+ * 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/slab.h>
+#include <linux/module.h>
+#include <linux/property.h>
+#include <linux/platform_device.h>
+#include <linux/usb.h>
+#include <linux/usb/intel-mux.h>
+
+#define INTEL_MUX_CFG0 0x00
+#define INTEL_MUX_CFG1 0x04
+#define CFG0_SW_IDPIN BIT(20)
+#define CFG0_SW_IDPIN_EN BIT(21)
+#define CFG0_SW_VBUS_VALID BIT(24)
+#define CFG1_SW_MODE BIT(29)
+#define CFG1_POLL_TIMEOUT 1000
+
+struct intel_mux_drcfg {
+ struct device *dev;
+ void __iomem *regs;
+};
+
+static struct intel_mux_drcfg *mux;
+
+static inline int intel_mux_drcfg_switch(struct device *dev, bool host)
+{
+ unsigned long timeout;
+ u32 data;
+
+ /* Check and set mux to SW controlled mode */
+ data = readl(mux->regs + INTEL_MUX_CFG0);
+ if (!(data & CFG0_SW_IDPIN_EN)) {
+ data |= CFG0_SW_IDPIN_EN;
+ writel(data, mux->regs + INTEL_MUX_CFG0);
+ }
+
+ /*
+ * Configure CFG0 to switch the mux and VBUS_VALID bit is
+ * required for device mode.
+ */
+ data = readl(mux->regs + INTEL_MUX_CFG0);
+ if (host)
+ data &= ~(CFG0_SW_IDPIN | CFG0_SW_VBUS_VALID);
+ else
+ data |= (CFG0_SW_IDPIN | CFG0_SW_VBUS_VALID);
+ writel(data, mux->regs + INTEL_MUX_CFG0);
+
+ /*
+ * Polling CFG1 for safety, most case it takes about 600ms
+ * to finish mode switching, set TIMEOUT long enough.
+ */
+ timeout = jiffies + msecs_to_jiffies(CFG1_POLL_TIMEOUT);
+
+ /* Polling on CFG1 register to confirm mode switch. */
+ while (!time_after(jiffies, timeout)) {
+ data = readl(mux->regs + INTEL_MUX_CFG1);
+ if (!(host ^ (data & CFG1_SW_MODE)))
+ return 0;
+ /* interval for polling is set to about 5ms */
+ usleep_range(5000, 5100);
+ }
+
+ return -ETIMEDOUT;
+}
+
+static int intel_mux_drcfg_cable_set(struct device *dev)
+{
+ dev_dbg(dev, "drcfg mux switch to HOST\n");
+
+ return intel_mux_drcfg_switch(dev, true);
+}
+
+static int intel_mux_drcfg_cable_unset(struct device *dev)
+{
+ dev_dbg(dev, "drcfg mux switch to DEVICE\n");
+
+ return intel_mux_drcfg_switch(dev, false);
+}
+
+static int intel_mux_drcfg_probe(struct platform_device *pdev)
+{
+ struct device *dev = &pdev->dev;
+ const char *extcon_name;
+ u64 start, size;
+ int ret;
+
+ mux = devm_kzalloc(dev, sizeof(*mux), GFP_KERNEL);
+ if (!mux)
+ return -ENOMEM;
+
+ ret = device_property_read_u64(dev, "reg-start", &start);
+ ret |= device_property_read_u64(dev, "reg-size", &size);
+ ret |= device_property_read_string(dev, "extcon-name", &extcon_name);
+ if (ret)
+ return -ENODEV;
+
+ mux->regs = devm_ioremap_nocache(dev, start, size);
+ if (!mux->regs)
+ return -ENOMEM;
+
+ mux->dev = dev;
+
+ return intel_usb_mux_bind_cable(dev, extcon_name,
+ intel_mux_drcfg_cable_set,
+ intel_mux_drcfg_cable_unset);
+}
+
+static int intel_mux_drcfg_remove(struct platform_device *pdev)
+{
+ return intel_usb_mux_unbind_cable(&pdev->dev);
+}
+
+#ifdef CONFIG_PM_SLEEP
+/*
+ * In case a micro A cable was plugged in while device was sleeping,
+ * we missed the interrupt. We need to poll usb id state when waking
+ * the driver to detect the missed event.
+ * We use 'complete' callback to give time to all extcon listeners to
+ * resume before we send new events.
+ */
+static const struct dev_pm_ops intel_mux_drcfg_pm_ops = {
+ .complete = intel_usb_mux_complete,
+};
+#endif
+
+static const struct platform_device_id intel_mux_drcfg_platform_ids[] = {
+ { .name = "intel-mux-drcfg", },
+ { /* sentinel */ }
+};
+MODULE_DEVICE_TABLE(platform, intel_mux_drcfg_platform_ids);
+
+static struct platform_driver intel_mux_drcfg_driver = {
+ .probe = intel_mux_drcfg_probe,
+ .remove = intel_mux_drcfg_remove,
+ .driver = {
+ .name = "intel-mux-drcfg",
+#ifdef CONFIG_PM_SLEEP
+ .pm = &intel_mux_drcfg_pm_ops,
+#endif
+ },
+ .id_table = intel_mux_drcfg_platform_ids,
+};
+
+module_platform_driver(intel_mux_drcfg_driver);
+
+MODULE_AUTHOR("Heikki Krogerus <heikki.krogerus@xxxxxxxxxxxxxxx>");
+MODULE_AUTHOR("Lu Baolu <baolu.lu@xxxxxxxxxxxxxxx>");
+MODULE_DESCRIPTION("Intel USB drcfg mux driver");
+MODULE_LICENSE("GPL v2");
--
2.1.4