Re: [PATCH 5/7] usb: misc: add driver for Intel drcfg controlled port mux

[Greg Kroah-Hartman <gregkh@linuxfoundation.org>]

On Thu, Mar 03, 2016 at 02:37:42PM +0800, Lu Baolu wrote:
> 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@linux.intel.com>
> Signed-off-by: Lu Baolu <baolu.lu@linux.intel.com>
> Signed-off-by: Wu Hao <hao.wu@intel.com>
> Reviewed-by: Felipe Balbi <balbi@kernel.org>
> ---
>  MAINTAINERS                        |   1 +
>  drivers/usb/misc/Kconfig           |   7 ++
>  drivers/usb/misc/Makefile          |   1 +
>  drivers/usb/misc/intel-mux-drcfg.c | 174 +++++++++++++++++++++++++++++++++++++
>  4 files changed, 183 insertions(+)
>  create mode 100644 drivers/usb/misc/intel-mux-drcfg.c
> 
> diff --git a/MAINTAINERS b/MAINTAINERS
> index 0f321e4..20eb873 100644
> --- a/MAINTAINERS
> +++ b/MAINTAINERS
> @@ -11396,6 +11396,7 @@ S:	Supported
>  F:	drivers/usb/misc/mux.c
>  F:	include/linux/usb/mux.h
>  F:	drivers/usb/misc/intel-mux-gpio.c
> +F:	drivers/usb/misc/intel-mux-drcfg.c
>  
>  USB PRINTER DRIVER (usblp)
>  M:	Pete Zaitcev <zaitcev@redhat.com>
> diff --git a/drivers/usb/misc/Kconfig b/drivers/usb/misc/Kconfig
> index 33e6386..befd910 100644
> --- a/drivers/usb/misc/Kconfig
> +++ b/drivers/usb/misc/Kconfig
> @@ -281,3 +281,10 @@ config INTEL_MUX_GPIO
>  	help
>  	  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"
> +	select USB_MUX
> +	help
> +	  Say Y here to enable support for Intel dual role port mux
> +	  controlled by the Dual Role Configuration Registers.
> diff --git a/drivers/usb/misc/Makefile b/drivers/usb/misc/Makefile
> index da4fb4e..c4d19a0 100644
> --- a/drivers/usb/misc/Makefile
> +++ b/drivers/usb/misc/Makefile
> @@ -32,3 +32,4 @@ obj-$(CONFIG_USB_LINK_LAYER_TEST)	+= lvstest.o
>  
>  obj-$(CONFIG_USB_MUX)			+= 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/misc/intel-mux-drcfg.c b/drivers/usb/misc/intel-mux-drcfg.c
> new file mode 100644
> index 0000000..29081c5
> --- /dev/null
> +++ b/drivers/usb/misc/intel-mux-drcfg.c
> @@ -0,0 +1,174 @@
> +/**
> + * intel-mux-drcfg.c - Driver for Intel USB mux via register
> + *
> + * Copyright (C) 2016 Intel Corporation
> + * Author: Heikki Krogerus <heikki.krogerus@linux.intel.com>
> + * Author: Lu Baolu <baolu.lu@linux.intel.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/slab.h>
> +#include <linux/module.h>
> +#include <linux/property.h>
> +#include <linux/usb/mux.h>
> +#include <linux/platform_device.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_usb_mux {
> +	struct usb_mux_dev umdev;
> +	void __iomem *regs;
> +	u32 cfg0_ctx;
> +};
> +
> +static inline int intel_mux_drcfg_switch(struct usb_mux_dev *umdev, bool host)
> +{
> +	struct intel_usb_mux *mux;
> +	unsigned long timeout;
> +	u32 data;
> +
> +	mux = container_of(umdev, struct intel_usb_mux, umdev);
> +
> +	/* 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 usb_mux_dev *umdev)
> +{
> +	dev_dbg(umdev->dev, "drcfg mux switch to HOST\n");
> +
> +	return intel_mux_drcfg_switch(umdev, true);
> +}
> +
> +static int intel_mux_drcfg_cable_unset(struct usb_mux_dev *umdev)
> +{
> +	dev_dbg(umdev->dev, "drcfg mux switch to DEVICE\n");
> +
> +	return intel_mux_drcfg_switch(umdev, false);
> +}
> +
> +static int intel_mux_drcfg_probe(struct platform_device *pdev)
> +{
> +	struct intel_usb_mux *mux;
> +	struct usb_mux_dev *umdev;
> +	struct device *dev = &pdev->dev;
> +	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);
> +	if (ret)
> +		return -ENODEV;

And you leaked memory :(

> +
> +	mux->regs = devm_ioremap_nocache(dev, start, size);
> +	if (!mux->regs)
> +		return -ENOMEM;

Memory gone :(

> +
> +	mux->cfg0_ctx = readl(mux->regs + INTEL_MUX_CFG0);
> +
> +	umdev = &mux->umdev;
> +	umdev->dev = dev;
> +	umdev->cable_name = "USB-HOST";
> +	umdev->cable_set_cb = intel_mux_drcfg_cable_set;
> +	umdev->cable_unset_cb = intel_mux_drcfg_cable_unset;
> +
> +	ret = usb_mux_register(umdev);
> +	if (ret)
> +		writel(mux->cfg0_ctx, mux->regs + INTEL_MUX_CFG0);

So if an error happens you just keep going?