Message-ID: <20140904173521.GA20343@localhost.localdomain>
Date:	Fri, 5 Sep 2014 01:35:21 +0800
From:	Wang YanQing <udknight@...il.com>
To:	gregkh@...uxfoundation.org
Cc:	linus.walleij@...aro.org, jhovold@...il.com, andi@...as.de,
	dforsi@...il.com, gnomes@...rguk.ukuu.org.uk,
	linux-usb@...r.kernel.org, linux-kernel@...r.kernel.org,
	zoobab@...il.com
Subject: Re: [PATCH v8] usb:serial:pl2303: add GPIOs interface on PL2303

On Sun, Aug 31, 2014 at 11:24:56PM +0800, Wang YanQing wrote:
> PL2303 USB Serial devices may has GPIOs, this patch add
> basic PL2303 gpio support.
> 
> Known issue:
> If gpios are in use(export to userspace through sysfs interface, etc),
> then call pl2303_release(unplug usb-serial convertor, modprobe -r, etc),
> will cause trouble, so we need to make sure there is no gpio user before
> call pl2303_release.
> 
> Signed-off-by: Wang YanQing <udknight@...il.com>
> ---
>  Note: I sniffed office HXD gpio test program to get 
>        gpios control protocol with PL2303 RA, so I only
>        test it with PL2303 RA and HXA, I don't have HXD,
>        but because it is *office* HXD gpio test program,
>        so if it doesn't work with HXD, I will feel surprise.
> 
>  Changes
>  v7-v8:
>  1: add support for four dedicated gpios on HXD and RA
>  2: fix problem reported by Johan Hovold in v7
>  3: fix checkpatch.pl's warning
> 
>  v6-v7:
>  1: add generic gpio support interfaces for pl2303 USB Serial devices
>     in pl2303_type_data and pl2303_serial_private suggested by Andreas Mohr.
>  2: drop different label names for different pl2303 instance suggested by Johan Hovold.
>  3: fix missing lock corrected by Johan Hovold.
>  4: use prefix pl2303hx_gpio instead pl2303_gpio, pl2303_gpio is over generic for current code,
>     and now we move gpio_startup|gpio_release into type-specified data structure, so pl2303hx_gpio
>     is a better prefix.
>  5: make words in Kconfig a little more useful and clarified.
>  6: many misc code quality enhancement suggested by Johan Hovold.
> 
>  v5-v6:
>  1: fix typo error in Kconfig reported by Andreas Mohr 
>  2: add const qulification to gpio_dir_mask and gpio_value_mask suggested by Andreas Mohr
> 
>  v4-v5:
>  1: fix gpio_chip.lable been overwrited by template_chip. 
>  2: use idr to manage minor instead of crude monotonous atomic increment. 
> 
>  v3-v4:
>  1: fix missing static for gpio_dir_mask and gpio_value_mask 
>  2: reduce unneeded compile macro defined suggested by gnomes@...rguk.ukuu.org.uk 
>  3: use true instead of 1 corrected by Linus Walleij
>  4: ignore return value of gpiochip_remove suggested by Linus Walleij
>  5: fix multi gpio_chips registered by pl2303 can't be distinguished in kernel space. 
> 
>  v2-v3:
>  1: fix errors and warnings reported by Daniele Forsi checked with checkpatch.pl 
>  2: fix missing GPIOLIB dependence in Kconfig 
>  3: fix pl2303_gpio_get can't work 
> 
>  v1-v2:  
>  1:drop gpio-pl2303.c and relation stuff 
>  2:hang gpio stuff off of pl2303.c  
> 
>  drivers/usb/serial/Kconfig  |  11 ++
>  drivers/usb/serial/pl2303.c | 250 ++++++++++++++++++++++++++++++++++++++++++++
>  2 files changed, 261 insertions(+)
> 
> diff --git a/drivers/usb/serial/Kconfig b/drivers/usb/serial/Kconfig
> index 3ce5c74..b4e0cf9 100644
> --- a/drivers/usb/serial/Kconfig
> +++ b/drivers/usb/serial/Kconfig
> @@ -516,6 +516,17 @@ config USB_SERIAL_PL2303
>  	  To compile this driver as a module, choose M here: the
>  	  module will be called pl2303.
>  
> +config USB_SERIAL_PL2303_GPIO
> +	bool "USB Prolific 2303 Single Port GPIOs support"
> +	depends on USB_SERIAL_PL2303 && GPIOLIB
> +	---help---
> +	  Say Y here if you want to use GPIOs on PL2303 USB Serial single port
> +	  adapter from Prolific.
> +
> +	  It supports 2 dedicated GPIOs on PL2303HXA, 4 dedicated GPIOs on
> +	  PL2303HXD and PL2303RA currently.
> +	  If unsure, say N.
> +
>  config USB_SERIAL_OTI6858
>  	tristate "USB Ours Technology Inc. OTi-6858 USB To RS232 Bridge Controller"
>  	help
> diff --git a/drivers/usb/serial/pl2303.c b/drivers/usb/serial/pl2303.c
> index e9bad92..a3f8411 100644
> --- a/drivers/usb/serial/pl2303.c
> +++ b/drivers/usb/serial/pl2303.c
> @@ -28,6 +28,8 @@
>  #include <linux/usb.h>
>  #include <linux/usb/serial.h>
>  #include <asm/unaligned.h>
> +#include <linux/gpio.h>
> +#include <linux/mutex.h>
>  #include "pl2303.h"
>  
>  
> @@ -132,6 +134,22 @@ MODULE_DEVICE_TABLE(usb, id_table);
>  #define UART_OVERRUN_ERROR		0x40
>  #define UART_CTS			0x80
>  
> +#define HXD_GPIO_01_CTRL		0x0001
> +#define HXD_GPIO_01_VALUE		0x0081
> +#define HXD_GPIO_23_DIR_CTRL		0x0c0c
> +#define HXD_GPIO_23_VALUE_CTRL		0x0d0d
> +#define HXD_GPIO_23_VALUE		0x8d8d
> +
> +#define HXD_GPIO0_DIR_MASK		0x10
> +#define HXD_GPIO1_DIR_MASK		0x20
> +#define HXD_GPIO2_DIR_MASK		0x03
> +#define HXD_GPIO3_DIR_MASK		0x0c
> +
> +#define HXD_GPIO0_VALUE_MASK		0x40
> +#define HXD_GPIO1_VALUE_MASK		0x80
> +#define HXD_GPIO2_VALUE_MASK		0x01
> +#define HXD_GPIO3_VALUE_MASK		0x02
> +
>  
>  enum pl2303_type {
>  	TYPE_01,	/* Type 0 and 1 (difference unknown) */
> @@ -144,9 +162,12 @@ struct pl2303_type_data {
>  	unsigned long quirks;
>  };
>  
> +struct pl2303_gpio;
>  struct pl2303_serial_private {
>  	const struct pl2303_type_data *type;
>  	unsigned long quirks;
> +	u8 ngpio;
> +	struct pl2303_gpio *gpio;
>  };
>  
>  struct pl2303_private {
> @@ -157,6 +178,14 @@ struct pl2303_private {
>  	u8 line_settings[7];
>  };
>  
> +#ifdef CONFIG_USB_SERIAL_PL2303_GPIO
> +static int pl2303_gpio_startup(struct usb_serial *serial);
> +static void pl2303_gpio_release(struct usb_serial *serial);
> +#else
> +static inline int pl2303_gpio_startup(struct usb_serial *serial) { return 0; }
> +static inline void pl2303_gpio_release(struct usb_serial *serial) {}
> +#endif
> +
>  static const struct pl2303_type_data pl2303_type_data[TYPE_COUNT] = {
>  	[TYPE_01] = {
>  		.max_baud_rate =	1228800,
> @@ -214,11 +243,213 @@ static int pl2303_probe(struct usb_serial *serial,
>  	return 0;
>  }
>  
> +#ifdef CONFIG_USB_SERIAL_PL2303_GPIO
> +struct pl2303_gpio_desc {
> +	u8 dir_offset;
> +	u8 dir_mask;
> +	u16 dir_ctrl;
> +	u8 value_offset;
> +	u8 value_mask;
> +	u16 value_ctrl;
> +	u16 read_ctrl;
> +};
> +
> +struct pl2303_gpio {
> +	struct pl2303_gpio_desc *descs;
> +	u8 data[3];
> +	struct mutex lock;
> +	struct usb_serial *serial;
> +	struct gpio_chip gpio_chip;
> +};
> +
> +static inline struct pl2303_gpio *to_pl2303_gpio(struct gpio_chip *chip)
> +{
> +	return container_of(chip, struct pl2303_gpio, gpio_chip);
> +}
> +
> +static void pl2303_gpio_add(struct usb_serial *serial, u8 num, u16 read_ctrl,
> +			u8 dir_offset, u8 dir_mask, u16 dir_ctrl,
> +			u8 value_offset, u8 value_mask, u16 value_ctrl)
> +{
> +	struct pl2303_serial_private *spriv = usb_get_serial_data(serial);
> +	struct pl2303_gpio *gpio = spriv->gpio;
> +
> +	BUG_ON(num >= spriv->ngpio);
> +	gpio->descs[num].dir_offset = dir_offset;
> +	gpio->descs[num].dir_mask = dir_mask;
> +	gpio->descs[num].dir_ctrl = dir_ctrl;
> +
> +	gpio->descs[num].value_offset = value_offset;
> +	gpio->descs[num].value_mask = value_mask;
> +	gpio->descs[num].value_ctrl = value_ctrl;
> +
> +	gpio->descs[num].read_ctrl = read_ctrl;
> +}
> +
> +static int pl2303_gpio_direction_in(struct gpio_chip *chip, unsigned offset)
> +{
> +	struct pl2303_gpio *gpio = to_pl2303_gpio(chip);
> +	struct pl2303_gpio_desc *desc;
> +	int ret;
> +
> +	mutex_lock(&gpio->lock);
> +	desc = gpio->descs+offset;
> +	gpio->data[desc->dir_offset] &= ~desc->dir_mask;
> +	ret = pl2303_vendor_write(gpio->serial, desc->dir_ctrl,
> +				gpio->data[desc->dir_offset]);
> +	mutex_unlock(&gpio->lock);
> +
> +	return ret;
> +}
> +
> +static int pl2303_gpio_direction_out(struct gpio_chip *chip,
> +				unsigned offset, int value)
> +{
> +	struct pl2303_gpio *gpio = to_pl2303_gpio(chip);
> +	struct pl2303_gpio_desc *desc;
> +	int ret;
> +
> +	mutex_lock(&gpio->lock);
> +	desc = gpio->descs+offset;
> +	gpio->data[desc->dir_offset] |= desc->dir_mask;
> +	ret = pl2303_vendor_write(gpio->serial, desc->dir_ctrl,
> +				gpio->data[desc->dir_offset]);
> +	if (ret)
> +		goto error;
> +
> +	if (value)
> +		gpio->data[desc->value_offset] |= desc->value_mask;
> +	else
> +		gpio->data[desc->value_offset] &= ~desc->value_mask;
> +
> +	ret = pl2303_vendor_write(gpio->serial, desc->value_ctrl,
> +				gpio->data[desc->value_offset]);
> +error:
> +	mutex_unlock(&gpio->lock);
> +
> +	return ret;
> +}
> +
> +static void pl2303_gpio_set(struct gpio_chip *chip, unsigned offset, int value)
> +{
> +	struct pl2303_gpio *gpio = to_pl2303_gpio(chip);
> +	struct pl2303_gpio_desc *desc;
> +
> +	mutex_lock(&gpio->lock);
> +	desc = gpio->descs+offset;
> +	if (value)
> +		gpio->data[desc->value_offset] |= desc->value_mask;
> +	else
> +		gpio->data[desc->value_offset] &= ~desc->value_mask;
> +
> +	pl2303_vendor_write(gpio->serial, desc->value_ctrl,
> +			gpio->data[desc->value_offset]);
> +	mutex_unlock(&gpio->lock);
> +}
> +
> +static int pl2303_gpio_get(struct gpio_chip *chip, unsigned offset)
> +{
> +	struct pl2303_gpio *gpio = to_pl2303_gpio(chip);
> +	struct pl2303_gpio_desc *desc;
> +	unsigned char *buf;
> +	int value;
> +
> +	buf = kzalloc(1, GFP_KERNEL);
> +	if (!buf)
> +		return -ENOMEM;
> +
> +	mutex_lock(&gpio->lock);
> +	desc = gpio->descs+offset;
> +
> +	if (pl2303_vendor_read(gpio->serial, desc->read_ctrl, buf)) {
> +		mutex_unlock(&gpio->lock);
> +		return -EIO;
> +	}
> +
> +	value = buf[0] & desc->value_mask;
> +	mutex_unlock(&gpio->lock);
> +	kfree(buf);
> +
> +	return value;
> +}
> +
> +static int pl2303_gpio_startup(struct usb_serial *serial)
> +{
> +	struct pl2303_serial_private *spriv = usb_get_serial_data(serial);
> +	struct pl2303_gpio *gpio;
> +	int ret;
> +
> +	gpio = kzalloc(sizeof(struct pl2303_gpio), GFP_KERNEL);
> +	if (!gpio)
> +		return -ENOMEM;
> +
> +	gpio->descs = kcalloc(spriv->ngpio, sizeof(struct pl2303_gpio_desc),
> +			GFP_KERNEL);
> +	if (!gpio->descs) {
> +		kfree(gpio);
> +		return -ENOMEM;
> +	}
> +	spriv->gpio = gpio;
> +
> +	pl2303_gpio_add(serial, 0, HXD_GPIO_01_VALUE,
> +			0, HXD_GPIO0_DIR_MASK, HXD_GPIO_01_CTRL,
> +			0, HXD_GPIO0_VALUE_MASK, HXD_GPIO_01_CTRL);
> +	pl2303_gpio_add(serial, 1, HXD_GPIO_01_VALUE,
> +			0, HXD_GPIO1_DIR_MASK, HXD_GPIO_01_CTRL,
> +			0, HXD_GPIO1_VALUE_MASK, HXD_GPIO_01_CTRL);
> +
> +	if (spriv->ngpio == 4) {
> +		pl2303_gpio_add(serial, 2, HXD_GPIO_23_VALUE,
> +				1, HXD_GPIO2_DIR_MASK, HXD_GPIO_23_DIR_CTRL,
> +				2, HXD_GPIO2_VALUE_MASK,
> +				HXD_GPIO_23_VALUE_CTRL);
> +		pl2303_gpio_add(serial, 3, HXD_GPIO_23_VALUE,
> +				1, HXD_GPIO3_DIR_MASK, HXD_GPIO_23_DIR_CTRL,
> +				2, HXD_GPIO3_VALUE_MASK,
> +				HXD_GPIO_23_VALUE_CTRL);
> +	}
> +
> +	gpio->serial = serial;
> +	mutex_init(&gpio->lock);
> +
> +	gpio->gpio_chip.label = "pl2303";
> +	gpio->gpio_chip.owner = THIS_MODULE;
> +	gpio->gpio_chip.direction_input = pl2303_gpio_direction_in;
> +	gpio->gpio_chip.get = pl2303_gpio_get;
> +	gpio->gpio_chip.direction_output = pl2303_gpio_direction_out;
> +	gpio->gpio_chip.set = pl2303_gpio_set;
> +	gpio->gpio_chip.can_sleep  = true;
> +	gpio->gpio_chip.ngpio = spriv->ngpio;
> +	gpio->gpio_chip.base = -1;
> +	gpio->gpio_chip.dev = &serial->interface->dev;
> +
> +	ret = gpiochip_add(&gpio->gpio_chip);
> +	if (ret < 0) {
> +		kfree(gpio);
> +		return ret;
> +	}
> +	return 0;
> +}
> +
> +static void pl2303_gpio_release(struct usb_serial *serial)
> +{
> +	struct pl2303_serial_private *spriv = usb_get_serial_data(serial);
> +	struct pl2303_gpio *gpio = (struct pl2303_gpio *)spriv->gpio;
> +
> +	gpiochip_remove(&gpio->gpio_chip);
> +	kfree(gpio->descs);
> +	kfree(gpio);
> +}
> +#endif
> +
>  static int pl2303_startup(struct usb_serial *serial)
>  {
>  	struct pl2303_serial_private *spriv;
>  	enum pl2303_type type = TYPE_01;
>  	unsigned char *buf;
> +	u16 bcdDevice;
> +	u8 major_revision;
> +	int ret;
>  
>  	spriv = kzalloc(sizeof(*spriv), GFP_KERNEL);
>  	if (!spriv)
> @@ -244,6 +475,16 @@ static int pl2303_startup(struct usb_serial *serial)
>  	spriv->quirks = (unsigned long)usb_get_serial_data(serial);
>  	spriv->quirks |= spriv->type->quirks;
>  
> +	spriv->ngpio = 0;
> +	if (type == TYPE_HX) {
> +		bcdDevice = le16_to_cpu(serial->dev->descriptor.bcdDevice);
> +		major_revision = bcdDevice = bcdDevice >> 8;
> +		if (major_revision == 3)
> +			spriv->ngpio = 2;
> +		else if (major_revision == 4)
> +			spriv->ngpio = 4;
> +	}
> +
>  	usb_set_serial_data(serial, spriv);
>  
>  	pl2303_vendor_read(serial, 0x8484, buf);
> @@ -263,6 +504,13 @@ static int pl2303_startup(struct usb_serial *serial)
>  
>  	kfree(buf);
>  
> +	if (spriv->ngpio > 0) {
> +		ret = pl2303_gpio_startup(serial);
> +		if (ret) {
> +			kfree(spriv);
> +			return ret;
> +		}
> +	}
>  	return 0;
>  }
>  
> @@ -270,6 +518,8 @@ static void pl2303_release(struct usb_serial *serial)
>  {
>  	struct pl2303_serial_private *spriv = usb_get_serial_data(serial);
>  
> +	if (spriv->ngpio > 0)
> +		pl2303_gpio_release(serial);
>  	kfree(spriv);
>  }
>  
> -- 
> 1.8.5.5.dirty

Add Benjamin Henrion <zoobab@...il.com> to CC list, thanks very much for his test work with this patch.
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