Date:   Wed, 28 Aug 2019 17:02:52 +0200
From:   Johan Hovold <johan@...nel.org>
To:     "Ji-Ze Hong (Peter Hong)" <hpeter@...il.com>
Cc:     johan@...nel.org, gregkh@...uxfoundation.org,
        linux-usb@...r.kernel.org, linux-kernel@...r.kernel.org,
        peter_hong@...tek.com.tw,
        "Ji-Ze Hong (Peter Hong)" <hpeter+linux_kernel@...il.com>
Subject: Re: [PATCH V1 3/6] USB: serial: f81232: Add generator for F81534A

On Thu, Jun 06, 2019 at 10:54:13AM +0800, Ji-Ze Hong (Peter Hong) wrote:
> The Fintek F81534A series is contains 1 HUB / 1 GPIO device / n UARTs,
> but the UART is default disable and need enabled by GPIO device(2c42/16F8).
> When F81534A plug to host, we can only see 1 HUB & 1 GPIO device, add
> GPIO device USB interface to device_list and trigger generate worker,
> f81534a_generate_worker to run f81534a_ctrl_generate_ports().
> 
> The operation in f81534a_ctrl_generate_ports() as following:
> 	1: Write 0x8fff to F81534A_CMD_ENABLE_PORT register for enable all
> 	   UART device.
> 
> 	2: Read port existence & current status from F81534A_CMD_PORT_STATUS
> 	   register. the higher 16bit will indicate the UART existence. If the
> 	   UART is existence, we'll check it GPIO mode as long as not default
> 	   value (default is all input mode).
> 
> 	3: 1 GPIO device will check with max 15s and check next GPIO device when
> 	   timeout. (F81534A_CTRL_RETRY * F81534A_CTRL_TIMER)
> 
> Signed-off-by: Ji-Ze Hong (Peter Hong) <hpeter+linux_kernel@...il.com>

This is all looks crazy... Please better describe how the device works,
and you want to implement support.

> ---
>  drivers/usb/serial/f81232.c | 356 +++++++++++++++++++++++++++++++++++++++++++-
>  1 file changed, 355 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/usb/serial/f81232.c b/drivers/usb/serial/f81232.c
> index 75dfc0b9ef30..e9470fb0d691 100644
> --- a/drivers/usb/serial/f81232.c
> +++ b/drivers/usb/serial/f81232.c
> @@ -41,6 +41,12 @@ static const struct usb_device_id id_table[] = {
>  };
>  MODULE_DEVICE_TABLE(usb, id_table);
>  
> +static const struct usb_device_id f81534a_ctrl_id_table[] = {
> +	{ USB_DEVICE(0x2c42, 0x16f8) },		/* Global control device */
> +	{ }					/* Terminating entry */
> +};
> +MODULE_DEVICE_TABLE(usb, f81534a_ctrl_id_table);

You can only have one MODULE_DEVICE_TABLE()...

> +
>  /* Maximum baudrate for F81232 */
>  #define F81232_MAX_BAUDRATE		1500000
>  #define F81232_DEF_BAUDRATE		9600
> @@ -49,6 +55,10 @@ MODULE_DEVICE_TABLE(usb, id_table);
>  #define F81232_REGISTER_REQUEST		0xa0
>  #define F81232_GET_REGISTER		0xc0
>  #define F81232_SET_REGISTER		0x40
> +#define F81534A_REGISTER_REQUEST	F81232_REGISTER_REQUEST
> +#define F81534A_GET_REGISTER		F81232_GET_REGISTER
> +#define F81534A_SET_REGISTER		F81232_SET_REGISTER
> +#define F81534A_ACCESS_REG_RETRY	2
>  
>  #define SERIAL_BASE_ADDRESS		0x0120
>  #define RECEIVE_BUFFER_REGISTER		(0x00 + SERIAL_BASE_ADDRESS)
> @@ -83,6 +93,10 @@ MODULE_DEVICE_TABLE(usb, id_table);
>  #define F81232_F81232_TYPE		1
>  #define F81232_F81534A_TYPE		2
>  
> +#define F81534A_MAX_PORT		12
> +#define F81534A_CTRL_TIMER		1000
> +#define F81534A_CTRL_RETRY		15
> +
>  /* Serial port self GPIO control, 2bytes [control&output data][input data] */
>  #define F81534A_GPIO_REG		0x10e
>  #define F81534A_GPIO_MODE2_DIR		BIT(6) /* 1: input, 0: output */
> @@ -92,6 +106,16 @@ MODULE_DEVICE_TABLE(usb, id_table);
>  #define F81534A_GPIO_MODE1_OUTPUT	BIT(1)
>  #define F81534A_GPIO_MODE0_OUTPUT	BIT(0)
>  
> +#define F81534A_CMD_ENABLE_PORT		0x116
> +#define F81534A_CMD_PORT_STATUS		0x117
> +
> +/*
> + * Control device global GPIO control,
> + * 2bytes [control&output data][input data]
> + */
> +#define F81534A_CTRL_GPIO_REG		0x1601
> +#define F81534A_CTRL_GPIO_MAX_PIN	3
> +
>  struct f81232_private {
>  	struct mutex lock;
>  	u8 modem_control;
> @@ -106,10 +130,27 @@ struct f81232_private {
>  	void (*process_read_urb)(struct urb *urb);
>  };
>  
> +struct f81534a_ctrl_private {
> +	struct usb_interface *intf;
> +	struct mutex lock;
> +	int device_idx;
> +};
> +
> +struct f81534a_device {
> +	struct list_head list;
> +	struct usb_interface *intf;
> +	int check_index;
> +	int check_retry;
> +};
> +
>  static u32 const baudrate_table[] = { 115200, 921600, 1152000, 1500000 };
>  static u8 const clock_table[] = { F81232_CLK_1_846_MHZ, F81232_CLK_14_77_MHZ,
>  				F81232_CLK_18_46_MHZ, F81232_CLK_24_MHZ };
>  
> +struct delayed_work f81534a_generate_worker;
> +static DEFINE_MUTEX(device_mutex);
> +static LIST_HEAD(device_list);
> +
>  static int calc_baud_divisor(speed_t baudrate, speed_t clockrate)
>  {
>  	if (!baudrate)
> @@ -859,6 +900,281 @@ static void f81232_lsr_worker(struct work_struct *work)
>  		dev_warn(&port->dev, "read LSR failed: %d\n", status);
>  }
>  
> +static int f81534a_ctrl_get_register(struct usb_device *dev, u16 reg, u16 size,
> +					void *val)
> +{
> +	int retry = F81534A_ACCESS_REG_RETRY;
> +	int status;
> +	u8 *tmp;
> +
> +	tmp = kmalloc(size, GFP_KERNEL);
> +	if (!tmp)
> +		return -ENOMEM;
> +
> +	while (retry--) {
> +		status = usb_control_msg(dev,
> +					usb_rcvctrlpipe(dev, 0),
> +					F81534A_REGISTER_REQUEST,
> +					F81534A_GET_REGISTER,
> +					reg,
> +					0,
> +					tmp,
> +					size,
> +					USB_CTRL_GET_TIMEOUT);
> +		if (status != size) {
> +			status = usb_translate_errors(status);
> +			if (status == -EIO)
> +				continue;
> +
> +			status = -EIO;
> +		} else {
> +			status = 0;
> +			memcpy(val, tmp, size);
> +		}
> +
> +		break;
> +	}
> +
> +	if (status) {
> +		dev_err(&dev->dev, "get reg: %x, failed status: %d\n", reg,
> +				status);
> +	}
> +
> +	kfree(tmp);
> +	return status;
> +}
> +
> +static int f81534a_ctrl_set_register(struct usb_device *dev, u16 reg, u16 size,
> +					void *val)
> +{
> +	int retry = F81534A_ACCESS_REG_RETRY;
> +	int status;
> +	u8 *tmp;
> +
> +	tmp = kmalloc(size, GFP_KERNEL);
> +	if (!tmp)
> +		return -ENOMEM;
> +
> +	memcpy(tmp, val, size);
> +
> +	while (retry--) {
> +		status = usb_control_msg(dev,
> +					usb_sndctrlpipe(dev, 0),
> +					F81534A_REGISTER_REQUEST,
> +					F81534A_SET_REGISTER,
> +					reg,
> +					0,
> +					tmp,
> +					size,
> +					USB_CTRL_SET_TIMEOUT);
> +		if (status != size) {
> +			status = usb_translate_errors(status);
> +			if (status == -EIO)
> +				continue;
> +
> +			status = -EIO;
> +		} else {
> +			status = 0;
> +		}
> +
> +		break;
> +	}
> +
> +	if (status) {
> +		dev_err(&dev->dev, "set ctrl reg: %x, failed status: %d\n", reg,
> +				status);
> +	}
> +
> +	kfree(tmp);
> +	return status;
> +}
> +
> +static int f81534a_ctrl_generate_ports(struct usb_interface *intf,
> +					struct f81534a_device *device)
> +{
> +	struct usb_device *dev = interface_to_usbdev(intf);
> +	uint32_t port_status;
> +	u8 enable[2];
> +	u8 tmp;
> +	u8 mask;
> +	int status;
> +
> +	/* enable all ports */
> +	mask = F81534A_GPIO_MODE2_DIR | F81534A_GPIO_MODE1_DIR |
> +			F81534A_GPIO_MODE0_DIR;
> +	enable[0] = 0xff;
> +	enable[1] = 0x8f;
> +
> +	status = f81534a_ctrl_set_register(dev, F81534A_CMD_ENABLE_PORT,
> +			sizeof(enable), enable);
> +	if (status) {
> +		dev_warn(&dev->dev, "set CMD_ENABLE_PORT failed: %d\n", status);
> +		return status;
> +	}
> +
> +	/* get port state */
> +	status = f81534a_ctrl_get_register(dev,
> +			F81534A_CMD_PORT_STATUS, sizeof(port_status),
> +			&port_status);
> +	if (status) {
> +		dev_warn(&dev->dev, "get CMD_PORT_STATUS failed: %d\n", status);
> +		return status;
> +	}
> +
> +	port_status >>= 16;
> +
> +	for (; device->check_index < F81534A_MAX_PORT; ++device->check_index) {
> +		/* check port is exist, skip when not exist */
> +		if (!(port_status & BIT(device->check_index)))
> +			continue;
> +
> +		/*
> +		 * All gpio for a port is default to input mode. It'll change
> +		 * to RS232 mode after f81232_port_probe()/f81534a_port_init()
> +		 * (2 output 0 & 1 input with pull high).
> +		 */
> +		status = f81534a_ctrl_get_register(dev,
> +					F81534A_CTRL_GPIO_REG +
> +					device->check_index, sizeof(tmp), &tmp);
> +		if (status) {
> +			dev_warn(&dev->dev, "get CTRL_GPIO_REG failed: %d\n",
> +					status);
> +			return status;
> +		}
> +
> +		/* Check port had inited by f81232_port_probe() */
> +		if ((tmp & mask) == mask)
> +			break;
> +	}
> +
> +	if (device->check_index < F81534A_MAX_PORT)
> +		return -EAGAIN;
> +
> +	return 0;
> +}
> +
> +static void f81534a_ctrl_generate_worker(struct work_struct *work)
> +{
> +	struct f81534a_device *device;
> +	int status;
> +
> +	mutex_lock(&device_mutex);
> +	list_for_each_entry(device, &device_list, list) {
> +		if (device->check_index >= F81534A_MAX_PORT)
> +			continue;
> +
> +		if (device->check_retry >= F81534A_CTRL_RETRY)
> +			continue;
> +
> +		device->check_retry++;
> +
> +		status = f81534a_ctrl_generate_ports(device->intf, device);
> +		if (status == -EAGAIN) {
> +			dev_dbg(&device->intf->dev, "delayed generating: %d\n",
> +					device->check_retry);
> +
> +			schedule_delayed_work(&f81534a_generate_worker,
> +					msecs_to_jiffies(F81534A_CTRL_TIMER));
> +			break;
> +		} else if (!status) {
> +			/* make this device generated */
> +			device->check_index = F81534A_MAX_PORT;
> +
> +			dev_dbg(&device->intf->dev, "generated complete\n");
> +		} else {
> +			/* skip this device to generate */
> +			device->check_index = F81534A_MAX_PORT;
> +
> +			dev_err(&device->intf->dev,
> +					"error: %d, do next device generate\n",
> +					status);
> +		}
> +	}
> +
> +	mutex_unlock(&device_mutex);
> +}
> +
> +static int f81534a_ctrl_probe(struct usb_interface *intf,
> +				const struct usb_device_id *id)
> +{
> +	struct usb_device *dev = interface_to_usbdev(intf);
> +	struct f81534a_ctrl_private *priv;
> +	struct f81534a_device *device;
> +
> +	priv = devm_kzalloc(&intf->dev, sizeof(*priv), GFP_KERNEL);
> +	if (!priv)
> +		return -ENOMEM;
> +
> +	device = devm_kzalloc(&intf->dev, sizeof(*device), GFP_KERNEL);
> +	if (!device)
> +		return -ENOMEM;
> +
> +	mutex_init(&priv->lock);
> +	usb_set_intfdata(intf, priv);
> +
> +	INIT_LIST_HEAD(&device->list);
> +	device->intf = intf;
> +
> +	mutex_lock(&device_mutex);
> +	list_add_tail(&device->list, &device_list);
> +	mutex_unlock(&device_mutex);
> +
> +	dev = usb_get_dev(dev);
> +	schedule_delayed_work(&f81534a_generate_worker,
> +				msecs_to_jiffies(F81534A_CTRL_TIMER));
> +
> +	return 0;
> +}
> +
> +static void f81534a_ctrl_disconnect(struct usb_interface *intf)
> +{
> +	struct f81534a_ctrl_private *priv;
> +	struct f81534a_device *device;
> +	struct usb_device *dev;
> +
> +	mutex_lock(&device_mutex);
> +
> +	list_for_each_entry(device, &device_list, list) {
> +		if (device->intf == intf) {
> +			list_del(&device->list);
> +
> +			priv = usb_get_intfdata(intf);
> +			dev = interface_to_usbdev(intf);
> +			usb_put_dev(dev);
> +			break;
> +		}
> +	}
> +
> +	mutex_unlock(&device_mutex);
> +}
> +
> +static int f81534a_ctrl_suspend(struct usb_interface *intf,
> +					pm_message_t message)
> +{
> +	struct f81534a_device *device;
> +
> +	flush_delayed_work(&f81534a_generate_worker);
> +
> +	mutex_lock(&device_mutex);
> +
> +	list_for_each_entry(device, &device_list, list) {
> +		device->check_index = 0;
> +		device->check_retry = 0;
> +	}
> +
> +	mutex_unlock(&device_mutex);
> +
> +	return 0;
> +}
> +
> +static int f81534a_ctrl_resume(struct usb_interface *intf)
> +{
> +	schedule_delayed_work(&f81534a_generate_worker,
> +				msecs_to_jiffies(F81534A_CTRL_TIMER));
> +
> +	return 0;
> +}
> +
>  static int f81232_port_probe(struct usb_serial_port *port)
>  {
>  	struct f81232_private *priv;
> @@ -976,7 +1292,45 @@ static struct usb_serial_driver * const serial_drivers[] = {
>  	NULL,
>  };
>  
> -module_usb_serial_driver(serial_drivers, id_table);
> +static struct usb_driver f81534a_ctrl_driver = {
> +	.name =		"f81534a_ctrl",
> +	.id_table =	f81534a_ctrl_id_table,
> +	.probe =	f81534a_ctrl_probe,
> +	.disconnect =	f81534a_ctrl_disconnect,
> +	.suspend =	f81534a_ctrl_suspend,
> +	.resume =	f81534a_ctrl_resume,
> +};
> +
> +static int __init f81232_init(void)
> +{
> +	int status;
> +
> +	INIT_DELAYED_WORK(&f81534a_generate_worker,
> +			f81534a_ctrl_generate_worker);
> +
> +	status = usb_register_driver(&f81534a_ctrl_driver, THIS_MODULE,
> +			KBUILD_MODNAME);
> +	if (status)
> +		return status;
> +
> +	status = usb_serial_register_drivers(serial_drivers, KBUILD_MODNAME,
> +			id_table);
> +	if (status) {
> +		usb_deregister(&f81534a_ctrl_driver);
> +		return status;
> +	}
> +
> +	return 0;
> +}
> +
> +static void __exit f81232_exit(void)
> +{
> +	usb_serial_deregister_drivers(serial_drivers);
> +	usb_deregister(&f81534a_ctrl_driver);
> +}
> +
> +module_init(f81232_init);
> +module_exit(f81232_exit);
>  
>  MODULE_DESCRIPTION("Fintek F81232/532A/534A/535/536 USB to serial driver");
>  MODULE_AUTHOR("Greg Kroah-Hartman <gregkh@...uxfoundation.org>");

Johan

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