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dm: Add a uclass for serial devices

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Serial devices support simple byte input/output and a few operations to find
out whether data is available. Add a basic uclass for serial devices to be
used by drivers that are converted to driver model.

Signed-off-by: Simon Glass <sjg@chromium.org>
This commit is contained in:
Simon Glass 2014-09-04 16:27:26 -06:00
parent 1f359e3611
commit 57d92753d4
4 changed files with 310 additions and 0 deletions
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92
include/serial.h
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@ -72,4 +72,96 @@ extern int write_port(struct stdio_dev *port, char *buf);
extern int read_port(struct stdio_dev *port, char *buf, int size);
#endif
struct udevice;
/**
* struct struct dm_serial_ops - Driver model serial operations
*
* The uclass interface is implemented by all serial devices which use
* driver model.
*/
struct dm_serial_ops {
/**
* setbrg() - Set up the baud rate generator
*
* Adjust baud rate divisors to set up a new baud rate for this
* device. Not all devices will support all rates. If the rate
* cannot be supported, the driver is free to select the nearest
* available rate. or return -EINVAL if this is not possible.
*
* @dev: Device pointer
* @baudrate: New baud rate to use
* @return 0 if OK, -ve on error
*/
int (*setbrg)(struct udevice *dev, int baudrate);
/**
* getc() - Read a character and return it
*
* If no character is available, this should return -EAGAIN without
* waiting.
*
* @dev: Device pointer
* @return character (0..255), -ve on error
*/
int (*getc)(struct udevice *dev);
/**
* putc() - Write a character
*
* @dev: Device pointer
* @ch: character to write
* @return 0 if OK, -ve on error
*/
int (*putc)(struct udevice *dev, const char ch);
/**
* pending() - Check if input/output characters are waiting
*
* This can be used to return an indication of the number of waiting
* characters if the driver knows this (e.g. by looking at the FIFO
* level). It is acceptable to return 1 if an indeterminant number
* of characters is waiting.
*
* This method is optional.
*
* @dev: Device pointer
* @input: true to check input characters, false for output
* @return number of waiting characters, 0 for none, -ve on error
*/
int (*pending)(struct udevice *dev, bool input);
/**
* clear() - Clear the serial FIFOs/holding registers
*
* This method is optional.
*
* This quickly clears any input/output characters from the UART.
* If this is not possible, but characters still exist, then it
* is acceptable to return -EAGAIN (try again) or -EINVAL (not
* supported).
*
* @dev: Device pointer
* @return 0 if OK, -ve on error
*/
int (*clear)(struct udevice *dev);
#if CONFIG_POST & CONFIG_SYS_POST_UART
/**
* loop() - Control serial device loopback mode
*
* @dev: Device pointer
* @on: 1 to turn loopback on, 0 to turn if off
*/
int (*loop)(struct udevice *dev, int on);
#endif
};
/**
* struct serial_dev_priv - information about a device used by the uclass
*
* @sdev: stdio device attached to this uart
*/
struct serial_dev_priv {
struct stdio_dev *sdev;
};
/* Access the serial operations for a device */
#define serial_get_ops(dev) ((struct dm_serial_ops *)(dev)->driver->ops)
#endif