Support for read/modify of uartclk via sysfs added. It may prove useful with some no-name cards that has different oscillator speeds and no distinguishing PCI IDs to allow autodetection. It allows better integration with udev and/or init scripts.
Signed-off-by: Tomas Hlavacek <[email protected]> --- drivers/tty/serial/serial_core.c | 54 ++++++++++++++++++++++++++++++++++++++ drivers/tty/tty_io.c | 17 ++++++++++++ include/linux/tty.h | 2 ++ 3 files changed, 73 insertions(+) diff --git a/drivers/tty/serial/serial_core.c b/drivers/tty/serial/serial_core.c index a21dc8e..059b438 100644 --- a/drivers/tty/serial/serial_core.c +++ b/drivers/tty/serial/serial_core.c @@ -2293,6 +2293,46 @@ struct tty_driver *uart_console_device(struct console *co, int *index) return p->tty_driver; } +static ssize_t get_attr_uartclk(struct device *dev, + struct device_attribute *attr, char *buf) +{ + int ret; + + struct uart_state *state = (struct uart_state *)(dev_get_drvdata(dev)); + mutex_lock(&state->port.mutex); + ret = snprintf(buf, PAGE_SIZE, "%d\n", state->uart_port->uartclk); + mutex_unlock(&state->port.mutex); + return ret; +} + +static ssize_t set_attr_uartclk(struct device *dev, + struct device_attribute *attr, const char *buf, size_t count) +{ + struct uart_state *state = (struct uart_state *)(dev_get_drvdata(dev)); + unsigned int val; + int ret; + + ret = kstrtouint(buf, 10, &val); + if (ret) + return ret; + + mutex_lock(&state->port.mutex); + + /* + * Check value: baud_base has to be more than 9600 + * and uartclock = baud_base * 16 . + */ + if (val >= 153600) + state->uart_port->uartclk = val; + + mutex_unlock(&state->port.mutex); + + return count; +} + +static DEVICE_ATTR(uartclk, S_IRUGO | S_IWUSR, get_attr_uartclk, + set_attr_uartclk); + /** * uart_add_one_port - attach a driver-defined port structure * @drv: pointer to the uart low level driver structure for this port @@ -2355,6 +2395,14 @@ int uart_add_one_port(struct uart_driver *drv, struct uart_port *uport) } /* + * Expose uartclk in sysfs. Use driverdata of the tty device for + * referencing the UART port. + */ + dev_set_drvdata(tty_dev, state); + if (device_create_file(tty_dev, &dev_attr_uartclk) < 0) + dev_err(tty_dev, "Failed to add uartclk attr\n"); + + /* * Ensure UPF_DEAD is not set. */ uport->flags &= ~UPF_DEAD; @@ -2397,6 +2445,12 @@ int uart_remove_one_port(struct uart_driver *drv, struct uart_port *uport) mutex_unlock(&port->mutex); /* + * Remove uartclk file from sysfs. + */ + device_remove_file(tty_lookup_device(drv->tty_driver, uport->line), + &dev_attr_uartclk); + + /* * Remove the devices from the tty layer */ tty_unregister_device(drv->tty_driver, uport->line); diff --git a/drivers/tty/tty_io.c b/drivers/tty/tty_io.c index b425c79..8ea8622 100644 --- a/drivers/tty/tty_io.c +++ b/drivers/tty/tty_io.c @@ -3049,6 +3049,23 @@ void tty_unregister_device(struct tty_driver *driver, unsigned index) } EXPORT_SYMBOL(tty_unregister_device); +/* + * tty_lookup_device - lookup a tty device + * @driver: the tty driver that describes the tty device + * @index: the index in the tty driver for this tty device + * + * This function returns a struct device pointer when device has + * been found and NULL otherwise. + * + * Locking: ?? + */ +struct device *tty_lookup_device(struct tty_driver *driver, unsigned index) +{ + dev_t devt = MKDEV(driver->major, driver->minor_start) + index; + return class_find_device(tty_class, NULL, &devt, dev_match_devt); +} +EXPORT_SYMBOL(tty_lookup_device); + struct tty_driver *__alloc_tty_driver(int lines, struct module *owner) { struct tty_driver *driver; diff --git a/include/linux/tty.h b/include/linux/tty.h index 9f47ab5..5d408a1 100644 --- a/include/linux/tty.h +++ b/include/linux/tty.h @@ -410,6 +410,8 @@ extern int tty_register_driver(struct tty_driver *driver); extern int tty_unregister_driver(struct tty_driver *driver); extern struct device *tty_register_device(struct tty_driver *driver, unsigned index, struct device *dev); +extern struct device *tty_lookup_device(struct tty_driver *driver, + unsigned index); extern void tty_unregister_device(struct tty_driver *driver, unsigned index); extern int tty_read_raw_data(struct tty_struct *tty, unsigned char *bufp, int buflen); -- 1.7.10.4 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
