From 6915c0e487c822e2436683e14302c0b8a6155cc7 Mon Sep 17 00:00:00 2001 From: Tomas Hlavacek Date: Thu, 6 Sep 2012 03:17:18 +0200 Subject: [PATCH] tty: uartclk value from serial_core exposed to sysfs Added file /sys/devices/.../tty/ttySX/uartclk to allow reading uartclk value in struct uart_port in serial_core via sysfs. tty_register_device() has been generalized and refactored in order to add support for setting drvdata and attribute_group to the device. Signed-off-by: Tomas Hlavacek Signed-off-by: Greg Kroah-Hartman --- Documentation/ABI/testing/sysfs-tty | 9 ++++ drivers/tty/serial/serial_core.c | 34 +++++++++++++- drivers/tty/tty_io.c | 69 ++++++++++++++++++++++++----- include/linux/tty.h | 4 ++ 4 files changed, 104 insertions(+), 12 deletions(-) diff --git a/Documentation/ABI/testing/sysfs-tty b/Documentation/ABI/testing/sysfs-tty index b138b663bf54..0c430150d929 100644 --- a/Documentation/ABI/testing/sysfs-tty +++ b/Documentation/ABI/testing/sysfs-tty @@ -17,3 +17,12 @@ Description: device, like 'tty1'. The file supports poll() to detect virtual console switches. + +What: /sys/class/tty/ttyS0/uartclk +Date: Sep 2012 +Contact: Tomas Hlavacek +Description: + Shows the current uartclk value associated with the + UART port in serial_core, that is bound to TTY like ttyS0. + uartclk = 16 * baud_base + diff --git a/drivers/tty/serial/serial_core.c b/drivers/tty/serial/serial_core.c index 19993d89db37..f629bdf2a8cf 100644 --- a/drivers/tty/serial/serial_core.c +++ b/drivers/tty/serial/serial_core.c @@ -2309,6 +2309,36 @@ struct tty_driver *uart_console_device(struct console *co, int *index) return p->tty_driver; } +static ssize_t uart_get_attr_uartclk(struct device *dev, + struct device_attribute *attr, char *buf) +{ + int ret; + + struct tty_port *port = dev_get_drvdata(dev); + struct uart_state *state = container_of(port, struct uart_state, port); + mutex_lock(&state->port.mutex); + ret = snprintf(buf, PAGE_SIZE, "%d\n", state->uart_port->uartclk); + mutex_unlock(&state->port.mutex); + + return ret; +} + +static DEVICE_ATTR(uartclk, S_IRUSR | S_IRGRP, uart_get_attr_uartclk, NULL); + +static struct attribute *tty_dev_attrs[] = { + &dev_attr_uartclk.attr, + NULL, + }; + +static struct attribute_group tty_dev_attr_group = { + .attrs = tty_dev_attrs, + }; + +static const struct attribute_group *tty_dev_attr_groups[] = { + &tty_dev_attr_group, + NULL + }; + /** * uart_add_one_port - attach a driver-defined port structure * @drv: pointer to the uart low level driver structure for this port @@ -2362,8 +2392,8 @@ int uart_add_one_port(struct uart_driver *drv, struct uart_port *uport) * Register the port whether it's detected or not. This allows * setserial to be used to alter this ports parameters. */ - tty_dev = tty_port_register_device(port, drv->tty_driver, uport->line, - uport->dev); + tty_dev = tty_register_device_attr(drv->tty_driver, uport->line, + uport->dev, port, tty_dev_attr_groups); if (likely(!IS_ERR(tty_dev))) { device_set_wakeup_capable(tty_dev, 1); } else { diff --git a/drivers/tty/tty_io.c b/drivers/tty/tty_io.c index d3bf91a29303..dcb30d55d39c 100644 --- a/drivers/tty/tty_io.c +++ b/drivers/tty/tty_io.c @@ -3041,9 +3041,39 @@ static int tty_cdev_add(struct tty_driver *driver, dev_t dev, struct device *tty_register_device(struct tty_driver *driver, unsigned index, struct device *device) { - struct device *ret; + return tty_register_device_attr(driver, index, device, NULL, NULL); +} +EXPORT_SYMBOL(tty_register_device); + +/** + * tty_register_device_attr - register a tty device + * @driver: the tty driver that describes the tty device + * @index: the index in the tty driver for this tty device + * @device: a struct device that is associated with this tty device. + * This field is optional, if there is no known struct device + * for this tty device it can be set to NULL safely. + * @drvdata: Driver data to be set to device. + * @attr_grp: Attribute group to be set on device. + * + * Returns a pointer to the struct device for this tty device + * (or ERR_PTR(-EFOO) on error). + * + * This call is required to be made to register an individual tty device + * if the tty driver's flags have the TTY_DRIVER_DYNAMIC_DEV bit set. If + * that bit is not set, this function should not be called by a tty + * driver. + * + * Locking: ?? + */ +struct device *tty_register_device_attr(struct tty_driver *driver, + unsigned index, struct device *device, + void *drvdata, + const struct attribute_group **attr_grp) +{ char name[64]; - dev_t dev = MKDEV(driver->major, driver->minor_start) + index; + dev_t devt = MKDEV(driver->major, driver->minor_start) + index; + struct device *dev = NULL; + int retval = -ENODEV; bool cdev = false; if (index >= driver->num) { @@ -3058,19 +3088,38 @@ struct device *tty_register_device(struct tty_driver *driver, unsigned index, tty_line_name(driver, index, name); if (!(driver->flags & TTY_DRIVER_DYNAMIC_ALLOC)) { - int error = tty_cdev_add(driver, dev, index, 1); - if (error) - return ERR_PTR(error); + retval = tty_cdev_add(driver, devt, index, 1); + if (retval) + goto error; cdev = true; } - ret = device_create(tty_class, device, dev, NULL, name); - if (IS_ERR(ret) && cdev) - cdev_del(&driver->cdevs[index]); + dev = kzalloc(sizeof(*dev), GFP_KERNEL); + if (!dev) { + retval = -ENOMEM; + goto error; + } - return ret; + dev->devt = devt; + dev->class = tty_class; + dev->parent = device; + dev_set_name(dev, "%s", name); + dev->groups = attr_grp; + dev_set_drvdata(dev, drvdata); + + retval = device_register(dev); + if (retval) + goto error; + + return dev; + +error: + put_device(dev); + if (cdev) + cdev_del(&driver->cdevs[index]); + return ERR_PTR(retval); } -EXPORT_SYMBOL(tty_register_device); +EXPORT_SYMBOL_GPL(tty_register_device_attr); /** * tty_unregister_device - unregister a tty device diff --git a/include/linux/tty.h b/include/linux/tty.h index 9892121354cd..599d60347bf0 100644 --- a/include/linux/tty.h +++ b/include/linux/tty.h @@ -412,6 +412,10 @@ 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_register_device_attr(struct tty_driver *driver, + unsigned index, struct device *device, + void *drvdata, + const struct attribute_group **attr_grp); 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); -- GitLab