Re: [PATCH 1/1] [RFC] uartclk from serial_core exposed to sysfs
> + /* > + * 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(>port.mutex); > + > + return count; This breaks if for example the port is in use. Fixing that looks pretty horrible as you need a valid tty pointer to stop and restart the pot. It's also not calling the verfy method of the port as is expected. At minimum I think you need to be able to do the same work uart_get_info/uart_set_info perform and with the same checks on ->verify etc. I'm not 100% sure the drvdata on the tty_dev is clear to use. It does seem to be in all the drivers I looked at. I'd rather however it pointed to the tty_port that each tty device has (or very soon will be required to have). You can still find the uart_foo structs from that but it means we can do the dev_set_drvdata() in a consistent manner for all tty devices in the kernel. That in turn means we can make some of the sysfs valid the same way. I want to have think about the setting side of it. Can you submit a revised version that just allows the user to read the value this way but does the drvdata setting etc and sysfs node create/delete. I'll merge that and we can throw it over the parapet and see if anything explodes. To make the setting part work properly I think I need to sort out uart_get_info/set_info so the core part of it can be called with kernel space structures and the caller handling locks. Alan -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
Re: [PATCH 1/1] [RFC] uartclk from serial_core exposed to sysfs
+ /* + * 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; This breaks if for example the port is in use. Fixing that looks pretty horrible as you need a valid tty pointer to stop and restart the pot. It's also not calling the verfy method of the port as is expected. At minimum I think you need to be able to do the same work uart_get_info/uart_set_info perform and with the same checks on -verify etc. I'm not 100% sure the drvdata on the tty_dev is clear to use. It does seem to be in all the drivers I looked at. I'd rather however it pointed to the tty_port that each tty device has (or very soon will be required to have). You can still find the uart_foo structs from that but it means we can do the dev_set_drvdata() in a consistent manner for all tty devices in the kernel. That in turn means we can make some of the sysfs valid the same way. I want to have think about the setting side of it. Can you submit a revised version that just allows the user to read the value this way but does the drvdata setting etc and sysfs node create/delete. I'll merge that and we can throw it over the parapet and see if anything explodes. To make the setting part work properly I think I need to sort out uart_get_info/set_info so the core part of it can be called with kernel space structures and the caller handling locks. Alan -- To unsubscribe from this list: send the line unsubscribe linux-kernel in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
Re: [PATCH 1/1] [RFC] uartclk from serial_core exposed to sysfs
Hello Marek,
On Tue, Aug 14, 2012 at 2:50 PM, Marek Vasut wrote:
> Dear Tomas Hlavacek,
>
>> +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));
>
> You don't need this cast here.
Yes, you are right. Thanks.
>
>> + mutex_lock(>port.mutex);
>> + ret = snprintf(buf, PAGE_SIZE, "%d\n", state->uart_port->uartclk);
>
> Do you really need such a large buffer (PAGE_SIZE) ?
Well no, but I believe that I get the buffer of length equal to
PAGE_SIZE anyway. Documentation/filesystems/sysfs.txt says so on line
179.
>
>> + mutex_unlock(>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, );
>> + if (ret)
>> + return ret;
>> +
>> + mutex_lock(>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;
>
> This magic value here would use some documentation.
OK. Do you think this would be sufficient comment?:
/*
* Check value: baud_base does not make sense to be set below 9600
* and since uartclock = (baud_base * 16) it has to be equal or greater than
* 9600 * 16 = 153600.
*/
PATCHv2 follows.
Tomas
--
Tomáš Hlaváček
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Re: [PATCH 1/1] [RFC] uartclk from serial_core exposed to sysfs
Hello Marek,
On Tue, Aug 14, 2012 at 2:50 PM, Marek Vasut marek.va...@gmail.com wrote:
Dear Tomas Hlavacek,
+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));
You don't need this cast here.
Yes, you are right. Thanks.
+ mutex_lock(state-port.mutex);
+ ret = snprintf(buf, PAGE_SIZE, %d\n, state-uart_port-uartclk);
Do you really need such a large buffer (PAGE_SIZE) ?
Well no, but I believe that I get the buffer of length equal to
PAGE_SIZE anyway. Documentation/filesystems/sysfs.txt says so on line
179.
+ 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;
This magic value here would use some documentation.
OK. Do you think this would be sufficient comment?:
/*
* Check value: baud_base does not make sense to be set below 9600
* and since uartclock = (baud_base * 16) it has to be equal or greater than
* 9600 * 16 = 153600.
*/
PATCHv2 follows.
Tomas
--
Tomáš Hlaváček tmshl...@gmail.com
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Re: [PATCH 1/1] [RFC] uartclk from serial_core exposed to sysfs
Dear Tomas Hlavacek,
> 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
> ---
> 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));
You don't need this cast here.
> + mutex_lock(>port.mutex);
> + ret = snprintf(buf, PAGE_SIZE, "%d\n", state->uart_port->uartclk);
Do you really need such a large buffer (PAGE_SIZE) ?
> + mutex_unlock(>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, );
> + if (ret)
> + return ret;
> +
> + mutex_lock(>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;
This magic value here would use some documentation.
> + mutex_unlock(>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, _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(>mutex);
>
> /*
> + * Remove uartclk file from sysfs.
> + */
> + device_remove_file(tty_lookup_device(drv->tty_driver, uport->line),
> + _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, , 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
>
[PATCH 1/1] [RFC] uartclk from serial_core exposed to sysfs
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
---
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(>port.mutex);
+ ret = snprintf(buf, PAGE_SIZE, "%d\n", state->uart_port->uartclk);
+ mutex_unlock(>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, );
+ if (ret)
+ return ret;
+
+ mutex_lock(>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(>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, _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(>mutex);
/*
+* Remove uartclk file from sysfs.
+*/
+ device_remove_file(tty_lookup_device(drv->tty_driver, uport->line),
+ _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, , 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
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Please read the FAQ
[PATCH 1/1] [RFC] uartclk from serial_core exposed to sysfs
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 tmshl...@gmail.com
---
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
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the body of a message to majord...@vger.kernel.org
More majordomo info at
Re: [PATCH 1/1] [RFC] uartclk from serial_core exposed to sysfs
Dear Tomas Hlavacek,
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 tmshl...@gmail.com
---
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));
You don't need this cast here.
+ mutex_lock(state-port.mutex);
+ ret = snprintf(buf, PAGE_SIZE, %d\n, state-uart_port-uartclk);
Do you really need such a large buffer (PAGE_SIZE) ?
+ 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;
This magic value here would use some documentation.
+ 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);
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