Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755339Ab2HNMua (ORCPT ); Tue, 14 Aug 2012 08:50:30 -0400 Received: from mail-we0-f174.google.com ([74.125.82.174]:46481 "EHLO mail-we0-f174.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755190Ab2HNMu1 (ORCPT ); Tue, 14 Aug 2012 08:50:27 -0400 From: Marek Vasut To: Tomas Hlavacek Subject: Re: [PATCH 1/1] [RFC] uartclk from serial_core exposed to sysfs Date: Tue, 14 Aug 2012 14:50:23 +0200 User-Agent: KMail/1.13.7 (Linux/3.4-trunk-amd64; KDE/4.8.4; x86_64; ; ) Cc: gregkh@linuxfoundation.org, alan@linux.intel.com, linux-serial@vger.kernel.org, linux-kernel@vger.kernel.org References: <1344929718-22736-1-git-send-email-tmshlvck@gmail.com> In-Reply-To: <1344929718-22736-1-git-send-email-tmshlvck@gmail.com> MIME-Version: 1.0 Content-Type: Text/Plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Message-Id: <201208141450.23453.marek.vasut@gmail.com> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 5008 Lines: 149 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(&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); -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/