From: Darren Hart <dvhart@linux.intel.com>
To: Linux Kernel Mailing List <linux-kernel@vger.kernel.org>
Cc: Darren Hart <dvhart@linux.intel.com>,
Tomoya MORINAGA <tomoya.rohm@gmail.com>,
Feng Tang <feng.tang@intel.com>,
Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
Alan Cox <alan@linux.intel.com>,
linux-serial@vger.kernel.org
Subject: [PATCH 3/5] pch_uart: Add user_uartclk parameter
Date: Fri, 9 Mar 2012 09:51:50 -0800 [thread overview]
Message-ID: <be97382520873accbb2eebe8a869fe04c730869d.1331315372.git.dvhart@linux.intel.com> (raw)
In-Reply-To: <ae0029b9e1131467232389e4dfa630f50e159de0.1331315372.git.dvhart@linux.intel.com>
In-Reply-To: <cover.1331315372.git.dvhart@linux.intel.com>
For cases where boards with non-default clocks are not yet added to the kernel
or when the clock varies across hardware revisions, it is useful to be
able to specify the UART clock on the kernel command line.
Add the user_uartclk parameter and prefer it, if set, to the default and
board specific UART clock settings. Specify user_uartclock on the command-line
with "pch_uart.user_uartclk=48000000".
Signed-off-by: Darren Hart <dvhart@linux.intel.com>
CC: Tomoya MORINAGA <tomoya.rohm@gmail.com>
CC: Feng Tang <feng.tang@intel.com>
CC: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
CC: Alan Cox <alan@linux.intel.com>
CC: linux-serial@vger.kernel.org
---
drivers/tty/serial/pch_uart.c | 5 +++++
1 files changed, 5 insertions(+), 0 deletions(-)
diff --git a/drivers/tty/serial/pch_uart.c b/drivers/tty/serial/pch_uart.c
index 88a1be0..46f6fbf 100644
--- a/drivers/tty/serial/pch_uart.c
+++ b/drivers/tty/serial/pch_uart.c
@@ -295,6 +295,7 @@ static struct pch_uart_driver_data drv_dat[] = {
static struct eg20t_port *pch_uart_ports[PCH_UART_NR];
#endif
static unsigned int default_baud = 9600;
+static unsigned int user_uartclk = 0;
static const int trigger_level_256[4] = { 1, 64, 128, 224 };
static const int trigger_level_64[4] = { 1, 16, 32, 56 };
static const int trigger_level_16[4] = { 1, 4, 8, 14 };
@@ -372,6 +373,9 @@ static int pch_uart_get_uartclk(void)
{
const char *cmp;
+ if (user_uartclk)
+ return user_uartclk;
+
cmp = dmi_get_system_info(DMI_BOARD_NAME);
if (cmp && strstr(cmp, "CM-iTC"))
return CMITC_UARTCLK;
@@ -1860,3 +1864,4 @@ module_exit(pch_uart_module_exit);
MODULE_LICENSE("GPL v2");
MODULE_DESCRIPTION("Intel EG20T PCH UART PCI Driver");
module_param(default_baud, uint, S_IRUGO);
+module_param(user_uartclk, uint, S_IRUGO);
--
1.7.6.5
next prev parent reply other threads:[~2012-03-09 17:53 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-03-09 17:51 [PATCH 0/5 V3] pch_uart: Cleanups, board quirks, and user uartclk parameter Darren Hart
2012-03-09 17:51 ` [PATCH 1/5] pch_uart: Use uartclk instead of base_baud Darren Hart
2012-03-09 17:51 ` [PATCH 2/5] pch_uart: Add Fish River Island II uart clock quirks Darren Hart
2012-03-09 17:51 ` Darren Hart [this message]
2012-03-09 17:51 ` [PATCH 4/5] pch_uart: Use existing default_baud in setup_console Darren Hart
2012-03-09 17:51 ` [PATCH 5/5] pch_uart: Add module parameter descriptions Darren Hart
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