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authorDarren Hart <dvhart@linux.intel.com>2012-03-09 09:51:50 -0800
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2012-03-09 12:43:20 -0800
commit2a44feb20bbe3db3b86bc5d976c8647cfda48588 (patch)
tree15afe47ef4d5421daf2da5ace173762cb391920c /drivers/tty
parent077175f08e365629312ce32918e0c8047151763d (diff)
pch_uart: Add user_uartclk parameter
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: Alan Cox <alan@linux.intel.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'drivers/tty')
-rw-r--r--drivers/tty/serial/pch_uart.c5
1 files changed, 5 insertions, 0 deletions
diff --git a/drivers/tty/serial/pch_uart.c b/drivers/tty/serial/pch_uart.c
index 88a1be058a4..46f6fbf41d9 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);