The patch titled
atmel_serial: keep clock off when it's not needed
has been removed from the -mm tree. Its filename was
atmel_serial-keep-clock-off-when-its-not-needed.patch
This patch was dropped because it was merged into mainline or a subsystem tree
The current -mm tree may be found at http://userweb.kernel.org/~akpm/mmotm/
------------------------------------------------------
Subject: atmel_serial: keep clock off when it's not needed
From: David Brownell <dbrownell@xxxxxxxxxxxxxxxxxxxxx>
The atmel_serial driver is mismanaging its clock by leaving it on at all
times ... the whole point of clock management is to leave it off unless
it's actively needed, which conserves power!!
Although the kernel doesn't actually hang without my fix, it does
discard quite a lot of early console output.
The result still looks correct:
usart users= 1 on 35000000 Hz, for atmel_usart.0
usart users= 0 off 35000000 Hz, for atmel_usart.2
when using ttyS0 as serial console.
[haavard.skinnemoen@xxxxxxxxx: Make sure clock is enabled early for console]
Signed-off-by: David Brownell <dbrownell@xxxxxxxxxxxxxxxxxxxxx>
Signed-off-by: Haavard Skinnemoen <haavard.skinnemoen@xxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
drivers/serial/atmel_serial.c | 17 ++++++++++++++---
1 file changed, 14 insertions(+), 3 deletions(-)
diff -puN drivers/serial/atmel_serial.c~atmel_serial-keep-clock-off-when-its-not-needed drivers/serial/atmel_serial.c
--- a/drivers/serial/atmel_serial.c~atmel_serial-keep-clock-off-when-its-not-needed
+++ a/drivers/serial/atmel_serial.c
@@ -1258,6 +1258,8 @@ static void __devinit atmel_init_port(st
atmel_port->clk = clk_get(&pdev->dev, "usart");
clk_enable(atmel_port->clk);
port->uartclk = clk_get_rate(atmel_port->clk);
+ clk_disable(atmel_port->clk);
+ /* only enable clock when USART is in use */
}
atmel_port->use_dma_rx = data->use_dma_rx;
@@ -1379,6 +1381,8 @@ static int __init atmel_console_setup(st
return -ENODEV;
}
+ clk_enable(atmel_ports[co->index].clk);
+
UART_PUT_IDR(port, -1);
UART_PUT_CR(port, ATMEL_US_RSTSTA | ATMEL_US_RSTRX);
UART_PUT_CR(port, ATMEL_US_TXEN | ATMEL_US_RXEN);
@@ -1403,7 +1407,7 @@ static struct console atmel_console = {
.data = &atmel_uart,
};
-#define ATMEL_CONSOLE_DEVICE &atmel_console
+#define ATMEL_CONSOLE_DEVICE (&atmel_console)
/*
* Early console initialization (before VM subsystem initialized).
@@ -1534,6 +1538,15 @@ static int __devinit atmel_serial_probe(
if (ret)
goto err_add_port;
+ if (atmel_is_console_port(&port->uart)
+ && ATMEL_CONSOLE_DEVICE->flags & CON_ENABLED) {
+ /*
+ * The serial core enabled the clock for us, so undo
+ * the clk_enable() in atmel_console_setup()
+ */
+ clk_disable(port->clk);
+ }
+
device_init_wakeup(&pdev->dev, 1);
platform_set_drvdata(pdev, port);
@@ -1544,7 +1557,6 @@ err_add_port:
port->rx_ring.buf = NULL;
err_alloc_ring:
if (!atmel_is_console_port(&port->uart)) {
- clk_disable(port->clk);
clk_put(port->clk);
port->clk = NULL;
}
@@ -1568,7 +1580,6 @@ static int __devexit atmel_serial_remove
/* "port" is allocated statically, so we shouldn't free it */
- clk_disable(atmel_port->clk);
clk_put(atmel_port->clk);
return ret;
_
Patches currently in -mm which might be from dbrownell@xxxxxxxxxxxxxxxxxxxxx are
linux-next.patch
acpi-fix-acpi_fadt_s4_rtc_wake-comment.patch
spi_gpio-driver.patch
spi_gpio-driver-cleanups.patch
rtc-ds1307-remove-legacy-probe-checks.patch
twl4030-gpio-cleanup-debounce.patch
genirq-warn-when-irqf_disabled-may-be-ignored.patch
genirq-record-irq_level-in-irq_desc.patch
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