Re: [PATCH 4/8] tty: atmel_serial: prepare clk before calling enable

From: Nicolas Ferre
Date: Thu Jun 20 2013 - 03:48:45 EST


On 19/06/2013 13:17, Boris BREZILLON :
Replace clk_enable/disable with clk_prepare_enable/disable_unprepare to
avoid common clk framework warnings.

Signed-off-by: Boris BREZILLON <b.brezillon@xxxxxxxxxxx>

Acked-by: Nicolas Ferre <nicolas.ferre@xxxxxxxxx>

(one comment though)

---
drivers/tty/serial/atmel_serial.c | 41 ++++++++++++++++++++++++++++---------
1 file changed, 31 insertions(+), 10 deletions(-)

diff --git a/drivers/tty/serial/atmel_serial.c b/drivers/tty/serial/atmel_serial.c
index 3467462..691265f 100644
--- a/drivers/tty/serial/atmel_serial.c
+++ b/drivers/tty/serial/atmel_serial.c
@@ -1100,7 +1100,7 @@ static void atmel_serial_pm(struct uart_port *port, unsigned int state,
* Enable the peripheral clock for this serial port.
* This is called on uart_open() or a resume event.
*/
- clk_enable(atmel_port->clk);
+ clk_prepare_enable(atmel_port->clk);

Do we need to check return code here?


/* re-enable interrupts if we disabled some on suspend */
UART_PUT_IER(port, atmel_port->backup_imr);
@@ -1114,7 +1114,7 @@ static void atmel_serial_pm(struct uart_port *port, unsigned int state,
* Disable the peripheral clock for this serial port.
* This is called on uart_close() or a suspend event.
*/
- clk_disable(atmel_port->clk);
+ clk_disable_unprepare(atmel_port->clk);
break;
default:
printk(KERN_ERR "atmel_serial: unknown pm %d\n", state);
@@ -1458,9 +1458,10 @@ static void atmel_of_init_port(struct atmel_uart_port *atmel_port,
/*
* Configure the port from the platform device resource info.
*/
-static void atmel_init_port(struct atmel_uart_port *atmel_port,
+static int atmel_init_port(struct atmel_uart_port *atmel_port,
struct platform_device *pdev)
{
+ int ret;
struct uart_port *port = &atmel_port->uart;
struct atmel_uart_data *pdata = pdev->dev.platform_data;

@@ -1496,9 +1497,19 @@ static void atmel_init_port(struct atmel_uart_port *atmel_port,
/* for console, the clock could already be configured */
if (!atmel_port->clk) {
atmel_port->clk = clk_get(&pdev->dev, "usart");
- clk_enable(atmel_port->clk);
+ if (IS_ERR(atmel_port->clk)) {
+ ret = PTR_ERR(atmel_port->clk);
+ atmel_port->clk = NULL;
+ return ret;
+ }
+ ret = clk_prepare_enable(atmel_port->clk);
+ if (ret) {
+ clk_put(atmel_port->clk);
+ atmel_port->clk = NULL;
+ return ret;
+ }
port->uartclk = clk_get_rate(atmel_port->clk);
- clk_disable(atmel_port->clk);
+ clk_disable_unprepare(atmel_port->clk);
/* only enable clock when USART is in use */
}

@@ -1511,6 +1522,8 @@ static void atmel_init_port(struct atmel_uart_port *atmel_port,
} else {
atmel_port->tx_done_mask = ATMEL_US_TXRDY;
}
+
+ return 0;
}

struct platform_device *atmel_default_console_device; /* the serial console device */
@@ -1601,6 +1614,7 @@ static void __init atmel_console_get_options(struct uart_port *port, int *baud,

static int __init atmel_console_setup(struct console *co, char *options)
{
+ int ret;
struct uart_port *port = &atmel_ports[co->index].uart;
int baud = 115200;
int bits = 8;
@@ -1612,7 +1626,9 @@ static int __init atmel_console_setup(struct console *co, char *options)
return -ENODEV;
}

- clk_enable(atmel_ports[co->index].clk);
+ ret = clk_prepare_enable(atmel_ports[co->index].clk);
+ if (ret)
+ return ret;

UART_PUT_IDR(port, -1);
UART_PUT_CR(port, ATMEL_US_RSTSTA | ATMEL_US_RSTRX);
@@ -1645,6 +1661,7 @@ static struct console atmel_console = {
*/
static int __init atmel_console_init(void)
{
+ int ret;
if (atmel_default_console_device) {
struct atmel_uart_data *pdata =
atmel_default_console_device->dev.platform_data;
@@ -1655,7 +1672,9 @@ static int __init atmel_console_init(void)
port->uart.line = id;

add_preferred_console(ATMEL_DEVICENAME, id, NULL);
- atmel_init_port(port, atmel_default_console_device);
+ ret = atmel_init_port(port, atmel_default_console_device);
+ if (ret)
+ return ret;
register_console(&atmel_console);
}

@@ -1786,7 +1805,9 @@ static int atmel_serial_probe(struct platform_device *pdev)
port->backup_imr = 0;
port->uart.line = ret;

- atmel_init_port(port, pdev);
+ ret = atmel_init_port(port, pdev);
+ if (ret)
+ goto err;

pinctrl = devm_pinctrl_get_select_default(&pdev->dev);
if (IS_ERR(pinctrl)) {
@@ -1812,9 +1833,9 @@ static int atmel_serial_probe(struct platform_device *pdev)
&& ATMEL_CONSOLE_DEVICE->flags & CON_ENABLED) {
/*
* The serial core enabled the clock for us, so undo
- * the clk_enable() in atmel_console_setup()
+ * the clk_prepare_enable() in atmel_console_setup()
*/
- clk_disable(port->clk);
+ clk_disable_unprepare(port->clk);
}
#endif




--
Nicolas Ferre
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