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Commit 30555476 authored by Ben Dooks's avatar Ben Dooks
Browse files

[ARM] CPUFREQ: S3C24XX serial CPU frequency scaling support. 



Add support for CPU frequency scalling to the S3C24XX serial
driver.

Signed-off-by: default avatarBen Dooks <ben-linux@fluff.org>
parent e24b864a

drivers/serial/samsung.c

+96 −0
Original line number Diff line number Diff line
@@ -42,6 +42,7 @@ 
#include <linux/serial.h>

#include <linux/delay.h>

#include <linux/clk.h>

#include <linux/cpufreq.h>



#include <asm/irq.h>
@@ -452,6 +453,8 @@ static void s3c24xx_serial_pm(struct uart_port *port, unsigned int level, 
{

	struct s3c24xx_uart_port *ourport = to_ourport(port);



	ourport->pm_level = level;



	switch (level) {

	case 3:

		if (!IS_ERR(ourport->baudclk) && ourport->baudclk != NULL)
@@ -661,6 +664,7 @@ static void s3c24xx_serial_set_termios(struct uart_port *port, 


		ourport->clksrc = clksrc;

		ourport->baudclk = clk;

		ourport->baudclk_rate = clk ? clk_get_rate(clk) : 0;

	}



	switch (termios->c_cflag & CSIZE) {
@@ -890,6 +894,93 @@ static inline int s3c24xx_serial_resetport(struct uart_port *port, 
	return (info->reset_port)(port, cfg);

}





#ifdef CONFIG_CPU_FREQ



static int s3c24xx_serial_cpufreq_transition(struct notifier_block *nb,

					     unsigned long val, void *data)

{

	struct s3c24xx_uart_port *port;

	struct uart_port *uport;



	port = container_of(nb, struct s3c24xx_uart_port, freq_transition);

	uport = &port->port;



	/* check to see if port is enabled */



	if (port->pm_level != 0)

		return 0;



	/* try and work out if the baudrate is changing, we can detect

	 * a change in rate, but we do not have support for detecting

	 * a disturbance in the clock-rate over the change.

	 */



	if (IS_ERR(port->clk))

		goto exit;



	if (port->baudclk_rate == clk_get_rate(port->clk))

		goto exit;



	if (val == CPUFREQ_PRECHANGE) {

		/* we should really shut the port down whilst the

		 * frequency change is in progress. */



	} else if (val == CPUFREQ_POSTCHANGE) {

		struct ktermios *termios;

		struct tty_struct *tty;



		if (uport->info == NULL) {

			printk(KERN_WARNING "%s: info NULL\n", __func__);

			goto exit;

		}



		tty = uport->info->port.tty;



		if (tty == NULL) {

			printk(KERN_WARNING "%s: tty is NULL\n", __func__);

			goto exit;

		}



		termios = tty->termios;



		if (termios == NULL) {

			printk(KERN_WARNING "%s: no termios?\n", __func__);

			goto exit;

		}



		s3c24xx_serial_set_termios(uport, termios, NULL);

	}



 exit:

	return 0;

}



static inline int s3c24xx_serial_cpufreq_register(struct s3c24xx_uart_port *port)

{

	port->freq_transition.notifier_call = s3c24xx_serial_cpufreq_transition;



	return cpufreq_register_notifier(&port->freq_transition,

					 CPUFREQ_TRANSITION_NOTIFIER);

}



static inline void s3c24xx_serial_cpufreq_deregister(struct s3c24xx_uart_port *port)

{

	cpufreq_unregister_notifier(&port->freq_transition,

				    CPUFREQ_TRANSITION_NOTIFIER);

}



#else

static inline int s3c24xx_serial_cpufreq_register(struct s3c24xx_uart_port *port)

{

	return 0;

}



static inline void s3c24xx_serial_cpufreq_deregister(struct s3c24xx_uart_port *port)

{

}

#endif



/* s3c24xx_serial_init_port

 *

 * initialise a single serial port from the platform device given
@@ -1002,6 +1093,10 @@ int s3c24xx_serial_probe(struct platform_device *dev, 
	if (ret < 0)

		printk(KERN_ERR "%s: failed to add clksrc attr.\n", __func__);



	ret = s3c24xx_serial_cpufreq_register(ourport);

	if (ret < 0)

		dev_err(&dev->dev, "failed to add cpufreq notifier\n");



	return 0;



 probe_err:
@@ -1015,6 +1110,7 @@ int s3c24xx_serial_remove(struct platform_device *dev) 
	struct uart_port *port = s3c24xx_dev_to_port(&dev->dev);



	if (port) {

		s3c24xx_serial_cpufreq_deregister(to_ourport(port));

		device_remove_file(&dev->dev, &dev_attr_clock_source);

		uart_remove_one_port(&s3c24xx_uart_drv, port);

	}

drivers/serial/samsung.h

+6 −0
Original line number Diff line number Diff line
@@ -33,12 +33,18 @@ struct s3c24xx_uart_info { 
struct s3c24xx_uart_port {

	unsigned char			rx_claimed;

	unsigned char			tx_claimed;

	unsigned int			pm_level;

	unsigned long			baudclk_rate;



	struct s3c24xx_uart_info	*info;

	struct s3c24xx_uart_clksrc	*clksrc;

	struct clk			*clk;

	struct clk			*baudclk;

	struct uart_port		port;



#ifdef CONFIG_CPU_FREQ

	struct notifier_block		freq_transition;

#endif

};



/* conversion functions */