[ARM] CPUFREQ: S3C24XX serial CPU frequency scaling support.
Add support for CPU frequency scalling to the S3C24XX serial driver. Signed-off-by: Ben Dooks <ben-linux@fluff.org>
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e24b864ab3
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@ -42,6 +42,7 @@
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#include <linux/serial.h>
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#include <linux/delay.h>
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#include <linux/clk.h>
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#include <linux/cpufreq.h>
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#include <asm/irq.h>
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@ -452,6 +453,8 @@ static void s3c24xx_serial_pm(struct uart_port *port, unsigned int level,
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{
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struct s3c24xx_uart_port *ourport = to_ourport(port);
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ourport->pm_level = level;
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switch (level) {
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case 3:
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if (!IS_ERR(ourport->baudclk) && ourport->baudclk != NULL)
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@ -661,6 +664,7 @@ static void s3c24xx_serial_set_termios(struct uart_port *port,
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ourport->clksrc = clksrc;
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ourport->baudclk = clk;
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ourport->baudclk_rate = clk ? clk_get_rate(clk) : 0;
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}
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switch (termios->c_cflag & CSIZE) {
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@ -890,6 +894,93 @@ static inline int s3c24xx_serial_resetport(struct uart_port *port,
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return (info->reset_port)(port, cfg);
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}
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#ifdef CONFIG_CPU_FREQ
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static int s3c24xx_serial_cpufreq_transition(struct notifier_block *nb,
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unsigned long val, void *data)
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{
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struct s3c24xx_uart_port *port;
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struct uart_port *uport;
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port = container_of(nb, struct s3c24xx_uart_port, freq_transition);
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uport = &port->port;
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/* check to see if port is enabled */
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if (port->pm_level != 0)
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return 0;
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/* try and work out if the baudrate is changing, we can detect
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* a change in rate, but we do not have support for detecting
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* a disturbance in the clock-rate over the change.
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*/
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if (IS_ERR(port->clk))
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goto exit;
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if (port->baudclk_rate == clk_get_rate(port->clk))
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goto exit;
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if (val == CPUFREQ_PRECHANGE) {
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/* we should really shut the port down whilst the
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* frequency change is in progress. */
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} else if (val == CPUFREQ_POSTCHANGE) {
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struct ktermios *termios;
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struct tty_struct *tty;
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if (uport->info == NULL) {
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printk(KERN_WARNING "%s: info NULL\n", __func__);
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goto exit;
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}
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tty = uport->info->port.tty;
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if (tty == NULL) {
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printk(KERN_WARNING "%s: tty is NULL\n", __func__);
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goto exit;
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}
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termios = tty->termios;
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if (termios == NULL) {
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printk(KERN_WARNING "%s: no termios?\n", __func__);
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goto exit;
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}
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s3c24xx_serial_set_termios(uport, termios, NULL);
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}
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exit:
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return 0;
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}
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static inline int s3c24xx_serial_cpufreq_register(struct s3c24xx_uart_port *port)
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{
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port->freq_transition.notifier_call = s3c24xx_serial_cpufreq_transition;
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return cpufreq_register_notifier(&port->freq_transition,
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CPUFREQ_TRANSITION_NOTIFIER);
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}
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static inline void s3c24xx_serial_cpufreq_deregister(struct s3c24xx_uart_port *port)
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{
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cpufreq_unregister_notifier(&port->freq_transition,
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CPUFREQ_TRANSITION_NOTIFIER);
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}
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#else
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static inline int s3c24xx_serial_cpufreq_register(struct s3c24xx_uart_port *port)
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{
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return 0;
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}
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static inline void s3c24xx_serial_cpufreq_deregister(struct s3c24xx_uart_port *port)
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{
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}
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#endif
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/* s3c24xx_serial_init_port
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*
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* initialise a single serial port from the platform device given
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@ -1002,6 +1093,10 @@ int s3c24xx_serial_probe(struct platform_device *dev,
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if (ret < 0)
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printk(KERN_ERR "%s: failed to add clksrc attr.\n", __func__);
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ret = s3c24xx_serial_cpufreq_register(ourport);
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if (ret < 0)
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dev_err(&dev->dev, "failed to add cpufreq notifier\n");
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return 0;
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probe_err:
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@ -1015,6 +1110,7 @@ int s3c24xx_serial_remove(struct platform_device *dev)
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struct uart_port *port = s3c24xx_dev_to_port(&dev->dev);
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if (port) {
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s3c24xx_serial_cpufreq_deregister(to_ourport(port));
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device_remove_file(&dev->dev, &dev_attr_clock_source);
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uart_remove_one_port(&s3c24xx_uart_drv, port);
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}
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@ -33,12 +33,18 @@ struct s3c24xx_uart_info {
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struct s3c24xx_uart_port {
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unsigned char rx_claimed;
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unsigned char tx_claimed;
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unsigned int pm_level;
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unsigned long baudclk_rate;
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struct s3c24xx_uart_info *info;
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struct s3c24xx_uart_clksrc *clksrc;
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struct clk *clk;
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struct clk *baudclk;
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struct uart_port port;
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#ifdef CONFIG_CPU_FREQ
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struct notifier_block freq_transition;
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#endif
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};
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/* conversion functions */
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