[3/9] serial: samsung: switch to clkdev based clock lookup

Message ID 1317064038-32428-4-git-send-email-thomas.abraham@linaro.org
State New
Headers show

Commit Message

thomas.abraham@linaro.org Sept. 26, 2011, 7:07 p.m.
Instead of using clock names supplied in platform data, use a generic
clock name 'clk_uart_baud' to look up clocks. The platform code should
register clocks with the name 'clk_uart_baud' which can be used by the
baud rate generator. The clock lookup and selection of the best clock
as baud rate clock is reworked.

Cc: Ben Dooks <ben-linux@fluff.org>
Signed-off-by: Thomas Abraham <thomas.abraham@linaro.org>
---
 arch/arm/plat-samsung/include/plat/regs-serial.h |    5 +
 drivers/tty/serial/samsung.c                     |  207 +++++++++-------------
 drivers/tty/serial/samsung.h                     |    4 +
 3 files changed, 95 insertions(+), 121 deletions(-)

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diff --git a/arch/arm/plat-samsung/include/plat/regs-serial.h b/arch/arm/plat-samsung/include/plat/regs-serial.h
index 7207348..b493d8d 100644
--- a/arch/arm/plat-samsung/include/plat/regs-serial.h
+++ b/arch/arm/plat-samsung/include/plat/regs-serial.h
@@ -222,6 +222,10 @@ 
 #define S5PV210_UFSTAT_RXSHIFT	(0)
 
 #define NO_NEED_CHECK_CLKSRC	1
+#define S3C2410_UCON_CLKSEL0	(1 << 0)
+#define S3C2410_UCON_CLKSEL1	(1 << 1)
+#define S3C2410_UCON_CLKSEL2	(1 << 2)
+#define S3C2410_UCON_CLKSEL3	(1 << 3)
 
 #ifndef __ASSEMBLY__
 
@@ -257,6 +261,7 @@  struct s3c2410_uartcfg {
 	unsigned char	   unused;
 	unsigned short	   flags;
 	upf_t		   uart_flags;	 /* default uart flags */
+	unsigned int	   clk_sel;
 
 	unsigned int	   has_fracval;
 
diff --git a/drivers/tty/serial/samsung.c b/drivers/tty/serial/samsung.c
index fc242b2..dc5a4ed 100644
--- a/drivers/tty/serial/samsung.c
+++ b/drivers/tty/serial/samsung.c
@@ -49,6 +49,7 @@ 
 #include <mach/map.h>
 
 #include <plat/regs-serial.h>
+#include <plat/clock.h>
 
 #include "samsung.h"
 
@@ -558,133 +559,98 @@  static void s3c24xx_serial_pm(struct uart_port *port, unsigned int level,
  *
 */
 
+#define MAX_CLK_NAME_LENGTH 15
 
-#define MAX_CLKS (8)
-
-static struct s3c24xx_uart_clksrc tmp_clksrc = {
-	.name		= "pclk",
-	.min_baud	= 0,
-	.max_baud	= 0,
-	.divisor	= 1,
-};
-
-static inline int
-s3c24xx_serial_getsource(struct uart_port *port, struct s3c24xx_uart_clksrc *c)
+static inline int s3c24xx_serial_getsource(struct uart_port *port)
 {
 	struct s3c24xx_uart_info *info = s3c24xx_port_to_info(port);
+	unsigned int ucon;
 
-	return (info->get_clksrc)(port, c);
-}
-
-static inline int
-s3c24xx_serial_setsource(struct uart_port *port, struct s3c24xx_uart_clksrc *c)
-{
-	struct s3c24xx_uart_info *info = s3c24xx_port_to_info(port);
+	if (info->num_clks == 1)
+		return 0;
 
-	return (info->set_clksrc)(port, c);
+	ucon = rd_regl(port, S3C2410_UCON);
+	ucon &= info->clksel_mask;
+	return ucon >> info->clksel_shift;
 }
 
-struct baud_calc {
-	struct s3c24xx_uart_clksrc	*clksrc;
-	unsigned int			 calc;
-	unsigned int			 divslot;
-	unsigned int			 quot;
-	struct clk			*src;
-};
-
-static int s3c24xx_serial_calcbaud(struct baud_calc *calc,
-				   struct uart_port *port,
-				   struct s3c24xx_uart_clksrc *clksrc,
-				   unsigned int baud)
+static void s3c24xx_serial_setsource(struct uart_port *port,
+			unsigned int clk_sel)
 {
-	struct s3c24xx_uart_port *ourport = to_ourport(port);
-	unsigned long rate;
-
-	calc->src = clk_get(port->dev, clksrc->name);
-	if (calc->src == NULL || IS_ERR(calc->src))
-		return 0;
-
-	rate = clk_get_rate(calc->src);
-	rate /= clksrc->divisor;
+	struct s3c24xx_uart_info *info = s3c24xx_port_to_info(port);
+	unsigned int ucon;
 
-	calc->clksrc = clksrc;
+	if (info->num_clks == 1)
+		return;
 
-	if (ourport->info->has_divslot) {
-		unsigned long div = rate / baud;
-
-		/* The UDIVSLOT register on the newer UARTs allows us to
-		 * get a divisor adjustment of 1/16th on the baud clock.
-		 *
-		 * We don't keep the UDIVSLOT value (the 16ths we calculated
-		 * by not multiplying the baud by 16) as it is easy enough
-		 * to recalculate.
-		 */
-
-		calc->quot = div / 16;
-		calc->calc = rate / div;
-	} else {
-		calc->quot = (rate + (8 * baud)) / (16 * baud);
-		calc->calc = (rate / (calc->quot * 16));
-	}
+	ucon = rd_regl(port, S3C2410_UCON);
+	if ((ucon & info->clksel_mask) >> info->clksel_shift == clk_sel)
+		return;
 
-	calc->quot--;
-	return 1;
+	ucon &= ~info->clksel_mask;
+	ucon |= clk_sel << info->clksel_shift;
+	wr_regl(port, S3C2410_UCON, ucon);
 }
 
-static unsigned int s3c24xx_serial_getclk(struct uart_port *port,
-					  struct s3c24xx_uart_clksrc **clksrc,
-					  struct clk **clk,
-					  unsigned int baud)
+static unsigned int s3c24xx_serial_getclk(struct s3c24xx_uart_port *ourport,
+			unsigned int req_baud, struct clk **best_clk,
+			unsigned int *clk_num)
 {
-	struct s3c2410_uartcfg *cfg = s3c24xx_port_to_cfg(port);
-	struct s3c24xx_uart_clksrc *clkp;
-	struct baud_calc res[MAX_CLKS];
-	struct baud_calc *resptr, *best, *sptr;
-	int i;
-
-	clkp = cfg->clocks;
-	best = NULL;
-
-	if (cfg->clocks_size < 2) {
-		if (cfg->clocks_size == 0)
-			clkp = &tmp_clksrc;
-
-		s3c24xx_serial_calcbaud(res, port, clkp, baud);
-		best = res;
-		resptr = best + 1;
-	} else {
-		resptr = res;
-
-		for (i = 0; i < cfg->clocks_size; i++, clkp++) {
-			if (s3c24xx_serial_calcbaud(resptr, port, clkp, baud))
-				resptr++;
+	struct s3c24xx_uart_info *info = ourport->info;
+	struct clk *clk;
+	unsigned long rate;
+	unsigned int cnt, baud, quot, clk_sel, best_quot = 0;
+	char clkname[MAX_CLK_NAME_LENGTH];
+	int calc_deviation, deviation = (1 << 30) - 1;
+
+	*best_clk = NULL;
+	clk_sel = (ourport->cfg->clk_sel) ? ourport->cfg->clk_sel :
+			ourport->info->def_clk_sel;
+	for (cnt = 0; cnt < info->num_clks; cnt++) {
+		if (!(clk_sel & (1 << cnt)))
+			continue;
+
+		sprintf(clkname, "clk_uart_baud%d", cnt);
+		clk = clk_get(ourport->port.dev, clkname);
+		if (IS_ERR_OR_NULL(clk))
+			continue;
+
+		rate = clk_get_rate(clk);
+		if (!rate)
+			continue;
+
+		if (ourport->info->has_divslot) {
+			unsigned long div = rate / req_baud;
+
+			/* The UDIVSLOT register on the newer UARTs allows us to
+			 * get a divisor adjustment of 1/16th on the baud clock.
+			 *
+			 * We don't keep the UDIVSLOT value (the 16ths we
+			 * calculated by not multiplying the baud by 16) as it
+			 * is easy enough to recalculate.
+			 */
+
+			quot = div / 16;
+			baud = rate / div;
+		} else {
+			quot = (rate + (8 * req_baud)) / (16 * req_baud);
+			baud = rate / (quot * 16);
 		}
-	}
-
-	/* ok, we now need to select the best clock we found */
-
-	if (!best) {
-		unsigned int deviation = (1<<30)|((1<<30)-1);
-		int calc_deviation;
+		quot--;
 
-		for (sptr = res; sptr < resptr; sptr++) {
-			calc_deviation = baud - sptr->calc;
-			if (calc_deviation < 0)
-				calc_deviation = -calc_deviation;
+		calc_deviation = req_baud - baud;
+		if (calc_deviation < 0)
+			calc_deviation = -calc_deviation;
 
-			if (calc_deviation < deviation) {
-				best = sptr;
-				deviation = calc_deviation;
-			}
+		if (calc_deviation < deviation) {
+			*best_clk = clk;
+			best_quot = quot;
+			*clk_num = cnt;
+			deviation = calc_deviation;
 		}
 	}
 
-	/* store results to pass back */
-
-	*clksrc = best->clksrc;
-	*clk    = best->src;
-
-	return best->quot;
+	return best_quot;
 }
 
 /* udivslot_table[]
@@ -717,10 +683,9 @@  static void s3c24xx_serial_set_termios(struct uart_port *port,
 {
 	struct s3c2410_uartcfg *cfg = s3c24xx_port_to_cfg(port);
 	struct s3c24xx_uart_port *ourport = to_ourport(port);
-	struct s3c24xx_uart_clksrc *clksrc = NULL;
 	struct clk *clk = NULL;
 	unsigned long flags;
-	unsigned int baud, quot;
+	unsigned int baud, quot, clk_sel = 0;
 	unsigned int ulcon;
 	unsigned int umcon;
 	unsigned int udivslot = 0;
@@ -736,17 +701,16 @@  static void s3c24xx_serial_set_termios(struct uart_port *port,
 	 */
 
 	baud = uart_get_baud_rate(port, termios, old, 0, 115200*8);
-
+	quot = s3c24xx_serial_getclk(ourport, baud, &clk, &clk_sel);
 	if (baud == 38400 && (port->flags & UPF_SPD_MASK) == UPF_SPD_CUST)
 		quot = port->custom_divisor;
-	else
-		quot = s3c24xx_serial_getclk(port, &clksrc, &clk, baud);
+	if (!clk)
+		return;
 
 	/* check to see if we need  to change clock source */
 
-	if (ourport->clksrc != clksrc || ourport->baudclk != clk) {
-		dbg("selecting clock %p\n", clk);
-		s3c24xx_serial_setsource(port, clksrc);
+	if (ourport->baudclk != clk) {
+		s3c24xx_serial_setsource(port, clk_sel);
 
 		if (ourport->baudclk != NULL && !IS_ERR(ourport->baudclk)) {
 			clk_disable(ourport->baudclk);
@@ -755,7 +719,6 @@  static void s3c24xx_serial_set_termios(struct uart_port *port,
 
 		clk_enable(clk);
 
-		ourport->clksrc = clksrc;
 		ourport->baudclk = clk;
 		ourport->baudclk_rate = clk ? clk_get_rate(clk) : 0;
 	}
@@ -1202,7 +1165,7 @@  static ssize_t s3c24xx_serial_show_clksrc(struct device *dev,
 	struct uart_port *port = s3c24xx_dev_to_port(dev);
 	struct s3c24xx_uart_port *ourport = to_ourport(port);
 
-	return snprintf(buf, PAGE_SIZE, "* %s\n", ourport->clksrc->name);
+	return snprintf(buf, PAGE_SIZE, "* %s\n", ourport->baudclk->name);
 }
 
 static DEVICE_ATTR(clock_source, S_IRUGO, s3c24xx_serial_show_clksrc, NULL);
@@ -1382,12 +1345,13 @@  static void __init
 s3c24xx_serial_get_options(struct uart_port *port, int *baud,
 			   int *parity, int *bits)
 {
-	struct s3c24xx_uart_clksrc clksrc;
 	struct clk *clk;
 	unsigned int ulcon;
 	unsigned int ucon;
 	unsigned int ubrdiv;
 	unsigned long rate;
+	unsigned int clk_sel;
+	char clk_name[MAX_CLK_NAME_LENGTH];
 
 	ulcon  = rd_regl(port, S3C2410_ULCON);
 	ucon   = rd_regl(port, S3C2410_UCON);
@@ -1432,11 +1396,12 @@  s3c24xx_serial_get_options(struct uart_port *port, int *baud,
 
 		/* now calculate the baud rate */
 
-		s3c24xx_serial_getsource(port, &clksrc);
+		clk_sel = s3c24xx_serial_getsource(port);
+		sprintf(clk_name, "clk_uart_baud%d", clk_sel);
 
-		clk = clk_get(port->dev, clksrc.name);
+		clk = clk_get(port->dev, clk_name);
 		if (!IS_ERR(clk) && clk != NULL)
-			rate = clk_get_rate(clk) / clksrc.divisor;
+			rate = clk_get_rate(clk);
 		else
 			rate = 1;
 
diff --git a/drivers/tty/serial/samsung.h b/drivers/tty/serial/samsung.h
index 6c9cb9d..11369f3 100644
--- a/drivers/tty/serial/samsung.h
+++ b/drivers/tty/serial/samsung.h
@@ -19,6 +19,10 @@  struct s3c24xx_uart_info {
 	unsigned long		tx_fifomask;
 	unsigned long		tx_fifoshift;
 	unsigned long		tx_fifofull;
+	unsigned int		def_clk_sel;
+	unsigned long		num_clks;
+	unsigned long		clksel_mask;
+	unsigned long		clksel_shift;
 
 	/* uart port features */