[PATCH 3/9] serial: samsung: switch to clkdev based clock lookup
Thomas Abraham
thomas.abraham at linaro.org
Mon Sep 26 15:07:12 EDT 2011
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 at fluff.org>
Signed-off-by: Thomas Abraham <thomas.abraham at 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(-)
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 */
--
1.6.6.rc2
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