ARM: S5P: pwm driver support

This is common pwm driver of S5P.

Signed-off-by: Donghwa Lee <dh09.lee@samsung.com>
Signed-off-by: Kyungmin Park <kyungmin.park@samsung.com>
Signed-off-by: Minkyu Kang <mk7.kang@samsung.com>

arch/arm/cpu/armv7/s5p-common/Makefile

@@ -27,6 +27,7 @@ LIB	= $(obj)libs5p-common.o
 
 COBJS-y		+= cpu_info.o
 COBJS-y		+= timer.o
+COBJS-$(CONFIG_PWM)		+= pwm.o
 
 SRCS	:= $(SOBJS:.o=.S) $(COBJS:.o=.c)
 OBJS	:= $(addprefix $(obj),$(COBJS-y) $(SOBJS))

arch/arm/cpu/armv7/s5p-common/pwm.c

@@ -0,0 +1,189 @@
+/*
+ * Copyright (C) 2011 Samsung Electronics
+ *
+ * Donghwa Lee <dh09.lee@samsung.com>
+ *
+ * See file CREDITS for list of people who contributed to this
+ * project.
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License as
+ * published by the Free Software Foundation; either version 2 of
+ * the License, or (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.	 See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 59 Temple Place, Suite 330, Boston,
+ * MA 02111-1307 USA
+ */
+
+#include <common.h>
+#include <errno.h>
+#include <pwm.h>
+#include <asm/io.h>
+#include <asm/arch/pwm.h>
+#include <asm/arch/clk.h>
+
+int pwm_enable(int pwm_id)
+{
+	const struct s5p_timer *pwm =
+			(struct s5p_timer *)samsung_get_base_timer();
+	unsigned long tcon;
+
+	tcon = readl(&pwm->tcon);
+	tcon |= TCON_START(pwm_id);
+
+	writel(tcon, &pwm->tcon);
+
+	return 0;
+}
+
+void pwm_disable(int pwm_id)
+{
+	const struct s5p_timer *pwm =
+			(struct s5p_timer *)samsung_get_base_timer();
+	unsigned long tcon;
+
+	tcon = readl(&pwm->tcon);
+	tcon &= ~TCON_START(pwm_id);
+
+	writel(tcon, &pwm->tcon);
+}
+
+static unsigned long pwm_calc_tin(int pwm_id, unsigned long freq)
+{
+	unsigned long tin_parent_rate;
+	unsigned int div;
+
+	tin_parent_rate = get_pwm_clk();
+
+	for (div = 2; div <= 16; div *= 2) {
+		if ((tin_parent_rate / (div << 16)) < freq)
+			return tin_parent_rate / div;
+	}
+
+	return tin_parent_rate / 16;
+}
+
+#define NS_IN_HZ (1000000000UL)
+
+int pwm_config(int pwm_id, int duty_ns, int period_ns)
+{
+	const struct s5p_timer *pwm =
+			(struct s5p_timer *)samsung_get_base_timer();
+	unsigned int offset;
+	unsigned long tin_rate;
+	unsigned long tin_ns;
+	unsigned long period;
+	unsigned long tcon;
+	unsigned long tcnt;
+	unsigned long timer_rate_hz;
+	unsigned long tcmp;
+
+	/*
+	 * We currently avoid using 64bit arithmetic by using the
+	 * fact that anything faster than 1GHz is easily representable
+	 * by 32bits.
+	 */
+	if (period_ns > NS_IN_HZ || duty_ns > NS_IN_HZ)
+		return -ERANGE;
+
+	if (duty_ns > period_ns)
+		return -EINVAL;
+
+	period = NS_IN_HZ / period_ns;
+
+	/* Check to see if we are changing the clock rate of the PWM */
+	tin_rate = pwm_calc_tin(pwm_id, period);
+	timer_rate_hz = tin_rate;
+
+	tin_ns = NS_IN_HZ / tin_rate;
+	tcnt = period_ns / tin_ns;
+
+	/* Note, counters count down */
+	tcmp = duty_ns / tin_ns;
+	tcmp = tcnt - tcmp;
+
+	/*
+	 * the pwm hw only checks the compare register after a decrement,
+	 * so the pin never toggles if tcmp = tcnt
+	 */
+	if (tcmp == tcnt)
+		tcmp--;
+
+	if (tcmp < 0)
+		tcmp = 0;
+
+	/* Update the PWM register block. */
+	offset = pwm_id * 3;
+	if (pwm_id < 4) {
+		writel(tcnt, &pwm->tcntb0 + offset);
+		writel(tcmp, &pwm->tcmpb0 + offset);
+	}
+
+	tcon = readl(&pwm->tcon);
+	tcon |= TCON_UPDATE(pwm_id);
+	if (pwm_id < 4)
+		tcon |= TCON_AUTO_RELOAD(pwm_id);
+	else
+		tcon |= TCON4_AUTO_RELOAD;
+	writel(tcon, &pwm->tcon);
+
+	tcon &= ~TCON_UPDATE(pwm_id);
+	writel(tcon, &pwm->tcon);
+
+	return 0;
+}
+
+int pwm_init(int pwm_id, int div, int invert)
+{
+	u32 val;
+	const struct s5p_timer *pwm =
+			(struct s5p_timer *)samsung_get_base_timer();
+	unsigned long timer_rate_hz;
+	unsigned int offset, prescaler;
+
+	/*
+	 * Timer Freq(HZ) =
+	 *	PWM_CLK / { (prescaler_value + 1) * (divider_value) }
+	 */
+
+	val = readl(&pwm->tcfg0);
+	if (pwm_id < 2) {
+		prescaler = PRESCALER_0;
+		val &= ~0xff;
+		val |= (prescaler & 0xff);
+	} else {
+		prescaler = PRESCALER_1;
+		val &= ~(0xff << 8);
+		val |= (prescaler & 0xff) << 8;
+	}
+	writel(val, &pwm->tcfg0);
+	val = readl(&pwm->tcfg1);
+	val &= ~(0xf << MUX_DIV_SHIFT(pwm_id));
+	val |= (div & 0xf) << MUX_DIV_SHIFT(pwm_id);
+	writel(val, &pwm->tcfg1);
+
+	timer_rate_hz = get_pwm_clk() / ((prescaler + 1) *
+			(div + 1));
+
+	timer_rate_hz = timer_rate_hz / 100;
+
+	/* set count value */
+	offset = pwm_id * 3;
+	writel(timer_rate_hz, &pwm->tcntb0 + offset);
+
+	val = readl(&pwm->tcon) & ~(0xf << TCON_OFFSET(pwm_id));
+	if (invert && (pwm_id < 4))
+		val |= TCON_INVERTER(pwm_id);
+	writel(val, &pwm->tcon);
+
+	pwm_enable(pwm_id);
+
+	return 0;
+}

arch/arm/include/asm/arch-s5pc1xx/pwm.h

@@ -22,6 +22,18 @@
 #ifndef __ASM_ARM_ARCH_PWM_H_
 #define __ASM_ARM_ARCH_PWM_H_
 
+#define PRESCALER_0		(8 - 1)		/* prescaler of timer 0, 1 */
+#define PRESCALER_1		(16 - 1)	/* prescaler of timer 2, 3, 4 */
+
+/* Divider MUX */
+#define MUX_DIV_1		0		/* 1/1 period */
+#define MUX_DIV_2		1		/* 1/2 period */
+#define MUX_DIV_4		2		/* 1/4 period */
+#define MUX_DIV_8		3		/* 1/8 period */
+#define MUX_DIV_16		4		/* 1/16 period */
+
+#define MUX_DIV_SHIFT(x)	(x * 4)
+
 /* Interval mode(Auto Reload) of PWM Timer 4 */
 #define TCON4_AUTO_RELOAD	(1 << 22)
 /* Update TCNTB4 */
@@ -29,6 +41,13 @@
 /* start bit of PWM Timer 4 */
 #define TCON4_START		(1 << 20)
 
+#define TCON_OFFSET(x)		((x + 1) * (!!x) << 2)
+
+#define TCON_START(x)		(1 << TCON_OFFSET(x))
+#define TCON_UPDATE(x)		(1 << (TCON_OFFSET(x) + 1))
+#define TCON_INVERTER(x)	(1 << (TCON_OFFSET(x) + 2))
+#define TCON_AUTO_RELOAD(x)	(1 << (TCON_OFFSET(x) + 3))
+
 #ifndef __ASSEMBLY__
 struct s5p_timer {
 	unsigned int	tcfg0;

arch/arm/include/asm/arch-s5pc2xx/pwm.h

@@ -22,6 +22,18 @@
 #ifndef __ASM_ARM_ARCH_PWM_H_
 #define __ASM_ARM_ARCH_PWM_H_
 
+#define PRESCALER_0		(8 - 1)		/* prescaler of timer 0, 1 */
+#define PRESCALER_1		(16 - 1)	/* prescaler of timer 2, 3, 4 */
+
+/* Divider MUX */
+#define MUX_DIV_1		0		/* 1/1 period */
+#define MUX_DIV_2		1		/* 1/2 period */
+#define MUX_DIV_4		2		/* 1/4 period */
+#define MUX_DIV_8		3		/* 1/8 period */
+#define MUX_DIV_16		4		/* 1/16 period */
+
+#define MUX_DIV_SHIFT(x)	(x * 4)
+
 /* Interval mode(Auto Reload) of PWM Timer 4 */
 #define TCON4_AUTO_RELOAD	(1 << 22)
 /* Update TCNTB4 */
@@ -29,6 +41,13 @@
 /* start bit of PWM Timer 4 */
 #define TCON4_START		(1 << 20)
 
+#define TCON_OFFSET(x)		((x + 1) * (!!x) << 2)
+
+#define TCON_START(x)		(1 << TCON_OFFSET(x))
+#define TCON_UPDATE(x)		(1 << (TCON_OFFSET(x) + 1))
+#define TCON_INVERTER(x)	(1 << (TCON_OFFSET(x) + 2))
+#define TCON_AUTO_RELOAD(x)	(1 << (TCON_OFFSET(x) + 3))
+
 #ifndef __ASSEMBLY__
 struct s5p_timer {
 	unsigned int	tcfg0;

include/pwm.h

@@ -0,0 +1,31 @@
+/*
+ * header file for pwm driver.
+ *
+ * Copyright (c) 2011 samsung electronics
+ * Donghwa Lee <dh09.lee@samsung.com>
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License as
+ * published by the Free Software Foundation; either version 2 of
+ * the License, or (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 59 Temple Place, Suite 330, Boston,
+ * MA 02111-1307 USA
+ */
+
+#ifndef _pwm_h_
+#define _pwm_h_
+
+int	pwm_init		(int pwm_id, int div, int invert);
+int	pwm_config		(int pwm_id, int duty_ns, int period_ns);
+int	pwm_enable		(int pwm_id);
+void	pwm_disable		(int pwm_id);
+
+#endif /* _pwm_h_ */