[PATCH] drivers/pwm: add PXA pulse width modulator controller

[Robert Jarzmik <robert.jarzmik@free.fr>]

Add PXA embedded pulse width modulator support. The PWM can
generate signals from 49.6kHz to 1.625MHz.
The driver is for pxa2xx family. The pxa3xx was not handled yet.

Signed-off-by: Robert Jarzmik <robert.jarzmik@free.fr>
---
 arch/arm/mach-pxa/Makefile                |    1 +
 arch/arm/mach-pxa/include/mach/clock.h    |    1 +
 arch/arm/mach-pxa/include/mach/regs-pwm.h |   20 ++++
 arch/arm/mach-pxa/speed-pxa27x.c          |    5 +
 drivers/pwm/Kconfig                       |    6 +
 drivers/pwm/Makefile                      |    1 +
 drivers/pwm/pxa_pwm.c                     |  163 +++++++++++++++++++++++++++++
 7 files changed, 197 insertions(+), 0 deletions(-)
 create mode 100644 arch/arm/mach-pxa/include/mach/regs-pwm.h
 create mode 100644 drivers/pwm/pxa_pwm.c

diff --git a/arch/arm/mach-pxa/Makefile b/arch/arm/mach-pxa/Makefile
index c01a9e0..6a02a54 100644
--- a/arch/arm/mach-pxa/Makefile
+++ b/arch/arm/mach-pxa/Makefile
@@ -1,6 +1,7 @@
 obj-y += clocksource.o
 obj-y += common.o
 obj-y += gpio.o
+obj-y += devices.o
 
 obj-$(CONFIG_ARCH_PXA2XX) += mfp-pxa2xx.o
 obj-$(CONFIG_ARCH_PXA27X) += speed-pxa27x.o
diff --git a/arch/arm/mach-pxa/include/mach/clock.h b/arch/arm/mach-pxa/include/mach/clock.h
index c53432f..f86152f 100644
--- a/arch/arm/mach-pxa/include/mach/clock.h
+++ b/arch/arm/mach-pxa/include/mach/clock.h
@@ -14,5 +14,6 @@
 unsigned long pxa_get_uartclk(void);
 unsigned long pxa_get_mmcclk(void);
 unsigned long pxa_get_lcdclk(void);
+unsigned long pxa_get_pwmclk(void);
 
 #endif	/* !__MACH_CLOCK_H */
diff --git a/arch/arm/mach-pxa/include/mach/regs-pwm.h b/arch/arm/mach-pxa/include/mach/regs-pwm.h
new file mode 100644
index 0000000..9fdcbb6
--- /dev/null
+++ b/arch/arm/mach-pxa/include/mach/regs-pwm.h
@@ -0,0 +1,20 @@
+/*
+ *
+ *  This program is free software; you can redistribute it and/or modify
+ *  it under the terms of the GNU General Public License version 2 as
+ *  published by the Free Software Foundation.
+ */
+#ifndef __ASM_MACH_REGS_PWM_H
+#define __ASM_MACH_REGS_PWM_H
+
+#include <mach/hardware.h>
+
+/*
+ * Pulse modulator registers
+ */
+#define PWM0		0x40B00000
+#define PWM1		0x40C00000
+#define PWM0slave	0x40B00010
+#define PWM1slave	0x40C00010
+
+#endif
diff --git a/arch/arm/mach-pxa/speed-pxa27x.c b/arch/arm/mach-pxa/speed-pxa27x.c
index 534eb1d..1de034c 100644
--- a/arch/arm/mach-pxa/speed-pxa27x.c
+++ b/arch/arm/mach-pxa/speed-pxa27x.c
@@ -47,3 +47,8 @@ unsigned long pxa_get_lcdclk(void)
 {
 	return pxa_get_lcdclk_10khz() * 10000;
 }
+
+unsigned long pxa_get_pwmclk(void)
+{
+	return BASE_CLK;
+}
diff --git a/drivers/pwm/Kconfig b/drivers/pwm/Kconfig
index 93c1052..50c956a 100644
--- a/drivers/pwm/Kconfig
+++ b/drivers/pwm/Kconfig
@@ -8,5 +8,11 @@ menuconfig PWM
 	  If unsure, say N.
 
 if PWM
+config PWM_PXA
+	bool "PXA PWM Support"
+	default y if ARCH_PXA2XX
+	help
+	  This enables PWM support for Intel/Marvell PXA chips, such
+	  as the PXA25x, PXA27x.
 
 endif
diff --git a/drivers/pwm/Makefile b/drivers/pwm/Makefile
index 3469c3d..c886bd5 100644
--- a/drivers/pwm/Makefile
+++ b/drivers/pwm/Makefile
@@ -1 +1,2 @@
 obj-$(CONFIG_PWM)		+= core.o
+obj-$(CONFIG_PWM_PXA)		+= pxa_pwm.o
\ No newline at end of file
diff --git a/drivers/pwm/pxa_pwm.c b/drivers/pwm/pxa_pwm.c
new file mode 100644
index 0000000..bb114aa
--- /dev/null
+++ b/drivers/pwm/pxa_pwm.c
@@ -0,0 +1,163 @@
+/*
+ * simple driver for PWM (Pulse Width Modulator) controller
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ *
+ * 2008-02-13	initial version
+ * 		eric miao <eric.miao@marvell.com>
+ * 2012         Robert Jarzmik <robert.jarzmik@free.fr>
+ */
+
+#include <common.h>
+#include <init.h>
+#include <errno.h>
+#include <io.h>
+#include <pwm.h>
+
+#include <mach/hardware.h>
+#include <mach/clock.h>
+#include <mach/pxa-regs.h>
+#include <mach/regs-pwm.h>
+#include <asm-generic/div64.h>
+#include <linux/compiler.h>
+
+/* PWM registers and bits definitions */
+#define PWMCR		(0x00)
+#define PWMDCR		(0x04)
+#define PWMPCR		(0x08)
+
+#define PWMCR_SD	(1 << 6)
+#define PWMDCR_FD	(1 << 10)
+
+#ifdef CONFIG_PWM
+
+static int pwm_get_pwm_idx(struct pwm_chip *chip)
+{
+	if (!strncmp(chip->devname, "pxa_pwm0", 8))
+		return 0;
+	else if (!strncmp(chip->devname, "pxa_pwm1", 8))
+		return 1;
+	else
+		return -EINVAL;
+}
+
+static void __iomem *pwm_bases[] = {
+	(void __iomem *)PWM0,
+	(void __iomem *)PWM1,
+	(void __iomem *)PWM0slave,
+	(void __iomem *)PWM1slave,
+};
+
+/*
+ * period_ns    = 10^9 * (PRESCALE + 1) * (PV + 1) / PWM_CLK_RATE
+ * duty_ns      = 10^9 * (PRESCALE + 1) * DC / PWM_CLK_RATE
+ * PWM_CLK_RATE = 13 MHz
+ */
+static int pxa_pwm_config(struct pwm_chip *chip, int duty_ns, int period_ns)
+{
+	int pwm_idx;
+	unsigned long long c;
+	unsigned long period_cycles, prescale, pv, dc;
+	void __iomem *iobase;
+
+	pwm_idx = pwm_get_pwm_idx(chip);
+	if (pwm_idx < 0 || period_ns == 0 || duty_ns > period_ns)
+		return -EINVAL;
+	iobase = pwm_bases[pwm_idx];
+
+	c = pxa_get_pwmclk();
+	c = c * period_ns;
+	do_div(c, 1000000000);
+	period_cycles = c;
+
+	if (period_cycles < 1)
+		period_cycles = 1;
+	prescale = (period_cycles - 1) / 1024;
+	pv = period_cycles / (prescale + 1) - 1;
+
+	if (prescale > 63)
+		return -EINVAL;
+
+	if (duty_ns == period_ns)
+		dc = PWMDCR_FD;
+	else
+		dc = (pv + 1) * duty_ns / period_ns;
+
+	/* NOTE: the clock to PWM has to be enabled first
+	 * before writing to the registers
+	 */
+	__raw_writel(prescale, iobase + PWMCR);
+	__raw_writel(dc, iobase + PWMDCR);
+	__raw_writel(pv, iobase + PWMPCR);
+
+	return 0;
+}
+
+static int pxa_pwm_enable(struct pwm_chip *chip)
+{
+	switch (pwm_get_pwm_idx(chip)) {
+	case 0:
+		CKEN |= CKEN_PWM0;
+		break;
+	case 1:
+		CKEN |= CKEN_PWM1;
+		break;
+	default:
+		return -EINVAL;
+	}
+	return 0;
+}
+
+static void pxa_pwm_disable(struct pwm_chip *chip)
+{
+	switch (pwm_get_pwm_idx(chip)) {
+	case 0:
+		CKEN &= ~CKEN_PWM0;
+		break;
+	case 1:
+		CKEN &= ~CKEN_PWM1;
+		break;
+	default:
+		break;
+	}
+}
+
+static struct pwm_ops pxa_pwm_ops = {
+	.config = pxa_pwm_config,
+	.enable = pxa_pwm_enable,
+	.disable = pxa_pwm_disable,
+};
+
+#define DECLARE_PXA_PWM(name) \
+	static struct pwm_chip name = { \
+	.devname = #name, \
+	.ops = &pxa_pwm_ops, \
+}
+
+DECLARE_PXA_PWM(pxa_pwm0);
+DECLARE_PXA_PWM(pxa_pwm1);
+DECLARE_PXA_PWM(pxa_pwm0slave);
+DECLARE_PXA_PWM(pxa_pwm1slave);
+
+static int pxa_pwm_init(void)
+{
+	CKEN &= ~CKEN_PWM0 & ~CKEN_PWM1;
+	pwmchip_add(&pxa_pwm0);
+	pwmchip_add(&pxa_pwm1);
+	if (cpu_is_pxa27x()) {
+		pwmchip_add(&pxa_pwm0slave);
+		pwmchip_add(&pxa_pwm1slave);
+	}
+	return 0;
+}
+
+#else
+static int pxa_pwm_init(void)
+{
+	return 0;
+}
+#endif
+
+coredevice_initcall(pxa_pwm_init);
-- 
1.7.5.4


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