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@xxxxxxx>
---
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@xxxxxxxxxxx>
+ * 2012 Robert Jarzmik <robert.jarzmik@xxxxxxx>
+ */
+
+#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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