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Message-Id: <c6c7ccbedbade4c8e4695f914d065d40b646587e.1265748264.git.bgat@billgatliff.com>
Date: Tue, 9 Feb 2010 14:46:34 -0600
From: Bill Gatliff <bgat@...lgatliff.com>
To: linux-embedded@...r.kernel.org
Cc: linux-kernel@...r.kernel.org, Bill Gatliff <bgat@...lgatliff.com>
Subject: [PWM PATCH 7/7] PWM API driver for MPC52xx GPT peripheral
Signed-off-by: Bill Gatliff <bgat@...lgatliff.com>
---
arch/powerpc/platforms/52xx/mpc52xx_gpt.c | 195 ++++++++++++++++++++++++++++-
1 files changed, 193 insertions(+), 2 deletions(-)
diff --git a/arch/powerpc/platforms/52xx/mpc52xx_gpt.c b/arch/powerpc/platforms/52xx/mpc52xx_gpt.c
index 6f8ebe1..b9aa4a5 100644
--- a/arch/powerpc/platforms/52xx/mpc52xx_gpt.c
+++ b/arch/powerpc/platforms/52xx/mpc52xx_gpt.c
@@ -1,6 +1,7 @@
/*
* MPC5200 General Purpose Timer device driver
*
+ * Copyright (c) 2010 Bill Gatliff <bgat@...lgatliff.com>
* Copyright (c) 2009 Secret Lab Technologies Ltd.
* Copyright (c) 2008 Sascha Hauer <s.hauer@...gutronix.de>, Pengutronix
*
@@ -50,6 +51,12 @@
* IO, or it can be an Open Collector (OC) output. At the moment it is the
* responsibility of either the bootloader or the platform setup code to set
* the output mode. This driver does not change the output mode setting.
+ *
+ * To use the PWM function, the following property must be added to
+ * the device tree node for the gpt device:
+ * pwm-controller;
+ * TODO: we could set polarity, initial period and duty cycle, on/off,
+ * and whatnot inside the dts file...
*/
#include <linux/device.h>
@@ -65,11 +72,12 @@
#include <linux/watchdog.h>
#include <linux/miscdevice.h>
#include <linux/uaccess.h>
+#include <linux/pwm/pwm.h>
#include <asm/div64.h>
#include <asm/mpc52xx.h>
MODULE_DESCRIPTION("Freescale MPC52xx gpt driver");
-MODULE_AUTHOR("Sascha Hauer, Grant Likely, Albrecht Dreß");
+MODULE_AUTHOR("Sascha Hauer, Grant Likely, Albrecht Dreß, Bill Gatliff");
MODULE_LICENSE("GPL");
/**
@@ -95,6 +103,9 @@ struct mpc52xx_gpt_priv {
#if defined(CONFIG_GPIOLIB)
struct of_gpio_chip of_gc;
#endif
+#if defined(CONFIG_GENERIC_PWM)
+ struct pwm_device pwm;
+#endif
};
LIST_HEAD(mpc52xx_gpt_list);
@@ -125,6 +136,10 @@ DEFINE_MUTEX(mpc52xx_gpt_list_mutex);
#define MPC52xx_GPT_STATUS_IRQMASK (0x000f)
+#define MPC52xx_GPT_PWM_WIDTH_MASK (0xffff0000)
+#define MPC52xx_GPT_PWM_PWMOP (0x100)
+#define MPC52xx_GPT_PWM_LOAD (0x1)
+
#define MPC52xx_GPT_CAN_WDT (1 << 0)
#define MPC52xx_GPT_IS_WDT (1 << 1)
@@ -274,6 +289,182 @@ mpc52xx_gpt_irq_setup(struct mpc52xx_gpt_priv *gpt, struct device_node *node)
/* ---------------------------------------------------------------------
+ * PWM API hooks
+ */
+#if defined(CONFIG_GENERIC_PWM)
+static inline struct mpc52xx_gpt_priv *pwm_to_mpc52xx_gpt(const struct pwm_channel *p)
+{
+ return container_of(p->pwm, struct mpc52xx_gpt_priv, pwm);
+}
+
+static int mpc52xx_gpt_pwm_request(struct pwm_channel *p)
+{
+ struct mpc52xx_gpt_priv *gpt = pwm_to_mpc52xx_gpt(p);
+
+ /* TODO: add hooks to prevent conflicts in use */
+ p->tick_hz = gpt->ipb_freq;
+ return 0;
+}
+
+static void mpc52xx_gpt_pwm_free(struct pwm_channel *p)
+{
+ /* TODO: add hooks to prevent conflicts in use */
+}
+
+static int __mpc52xx_gpt_pwm_config_period_ticks(struct pwm_channel *p,
+ struct pwm_channel_config *c)
+{
+ struct mpc52xx_gpt_priv *gpt = pwm_to_mpc52xx_gpt(p);
+ u64 prescale, count;
+
+ prescale = (c->period_ticks >> 16) + 1;
+ count = c->period_ticks;
+ do_div(count, prescale);
+ out_be32(&gpt->regs->count, prescale << 16 | count);
+
+ p->period_ticks = count * prescale;
+ dev_dbg(p->pwm->dev, "prescale %4x count %4x period_ticks %8x\n",
+ (unsigned int)prescale, (unsigned int)count,
+ (unsigned int)p->period_ticks);
+
+ return 0;
+}
+
+static int __mpc52xx_gpt_pwm_config_duty_ticks(struct pwm_channel *p,
+ struct pwm_channel_config *c)
+{
+ struct mpc52xx_gpt_priv *gpt = pwm_to_mpc52xx_gpt(p);
+ unsigned long flags;
+ u64 width = c->duty_ticks;
+ u32 prescale, count;
+
+ spin_lock_irqsave(&gpt->lock, flags);
+
+ count = in_be32(&gpt->regs->count);
+ prescale = count >> 16;
+ count &= 0xffffUL;
+
+ /* TODO: this probably isn't the best place to do a divide... */
+ do_div(width, prescale);
+
+ clrsetbits_be32(&gpt->regs->pwm, MPC52xx_GPT_PWM_WIDTH_MASK,
+ MPC52xx_GPT_PWM_WIDTH_MASK & (width << 16));
+ spin_unlock_irqrestore(&gpt->lock, flags);
+
+ p->duty_ticks = width * prescale;
+ dev_dbg(p->pwm->dev, "prescale %4x count %4x width %4x duty_ticks %8x\n",
+ (unsigned int)prescale, (unsigned int)count,
+ (unsigned int)width, (unsigned int)p->duty_ticks);
+
+ return 0;
+}
+
+static int __mpc52xx_gpt_pwm_config_polarity(struct pwm_channel *p,
+ struct pwm_channel_config *c)
+{
+ struct mpc52xx_gpt_priv *gpt = pwm_to_mpc52xx_gpt(p);
+ unsigned long flags;
+
+ spin_lock_irqsave(&gpt->lock, flags);
+ if (c->polarity)
+ setbits32(&gpt->regs->pwm, MPC52xx_GPT_PWM_PWMOP);
+ else
+ clrbits32(&gpt->regs->pwm, MPC52xx_GPT_PWM_PWMOP);
+ spin_unlock_irqrestore(&gpt->lock, flags);
+ return 0;
+}
+
+static int __mpc52xx_gpt_pwm_start(struct pwm_channel *p)
+{
+ struct mpc52xx_gpt_priv *gpt = pwm_to_mpc52xx_gpt(p);
+ unsigned long flags;
+
+ spin_lock_irqsave(&gpt->lock, flags);
+ clrsetbits_be32(&gpt->regs->mode, MPC52xx_GPT_MODE_MS_MASK,
+ MPC52xx_GPT_MODE_MS_PWM);
+ spin_unlock_irqrestore(&gpt->lock, flags);
+ return 0;
+}
+
+static int __mpc52xx_gpt_pwm_stop(struct pwm_channel *p)
+{
+ struct mpc52xx_gpt_priv *gpt = pwm_to_mpc52xx_gpt(p);
+ unsigned long flags;
+
+ spin_lock_irqsave(&gpt->lock, flags);
+ clrbits32(&gpt->regs->mode, MPC52xx_GPT_MODE_MS_MASK);
+ spin_unlock_irqrestore(&gpt->lock, flags);
+ return 0;
+}
+
+static int mpc52xx_gpt_pwm_config_nosleep(struct pwm_channel *p,
+ struct pwm_channel_config *c)
+{
+ int ret = -EINVAL;
+
+ if (c->config_mask & PWM_CONFIG_PERIOD_TICKS)
+ if ((ret = __mpc52xx_gpt_pwm_config_period_ticks(p, c)))
+ goto done;
+
+ if (c->config_mask & PWM_CONFIG_DUTY_TICKS)
+ if ((ret = __mpc52xx_gpt_pwm_config_duty_ticks(p, c)))
+ goto done;
+
+ if (c->config_mask & PWM_CONFIG_POLARITY)
+ if ((ret = __mpc52xx_gpt_pwm_config_polarity(p, c)))
+ goto done;
+
+ if (c->config_mask & PWM_CONFIG_START)
+ if ((ret = __mpc52xx_gpt_pwm_start(p)))
+ goto done;
+
+ if (c->config_mask & PWM_CONFIG_STOP)
+ if ((ret = __mpc52xx_gpt_pwm_stop(p)))
+ goto done;
+
+done:
+ return ret;
+}
+
+static int mpc52xx_gpt_pwm_config(struct pwm_channel *p,
+ struct pwm_channel_config *c)
+{
+ dev_dbg(p->pwm->dev, "config_mask %x\n", c->config_mask);
+
+ if (!mpc52xx_gpt_pwm_config_nosleep(p, c))
+ return 0;
+
+ might_sleep();
+
+ /* TODO: add other API entry points */
+
+ return -EINVAL;
+}
+
+static void
+mpc52xx_gpt_pwm_setup(struct mpc52xx_gpt_priv *gpt, struct device_node *node)
+{
+ if (!of_find_property(node, "pwm-controller", NULL))
+ return;
+
+ gpt->pwm.dev = gpt->dev;
+ gpt->pwm.bus_id = dev_name(gpt->dev);
+ gpt->pwm.nchan = 1;
+ gpt->pwm.owner = THIS_MODULE;
+
+ gpt->pwm.request = mpc52xx_gpt_pwm_request;
+ gpt->pwm.free = mpc52xx_gpt_pwm_free;
+ gpt->pwm.config_nosleep = mpc52xx_gpt_pwm_config_nosleep;
+ gpt->pwm.config = mpc52xx_gpt_pwm_config;
+
+ pwm_register(&gpt->pwm);
+}
+#else
+static void
+mpc52xx_gpt_pwm_setup(struct mpc52xx_gpt_priv *p, struct device_node *np) {}
+#endif
+
+/* ---------------------------------------------------------------------
* GPIOLIB hooks
*/
#if defined(CONFIG_GPIOLIB)
@@ -737,9 +928,9 @@ static int __devinit mpc52xx_gpt_probe(struct of_device *ofdev,
}
dev_set_drvdata(&ofdev->dev, gpt);
-
mpc52xx_gpt_gpio_setup(gpt, ofdev->node);
mpc52xx_gpt_irq_setup(gpt, ofdev->node);
+ mpc52xx_gpt_pwm_setup(gpt, ofdev->node);
mutex_lock(&mpc52xx_gpt_list_mutex);
list_add(&gpt->list, &mpc52xx_gpt_list);
--
1.6.5
--
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