[PATCH] ARM: i.MX23/28: Add pwm driver

* [PATCH] ARM: i.MX23/28: Add pwm driver
@ 2011-01-27 11:48 Sascha Hauer
  2011-01-27 17:29 ` Wolfram Sang
  0 siblings, 1 reply; 2+ messages in thread
From: Sascha Hauer @ 2011-01-27 11:48 UTC (permalink / raw)
  To: linux-arm-kernel


Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>
---
 arch/arm/mach-mxs/Kconfig                       |    2 +
 arch/arm/mach-mxs/Makefile                      |    2 +
 arch/arm/mach-mxs/clock-mx23.c                  |    6 +-
 arch/arm/mach-mxs/clock-mx28.c                  |    9 +-
 arch/arm/mach-mxs/devices-mx23.h                |    3 +
 arch/arm/mach-mxs/devices-mx28.h                |    3 +
 arch/arm/mach-mxs/devices/Kconfig               |    4 +
 arch/arm/mach-mxs/devices/Makefile              |    1 +
 arch/arm/mach-mxs/devices/platform-pwm.c        |   25 ++
 arch/arm/mach-mxs/include/mach/devices-common.h |    5 +
 arch/arm/mach-mxs/pwm.c                         |  318 +++++++++++++++++++++++
 11 files changed, 376 insertions(+), 2 deletions(-)
 create mode 100644 arch/arm/mach-mxs/devices/platform-pwm.c
 create mode 100644 arch/arm/mach-mxs/pwm.c

diff --git a/arch/arm/mach-mxs/Kconfig b/arch/arm/mach-mxs/Kconfig
index cd2fbdf..99813e0 100644
--- a/arch/arm/mach-mxs/Kconfig
+++ b/arch/arm/mach-mxs/Kconfig
@@ -8,10 +8,12 @@ config MXS_OCOTP
 config SOC_IMX23
 	bool
 	select CPU_ARM926T
+	select HAVE_PWM
 
 config SOC_IMX28
 	bool
 	select CPU_ARM926T
+	select HAVE_PWM
 
 comment "MXS platforms:"
 
diff --git a/arch/arm/mach-mxs/Makefile b/arch/arm/mach-mxs/Makefile
index 6b26f02..5c7ce1f 100644
--- a/arch/arm/mach-mxs/Makefile
+++ b/arch/arm/mach-mxs/Makefile
@@ -7,6 +7,8 @@ obj-$(CONFIG_PM) += pm.o
 obj-$(CONFIG_SOC_IMX23) += clock-mx23.o mm-mx23.o
 obj-$(CONFIG_SOC_IMX28) += clock-mx28.o mm-mx28.o
 
+obj-$(CONFIG_MXS_HAVE_PLATFORM_PWM) += pwm.o
+
 obj-$(CONFIG_MACH_MX23EVK) += mach-mx23evk.o
 obj-$(CONFIG_MACH_MX28EVK) += mach-mx28evk.o
 
diff --git a/arch/arm/mach-mxs/clock-mx23.c b/arch/arm/mach-mxs/clock-mx23.c
index b1a362e..017d4a3 100644
--- a/arch/arm/mach-mxs/clock-mx23.c
+++ b/arch/arm/mach-mxs/clock-mx23.c
@@ -446,7 +446,11 @@ static struct clk_lookup lookups[] = {
 	_REGISTER_CLOCK(NULL, "hclk", hbus_clk)
 	_REGISTER_CLOCK(NULL, "usb", usb_clk)
 	_REGISTER_CLOCK(NULL, "audio", audio_clk)
-	_REGISTER_CLOCK(NULL, "pwm", pwm_clk)
+	_REGISTER_CLOCK("mxs-pwm.0", NULL, pwm_clk)
+	_REGISTER_CLOCK("mxs-pwm.1", NULL, pwm_clk)
+	_REGISTER_CLOCK("mxs-pwm.2", NULL, pwm_clk)
+	_REGISTER_CLOCK("mxs-pwm.3", NULL, pwm_clk)
+	_REGISTER_CLOCK("mxs-pwm.4", NULL, pwm_clk)
 };
 
 static int clk_misc_init(void)
diff --git a/arch/arm/mach-mxs/clock-mx28.c b/arch/arm/mach-mxs/clock-mx28.c
index 2f1a990..4b48b0a 100644
--- a/arch/arm/mach-mxs/clock-mx28.c
+++ b/arch/arm/mach-mxs/clock-mx28.c
@@ -623,7 +623,14 @@ static struct clk_lookup lookups[] = {
 	_REGISTER_CLOCK(NULL, "can1", can1_clk)
 	_REGISTER_CLOCK(NULL, "usb0", usb0_clk)
 	_REGISTER_CLOCK(NULL, "usb1", usb1_clk)
-	_REGISTER_CLOCK(NULL, "pwm", pwm_clk)
+	_REGISTER_CLOCK("mxs-pwm.0", NULL, pwm_clk)
+	_REGISTER_CLOCK("mxs-pwm.1", NULL, pwm_clk)
+	_REGISTER_CLOCK("mxs-pwm.2", NULL, pwm_clk)
+	_REGISTER_CLOCK("mxs-pwm.3", NULL, pwm_clk)
+	_REGISTER_CLOCK("mxs-pwm.4", NULL, pwm_clk)
+	_REGISTER_CLOCK("mxs-pwm.5", NULL, pwm_clk)
+	_REGISTER_CLOCK("mxs-pwm.6", NULL, pwm_clk)
+	_REGISTER_CLOCK("mxs-pwm.7", NULL, pwm_clk)
 	_REGISTER_CLOCK(NULL, "lradc", lradc_clk)
 	_REGISTER_CLOCK(NULL, "spdif", spdif_clk)
 };
diff --git a/arch/arm/mach-mxs/devices-mx23.h b/arch/arm/mach-mxs/devices-mx23.h
index 1256788..fb9def8 100644
--- a/arch/arm/mach-mxs/devices-mx23.h
+++ b/arch/arm/mach-mxs/devices-mx23.h
@@ -14,3 +14,6 @@
 extern const struct amba_device mx23_duart_device __initconst;
 #define mx23_add_duart() \
 	mxs_add_duart(&mx23_duart_device)
+
+#define mx23_add_pwm(id)		mxs_add_pwm(MX23_PWM_BASE_ADDR, pdata)
+
diff --git a/arch/arm/mach-mxs/devices-mx28.h b/arch/arm/mach-mxs/devices-mx28.h
index 1ab7bf0..6927250 100644
--- a/arch/arm/mach-mxs/devices-mx28.h
+++ b/arch/arm/mach-mxs/devices-mx28.h
@@ -26,3 +26,6 @@ extern const struct mxs_auart_data mx28_auart_data[] __initconst;
 extern const struct mxs_fec_data mx28_fec_data[] __initconst;
 #define mx28_add_fec(id, pdata) \
 	mxs_add_fec(&mx28_fec_data[id], pdata)
+
+#define mx28_add_pwm(id)		mxs_add_pwm(MX28_PWM_BASE_ADDR, id)
+
diff --git a/arch/arm/mach-mxs/devices/Kconfig b/arch/arm/mach-mxs/devices/Kconfig
index 3001b75..f8599e5 100644
--- a/arch/arm/mach-mxs/devices/Kconfig
+++ b/arch/arm/mach-mxs/devices/Kconfig
@@ -7,3 +7,7 @@ config MXS_HAVE_PLATFORM_AUART
 
 config MXS_HAVE_PLATFORM_FEC
 	bool
+
+config MXS_HAVE_PLATFORM_PWM
+	bool
+
diff --git a/arch/arm/mach-mxs/devices/Makefile b/arch/arm/mach-mxs/devices/Makefile
index c814d05..cdb026e 100644
--- a/arch/arm/mach-mxs/devices/Makefile
+++ b/arch/arm/mach-mxs/devices/Makefile
@@ -1,3 +1,4 @@
 obj-$(CONFIG_MXS_HAVE_AMBA_DUART) += amba-duart.o
 obj-$(CONFIG_MXS_HAVE_PLATFORM_AUART) += platform-auart.o
 obj-$(CONFIG_MXS_HAVE_PLATFORM_FEC) += platform-fec.o
+obj-$(CONFIG_MXS_HAVE_PLATFORM_PWM) += platform-pwm.o
diff --git a/arch/arm/mach-mxs/devices/platform-pwm.c b/arch/arm/mach-mxs/devices/platform-pwm.c
new file mode 100644
index 0000000..2f1f549
--- /dev/null
+++ b/arch/arm/mach-mxs/devices/platform-pwm.c
@@ -0,0 +1,25 @@
+/*
+ * Copyright (C) 2010 Pengutronix
+ * Sascha Hauer <s.hauer@pengutronix.de>
+ *
+ * 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.
+ */
+#include <asm/sizes.h>
+#include <mach/mx23.h>
+#include <mach/mx28.h>
+#include <mach/devices-common.h>
+
+struct platform_device *__init mxs_add_pwm(resource_size_t iobase, int id)
+{
+	struct resource res = {
+		.flags = IORESOURCE_MEM,
+	};
+
+	res.start = iobase + 0x10 + 0x20 * id;
+	res.end = res.start + 0x1f;
+
+	return mxs_add_platform_device("mxs-pwm", id, &res, 1, NULL, 0);
+}
+
diff --git a/arch/arm/mach-mxs/include/mach/devices-common.h b/arch/arm/mach-mxs/include/mach/devices-common.h
index bed4002..82d5311 100644
--- a/arch/arm/mach-mxs/include/mach/devices-common.h
+++ b/arch/arm/mach-mxs/include/mach/devices-common.h
@@ -51,3 +51,8 @@ struct mxs_fec_data {
 struct platform_device *__init mxs_add_fec(
 		const struct mxs_fec_data *data,
 		const struct fec_platform_data *pdata);
+
+/* pwm */
+struct platform_device *__init mxs_add_pwm(
+		resource_size_t iobase, int id);
+
diff --git a/arch/arm/mach-mxs/pwm.c b/arch/arm/mach-mxs/pwm.c
new file mode 100644
index 0000000..f2c83a6
--- /dev/null
+++ b/arch/arm/mach-mxs/pwm.c
@@ -0,0 +1,318 @@
+/*
+ * Copyright (C) 2010 Pengutronix
+ * Sascha Hauer <s.hauer@pengutronix.de>
+ *
+ * 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.
+ *
+ * Derived from pxa PWM driver by eric miao <eric.miao@marvell.com>
+ */
+
+#include <linux/module.h>
+#include <linux/kernel.h>
+#include <linux/platform_device.h>
+#include <linux/slab.h>
+#include <linux/err.h>
+#include <linux/clk.h>
+#include <linux/delay.h>
+#include <linux/io.h>
+#include <linux/pwm.h>
+#include <mach/hardware.h>
+#include <mach/mxs.h>
+#include <mach/mx23.h>
+#include <mach/mx28.h>
+#include <asm/div64.h>
+
+struct pwm_device {
+	struct list_head	node;
+	struct device		*dev;
+
+	const char	*label;
+	struct clk	*clk;
+
+	int		enabled;
+	void __iomem	*mmio_base;
+
+	unsigned int	use_count;
+	unsigned int	pwm_id;
+
+	u32		val_active;
+	u32		val_period;
+	int		period_us;
+};
+
+/* common register space */
+static void __iomem *pwm_base_common;
+#define REG_PWM_CTRL	0x0
+#define PWM_SFTRST	(1 << 31)
+#define PWM_CLKGATE	(1 << 30)
+#define PWM_ENABLE(p)	(1 << (p))
+
+/* per pwm register space */
+#define REG_ACTIVE	0x0
+#define REG_PERIOD	0x10
+
+#define PERIOD_PERIOD(p)	((p) & 0xffff)
+#define PERIOD_ACTIVE_HIGH	(3 << 16)
+#define PERIOD_INACTIVE_LOW	(2 << 18)
+#define PERIOD_CDIV(div)	(((div) & 0x7) << 20)
+
+static void pwm_update(struct pwm_device *pwm)
+{
+	writel(pwm->val_active, pwm->mmio_base + REG_ACTIVE);
+	writel(pwm->val_period, pwm->mmio_base + REG_PERIOD);
+}
+
+int pwm_config(struct pwm_device *pwm, int duty_ns, int period_ns)
+{
+	int div = 0;
+	unsigned long rate;
+	unsigned long long c;
+	unsigned long period_cycles, duty_cycles;
+
+	if (pwm == NULL || period_ns == 0 || duty_ns > period_ns)
+		return -EINVAL;
+
+	rate = clk_get_rate(pwm->clk);
+
+	dev_dbg(pwm->dev, "config: duty_ns: %d, period_ns: %d (clkrate %ld)\n",
+			duty_ns, period_ns, rate);
+
+	while (1) {
+		c = rate / (1 << div);
+		c = c * period_ns;
+		do_div(c, 1000000000);
+		if (c < 0x10000)
+			break;
+		div++;
+
+		if (div > 8)
+			return -EINVAL;
+	}
+
+	period_cycles = c;
+	duty_cycles = period_cycles * duty_ns / period_ns;
+
+	dev_dbg(pwm->dev, "config period_cycles: %ld duty_cycles: %ld\n",
+			period_cycles, duty_cycles);
+
+	pwm->val_active = period_cycles << 16 | duty_cycles;
+	pwm->val_period = PERIOD_PERIOD(period_cycles) | PERIOD_ACTIVE_HIGH |
+			PERIOD_INACTIVE_LOW | PERIOD_CDIV(div);
+	pwm->period_us = period_ns / 1000;
+
+	pwm_update(pwm);
+
+	return 0;
+}
+EXPORT_SYMBOL(pwm_config);
+
+static void __pwm_enable(struct pwm_device *pwm, int enable)
+{
+	if (enable)
+		__mxs_setl(PWM_ENABLE(pwm->pwm_id), pwm_base_common + REG_PWM_CTRL);
+	else
+		__mxs_clrl(PWM_ENABLE(pwm->pwm_id), pwm_base_common + REG_PWM_CTRL);
+}
+
+int pwm_enable(struct pwm_device *pwm)
+{
+	int rc = 0;
+
+	dev_dbg(pwm->dev, "enable\n");
+
+	if (!pwm->enabled) {
+		rc = clk_enable(pwm->clk);
+		if (!rc) {
+			pwm->enabled = 1;
+			__pwm_enable(pwm, 1);
+			pwm_update(pwm);
+		}
+	}
+	return rc;
+}
+EXPORT_SYMBOL(pwm_enable);
+
+void pwm_disable(struct pwm_device *pwm)
+{
+	dev_dbg(pwm->dev, "disable\n");
+
+	if (pwm->enabled) {
+		/*
+		 * We need a little delay here, it takes one period for
+		 * the last pwm_config call to take effect. If we disable
+		 * the pwm too early it just freezes the current output
+		 * state.
+		 */
+		usleep_range(pwm->period_us, pwm->period_us * 2);
+		__pwm_enable(pwm, 0);
+		clk_disable(pwm->clk);
+		pwm->enabled = 0;
+	}
+}
+EXPORT_SYMBOL(pwm_disable);
+
+static DEFINE_MUTEX(pwm_lock);
+static LIST_HEAD(pwm_list);
+
+struct pwm_device *pwm_request(int pwm_id, const char *label)
+{
+	struct pwm_device *pwm;
+	int found = 0;
+
+	mutex_lock(&pwm_lock);
+
+	list_for_each_entry(pwm, &pwm_list, node) {
+		if (pwm->pwm_id == pwm_id) {
+			found = 1;
+			break;
+		}
+	}
+
+	if (found) {
+		if (pwm->use_count == 0) {
+			pwm->use_count++;
+			pwm->label = label;
+		} else
+			pwm = ERR_PTR(-EBUSY);
+	} else
+		pwm = ERR_PTR(-ENOENT);
+
+	mutex_unlock(&pwm_lock);
+
+	return pwm;
+}
+EXPORT_SYMBOL(pwm_request);
+
+void pwm_free(struct pwm_device *pwm)
+{
+	mutex_lock(&pwm_lock);
+
+	if (pwm->use_count) {
+		pwm->use_count--;
+		pwm->label = NULL;
+	} else
+		pr_warning("PWM device already freed\n");
+
+	mutex_unlock(&pwm_lock);
+}
+EXPORT_SYMBOL(pwm_free);
+
+static int __devinit mxs_pwm_probe(struct platform_device *pdev)
+{
+	struct pwm_device *pwm;
+	struct resource *r;
+	int ret = 0;
+
+	pwm = kzalloc(sizeof(struct pwm_device), GFP_KERNEL);
+	if (pwm == NULL) {
+		dev_err(&pdev->dev, "failed to allocate memory\n");
+		return -ENOMEM;
+	}
+
+	pwm->clk = clk_get(&pdev->dev, NULL);
+
+	if (IS_ERR(pwm->clk)) {
+		ret = PTR_ERR(pwm->clk);
+		goto err_free;
+	}
+
+	pwm->enabled = 0;
+
+	pwm->use_count = 0;
+	pwm->pwm_id = pdev->id;
+	pwm->dev = &pdev->dev;
+
+	r = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+	if (r == NULL) {
+		dev_err(&pdev->dev, "no memory resource defined\n");
+		ret = -ENODEV;
+		goto err_free_clk;
+	}
+
+	r = request_mem_region(r->start, resource_size(r), pdev->name);
+	if (r == NULL) {
+		dev_err(&pdev->dev, "failed to request memory resource\n");
+		ret = -EBUSY;
+		goto err_free_clk;
+	}
+
+	pwm->mmio_base = ioremap(r->start, resource_size(r));
+	if (pwm->mmio_base == NULL) {
+		dev_err(&pdev->dev, "failed to ioremap() registers\n");
+		ret = -ENODEV;
+		goto err_free_mem;
+	}
+
+	mutex_lock(&pwm_lock);
+	list_add_tail(&pwm->node, &pwm_list);
+	mutex_unlock(&pwm_lock);
+
+	platform_set_drvdata(pdev, pwm);
+	return 0;
+
+err_free_mem:
+	release_mem_region(r->start, resource_size(r));
+err_free_clk:
+	clk_put(pwm->clk);
+err_free:
+	kfree(pwm);
+	return ret;
+}
+
+static int __devexit mxs_pwm_remove(struct platform_device *pdev)
+{
+	struct pwm_device *pwm;
+	struct resource *r;
+
+	pwm = platform_get_drvdata(pdev);
+	if (pwm == NULL)
+		return -ENODEV;
+
+	mutex_lock(&pwm_lock);
+	list_del(&pwm->node);
+	mutex_unlock(&pwm_lock);
+
+	iounmap(pwm->mmio_base);
+
+	r = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+	release_mem_region(r->start, resource_size(r));
+
+	clk_put(pwm->clk);
+
+	kfree(pwm);
+	return 0;
+}
+
+static struct platform_driver mxs_pwm_driver = {
+	.driver		= {
+		.name	= "mxs-pwm",
+	},
+	.probe		= mxs_pwm_probe,
+	.remove		= __devexit_p(mxs_pwm_remove),
+};
+
+static int __init mxs_pwm_init(void)
+{
+	if (cpu_is_mx28())
+		pwm_base_common = MX28_IO_ADDRESS(MX28_PWM_BASE_ADDR);
+	else
+		pwm_base_common = MX23_IO_ADDRESS(MX23_PWM_BASE_ADDR);
+
+	__mxs_clrl(PWM_SFTRST | PWM_CLKGATE, pwm_base_common + REG_PWM_CTRL);
+
+	return platform_driver_register(&mxs_pwm_driver);
+}
+arch_initcall(mxs_pwm_init);
+
+static void __exit mxs_pwm_exit(void)
+{
+	platform_driver_unregister(&mxs_pwm_driver);
+}
+module_exit(mxs_pwm_exit);
+
+MODULE_LICENSE("GPL v2");
+MODULE_AUTHOR("Sascha Hauer <s.hauer@pengutronix.de>");
-- 
1.7.2.3

-- 
Pengutronix e.K.                           |                             |
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Amtsgericht Hildesheim, HRA 2686           | Fax:   +49-5121-206917-5555 |

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