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Commit 75540c1a authored by eric miao's avatar eric miao Committed by Russell King
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[ARM] pxa: Add PXA support for PWM API



Patch mainly from Eric Miao, with minor edits by rmk.

Note: PWM0 and PWM2 share the same register I/O space and clock gating
on pxa{27x, 3xx}, thus PWM2 is treated in the driver as a child PWM of
PWM0. And this is also true for PWM1/3.

Signed-off-by: default avatareric miao <eric.miao@marvell.com>
Signed-off-by: default avatarRussell King <rmk+kernel@arm.linux.org.uk>
parent 1a189b97
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+5 −0
Original line number Diff line number Diff line
@@ -273,4 +273,9 @@ config PXA_SSP
	tristate
	help
	  Enable support for PXA2xx SSP ports

config PXA_PWM
	tristate
	help
	  Enable support for PXA2xx/PXA3xx PWM controllers
endif
+1 −0
Original line number Diff line number Diff line
@@ -10,6 +10,7 @@ obj-$(CONFIG_CPU_FREQ) += cpu-pxa.o

# Generic drivers that other drivers may depend upon
obj-$(CONFIG_PXA_SSP)		+= ssp.o
obj-$(CONFIG_PXA_PWM)		+= pwm.o

# SoC-specific code
obj-$(CONFIG_PXA25x)		+= mfp-pxa2xx.o pxa25x.o
+60 −0
Original line number Diff line number Diff line
@@ -280,6 +280,36 @@ struct platform_device pxa_device_rtc = {

#ifdef CONFIG_PXA25x

static struct resource pxa25x_resource_pwm0[] = {
	[0] = {
		.start	= 0x40b00000,
		.end	= 0x40b0000f,
		.flags	= IORESOURCE_MEM,
	},
};

struct platform_device pxa25x_device_pwm0 = {
	.name		= "pxa25x-pwm",
	.id		= 0,
	.resource	= pxa25x_resource_pwm0,
	.num_resources	= ARRAY_SIZE(pxa25x_resource_pwm0),
};

static struct resource pxa25x_resource_pwm1[] = {
	[0] = {
		.start	= 0x40c00000,
		.end	= 0x40c0000f,
		.flags	= IORESOURCE_MEM,
	},
};

struct platform_device pxa25x_device_pwm1 = {
	.name		= "pxa25x-pwm",
	.id		= 1,
	.resource	= pxa25x_resource_pwm1,
	.num_resources	= ARRAY_SIZE(pxa25x_resource_pwm1),
};

static u64 pxa25x_ssp_dma_mask = DMA_BIT_MASK(32);

static struct resource pxa25x_resource_ssp[] = {
@@ -568,6 +598,36 @@ struct platform_device pxa27x_device_ssp3 = {
	.num_resources	= ARRAY_SIZE(pxa27x_resource_ssp3),
};

static struct resource pxa27x_resource_pwm0[] = {
	[0] = {
		.start	= 0x40b00000,
		.end	= 0x40b0001f,
		.flags	= IORESOURCE_MEM,
	},
};

struct platform_device pxa27x_device_pwm0 = {
	.name		= "pxa27x-pwm",
	.id		= 0,
	.resource	= pxa27x_resource_pwm0,
	.num_resources	= ARRAY_SIZE(pxa27x_resource_pwm0),
};

static struct resource pxa27x_resource_pwm1[] = {
	[0] = {
		.start	= 0x40c00000,
		.end	= 0x40c0001f,
		.flags	= IORESOURCE_MEM,
	},
};

struct platform_device pxa27x_device_pwm1 = {
	.name		= "pxa27x-pwm",
	.id		= 1,
	.resource	= pxa27x_resource_pwm1,
	.num_resources	= ARRAY_SIZE(pxa27x_resource_pwm1),
};

static struct resource pxa27x_resource_camera[] = {
	[0] = {
		.start	= 0x50000000,
+5 −0
Original line number Diff line number Diff line
@@ -24,4 +24,9 @@ extern struct platform_device pxa27x_device_ssp2;
extern struct platform_device pxa27x_device_ssp3;
extern struct platform_device pxa3xx_device_ssp4;

extern struct platform_device pxa25x_device_pwm0;
extern struct platform_device pxa25x_device_pwm1;
extern struct platform_device pxa27x_device_pwm0;
extern struct platform_device pxa27x_device_pwm1;

void __init pxa_register_device(struct platform_device *dev, void *data);
+299 −0
Original line number Diff line number Diff line
/*
 * linux/arch/arm/mach-pxa/pwm.c
 *
 * 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>
 */

#include <linux/module.h>
#include <linux/kernel.h>
#include <linux/platform_device.h>
#include <linux/err.h>
#include <linux/clk.h>
#include <linux/io.h>
#include <linux/pwm.h>

#include <asm/div64.h>
#include <asm/arch/pxa-regs.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)

struct pwm_device {
	struct list_head	node;
	struct platform_device *pdev;

	const char	*label;
	struct clk	*clk;
	void __iomem	*mmio_base;

	unsigned int	use_count;
	unsigned int	pwm_id;
};

/*
 * period_ns = 10^9 * (PRESCALE + 1) * (PV + 1) / PWM_CLK_RATE
 * duty_ns   = 10^9 * (PRESCALE + 1) * DC / PWM_CLK_RATE
 */
int pwm_config(struct pwm_device *pwm, int duty_ns, int period_ns)
{
	unsigned long long c;
	unsigned long period_cycles, prescale, pv, dc;

	if (pwm == NULL || period_ns == 0 || duty_ns > period_ns)
		return -EINVAL;

	c = clk_get_rate(pwm->clk);
	c = c * period_ns;
	do_div(c, 1000000000);
	period_cycles = c;

	if (period_cycles < 0)
		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
	 */
	clk_enable(pwm->clk);
	__raw_writel(prescale, pwm->mmio_base + PWMCR);
	__raw_writel(dc, pwm->mmio_base + PWMDCR);
	__raw_writel(pv, pwm->mmio_base + PWMPCR);
	clk_disable(pwm->clk);

	return 0;
}
EXPORT_SYMBOL(pwm_config);

int pwm_enable(struct pwm_device *pwm)
{
	return clk_enable(pwm->clk);
}
EXPORT_SYMBOL(pwm_enable);

void pwm_disable(struct pwm_device *pwm)
{
	clk_disable(pwm->clk);
}
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 && pwm->use_count == 0) {
			pwm->use_count++;
			pwm->label = label;
			found = 1;
			break;
		}
	}

	mutex_unlock(&pwm_lock);

	return (found) ? pwm : NULL;
}
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 inline void __add_pwm(struct pwm_device *pwm)
{
	mutex_lock(&pwm_lock);
	list_add_tail(&pwm->node, &pwm_list);
	mutex_unlock(&pwm_lock);
}

static struct pwm_device *pwm_probe(struct platform_device *pdev,
		unsigned int pwm_id, struct pwm_device *parent_pwm)
{
	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 ERR_PTR(-ENOMEM);
	}

	pwm->clk = clk_get(&pdev->dev, "PWMCLK");
	if (IS_ERR(pwm->clk)) {
		ret = PTR_ERR(pwm->clk);
		goto err_free;
	}

	pwm->use_count = 0;
	pwm->pwm_id = pwm_id;
	pwm->pdev = pdev;

	if (parent_pwm != NULL) {
		/* registers for the second PWM has offset of 0x10 */
		pwm->mmio_base = parent_pwm->mmio_base + 0x10;
		__add_pwm(pwm);
		return pwm;
	}

	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, r->end - r->start + 1, 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, r->end - r->start + 1);
	if (pwm->mmio_base == NULL) {
		dev_err(&pdev->dev, "failed to ioremap() registers\n");
		ret = -ENODEV;
		goto err_free_mem;
	}

	__add_pwm(pwm);
	platform_set_drvdata(pdev, pwm);
	return pwm;

err_free_mem:
	release_mem_region(r->start, r->end - r->start + 1);
err_free_clk:
	clk_put(pwm->clk);
err_free:
	kfree(pwm);
	return ERR_PTR(ret);
}

static int __devinit pxa25x_pwm_probe(struct platform_device *pdev)
{
	struct pwm_device *pwm = pwm_probe(pdev, pdev->id, NULL);

	if (IS_ERR(pwm))
		return PTR_ERR(pwm);

	return 0;
}

static int __devinit pxa27x_pwm_probe(struct platform_device *pdev)
{
	struct pwm_device *pwm;

	pwm = pwm_probe(pdev, pdev->id * 2, NULL);
	if (IS_ERR(pwm))
		return PTR_ERR(pwm);

	pwm = pwm_probe(pdev, pdev->id * 2 + 1, pwm);
	if (IS_ERR(pwm))
		return PTR_ERR(pwm);

	return 0;
}

static int __devexit 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, r->end - r->start + 1);

	clk_put(pwm->clk);
	kfree(pwm);
	return 0;
}

static struct platform_driver pxa25x_pwm_driver = {
	.driver		= {
		.name	= "pxa25x-pwm",
	},
	.probe		= pxa25x_pwm_probe,
	.remove		= __devexit_p(pwm_remove),
};

static struct platform_driver pxa27x_pwm_driver = {
	.driver		= {
		.name	= "pxa27x-pwm",
	},
	.probe		= pxa27x_pwm_probe,
	.remove		= __devexit_p(pwm_remove),
};

static int __init pwm_init(void)
{
	int ret = 0;

	ret = platform_driver_register(&pxa25x_pwm_driver);
	if (ret) {
		printk(KERN_ERR "failed to register pxa25x_pwm_driver\n");
		return ret;
	}

	ret = platform_driver_register(&pxa27x_pwm_driver);
	if (ret) {
		printk(KERN_ERR "failed to register pxa27x_pwm_driver\n");
		return ret;
	}

	return ret;
}
arch_initcall(pwm_init);

static void __exit pwm_exit(void)
{
	platform_driver_unregister(&pxa25x_pwm_driver);
	platform_driver_unregister(&pxa27x_pwm_driver);
}
module_exit(pwm_exit);
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