1 files changed, 147 insertions, 40 deletions

diff --git a/drivers/pwm/pwm-vt8500.c b/drivers/pwm/pwm-vt8500.c
index ad14389b7144..69effd19afc7 100644
--- a/drivers/pwm/pwm-vt8500.c
+++ b/drivers/pwm/pwm-vt8500.c
@@ -1,7 +1,8 @@
 /*
  * drivers/pwm/pwm-vt8500.c
  *
- *  Copyright (C) 2010 Alexey Charkov <alchark@gmail.com>
+ * Copyright (C) 2012 Tony Prisk <linux@prisktech.co.nz>
+ * Copyright (C) 2010 Alexey Charkov <alchark@gmail.com>
  *
  * This software is licensed under the terms of the GNU General Public
  * License version 2, as published by the Free Software Foundation, and
@@ -21,28 +22,59 @@
 #include <linux/io.h>
 #include <linux/pwm.h>
 #include <linux/delay.h>
+#include <linux/clk.h>
 
 #include <asm/div64.h>
 
-#define VT8500_NR_PWMS 4
+#include <linux/of.h>
+#include <linux/of_device.h>
+#include <linux/of_address.h>
+
+/*
+ * SoC architecture allocates register space for 4 PWMs but only
+ * 2 are currently implemented.
+ */
+#define VT8500_NR_PWMS	2
+
+#define REG_CTRL(pwm)		(((pwm) << 4) + 0x00)
+#define REG_SCALAR(pwm)		(((pwm) << 4) + 0x04)
+#define REG_PERIOD(pwm)		(((pwm) << 4) + 0x08)
+#define REG_DUTY(pwm)		(((pwm) << 4) + 0x0C)
+#define REG_STATUS		0x40
+
+#define CTRL_ENABLE		BIT(0)
+#define CTRL_INVERT		BIT(1)
+#define CTRL_AUTOLOAD		BIT(2)
+#define CTRL_STOP_IMM		BIT(3)
+#define CTRL_LOAD_PRESCALE	BIT(4)
+#define CTRL_LOAD_PERIOD	BIT(5)
+
+#define STATUS_CTRL_UPDATE	BIT(0)
+#define STATUS_SCALAR_UPDATE	BIT(1)
+#define STATUS_PERIOD_UPDATE	BIT(2)
+#define STATUS_DUTY_UPDATE	BIT(3)
+#define STATUS_ALL_UPDATE	0x0F
 
 struct vt8500_chip {
 	struct pwm_chip chip;
 	void __iomem *base;
+	struct clk *clk;
 };
 
 #define to_vt8500_chip(chip)	container_of(chip, struct vt8500_chip, chip)
 
 #define msecs_to_loops(t) (loops_per_jiffy / 1000 * HZ * t)
-static inline void pwm_busy_wait(void __iomem *reg, u8 bitmask)
+static inline void pwm_busy_wait(struct vt8500_chip *vt8500, int nr, u8 bitmask)
 {
 	int loops = msecs_to_loops(10);
-	while ((readb(reg) & bitmask) && --loops)
+	u32 mask = bitmask << (nr << 8);
+
+	while ((readl(vt8500->base + REG_STATUS) & mask) && --loops)
 		cpu_relax();
 
 	if (unlikely(!loops))
-		pr_warn("Waiting for status bits 0x%x to clear timed out\n",
-			   bitmask);
+		dev_warn(vt8500->chip.dev, "Waiting for status bits 0x%x to clear timed out\n",
+			 mask);
 }
 
 static int vt8500_pwm_config(struct pwm_chip *chip, struct pwm_device *pwm,
@@ -51,8 +83,16 @@ static int vt8500_pwm_config(struct pwm_chip *chip, struct pwm_device *pwm,
 	struct vt8500_chip *vt8500 = to_vt8500_chip(chip);
 	unsigned long long c;
 	unsigned long period_cycles, prescale, pv, dc;
+	int err;
+	u32 val;
+
+	err = clk_enable(vt8500->clk);
+	if (err < 0) {
+		dev_err(chip->dev, "failed to enable clock\n");
+		return err;
+	}
 
-	c = 25000000/2; /* wild guess --- need to implement clocks */
+	c = clk_get_rate(vt8500->clk);
 	c = c * period_ns;
 	do_div(c, 1000000000);
 	period_cycles = c;
@@ -64,55 +104,112 @@ static int vt8500_pwm_config(struct pwm_chip *chip, struct pwm_device *pwm,
 	if (pv > 4095)
 		pv = 4095;
 
-	if (prescale > 1023)
+	if (prescale > 1023) {
+		clk_disable(vt8500->clk);
 		return -EINVAL;
+	}
 
 	c = (unsigned long long)pv * duty_ns;
 	do_div(c, period_ns);
 	dc = c;
 
-	pwm_busy_wait(vt8500->base + 0x40 + pwm->hwpwm, (1 << 1));
-	writel(prescale, vt8500->base + 0x4 + (pwm->hwpwm << 4));
+	writel(prescale, vt8500->base + REG_SCALAR(pwm->hwpwm));
+	pwm_busy_wait(vt8500, pwm->hwpwm, STATUS_SCALAR_UPDATE);
+
+	writel(pv, vt8500->base + REG_PERIOD(pwm->hwpwm));
+	pwm_busy_wait(vt8500, pwm->hwpwm, STATUS_PERIOD_UPDATE);
 
-	pwm_busy_wait(vt8500->base + 0x40 + pwm->hwpwm, (1 << 2));
-	writel(pv, vt8500->base + 0x8 + (pwm->hwpwm << 4));
+	writel(dc, vt8500->base + REG_DUTY(pwm->hwpwm));
+	pwm_busy_wait(vt8500, pwm->hwpwm, STATUS_DUTY_UPDATE);
 
-	pwm_busy_wait(vt8500->base + 0x40 + pwm->hwpwm, (1 << 3));
-	writel(dc, vt8500->base + 0xc + (pwm->hwpwm << 4));
+	val = readl(vt8500->base + REG_CTRL(pwm->hwpwm));
+	val |= CTRL_AUTOLOAD;
+	writel(val, vt8500->base + REG_CTRL(pwm->hwpwm));
+	pwm_busy_wait(vt8500, pwm->hwpwm, STATUS_CTRL_UPDATE);
 
+	clk_disable(vt8500->clk);
 	return 0;
 }
 
 static int vt8500_pwm_enable(struct pwm_chip *chip, struct pwm_device *pwm)
 {
 	struct vt8500_chip *vt8500 = to_vt8500_chip(chip);
+	int err;
+	u32 val;
+
+	err = clk_enable(vt8500->clk);
+	if (err < 0) {
+		dev_err(chip->dev, "failed to enable clock\n");
+		return err;
+	}
+
+	val = readl(vt8500->base + REG_CTRL(pwm->hwpwm));
+	val |= CTRL_ENABLE;
+	writel(val, vt8500->base + REG_CTRL(pwm->hwpwm));
+	pwm_busy_wait(vt8500, pwm->hwpwm, STATUS_CTRL_UPDATE);
 
-	pwm_busy_wait(vt8500->base + 0x40 + pwm->hwpwm, (1 << 0));
-	writel(5, vt8500->base + (pwm->hwpwm << 4));
 	return 0;
 }
 
 static void vt8500_pwm_disable(struct pwm_chip *chip, struct pwm_device *pwm)
 {
 	struct vt8500_chip *vt8500 = to_vt8500_chip(chip);
+	u32 val;
+
+	val = readl(vt8500->base + REG_CTRL(pwm->hwpwm));
+	val &= ~CTRL_ENABLE;
+	writel(val, vt8500->base + REG_CTRL(pwm->hwpwm));
+	pwm_busy_wait(vt8500, pwm->hwpwm, STATUS_CTRL_UPDATE);
 
-	pwm_busy_wait(vt8500->base + 0x40 + pwm->hwpwm, (1 << 0));
-	writel(0, vt8500->base + (pwm->hwpwm << 4));
+	clk_disable(vt8500->clk);
+}
+
+static int vt8500_pwm_set_polarity(struct pwm_chip *chip,
+				   struct pwm_device *pwm,
+				   enum pwm_polarity polarity)
+{
+	struct vt8500_chip *vt8500 = to_vt8500_chip(chip);
+	u32 val;
+
+	val = readl(vt8500->base + REG_CTRL(pwm->hwpwm));
+
+	if (polarity == PWM_POLARITY_INVERSED)
+		val |= CTRL_INVERT;
+	else
+		val &= ~CTRL_INVERT;
+
+	writel(val, vt8500->base + REG_CTRL(pwm->hwpwm));
+	pwm_busy_wait(vt8500, pwm->hwpwm, STATUS_CTRL_UPDATE);
+
+	return 0;
 }
 
 static struct pwm_ops vt8500_pwm_ops = {
 	.enable = vt8500_pwm_enable,
 	.disable = vt8500_pwm_disable,
 	.config = vt8500_pwm_config,
+	.set_polarity = vt8500_pwm_set_polarity,
 	.owner = THIS_MODULE,
 };
 
-static int __devinit pwm_probe(struct platform_device *pdev)
+static const struct of_device_id vt8500_pwm_dt_ids[] = {
+	{ .compatible = "via,vt8500-pwm", },
+	{ /* Sentinel */ }
+};
+MODULE_DEVICE_TABLE(of, vt8500_pwm_dt_ids);
+
+static int vt8500_pwm_probe(struct platform_device *pdev)
 {
 	struct vt8500_chip *chip;
 	struct resource *r;
+	struct device_node *np = pdev->dev.of_node;
 	int ret;
 
+	if (!np) {
+		dev_err(&pdev->dev, "invalid devicetree node\n");
+		return -EINVAL;
+	}
+
 	chip = devm_kzalloc(&pdev->dev, sizeof(*chip), GFP_KERNEL);
 	if (chip == NULL) {
 		dev_err(&pdev->dev, "failed to allocate memory\n");
@@ -121,28 +218,44 @@ static int __devinit pwm_probe(struct platform_device *pdev)
 
 	chip->chip.dev = &pdev->dev;
 	chip->chip.ops = &vt8500_pwm_ops;
+	chip->chip.of_xlate = of_pwm_xlate_with_flags;
+	chip->chip.of_pwm_n_cells = 3;
 	chip->chip.base = -1;
 	chip->chip.npwm = VT8500_NR_PWMS;
 
+	chip->clk = devm_clk_get(&pdev->dev, NULL);
+	if (IS_ERR(chip->clk)) {
+		dev_err(&pdev->dev, "clock source not specified\n");
+		return PTR_ERR(chip->clk);
+	}
+
 	r = platform_get_resource(pdev, IORESOURCE_MEM, 0);
 	if (r == NULL) {
 		dev_err(&pdev->dev, "no memory resource defined\n");
 		return -ENODEV;
 	}
 
-	chip->base = devm_request_and_ioremap(&pdev->dev, r);
-	if (chip->base == NULL)
-		return -EADDRNOTAVAIL;
+	chip->base = devm_ioremap_resource(&pdev->dev, r);
+	if (IS_ERR(chip->base))
+		return PTR_ERR(chip->base);
+
+	ret = clk_prepare(chip->clk);
+	if (ret < 0) {
+		dev_err(&pdev->dev, "failed to prepare clock\n");
+		return ret;
+	}
 
 	ret = pwmchip_add(&chip->chip);
-	if (ret < 0)
+	if (ret < 0) {
+		dev_err(&pdev->dev, "failed to add PWM chip\n");
 		return ret;
+	}
 
 	platform_set_drvdata(pdev, chip);
 	return ret;
 }
 
-static int __devexit pwm_remove(struct platform_device *pdev)
+static int vt8500_pwm_remove(struct platform_device *pdev)
 {
 	struct vt8500_chip *chip;
 
@@ -150,28 +263,22 @@ static int __devexit pwm_remove(struct platform_device *pdev)
 	if (chip == NULL)
 		return -ENODEV;
 
+	clk_unprepare(chip->clk);
+
 	return pwmchip_remove(&chip->chip);
 }
 
-static struct platform_driver pwm_driver = {
+static struct platform_driver vt8500_pwm_driver = {
+	.probe		= vt8500_pwm_probe,
+	.remove		= vt8500_pwm_remove,
 	.driver		= {
 		.name	= "vt8500-pwm",
 		.owner	= THIS_MODULE,
+		.of_match_table = vt8500_pwm_dt_ids,
 	},
-	.probe		= pwm_probe,
-	.remove		= __devexit_p(pwm_remove),
 };
+module_platform_driver(vt8500_pwm_driver);
 
-static int __init pwm_init(void)
-{
-	return platform_driver_register(&pwm_driver);
-}
-arch_initcall(pwm_init);
-
-static void __exit pwm_exit(void)
-{
-	platform_driver_unregister(&pwm_driver);
-}
-module_exit(pwm_exit);
-
-MODULE_LICENSE("GPL");
+MODULE_DESCRIPTION("VT8500 PWM Driver");
+MODULE_AUTHOR("Tony Prisk <linux@prisktech.co.nz>");
+MODULE_LICENSE("GPL v2");