pwm: add lpc32xx PWM support

Add lpc32xx SOC PWM driver.
Signed-off-by: NAlexandre Pereira da Silva <aletes.xgr@gmail.com>
Acked-by: NRoland Stigge <stigge@antcom.de>
Signed-off-by: NThierry Reding <thierry.reding@avionic-design.de>

Documentation/devicetree/bindings/pwm/lpc32xx-pwm.txt

+LPC32XX PWM controller
+
+Required properties:
+- compatible: should be "nxp,lpc3220-pwm"
+- reg: physical base address and length of the controller's registers
+
+Examples:
+
+pwm@0x4005C000 {
+	compatible = "nxp,lpc3220-pwm";
+	reg = <0x4005C000 0x8>;
+};

drivers/pwm/Kconfig

@@ -28,6 +28,16 @@ config PWM_IMX
 	  To compile this driver as a module, choose M here: the module
 	  will be called pwm-imx.
 
+config PWM_LPC32XX
+	tristate "LPC32XX PWM support"
+	depends on ARCH_LPC32XX
+	help
+	  Generic PWM framework driver for LPC32XX. The LPC32XX SOC has two
+	  PWM controllers.
+
+	  To compile this driver as a module, choose M here: the module
+	  will be called pwm-lpc32xx.
+
 config PWM_MXS
 	tristate "Freescale MXS PWM support"
 	depends on ARCH_MXS && OF

drivers/pwm/Makefile

 obj-$(CONFIG_PWM)		+= core.o
 obj-$(CONFIG_PWM_BFIN)		+= pwm-bfin.o
 obj-$(CONFIG_PWM_IMX)		+= pwm-imx.o
+obj-$(CONFIG_PWM_LPC32XX)	+= pwm-lpc32xx.o
 obj-$(CONFIG_PWM_MXS)		+= pwm-mxs.o
 obj-$(CONFIG_PWM_PXA)		+= pwm-pxa.o
 obj-$(CONFIG_PWM_SAMSUNG)	+= pwm-samsung.o

drivers/pwm/pwm-lpc32xx.c

+/*
+ * Copyright 2012 Alexandre Pereira da Silva <aletes.xgr@gmail.com>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; version 2.
+ *
+ */
+
+#include <linux/clk.h>
+#include <linux/err.h>
+#include <linux/io.h>
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/of.h>
+#include <linux/of_address.h>
+#include <linux/platform_device.h>
+#include <linux/pwm.h>
+#include <linux/slab.h>
+
+struct lpc32xx_pwm_chip {
+	struct pwm_chip chip;
+	struct clk *clk;
+	void __iomem *base;
+};
+
+#define PWM_ENABLE	(1 << 31)
+#define PWM_RELOADV(x)	(((x) & 0xFF) << 8)
+#define PWM_DUTY(x)	((x) & 0xFF)
+
+#define to_lpc32xx_pwm_chip(_chip) \
+	container_of(_chip, struct lpc32xx_pwm_chip, chip)
+
+static int lpc32xx_pwm_config(struct pwm_chip *chip, struct pwm_device *pwm,
+			      int duty_ns, int period_ns)
+{
+	struct lpc32xx_pwm_chip *lpc32xx = to_lpc32xx_pwm_chip(chip);
+	unsigned long long c;
+	int period_cycles, duty_cycles;
+
+	c = clk_get_rate(lpc32xx->clk) / 256;
+	c = c * period_ns;
+	do_div(c, NSEC_PER_SEC);
+
+	/* Handle high and low extremes */
+	if (c == 0)
+		c = 1;
+	if (c > 255)
+		c = 0; /* 0 set division by 256 */
+	period_cycles = c;
+
+	c = 256 * duty_ns;
+	do_div(c, period_ns);
+	duty_cycles = c;
+
+	writel(PWM_ENABLE | PWM_RELOADV(period_cycles) | PWM_DUTY(duty_cycles),
+		lpc32xx->base + (pwm->hwpwm << 2));
+
+	return 0;
+}
+
+static int lpc32xx_pwm_enable(struct pwm_chip *chip, struct pwm_device *pwm)
+{
+	struct lpc32xx_pwm_chip *lpc32xx = to_lpc32xx_pwm_chip(chip);
+
+	return clk_enable(lpc32xx->clk);
+}
+
+static void lpc32xx_pwm_disable(struct pwm_chip *chip, struct pwm_device *pwm)
+{
+	struct lpc32xx_pwm_chip *lpc32xx = to_lpc32xx_pwm_chip(chip);
+
+	writel(0, lpc32xx->base + (pwm->hwpwm << 2));
+	clk_disable(lpc32xx->clk);
+}
+
+static const struct pwm_ops lpc32xx_pwm_ops = {
+	.config = lpc32xx_pwm_config,
+	.enable = lpc32xx_pwm_enable,
+	.disable = lpc32xx_pwm_disable,
+	.owner = THIS_MODULE,
+};
+
+static int lpc32xx_pwm_probe(struct platform_device *pdev)
+{
+	struct lpc32xx_pwm_chip *lpc32xx;
+	struct resource *res;
+	int ret;
+
+	lpc32xx = devm_kzalloc(&pdev->dev, sizeof(*lpc32xx), GFP_KERNEL);
+	if (!lpc32xx)
+		return -ENOMEM;
+
+	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+	if (!res)
+		return -EINVAL;
+
+	lpc32xx->base = devm_request_and_ioremap(&pdev->dev, res);
+	if (!lpc32xx->base)
+		return -EADDRNOTAVAIL;
+
+	lpc32xx->clk = devm_clk_get(&pdev->dev, NULL);
+	if (IS_ERR(lpc32xx->clk))
+		return PTR_ERR(lpc32xx->clk);
+
+	lpc32xx->chip.dev = &pdev->dev;
+	lpc32xx->chip.ops = &lpc32xx_pwm_ops;
+	lpc32xx->chip.npwm = 2;
+
+	ret = pwmchip_add(&lpc32xx->chip);
+	if (ret < 0) {
+		dev_err(&pdev->dev, "failed to add PWM chip, error %d\n", ret);
+		return ret;
+	}
+
+	platform_set_drvdata(pdev, lpc32xx);
+
+	return 0;
+}
+
+static int __devexit lpc32xx_pwm_remove(struct platform_device *pdev)
+{
+	struct lpc32xx_pwm_chip *lpc32xx = platform_get_drvdata(pdev);
+
+	clk_disable(lpc32xx->clk);
+	return pwmchip_remove(&lpc32xx->chip);
+}
+
+static struct of_device_id lpc32xx_pwm_dt_ids[] = {
+	{ .compatible = "nxp,lpc3220-pwm", },
+	{ /* sentinel */ }
+};
+MODULE_DEVICE_TABLE(of, lpc32xx_pwm_dt_ids);
+
+static struct platform_driver lpc32xx_pwm_driver = {
+	.driver = {
+		.name = "lpc32xx-pwm",
+		.of_match_table = of_match_ptr(lpc32xx_pwm_dt_ids),
+	},
+	.probe = lpc32xx_pwm_probe,
+	.remove = __devexit_p(lpc32xx_pwm_remove),
+};
+module_platform_driver(lpc32xx_pwm_driver);
+
+MODULE_ALIAS("platform:lpc32xx-pwm");
+MODULE_AUTHOR("Alexandre Pereira da Silva <aletes.xgr@gmail.com>");
+MODULE_DESCRIPTION("LPC32XX PWM Driver");
+MODULE_LICENSE("GPL v2");