From fc8f96309c21c1bc3276427309cd7d361347d66e Mon Sep 17 00:00:00 2001
From: John Crispin <blogic@openwrt.org>
Date: Mon, 7 Dec 2015 17:16:50 +0100
Subject: [PATCH 52/53] pwm: add mediatek support

Signed-off-by: John Crispin <blogic@openwrt.org>
---
 drivers/pwm/Kconfig        |    9 +++
 drivers/pwm/Makefile       |    1 +
 drivers/pwm/pwm-mediatek.c |  173 ++++++++++++++++++++++++++++++++++++++++++++
 3 files changed, 183 insertions(+)
 create mode 100644 drivers/pwm/pwm-mediatek.c

--- a/drivers/pwm/Kconfig
+++ b/drivers/pwm/Kconfig
@@ -282,6 +282,15 @@ config PWM_MTK_DISP
 	  To compile this driver as a module, choose M here: the module
 	  will be called pwm-mtk-disp.
 
+config PWM_MEDIATEK
+	tristate "Mediatek PWM support"
+	depends on RALINK && OF
+	help
+	  Generic PWM framework driver for Mediatek ARM SoC.
+
+	  To compile this driver as a module, choose M here: the module
+	  will be called pwm-mxs.
+
 config PWM_MXS
 	tristate "Freescale MXS PWM support"
 	depends on ARCH_MXS && OF
--- a/drivers/pwm/Makefile
+++ b/drivers/pwm/Makefile
@@ -25,6 +25,7 @@ obj-$(CONFIG_PWM_LPSS)		+= pwm-lpss.o
 obj-$(CONFIG_PWM_LPSS_PCI)	+= pwm-lpss-pci.o
 obj-$(CONFIG_PWM_LPSS_PLATFORM)	+= pwm-lpss-platform.o
 obj-$(CONFIG_PWM_MESON)		+= pwm-meson.o
+obj-$(CONFIG_PWM_MEDIATEK)	+= pwm-mediatek.o
 obj-$(CONFIG_PWM_MTK_DISP)	+= pwm-mtk-disp.o
 obj-$(CONFIG_PWM_MXS)		+= pwm-mxs.o
 obj-$(CONFIG_PWM_OMAP_DMTIMER)	+= pwm-omap-dmtimer.o
--- /dev/null
+++ b/drivers/pwm/pwm-mediatek.c
@@ -0,0 +1,173 @@
+/*
+ * Mediatek Pulse Width Modulator driver
+ *
+ * Copyright (C) 2015 John Crispin <blogic@openwrt.org>
+ *
+ * This file is licensed under the terms of the GNU General Public
+ * License version 2. This program is licensed "as is" without any
+ * warranty of any kind, whether express or implied.
+ */
+
+#include <linux/err.h>
+#include <linux/io.h>
+#include <linux/ioport.h>
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/of.h>
+#include <linux/platform_device.h>
+#include <linux/pwm.h>
+#include <linux/slab.h>
+#include <linux/types.h>
+
+#define NUM_PWM		4
+
+/* PWM registers and bits definitions */
+#define PWMCON			0x00
+#define PWMHDUR			0x04
+#define PWMLDUR			0x08
+#define PWMGDUR			0x0c
+#define PWMWAVENUM		0x28
+#define PWMDWIDTH		0x2c
+#define PWMTHRES		0x30
+
+/**
+ * struct mtk_pwm_chip - struct representing pwm chip
+ *
+ * @mmio_base: base address of pwm chip
+ * @chip: linux pwm chip representation
+ */
+struct mtk_pwm_chip {
+	void __iomem *mmio_base;
+	struct pwm_chip chip;
+};
+
+static inline struct mtk_pwm_chip *to_mtk_pwm_chip(struct pwm_chip *chip)
+{
+	return container_of(chip, struct mtk_pwm_chip, chip);
+}
+
+static inline u32 mtk_pwm_readl(struct mtk_pwm_chip *chip, unsigned int num,
+				  unsigned long offset)
+{
+	return ioread32(chip->mmio_base + 0x10 + (num * 0x40) + offset);
+}
+
+static inline void mtk_pwm_writel(struct mtk_pwm_chip *chip,
+				    unsigned int num, unsigned long offset,
+				    unsigned long val)
+{
+	iowrite32(val, chip->mmio_base + 0x10 + (num * 0x40) + offset);
+}
+
+static int mtk_pwm_config(struct pwm_chip *chip, struct pwm_device *pwm,
+			    int duty_ns, int period_ns)
+{
+	struct mtk_pwm_chip *pc = to_mtk_pwm_chip(chip);
+	u32 resolution = 100 / 4;
+	u32 clkdiv = 0;
+
+	while (period_ns / resolution  > 8191) {
+		clkdiv++;
+		resolution *= 2;
+	}
+
+	if (clkdiv > 7)
+		return -1;
+
+	mtk_pwm_writel(pc, pwm->hwpwm, PWMCON, BIT(15) | BIT(3) | clkdiv);
+	mtk_pwm_writel(pc, pwm->hwpwm, PWMDWIDTH, period_ns / resolution);
+	mtk_pwm_writel(pc, pwm->hwpwm, PWMTHRES, duty_ns / resolution);
+	return 0;
+}
+
+static int mtk_pwm_enable(struct pwm_chip *chip, struct pwm_device *pwm)
+{
+	struct mtk_pwm_chip *pc = to_mtk_pwm_chip(chip);
+	u32 val;
+
+	val = ioread32(pc->mmio_base);
+	val |= BIT(pwm->hwpwm);
+	iowrite32(val, pc->mmio_base);
+
+	return 0;
+}
+
+static void mtk_pwm_disable(struct pwm_chip *chip, struct pwm_device *pwm)
+{
+	struct mtk_pwm_chip *pc = to_mtk_pwm_chip(chip);
+	u32 val;
+
+	val = ioread32(pc->mmio_base);
+	val &= ~BIT(pwm->hwpwm);
+	iowrite32(val, pc->mmio_base);
+}
+
+static const struct pwm_ops mtk_pwm_ops = {
+	.config = mtk_pwm_config,
+	.enable = mtk_pwm_enable,
+	.disable = mtk_pwm_disable,
+	.owner = THIS_MODULE,
+};
+
+static int mtk_pwm_probe(struct platform_device *pdev)
+{
+	struct mtk_pwm_chip *pc;
+	struct resource *r;
+	int ret;
+
+	pc = devm_kzalloc(&pdev->dev, sizeof(*pc), GFP_KERNEL);
+	if (!pc)
+		return -ENOMEM;
+
+	r = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+	pc->mmio_base = devm_ioremap_resource(&pdev->dev, r);
+	if (IS_ERR(pc->mmio_base))
+		return PTR_ERR(pc->mmio_base);
+
+	platform_set_drvdata(pdev, pc);
+
+	pc->chip.dev = &pdev->dev;
+	pc->chip.ops = &mtk_pwm_ops;
+	pc->chip.base = -1;
+	pc->chip.npwm = NUM_PWM;
+
+	ret = pwmchip_add(&pc->chip);
+	if (ret < 0)
+		dev_err(&pdev->dev, "pwmchip_add() failed: %d\n", ret);
+
+	return ret;
+}
+
+static int mtk_pwm_remove(struct platform_device *pdev)
+{
+	struct mtk_pwm_chip *pc = platform_get_drvdata(pdev);
+	int i;
+
+	for (i = 0; i < NUM_PWM; i++)
+		pwm_disable(&pc->chip.pwms[i]);
+
+	return pwmchip_remove(&pc->chip);
+}
+
+static const struct of_device_id mtk_pwm_of_match[] = {
+	{ .compatible = "mediatek,mt7628-pwm" },
+	{ }
+};
+
+MODULE_DEVICE_TABLE(of, mtk_pwm_of_match);
+
+static struct platform_driver mtk_pwm_driver = {
+	.driver = {
+		.name = "mtk-pwm",
+		.owner = THIS_MODULE,
+		.of_match_table = mtk_pwm_of_match,
+	},
+	.probe = mtk_pwm_probe,
+	.remove = mtk_pwm_remove,
+};
+
+module_platform_driver(mtk_pwm_driver);
+
+MODULE_LICENSE("GPL");
+MODULE_AUTHOR("John Crispin <blogic@openwrt.org>");
+MODULE_ALIAS("platform:mtk-pwm");
