Fixed MTP to work with TWRP

drivers/pwm/pwm-lpss.c

@@ -0,0 +1,163 @@
+/*
+ * Intel Low Power Subsystem PWM controller driver
+ *
+ * Copyright (C) 2014, Intel Corporation
+ * Author: Mika Westerberg <mika.westerberg@linux.intel.com>
+ * Author: Chew Kean Ho <kean.ho.chew@intel.com>
+ * Author: Chang Rebecca Swee Fun <rebecca.swee.fun.chang@intel.com>
+ * Author: Chew Chiau Ee <chiau.ee.chew@intel.com>
+ * Author: Alan Cox <alan@linux.intel.com>
+ *
+ * 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 <linux/io.h>
+#include <linux/kernel.h>
+#include <linux/module.h>
+
+#include "pwm-lpss.h"
+
+#define PWM				0x00000000
+#define PWM_ENABLE			BIT(31)
+#define PWM_SW_UPDATE			BIT(30)
+#define PWM_BASE_UNIT_SHIFT		8
+#define PWM_BASE_UNIT_MASK		0x00ffff00
+#define PWM_ON_TIME_DIV_MASK		0x000000ff
+#define PWM_DIVISION_CORRECTION		0x2
+#define PWM_LIMIT			(0x8000 + PWM_DIVISION_CORRECTION)
+#define NSECS_PER_SEC			1000000000UL
+
+struct pwm_lpss_chip {
+	struct pwm_chip chip;
+	void __iomem *regs;
+	unsigned long clk_rate;
+};
+
+/* BayTrail */
+const struct pwm_lpss_boardinfo pwm_lpss_byt_info = {
+	.clk_rate = 25000000
+};
+EXPORT_SYMBOL_GPL(pwm_lpss_byt_info);
+
+/* Braswell */
+const struct pwm_lpss_boardinfo pwm_lpss_bsw_info = {
+	.clk_rate = 19200000
+};
+EXPORT_SYMBOL_GPL(pwm_lpss_bsw_info);
+
+static inline struct pwm_lpss_chip *to_lpwm(struct pwm_chip *chip)
+{
+	return container_of(chip, struct pwm_lpss_chip, chip);
+}
+
+static int pwm_lpss_config(struct pwm_chip *chip, struct pwm_device *pwm,
+			   int duty_ns, int period_ns)
+{
+	struct pwm_lpss_chip *lpwm = to_lpwm(chip);
+	u8 on_time_div;
+	unsigned long c;
+	unsigned long long base_unit, freq = NSECS_PER_SEC;
+	u32 ctrl;
+
+	do_div(freq, period_ns);
+
+	/* The equation is: base_unit = ((freq / c) * 65536) + correction */
+	base_unit = freq * 65536;
+
+	c = lpwm->clk_rate;
+	if (!c)
+		return -EINVAL;
+
+	do_div(base_unit, c);
+	base_unit += PWM_DIVISION_CORRECTION;
+	if (base_unit > PWM_LIMIT)
+		return -EINVAL;
+
+	if (duty_ns <= 0)
+		duty_ns = 1;
+	on_time_div = 255 - (255 * duty_ns / period_ns);
+
+	ctrl = readl(lpwm->regs + PWM);
+	ctrl &= ~(PWM_BASE_UNIT_MASK | PWM_ON_TIME_DIV_MASK);
+	ctrl |= (u16) base_unit << PWM_BASE_UNIT_SHIFT;
+	ctrl |= on_time_div;
+	/* request PWM to update on next cycle */
+	ctrl |= PWM_SW_UPDATE;
+	writel(ctrl, lpwm->regs + PWM);
+
+	return 0;
+}
+
+static int pwm_lpss_enable(struct pwm_chip *chip, struct pwm_device *pwm)
+{
+	struct pwm_lpss_chip *lpwm = to_lpwm(chip);
+	u32 ctrl;
+
+	ctrl = readl(lpwm->regs + PWM);
+	writel(ctrl | PWM_ENABLE, lpwm->regs + PWM);
+
+	return 0;
+}
+
+static void pwm_lpss_disable(struct pwm_chip *chip, struct pwm_device *pwm)
+{
+	struct pwm_lpss_chip *lpwm = to_lpwm(chip);
+	u32 ctrl;
+
+	ctrl = readl(lpwm->regs + PWM);
+	writel(ctrl & ~PWM_ENABLE, lpwm->regs + PWM);
+}
+
+static const struct pwm_ops pwm_lpss_ops = {
+	.config = pwm_lpss_config,
+	.enable = pwm_lpss_enable,
+	.disable = pwm_lpss_disable,
+	.owner = THIS_MODULE,
+};
+
+struct pwm_lpss_chip *pwm_lpss_probe(struct device *dev, struct resource *r,
+				     const struct pwm_lpss_boardinfo *info)
+{
+	struct pwm_lpss_chip *lpwm;
+	int ret;
+
+	lpwm = devm_kzalloc(dev, sizeof(*lpwm), GFP_KERNEL);
+	if (!lpwm)
+		return ERR_PTR(-ENOMEM);
+
+	lpwm->regs = devm_ioremap_resource(dev, r);
+	if (IS_ERR(lpwm->regs))
+		return ERR_CAST(lpwm->regs);
+
+	lpwm->clk_rate = info->clk_rate;
+	lpwm->chip.dev = dev;
+	lpwm->chip.ops = &pwm_lpss_ops;
+	lpwm->chip.base = -1;
+	lpwm->chip.npwm = 1;
+
+	ret = pwmchip_add(&lpwm->chip);
+	if (ret) {
+		dev_err(dev, "failed to add PWM chip: %d\n", ret);
+		return ERR_PTR(ret);
+	}
+
+	return lpwm;
+}
+EXPORT_SYMBOL_GPL(pwm_lpss_probe);
+
+int pwm_lpss_remove(struct pwm_lpss_chip *lpwm)
+{
+	u32 ctrl;
+
+	ctrl = readl(lpwm->regs + PWM);
+	writel(ctrl & ~PWM_ENABLE, lpwm->regs + PWM);
+
+	return pwmchip_remove(&lpwm->chip);
+}
+EXPORT_SYMBOL_GPL(pwm_lpss_remove);
+
+MODULE_DESCRIPTION("PWM driver for Intel LPSS");
+MODULE_AUTHOR("Mika Westerberg <mika.westerberg@linux.intel.com>");
+MODULE_LICENSE("GPL v2");