pinctrl: mediatek: refactor EINT related code for all MediaTek pinctrl can fit

This patch is in preparation for adding EINT support to MT7622 pinctrl,
and the refactoring doesn't alter any existent logic.

A reason we have to refactor EINT code pieces into a generic way is that
currently, they're tightly coupled with a certain type of MediaTek pinctrl
would cause a grown in a very bad way as there is different types of
pinctrl devices getting to join.

Therefore, it is an essential or urgent thing that EINT code pieces are
refactored to eliminate any dependencies across GPIO and EINT as possible.

Additional structure mtk_eint_[xt, hw, regs] are being introduced for
indicating how maps being designed between GPIO and EINT hw number, how to
set and get GPIO state for a certain EINT pin, what characteristic on a
EINT device is present on various SoCs.

Signed-off-by: Sean Wang <sean.wang@mediatek.com>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>

1 files changed, 492 insertions, 0 deletions

diff --git a/drivers/pinctrl/mediatek/mtk-eint.c b/drivers/pinctrl/mediatek/mtk-eint.c
new file mode 100644
index 000000000000..30f3316747e2
--- /dev/null
+++ b/drivers/pinctrl/mediatek/mtk-eint.c
@@ -0,0 +1,492 @@
+// SPDX-License-Identifier: GPL-2.0
+// Copyright (c) 2014-2018 MediaTek Inc.
+
+/*
+ * Library for MediaTek External Interrupt Support
+ *
+ * Author: Maoguang Meng <maoguang.meng@mediatek.com>
+ *	   Sean Wang <sean.wang@mediatek.com>
+ *
+ */
+
+#include <linux/delay.h>
+#include <linux/err.h>
+#include <linux/gpio.h>
+#include <linux/io.h>
+#include <linux/irqdomain.h>
+#include <linux/of_irq.h>
+#include <linux/platform_device.h>
+
+#include "mtk-eint.h"
+
+#define MTK_EINT_EDGE_SENSITIVE           0
+#define MTK_EINT_LEVEL_SENSITIVE          1
+#define MTK_EINT_DBNC_SET_DBNC_BITS	  4
+#define MTK_EINT_DBNC_RST_BIT		  (0x1 << 1)
+#define MTK_EINT_DBNC_SET_EN		  (0x1 << 0)
+
+static const struct mtk_eint_regs mtk_generic_eint_regs = {
+	.stat      = 0x000,
+	.ack       = 0x040,
+	.mask      = 0x080,
+	.mask_set  = 0x0c0,
+	.mask_clr  = 0x100,
+	.sens      = 0x140,
+	.sens_set  = 0x180,
+	.sens_clr  = 0x1c0,
+	.soft      = 0x200,
+	.soft_set  = 0x240,
+	.soft_clr  = 0x280,
+	.pol       = 0x300,
+	.pol_set   = 0x340,
+	.pol_clr   = 0x380,
+	.dom_en    = 0x400,
+	.dbnc_ctrl = 0x500,
+	.dbnc_set  = 0x600,
+	.dbnc_clr  = 0x700,
+};
+
+static void __iomem *mtk_eint_get_offset(struct mtk_eint *eint,
+					 unsigned int eint_num,
+					 unsigned int offset)
+{
+	unsigned int eint_base = 0;
+	void __iomem *reg;
+
+	if (eint_num >= eint->hw->ap_num)
+		eint_base = eint->hw->ap_num;
+
+	reg = eint->base + offset + ((eint_num - eint_base) / 32) * 4;
+
+	return reg;
+}
+
+static unsigned int mtk_eint_can_en_debounce(struct mtk_eint *eint,
+					     unsigned int eint_num)
+{
+	unsigned int sens;
+	unsigned int bit = BIT(eint_num % 32);
+	void __iomem *reg = mtk_eint_get_offset(eint, eint_num,
+						eint->regs->sens);
+
+	if (readl(reg) & bit)
+		sens = MTK_EINT_LEVEL_SENSITIVE;
+	else
+		sens = MTK_EINT_EDGE_SENSITIVE;
+
+	if (eint_num < eint->hw->db_cnt && sens != MTK_EINT_EDGE_SENSITIVE)
+		return 1;
+	else
+		return 0;
+}
+
+static int mtk_eint_flip_edge(struct mtk_eint *eint, int hwirq)
+{
+	int start_level, curr_level;
+	unsigned int reg_offset;
+	u32 mask = BIT(hwirq & 0x1f);
+	u32 port = (hwirq >> 5) & eint->hw->port_mask;
+	void __iomem *reg = eint->base + (port << 2);
+
+	curr_level = eint->gpio_xlate->get_gpio_state(eint->pctl, hwirq);
+
+	do {
+		start_level = curr_level;
+		if (start_level)
+			reg_offset = eint->regs->pol_clr;
+		else
+			reg_offset = eint->regs->pol_set;
+		writel(mask, reg + reg_offset);
+
+		curr_level = eint->gpio_xlate->get_gpio_state(eint->pctl,
+							      hwirq);
+	} while (start_level != curr_level);
+
+	return start_level;
+}
+
+static void mtk_eint_mask(struct irq_data *d)
+{
+	struct mtk_eint *eint = irq_data_get_irq_chip_data(d);
+	u32 mask = BIT(d->hwirq & 0x1f);
+	void __iomem *reg = mtk_eint_get_offset(eint, d->hwirq,
+						eint->regs->mask_set);
+
+	writel(mask, reg);
+}
+
+static void mtk_eint_unmask(struct irq_data *d)
+{
+	struct mtk_eint *eint = irq_data_get_irq_chip_data(d);
+	u32 mask = BIT(d->hwirq & 0x1f);
+	void __iomem *reg = mtk_eint_get_offset(eint, d->hwirq,
+						eint->regs->mask_clr);
+
+	writel(mask, reg);
+
+	if (eint->dual_edge[d->hwirq])
+		mtk_eint_flip_edge(eint, d->hwirq);
+}
+
+static unsigned int mtk_eint_get_mask(struct mtk_eint *eint,
+				      unsigned int eint_num)
+{
+	unsigned int bit = BIT(eint_num % 32);
+	void __iomem *reg = mtk_eint_get_offset(eint, eint_num,
+						eint->regs->mask);
+
+	return !!(readl(reg) & bit);
+}
+
+static void mtk_eint_ack(struct irq_data *d)
+{
+	struct mtk_eint *eint = irq_data_get_irq_chip_data(d);
+	u32 mask = BIT(d->hwirq & 0x1f);
+	void __iomem *reg = mtk_eint_get_offset(eint, d->hwirq,
+						eint->regs->ack);
+
+	writel(mask, reg);
+}
+
+static int mtk_eint_set_type(struct irq_data *d, unsigned int type)
+{
+	struct mtk_eint *eint = irq_data_get_irq_chip_data(d);
+	u32 mask = BIT(d->hwirq & 0x1f);
+	void __iomem *reg;
+
+	if (((type & IRQ_TYPE_EDGE_BOTH) && (type & IRQ_TYPE_LEVEL_MASK)) ||
+	    ((type & IRQ_TYPE_LEVEL_MASK) == IRQ_TYPE_LEVEL_MASK)) {
+		dev_err(eint->dev,
+			"Can't configure IRQ%d (EINT%lu) for type 0x%X\n",
+			d->irq, d->hwirq, type);
+		return -EINVAL;
+	}
+
+	if ((type & IRQ_TYPE_EDGE_BOTH) == IRQ_TYPE_EDGE_BOTH)
+		eint->dual_edge[d->hwirq] = 1;
+	else
+		eint->dual_edge[d->hwirq] = 0;
+
+	if (type & (IRQ_TYPE_LEVEL_LOW | IRQ_TYPE_EDGE_FALLING)) {
+		reg = mtk_eint_get_offset(eint, d->hwirq, eint->regs->pol_clr);
+		writel(mask, reg);
+	} else {
+		reg = mtk_eint_get_offset(eint, d->hwirq, eint->regs->pol_set);
+		writel(mask, reg);
+	}
+
+	if (type & (IRQ_TYPE_EDGE_RISING | IRQ_TYPE_EDGE_FALLING)) {
+		reg = mtk_eint_get_offset(eint, d->hwirq, eint->regs->sens_clr);
+		writel(mask, reg);
+	} else {
+		reg = mtk_eint_get_offset(eint, d->hwirq, eint->regs->sens_set);
+		writel(mask, reg);
+	}
+
+	if (eint->dual_edge[d->hwirq])
+		mtk_eint_flip_edge(eint, d->hwirq);
+
+	return 0;
+}
+
+static int mtk_eint_irq_set_wake(struct irq_data *d, unsigned int on)
+{
+	struct mtk_eint *eint = irq_data_get_irq_chip_data(d);
+	int shift = d->hwirq & 0x1f;
+	int reg = d->hwirq >> 5;
+
+	if (on)
+		eint->wake_mask[reg] |= BIT(shift);
+	else
+		eint->wake_mask[reg] &= ~BIT(shift);
+
+	return 0;
+}
+
+static void mtk_eint_chip_write_mask(const struct mtk_eint *eint,
+				     void __iomem *base, u32 *buf)
+{
+	int port;
+	void __iomem *reg;
+
+	for (port = 0; port < eint->hw->ports; port++) {
+		reg = base + (port << 2);
+		writel_relaxed(~buf[port], reg + eint->regs->mask_set);
+		writel_relaxed(buf[port], reg + eint->regs->mask_clr);
+	}
+}
+
+static void mtk_eint_chip_read_mask(const struct mtk_eint *eint,
+				    void __iomem *base, u32 *buf)
+{
+	int port;
+	void __iomem *reg;
+
+	for (port = 0; port < eint->hw->ports; port++) {
+		reg = base + eint->regs->mask + (port << 2);
+		buf[port] = ~readl_relaxed(reg);
+		/* Mask is 0 when irq is enabled, and 1 when disabled. */
+	}
+}
+
+static int mtk_eint_irq_request_resources(struct irq_data *d)
+{
+	struct mtk_eint *eint = irq_data_get_irq_chip_data(d);
+	struct gpio_chip *gpio_c;
+	unsigned int gpio_n;
+	int err;
+
+	err = eint->gpio_xlate->get_gpio_n(eint->pctl, d->hwirq,
+					   &gpio_n, &gpio_c);
+	if (err < 0) {
+		dev_err(eint->dev, "Can not find pin\n");
+		return err;
+	}
+
+	err = gpiochip_lock_as_irq(gpio_c, gpio_n);
+	if (err < 0) {
+		dev_err(eint->dev, "unable to lock HW IRQ %lu for IRQ\n",
+			irqd_to_hwirq(d));
+		return err;
+	}
+
+	err = eint->gpio_xlate->set_gpio_as_eint(eint->pctl, d->hwirq);
+	if (err < 0) {
+		dev_err(eint->dev, "Can not eint mode\n");
+		return err;
+	}
+
+	return 0;
+}
+
+static void mtk_eint_irq_release_resources(struct irq_data *d)
+{
+	struct mtk_eint *eint = irq_data_get_irq_chip_data(d);
+	struct gpio_chip *gpio_c;
+	unsigned int gpio_n;
+
+	eint->gpio_xlate->get_gpio_n(eint->pctl, d->hwirq, &gpio_n,
+				     &gpio_c);
+
+	gpiochip_unlock_as_irq(gpio_c, gpio_n);
+}
+
+static struct irq_chip mtk_eint_irq_chip = {
+	.name = "mt-eint",
+	.irq_disable = mtk_eint_mask,
+	.irq_mask = mtk_eint_mask,
+	.irq_unmask = mtk_eint_unmask,
+	.irq_ack = mtk_eint_ack,
+	.irq_set_type = mtk_eint_set_type,
+	.irq_set_wake = mtk_eint_irq_set_wake,
+	.irq_request_resources = mtk_eint_irq_request_resources,
+	.irq_release_resources = mtk_eint_irq_release_resources,
+};
+
+static unsigned int mtk_eint_hw_init(struct mtk_eint *eint)
+{
+	void __iomem *reg = eint->base + eint->regs->dom_en;
+	unsigned int i;
+
+	for (i = 0; i < eint->hw->ap_num; i += 32) {
+		writel(0xffffffff, reg);
+		reg += 4;
+	}
+
+	return 0;
+}
+
+static inline void
+mtk_eint_debounce_process(struct mtk_eint *eint, int index)
+{
+	unsigned int rst, ctrl_offset;
+	unsigned int bit, dbnc;
+
+	ctrl_offset = (index / 4) * 4 + eint->regs->dbnc_ctrl;
+	dbnc = readl(eint->base + ctrl_offset);
+	bit = MTK_EINT_DBNC_SET_EN << ((index % 4) * 8);
+	if ((bit & dbnc) > 0) {
+		ctrl_offset = (index / 4) * 4 + eint->regs->dbnc_set;
+		rst = MTK_EINT_DBNC_RST_BIT << ((index % 4) * 8);
+		writel(rst, eint->base + ctrl_offset);
+	}
+}
+
+static void mtk_eint_irq_handler(struct irq_desc *desc)
+{
+	struct irq_chip *chip = irq_desc_get_chip(desc);
+	struct mtk_eint *eint = irq_desc_get_handler_data(desc);
+	unsigned int status, eint_num;
+	int offset, index, virq;
+	void __iomem *reg =  mtk_eint_get_offset(eint, 0, eint->regs->stat);
+	int dual_edge, start_level, curr_level;
+
+	chained_irq_enter(chip, desc);
+	for (eint_num = 0; eint_num < eint->hw->ap_num; eint_num += 32,
+	     reg += 4) {
+		status = readl(reg);
+		while (status) {
+			offset = __ffs(status);
+			index = eint_num + offset;
+			virq = irq_find_mapping(eint->domain, index);
+			status &= ~BIT(offset);
+
+			dual_edge = eint->dual_edge[index];
+			if (dual_edge) {
+				/*
+				 * Clear soft-irq in case we raised it last
+				 * time.
+				 */
+				writel(BIT(offset), reg - eint->regs->stat +
+				       eint->regs->soft_clr);
+
+				start_level =
+				eint->gpio_xlate->get_gpio_state(eint->pctl,
+								 index);
+			}
+
+			generic_handle_irq(virq);
+
+			if (dual_edge) {
+				curr_level = mtk_eint_flip_edge(eint, index);
+
+				/*
+				 * If level changed, we might lost one edge
+				 * interrupt, raised it through soft-irq.
+				 */
+				if (start_level != curr_level)
+					writel(BIT(offset), reg -
+					       eint->regs->stat +
+					       eint->regs->soft_set);
+			}
+
+			if (index < eint->hw->db_cnt)
+				mtk_eint_debounce_process(eint, index);
+		}
+	}
+	chained_irq_exit(chip, desc);
+}
+
+int mtk_eint_do_suspend(struct mtk_eint *eint)
+{
+	mtk_eint_chip_read_mask(eint, eint->base, eint->cur_mask);
+	mtk_eint_chip_write_mask(eint, eint->base, eint->wake_mask);
+
+	return 0;
+}
+
+int mtk_eint_do_resume(struct mtk_eint *eint)
+{
+	mtk_eint_chip_write_mask(eint, eint->base, eint->cur_mask);
+
+	return 0;
+}
+
+int mtk_eint_set_debounce(struct mtk_eint *eint, unsigned long eint_num,
+			  unsigned int debounce)
+{
+	int virq, eint_offset;
+	unsigned int set_offset, bit, clr_bit, clr_offset, rst, i, unmask,
+		     dbnc;
+	static const unsigned int debounce_time[] = {500, 1000, 16000, 32000,
+						     64000, 128000, 256000};
+	struct irq_data *d;
+
+	virq = irq_find_mapping(eint->domain, eint_num);
+	eint_offset = (eint_num % 4) * 8;
+	d = irq_get_irq_data(virq);
+
+	set_offset = (eint_num / 4) * 4 + eint->regs->dbnc_set;
+	clr_offset = (eint_num / 4) * 4 + eint->regs->dbnc_clr;
+
+	if (!mtk_eint_can_en_debounce(eint, eint_num))
+		return -EINVAL;
+
+	dbnc = ARRAY_SIZE(debounce_time);
+	for (i = 0; i < ARRAY_SIZE(debounce_time); i++) {
+		if (debounce <= debounce_time[i]) {
+			dbnc = i;
+			break;
+		}
+	}
+
+	if (!mtk_eint_get_mask(eint, eint_num)) {
+		mtk_eint_mask(d);
+		unmask = 1;
+	} else {
+		unmask = 0;
+	}
+
+	clr_bit = 0xff << eint_offset;
+	writel(clr_bit, eint->base + clr_offset);
+
+	bit = ((dbnc << MTK_EINT_DBNC_SET_DBNC_BITS) | MTK_EINT_DBNC_SET_EN) <<
+		eint_offset;
+	rst = MTK_EINT_DBNC_RST_BIT << eint_offset;
+	writel(rst | bit, eint->base + set_offset);
+
+	/*
+	 * Delay a while (more than 2T) to wait for hw debounce counter reset
+	 * work correctly.
+	 */
+	udelay(1);
+	if (unmask == 1)
+		mtk_eint_unmask(d);
+
+	return 0;
+}
+
+int mtk_eint_find_irq(struct mtk_eint *eint, unsigned long eint_n)
+{
+	int irq;
+
+	irq = irq_find_mapping(eint->domain, eint_n);
+	if (!irq)
+		return -EINVAL;
+
+	return irq;
+}
+
+int mtk_eint_do_init(struct mtk_eint *eint)
+{
+	int i;
+
+	/* If clients don't assign a specific regs, let's use generic one */
+	if (!eint->regs)
+		eint->regs = &mtk_generic_eint_regs;
+
+	eint->wake_mask = devm_kcalloc(eint->dev, eint->hw->ports,
+				       sizeof(*eint->wake_mask), GFP_KERNEL);
+	if (!eint->wake_mask)
+		return -ENOMEM;
+
+	eint->cur_mask = devm_kcalloc(eint->dev, eint->hw->ports,
+				      sizeof(*eint->cur_mask), GFP_KERNEL);
+	if (!eint->cur_mask)
+		return -ENOMEM;
+
+	eint->dual_edge = devm_kcalloc(eint->dev, eint->hw->ap_num,
+				       sizeof(int), GFP_KERNEL);
+	if (!eint->dual_edge)
+		return -ENOMEM;
+
+	eint->domain = irq_domain_add_linear(eint->dev->of_node,
+					     eint->hw->ap_num,
+					     &irq_domain_simple_ops, NULL);
+	if (!eint->domain)
+		return -ENOMEM;
+
+	mtk_eint_hw_init(eint);
+	for (i = 0; i < eint->hw->ap_num; i++) {
+		int virq = irq_create_mapping(eint->domain, i);
+
+		irq_set_chip_and_handler(virq, &mtk_eint_irq_chip,
+					 handle_level_irq);
+		irq_set_chip_data(virq, eint);
+	}
+
+	irq_set_chained_handler_and_data(eint->irq, mtk_eint_irq_handler,
+					 eint);
+
+	return 0;
+}