0111-i2c-MIPS-add-mt7621-I2C-driver.patch

--- a/drivers/i2c/busses/Kconfig
+++ b/drivers/i2c/busses/Kconfig
@@ -715,6 +715,10 @@ config I2C_RALINK
 	tristate "Ralink I2C Controller"
 	select OF_I2C
 
+config I2C_MT7621
+	tristate "MT7621/MT7628 I2C Controller"
+	select OF_I2C
+
 config HAVE_S3C2410_I2C
 	bool
 	help
--- a/drivers/i2c/busses/Makefile
+++ b/drivers/i2c/busses/Makefile
@@ -67,6 +67,7 @@ obj-$(CONFIG_I2C_PUV3)		+= i2c-puv3.o
 obj-$(CONFIG_I2C_PXA)		+= i2c-pxa.o
 obj-$(CONFIG_I2C_PXA_PCI)	+= i2c-pxa-pci.o
 obj-$(CONFIG_I2C_RALINK)	+= i2c-ralink.o
+obj-$(CONFIG_I2C_MT7621)	+= i2c-mt7621.o
 obj-$(CONFIG_I2C_QUP)		+= i2c-qup.o
 obj-$(CONFIG_I2C_RIIC)		+= i2c-riic.o
 obj-$(CONFIG_I2C_RK3X)		+= i2c-rk3x.o
--- /dev/null
+++ b/drivers/i2c/busses/i2c-mt7621.c
@@ -0,0 +1,397 @@
+/*
+ * drivers/i2c/busses/i2c-mt7621.c
+ *
+ * Copyright (C) 2013 Steven Liu <steven_liu@mediatek.com>
+ * Copyright (C) 2016 Michael Lee <igvtee@gmail.com>
+ * Copyright (C) 2018 Jan Breuer <jan.breuer@jaybee.cz>
+ *
+ * Improve driver for i2cdetect from i2c-tools to detect i2c devices on the bus.
+ * (C) 2014 Sittisak <sittisaks@hotmail.com>
+ *
+ * This software is licensed under the terms of the GNU General Public
+ * License version 2, as published by the Free Software Foundation, and
+ * may be copied, distributed, and modified under those terms.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ */
+
+#include <linux/interrupt.h>
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/reset.h>
+#include <linux/delay.h>
+#include <linux/slab.h>
+#include <linux/init.h>
+#include <linux/errno.h>
+#include <linux/platform_device.h>
+#include <linux/of_platform.h>
+#include <linux/i2c.h>
+#include <linux/io.h>
+#include <linux/err.h>
+
+#define REG_SM0CFG2_REG		0x28
+#define REG_SM0CTL0_REG		0x40
+#define REG_SM0CTL1_REG		0x44
+#define REG_SM0D0_REG		0x50
+#define REG_SM0D1_REG		0x54
+#define REG_PINTEN_REG		0x5C
+#define REG_PINTST_REG		0x60
+#define REG_PINTCL_REG		0x64
+
+/* REG_SM0CFG2_REG */
+#define SM0CFG2_IS_AUTOMODE	BIT(0)
+
+/* REG_SM0CTL0_REG */
+#define SM0CTL0_ODRAIN		BIT(31)
+#define SM0CTL0_CLK_DIV_MASK	(0x7FF << 16)
+#define SM0CTL0_CLK_DIV_MAX	0x7ff
+#define SM0CTL0_CS_STATUS       BIT(4)
+#define SM0CTL0_SCL_STATE       BIT(3)
+#define SM0CTL0_SDA_STATE       BIT(2)
+#define SM0CTL0_EN              BIT(1)
+#define SM0CTL0_SCL_STRETCH     BIT(0)
+
+/* REG_SM0CTL1_REG */
+#define SM0CTL1_ACK_MASK	(0xFF << 16)
+#define SM0CTL1_PGLEN_MASK	(0x7 << 8)
+#define SM0CTL1_PGLEN(x)	(((x - 1) << 8) & SM0CTL1_PGLEN_MASK)
+#define SM0CTL1_READ		(5 << 4)
+#define SM0CTL1_READ_LAST	(4 << 4)
+#define SM0CTL1_STOP		(3 << 4)
+#define SM0CTL1_WRITE		(2 << 4)
+#define SM0CTL1_START		(1 << 4)
+#define SM0CTL1_MODE_MASK	(0x7 << 4)
+#define SM0CTL1_TRI		BIT(0)
+
+/* timeout waiting for I2C devices to respond (clock streching) */
+#define TIMEOUT_MS              1000
+#define DELAY_INTERVAL_US       100
+
+struct mtk_i2c {
+	void __iomem *base;
+	struct device *dev;
+	struct i2c_adapter adap;
+	u32 cur_clk;
+	u32 clk_div;
+	u32 flags;
+};
+
+static void mtk_i2c_w32(struct mtk_i2c *i2c, u32 val, unsigned reg)
+{
+	iowrite32(val, i2c->base + reg);
+}
+
+static u32 mtk_i2c_r32(struct mtk_i2c *i2c, unsigned reg)
+{
+	return ioread32(i2c->base + reg);
+}
+
+static int poll_down_timeout(void __iomem *addr, u32 mask)
+{
+	unsigned long timeout = jiffies + msecs_to_jiffies(TIMEOUT_MS);
+	int current_delay = 1;
+
+	do {
+		if (!(readl_relaxed(addr) & mask))
+			return 0;
+
+		if (current_delay > 0 && current_delay < 10) {
+			udelay(current_delay);
+		} else if (current_delay >= 10) {
+			usleep_range(current_delay, current_delay + 50);
+		}
+		current_delay *= current_delay;
+		if (current_delay > DELAY_INTERVAL_US) {
+			current_delay = DELAY_INTERVAL_US;
+		}
+	} while (time_before(jiffies, timeout));
+
+	return (readl_relaxed(addr) & mask) ? -EAGAIN : 0;
+}
+
+static int mtk_i2c_wait_idle(struct mtk_i2c *i2c)
+{
+	int ret;
+
+	ret = poll_down_timeout(i2c->base + REG_SM0CTL1_REG, SM0CTL1_TRI);
+	if (ret < 0)
+		dev_dbg(i2c->dev, "idle err(%d)\n", ret);
+
+	return ret;
+}
+
+static void mtk_i2c_reset(struct mtk_i2c *i2c)
+{
+	device_reset(i2c->adap.dev.parent);
+	barrier();
+	mtk_i2c_w32(i2c,
+		   SM0CTL0_ODRAIN
+		   | ((i2c->clk_div << 16) & SM0CTL0_CLK_DIV_MASK)
+		   | SM0CTL0_EN
+		   | SM0CTL0_SCL_STRETCH, REG_SM0CTL0_REG);
+	mtk_i2c_w32(i2c, 0, REG_SM0CFG2_REG);
+}
+
+static void mtk_i2c_dump_reg(struct mtk_i2c *i2c)
+{
+	dev_dbg(i2c->dev, "SM0CFG2 %08x, SM0CTL0 %08x, SM0CTL1 %08x, " \
+			"SM0D0 %08x, SM0D1 %08x\n",
+			mtk_i2c_r32(i2c, REG_SM0CFG2_REG),
+			mtk_i2c_r32(i2c, REG_SM0CTL0_REG),
+			mtk_i2c_r32(i2c, REG_SM0CTL1_REG),
+			mtk_i2c_r32(i2c, REG_SM0D0_REG),
+			mtk_i2c_r32(i2c, REG_SM0D1_REG));
+}
+
+static int mtk_i2c_check_ack(struct mtk_i2c *i2c, u32 expected)
+{
+	u32 ack = readl_relaxed(i2c->base + REG_SM0CTL1_REG);
+	u32 ack_expected = (expected << 16) & SM0CTL1_ACK_MASK;
+	return ((ack & ack_expected) == ack_expected) ? 0 : -ENXIO;
+}
+
+static int mtk_i2c_master_start(struct mtk_i2c *i2c)
+{
+	mtk_i2c_w32(i2c, SM0CTL1_START | SM0CTL1_TRI, REG_SM0CTL1_REG);
+	return mtk_i2c_wait_idle(i2c);
+}
+
+static int mtk_i2c_master_stop(struct mtk_i2c *i2c)
+{
+	mtk_i2c_w32(i2c, SM0CTL1_STOP | SM0CTL1_TRI, REG_SM0CTL1_REG);
+	return mtk_i2c_wait_idle(i2c);
+}
+
+static int mtk_i2c_master_cmd(struct mtk_i2c *i2c, u32 cmd, int page_len)
+{
+	mtk_i2c_w32(i2c, cmd | SM0CTL1_TRI | SM0CTL1_PGLEN(page_len), REG_SM0CTL1_REG);
+	return mtk_i2c_wait_idle(i2c);
+}
+static int mtk_i2c_master_xfer(struct i2c_adapter *adap, struct i2c_msg *msgs,
+		int num)
+{
+	struct mtk_i2c *i2c;
+	struct i2c_msg *pmsg;
+	u16 addr;
+	int i, j, ret, len, page_len;
+	u32 cmd;
+	u32 data[2];
+
+	i2c = i2c_get_adapdata(adap);
+
+	for (i = 0; i < num; i++) {
+		pmsg = &msgs[i];
+
+		dev_dbg(i2c->dev, "addr: 0x%x, len: %d, flags: 0x%x\n",
+				pmsg->addr, pmsg->len, pmsg->flags);
+
+		/* wait hardware idle */
+		if ((ret = mtk_i2c_wait_idle(i2c)))
+			goto err_timeout;
+
+		/* start sequence */
+		if ((ret = mtk_i2c_master_start(i2c)))
+			goto err_timeout;
+
+		/* write address */
+		if (pmsg->flags & I2C_M_TEN) {
+			/* 10 bits address */
+			addr = 0xf0 | ((pmsg->addr >> 7) & 0x06);
+			addr |= (pmsg->addr & 0xff) << 8;
+			if (pmsg->flags & I2C_M_RD)
+				addr |= 1;
+			mtk_i2c_w32(i2c, addr, REG_SM0D0_REG);
+			if ((ret = mtk_i2c_master_cmd(i2c, SM0CTL1_WRITE, 2)))
+				goto err_timeout;
+		} else {
+			/* 7 bits address */
+			addr = pmsg->addr << 1;
+			if (pmsg->flags & I2C_M_RD)
+				addr |= 1;
+			mtk_i2c_w32(i2c, addr, REG_SM0D0_REG);
+			if ((ret = mtk_i2c_master_cmd(i2c, SM0CTL1_WRITE, 1)))
+				goto err_timeout;
+		}
+
+		/* check address ACK */
+		if (!(pmsg->flags & I2C_M_IGNORE_NAK)) {
+			if ((ret = mtk_i2c_check_ack(i2c, BIT(0))))
+				goto err_ack;
+		}
+
+		/* transfer data */
+		j = 0;
+		for (len = pmsg->len; len > 0; len -= 8) {
+			page_len = (len >= 8) ? 8 : len;
+
+			if (pmsg->flags & I2C_M_RD) {
+				cmd = (len > 8) ? SM0CTL1_READ : SM0CTL1_READ_LAST;
+			} else {
+				memcpy(data, &pmsg->buf[j], page_len);
+				mtk_i2c_w32(i2c, data[0], REG_SM0D0_REG);
+				mtk_i2c_w32(i2c, data[1], REG_SM0D1_REG);
+				cmd = SM0CTL1_WRITE;
+			}
+
+			if ((ret = mtk_i2c_master_cmd(i2c, cmd, page_len)))
+				goto err_timeout;
+
+			if (pmsg->flags & I2C_M_RD) {
+				data[0] = mtk_i2c_r32(i2c, REG_SM0D0_REG);
+				data[1] = mtk_i2c_r32(i2c, REG_SM0D1_REG);
+				memcpy(&pmsg->buf[j], data, page_len);
+			} else {
+				if (!(pmsg->flags & I2C_M_IGNORE_NAK)) {
+					if ((ret = mtk_i2c_check_ack(i2c, (1 << page_len) - 1)))
+						goto err_ack;
+				}
+			}
+			j += 8;
+		}
+	}
+
+	if ((ret = mtk_i2c_master_stop(i2c)))
+		goto err_timeout;
+
+	/* the return value is number of executed messages */
+	ret = i;
+
+	return ret;
+
+err_ack:
+	if ((ret = mtk_i2c_master_stop(i2c)))
+		goto err_timeout;
+	return -ENXIO;
+
+err_timeout:
+	mtk_i2c_dump_reg(i2c);
+	mtk_i2c_reset(i2c);
+	return ret;
+}
+
+static u32 mtk_i2c_func(struct i2c_adapter *a)
+{
+	return I2C_FUNC_I2C | I2C_FUNC_SMBUS_EMUL;
+}
+
+static const struct i2c_algorithm mtk_i2c_algo = {
+	.master_xfer	= mtk_i2c_master_xfer,
+	.functionality	= mtk_i2c_func,
+};
+
+static const struct of_device_id i2c_mtk_dt_ids[] = {
+	{ .compatible = "mediatek,mt7621-i2c" },
+	{ .compatible = "mediatek,mt7628-i2c" },
+	{ /* sentinel */ }
+};
+
+MODULE_DEVICE_TABLE(of, i2c_mtk_dt_ids);
+
+static void mtk_i2c_init(struct mtk_i2c *i2c)
+{
+	i2c->clk_div = 40000000 / i2c->cur_clk - 1;
+	if (i2c->clk_div < 99)
+		i2c->clk_div = 99;
+	if (i2c->clk_div > SM0CTL0_CLK_DIV_MAX)
+		i2c->clk_div = SM0CTL0_CLK_DIV_MAX;
+
+	mtk_i2c_reset(i2c);
+}
+
+static int mtk_i2c_probe(struct platform_device *pdev)
+{
+	struct resource *res;
+	struct mtk_i2c *i2c;
+	struct i2c_adapter *adap;
+	const struct of_device_id *match;
+	int ret;
+
+	match = of_match_device(i2c_mtk_dt_ids, &pdev->dev);
+
+	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+	if (!res) {
+		dev_err(&pdev->dev, "no memory resource found\n");
+		return -ENODEV;
+	}
+
+	i2c = devm_kzalloc(&pdev->dev, sizeof(struct mtk_i2c), GFP_KERNEL);
+	if (!i2c) {
+		dev_err(&pdev->dev, "failed to allocate i2c_adapter\n");
+		return -ENOMEM;
+	}
+
+	i2c->base = devm_ioremap_resource(&pdev->dev, res);
+	if (IS_ERR(i2c->base))
+		return PTR_ERR(i2c->base);
+
+	i2c->dev = &pdev->dev;
+
+	if (of_property_read_u32(pdev->dev.of_node,
+				"clock-frequency", &i2c->cur_clk))
+		i2c->cur_clk = 100000;
+
+	adap = &i2c->adap;
+	adap->owner = THIS_MODULE;
+	adap->class = I2C_CLASS_HWMON | I2C_CLASS_SPD;
+	adap->algo = &mtk_i2c_algo;
+	adap->retries = 3;
+	adap->dev.parent = &pdev->dev;
+	i2c_set_adapdata(adap, i2c);
+	adap->dev.of_node = pdev->dev.of_node;
+	strlcpy(adap->name, dev_name(&pdev->dev), sizeof(adap->name));
+
+	platform_set_drvdata(pdev, i2c);
+
+	mtk_i2c_init(i2c);
+
+	ret = i2c_add_adapter(adap);
+	if (ret < 0) {
+		dev_err(&pdev->dev, "failed to add adapter\n");
+		return ret;
+	}
+
+	dev_info(&pdev->dev, "clock %u kHz\n",
+			i2c->cur_clk/1000);
+
+	return ret;
+}
+
+static int mtk_i2c_remove(struct platform_device *pdev)
+{
+	struct mtk_i2c *i2c = platform_get_drvdata(pdev);
+
+	i2c_del_adapter(&i2c->adap);
+
+	return 0;
+}
+
+static struct platform_driver mtk_i2c_driver = {
+	.probe		= mtk_i2c_probe,
+	.remove		= mtk_i2c_remove,
+	.driver		= {
+		.owner	= THIS_MODULE,
+		.name	= "i2c-mt7621",
+		.of_match_table = i2c_mtk_dt_ids,
+	},
+};
+
+static int __init i2c_mtk_init (void)
+{
+	return platform_driver_register(&mtk_i2c_driver);
+}
+subsys_initcall(i2c_mtk_init);
+
+static void __exit i2c_mtk_exit (void)
+{
+	platform_driver_unregister(&mtk_i2c_driver);
+}
+module_exit(i2c_mtk_exit);
+
+MODULE_AUTHOR("Steven Liu <steven_liu@mediatek.com>");
+MODULE_DESCRIPTION("MT7621 I2c host driver");
+MODULE_LICENSE("GPL");
+MODULE_ALIAS("platform:MT7621-I2C");