OpenWrt – Rev 1
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From d5c54ff3d1db0a4348fa04d8e78f3bf6063e3afc Mon Sep 17 00:00:00 2001
From: John Crispin <blogic@openwrt.org>
Date: Mon, 7 Dec 2015 17:21:27 +0100
Subject: [PATCH 45/53] i2c: add mt7621 driver
Signed-off-by: John Crispin <blogic@openwrt.org>
---
drivers/i2c/busses/Kconfig | 4 +
drivers/i2c/busses/Makefile | 1 +
drivers/i2c/busses/i2c-mt7621.c | 303 +++++++++++++++++++++++++++++++++++++++
3 files changed, 308 insertions(+)
create mode 100644 drivers/i2c/busses/i2c-mt7621.c
--- a/drivers/i2c/busses/Kconfig
+++ b/drivers/i2c/busses/Kconfig
@@ -868,6 +868,11 @@ config I2C_RALINK
depends on RALINK && !SOC_MT7621
select OF_I2C
+config I2C_MT7621
+ tristate "MT7621/MT7628 I2C Controller"
+ depends on RALINK && (SOC_MT7620 || SOC_MT7621)
+ select OF_I2C
+
config HAVE_S3C2410_I2C
bool
help
--- a/drivers/i2c/busses/Makefile
+++ b/drivers/i2c/busses/Makefile
@@ -85,6 +85,7 @@ 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 +1,433 @@
+/*
+ * drivers/i2c/busses/i2c-mt7621.c
+ *
+ * Copyright (C) 2013 Steven Liu <steven_liu@mediatek.com>
+ * Copyright (C) 2016 Michael Lee <igvtee@gmail.com>
+ *
+ * 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>
+#include <linux/clk.h>
+
+#define REG_SM0CFG0 0x08
+#define REG_SM0DOUT 0x10
+#define REG_SM0DIN 0x14
+#define REG_SM0ST 0x18
+#define REG_SM0AUTO 0x1C
+#define REG_SM0CFG1 0x20
+#define REG_SM0CFG2 0x28
+#define REG_SM0CTL0 0x40
+#define REG_SM0CTL1 0x44
+#define REG_SM0D0 0x50
+#define REG_SM0D1 0x54
+#define REG_PINTEN 0x5C
+#define REG_PINTST 0x60
+#define REG_PINTCL 0x64
+
+/* REG_SM0CFG0 */
+#define I2C_DEVADDR_MASK 0x7f
+
+/* REG_SM0ST */
+#define I2C_DATARDY BIT(2)
+#define I2C_SDOEMPTY BIT(1)
+#define I2C_BUSY BIT(0)
+
+/* REG_SM0AUTO */
+#define READ_CMD BIT(0)
+
+/* REG_SM0CFG1 */
+#define BYTECNT_MAX 64
+#define SET_BYTECNT(x) (x - 1)
+
+/* REG_SM0CFG2 */
+#define AUTOMODE_EN BIT(0)
+
+/* REG_SM0CTL0 */
+#define ODRAIN_HIGH_SM0 BIT(31)
+#define VSYNC_SHIFT 28
+#define VSYNC_MASK 0x3
+#define VSYNC_PULSE (0x1 << VSYNC_SHIFT)
+#define VSYNC_RISING (0x2 << VSYNC_SHIFT)
+#define CLK_DIV_SHIFT 16
+#define CLK_DIV_MASK 0xfff
+#define DEG_CNT_SHIFT 8
+#define DEG_CNT_MASK 0xff
+#define WAIT_HIGH BIT(6)
+#define DEG_EN BIT(5)
+#define CS_STATUA BIT(4)
+#define SCL_STATUS BIT(3)
+#define SDA_STATUS BIT(2)
+#define SM0_EN BIT(1)
+#define SCL_STRECH BIT(0)
+
+/* REG_SM0CTL1 */
+#define ACK_SHIFT 16
+#define ACK_MASK 0xff
+#define PGLEN_SHIFT 8
+#define PGLEN_MASK 0x7
+#define SM0_MODE_SHIFT 4
+#define SM0_MODE_MASK 0x7
+#define SM0_MODE_START 0x1
+#define SM0_MODE_WRITE 0x2
+#define SM0_MODE_STOP 0x3
+#define SM0_MODE_READ_NACK 0x4
+#define SM0_MODE_READ_ACK 0x5
+#define SM0_TRI_BUSY 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 clk *clk;
+ 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);
+
+ do {
+ if (!(readl_relaxed(addr) & mask))
+ return 0;
+
+ usleep_range(DELAY_INTERVAL_US, DELAY_INTERVAL_US + 50);
+ } 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_SM0ST, I2C_BUSY);
+ if (ret < 0)
+ dev_dbg(i2c->dev, "idle err(%d)\n", ret);
+
+ return ret;
+}
+
+static int poll_up_timeout(void __iomem *addr, u32 mask)
+{
+ unsigned long timeout = jiffies + msecs_to_jiffies(TIMEOUT_MS);
+ u32 status;
+
+ do {
+ status = readl_relaxed(addr);
+ if (status & mask)
+ return 0;
+ usleep_range(DELAY_INTERVAL_US, DELAY_INTERVAL_US + 50);
+ } while (time_before(jiffies, timeout));
+
+ return -ETIMEDOUT;
+}
+
+static int mtk_i2c_wait_rx_done(struct mtk_i2c *i2c)
+{
+ int ret;
+
+ ret = poll_up_timeout(i2c->base + REG_SM0ST, I2C_DATARDY);
+ if (ret < 0)
+ dev_dbg(i2c->dev, "rx err(%d)\n", ret);
+
+ return ret;
+}
+
+static int mtk_i2c_wait_tx_done(struct mtk_i2c *i2c)
+{
+ int ret;
+
+ ret = poll_up_timeout(i2c->base + REG_SM0ST, I2C_SDOEMPTY);
+ if (ret < 0)
+ dev_dbg(i2c->dev, "tx err(%d)\n", ret);
+
+ return ret;
+}
+
+static void mtk_i2c_reset(struct mtk_i2c *i2c)
+{
+ u32 reg;
+ device_reset(i2c->adap.dev.parent);
+ barrier();
+
+ /* ctrl0 */
+ reg = ODRAIN_HIGH_SM0 | VSYNC_PULSE | (i2c->clk_div << CLK_DIV_SHIFT) |
+ WAIT_HIGH | SM0_EN;
+ mtk_i2c_w32(i2c, reg, REG_SM0CTL0);
+
+ /* auto mode */
+ mtk_i2c_w32(i2c, AUTOMODE_EN, REG_SM0CFG2);
+}
+
+static void mtk_i2c_dump_reg(struct mtk_i2c *i2c)
+{
+ dev_dbg(i2c->dev, "cfg0 %08x, dout %08x, din %08x, " \
+ "status %08x, auto %08x, cfg1 %08x, " \
+ "cfg2 %08x, ctl0 %08x, ctl1 %08x\n",
+ mtk_i2c_r32(i2c, REG_SM0CFG0),
+ mtk_i2c_r32(i2c, REG_SM0DOUT),
+ mtk_i2c_r32(i2c, REG_SM0DIN),
+ mtk_i2c_r32(i2c, REG_SM0ST),
+ mtk_i2c_r32(i2c, REG_SM0AUTO),
+ mtk_i2c_r32(i2c, REG_SM0CFG1),
+ mtk_i2c_r32(i2c, REG_SM0CFG2),
+ mtk_i2c_r32(i2c, REG_SM0CTL0),
+ mtk_i2c_r32(i2c, REG_SM0CTL1));
+}
+
+static int mtk_i2c_master_xfer(struct i2c_adapter *adap, struct i2c_msg *msgs,
+ int num)
+{
+ struct mtk_i2c *i2c;
+ struct i2c_msg *pmsg;
+ int i, j, ret;
+ u32 cmd;
+
+ i2c = i2c_get_adapdata(adap);
+
+ for (i = 0; i < num; i++) {
+ pmsg = &msgs[i];
+ cmd = 0;
+
+ 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;
+
+ if (pmsg->flags & I2C_M_TEN) {
+ dev_dbg(i2c->dev, "10 bits addr not supported\n");
+ return -EINVAL;
+ } else {
+ /* 7 bits address */
+ mtk_i2c_w32(i2c, pmsg->addr & I2C_DEVADDR_MASK,
+ REG_SM0CFG0);
+ }
+
+ /* buffer length */
+ if (pmsg->len == 0) {
+ dev_dbg(i2c->dev, "length is 0\n");
+ return -EINVAL;
+ } else
+ mtk_i2c_w32(i2c, SET_BYTECNT(pmsg->len),
+ REG_SM0CFG1);
+
+ j = 0;
+ if (pmsg->flags & I2C_M_RD) {
+ cmd |= READ_CMD;
+ /* start transfer */
+ barrier();
+ mtk_i2c_w32(i2c, cmd, REG_SM0AUTO);
+ do {
+ /* wait */
+ if ((ret = mtk_i2c_wait_rx_done(i2c)))
+ goto err_timeout;
+ /* read data */
+ if (pmsg->len)
+ pmsg->buf[j] = mtk_i2c_r32(i2c,
+ REG_SM0DIN);
+ j++;
+ } while (j < pmsg->len);
+ } else {
+ do {
+ /* write data */
+ if (pmsg->len)
+ mtk_i2c_w32(i2c, pmsg->buf[j],
+ REG_SM0DOUT);
+ /* start transfer */
+ if (j == 0) {
+ barrier();
+ mtk_i2c_w32(i2c, cmd, REG_SM0AUTO);
+ }
+ /* wait */
+ if ((ret = mtk_i2c_wait_tx_done(i2c)))
+ goto err_timeout;
+ j++;
+ } while (j < pmsg->len);
+ }
+ }
+ /* the return value is number of executed messages */
+ ret = i;
+
+ return ret;
+
+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" },
+ { /* sentinel */ }
+};
+
+MODULE_DEVICE_TABLE(of, i2c_mtk_dt_ids);
+
+static struct i2c_adapter_quirks mtk_i2c_quirks = {
+ .max_write_len = BYTECNT_MAX,
+ .max_read_len = BYTECNT_MAX,
+};
+
+static void mtk_i2c_init(struct mtk_i2c *i2c)
+{
+ i2c->clk_div = clk_get_rate(i2c->clk) / i2c->cur_clk;
+ if (i2c->clk_div > CLK_DIV_MASK)
+ i2c->clk_div = CLK_DIV_MASK;
+
+ 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->clk = devm_clk_get(&pdev->dev, NULL);
+ if (IS_ERR(i2c->clk)) {
+ dev_err(&pdev->dev, "no clock defined\n");
+ return -ENODEV;
+ }
+ clk_prepare_enable(i2c->clk);
+ 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));
+ adap->quirks = &mtk_i2c_quirks;
+
+ 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");
+ clk_disable_unprepare(i2c->clk);
+ return ret;
+ }
+
+ dev_info(&pdev->dev, "clock %uKHz, re-start not support\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);
+ clk_disable_unprepare(i2c->clk);
+
+ 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");
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