This patch adds a driver for the I2C controller found on the MediaTek
MT7621/7628/7688 SoC's. The base version of this driver was done by
Steven Liu (according to the copyright and MODULE_AUTHOR lines). It
can be found in the OpenWRT repositories (v4.14 at the time I looked).
The base driver had many issues, which are disccussed here:
https://en.forum.labs.mediatek.com/t/openwrt-15-05-loads-non-working-i2c-kernel-module-for-mt7688/1286/3
From this link an enhanced driver version (complete rewrite, mayor
changes: support clock stretching, repeated start, ACK handling and
unlimited message length) from Jan Breuer can be found here:
https://gist.github.com/j123b567/9b555b635c2b4069d716b24198546954
This patch now adds this enhanced I2C driver to mainline.
Changes by Stefan Roese for upstreaming:
- Add devicetree bindings
- checkpatch clean
- Use module_platform_driver()
- Minor cosmetic enhancements
- Removed IO warpped functions
- Use readl_relaxed_poll_timeout() and drop poll_down_timeout()
- Removed superfluous barrier() in mtk_i2c_reset()
- Use i2c_8bit_addr_from_msg()
- Added I2C_FUNC_PROTOCOL_MANGLING
- Removed adap->class = I2C_CLASS_HWMON | I2C_CLASS_SPD;
Signed-off-by: Stefan Roese <sr@xxxxxxx>
Cc: Jan Breuer <jan.breuer@xxxxxxxxx>
Cc: John Crispin <john@xxxxxxxxxxx>
Cc: René van Dorst <opensource@xxxxxxxxxx>
Cc: Wolfram Sang <wsa+renesas@xxxxxxxxxxxxxxxxxxxx>
---
v3:
- Added myself as maintainer for this driver
- Added René van Dorst to Cc as he tested an earlier version of this
driver. The tested-by tag is not added, as the driver has now
undergone some notable changes. A new testing would be very welcome.
- Removed Steven Liu from Cc, as his email address is not valid any
more
- Moved bindings documentation into separate patch
- Removed IO warpped functions
- Use readl_relaxed_poll_timeout() and drop poll_down_timeout()
- Removed superfluous barrier() in mtk_i2c_reset()
- Use i2c_8bit_addr_from_msg()
- Added I2C_FUNC_PROTOCOL_MANGLING
- Removed adap->class = I2C_CLASS_HWMON | I2C_CLASS_SPD;
- Misc minor mostly cosmitic enhancements suggested by Wolfram
v2:
- Configure I2C controller to open-drain instead of push-pull, as
noticed and suggested by Jan (misleading bit description)
MAINTAINERS | 7 +
drivers/i2c/busses/Kconfig | 8 +
drivers/i2c/busses/Makefile | 1 +
drivers/i2c/busses/i2c-mt7621.c | 346 ++++++++++++++++++++++++++++++++
4 files changed, 362 insertions(+)
create mode 100644 drivers/i2c/busses/i2c-mt7621.c
diff --git a/MAINTAINERS b/MAINTAINERS
index a6954776a37e..8472dfbffcfa 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -9957,6 +9957,13 @@ L: linux-wireless@xxxxxxxxxxxxxxx
S: Maintained
F: drivers/net/wireless/mediatek/mt7601u/
+MEDIATEK MT7621/28/88 I2C DRIVER
+M: Stefan Roese <sr@xxxxxxx>
+L: linux-i2c@xxxxxxxxxxxxxxx
+S: Maintained
+F: drivers/i2c/busses/i2c-mt7621.c
+F: Documentation/devicetree/bindings/i2c/i2c-mt7621.txt
+
MEDIATEK NAND CONTROLLER DRIVER
M: Xiaolei Li <xiaolei.li@xxxxxxxxxxxx>
L: linux-mtd@xxxxxxxxxxxxxxxxxxx
diff --git a/drivers/i2c/busses/Kconfig b/drivers/i2c/busses/Kconfig
index ee5dfb5aee2a..f9ae8bcd4d8b 100644
--- a/drivers/i2c/busses/Kconfig
+++ b/drivers/i2c/busses/Kconfig
@@ -746,6 +746,14 @@ config I2C_MT65XX
If you want to use MediaTek(R) I2C interface, say Y or M here.
If unsure, say N.
+config I2C_MT7621
+ tristate "MT7621/MT7628 I2C Controller"
+ depends on (RALINK && (SOC_MT7620 || SOC_MT7621)) || COMPILE_TEST
+ select OF_I2C
+ help
+ Say Y here to include support for I2C controller in the
+ MediaTek MT7621/MT7628 SoCs.
+
config I2C_MV64XXX
tristate "Marvell mv64xxx I2C Controller"
depends on MV64X60 || PLAT_ORION || ARCH_SUNXI || ARCH_MVEBU
diff --git a/drivers/i2c/busses/Makefile b/drivers/i2c/busses/Makefile
index a3245231b0b7..80c23895eaaf 100644
--- a/drivers/i2c/busses/Makefile
+++ b/drivers/i2c/busses/Makefile
@@ -77,6 +77,7 @@ obj-$(CONFIG_I2C_LPC2K) += i2c-lpc2k.o
obj-$(CONFIG_I2C_MESON) += i2c-meson.o
obj-$(CONFIG_I2C_MPC) += i2c-mpc.o
obj-$(CONFIG_I2C_MT65XX) += i2c-mt65xx.o
+obj-$(CONFIG_I2C_MT7621) += i2c-mt7621.o
obj-$(CONFIG_I2C_MV64XXX) += i2c-mv64xxx.o
obj-$(CONFIG_I2C_MXS) += i2c-mxs.o
obj-$(CONFIG_I2C_NOMADIK) += i2c-nomadik.o
diff --git a/drivers/i2c/busses/i2c-mt7621.c
b/drivers/i2c/busses/i2c-mt7621.c
new file mode 100644
index 000000000000..ff8f8c80aa27
--- /dev/null
+++ b/drivers/i2c/busses/i2c-mt7621.c
@@ -0,0 +1,346 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * drivers/i2c/busses/i2c-mt7621.c
+ *
+ * Copyright (C) 2013 Steven Liu <steven_liu@xxxxxxxxxxxx>
+ * Copyright (C) 2016 Michael Lee <igvtee@xxxxxxxxx>
+ * Copyright (C) 2018 Jan Breuer <jan.breuer@xxxxxxxxx>
+ *
+ * Improve driver for i2cdetect from i2c-tools to detect i2c
devices on the bus.
+ * (C) 2014 Sittisak <sittisaks@xxxxxxxxxxx>
+ */
+
+#include <linux/delay.h>
+#include <linux/i2c.h>
+#include <linux/io.h>
+#include <linux/iopoll.h>
+#include <linux/module.h>
+#include <linux/of_platform.h>
+#include <linux/reset.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 */
+#define TIMEOUT_MS 1000
+
+#define MT76XX_I2C_INPUT_CLOCK 40000000
+
+struct mtk_i2c {
+ void __iomem *base;
+ struct device *dev;
+ struct i2c_adapter adap;
+ u32 bus_freq;
+ u32 clk_div;
+ u32 flags;
+};
+
+static int mtk_i2c_wait_idle(struct mtk_i2c *i2c)
+{
+ int ret;
+ u32 val;
+
+ ret = readl_relaxed_poll_timeout(i2c->base + REG_SM0CTL1_REG,
+ val, !(val & SM0CTL1_TRI),
+ 10, TIMEOUT_MS * 1000);
+ if (ret)
+ dev_dbg(i2c->dev, "idle err(%d)\n", ret);
+
+ return ret;
+}
+
+static void mtk_i2c_reset(struct mtk_i2c *i2c)
+{
+ int ret;
+
+ ret = device_reset(i2c->adap.dev.parent);
+ if (ret)
+ dev_err(i2c->dev, "I2C reset failed!\n");
+
+ /*
+ * Don't set SM0CTL0_ODRAIN as its bit meaning is inverted. To
+ * configure open-drain mode, this bit needs to be cleared.
+ */
+ iowrite32(((i2c->clk_div << 16) & SM0CTL0_CLK_DIV_MASK) | SM0CTL0_EN |
+ SM0CTL0_SCL_STRETCH, i2c->base + REG_SM0CTL0_REG);
+ iowrite32(0, i2c->base + 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",
+ ioread32(i2c->base + REG_SM0CFG2_REG),
+ ioread32(i2c->base + REG_SM0CTL0_REG),
+ ioread32(i2c->base + REG_SM0CTL1_REG),
+ ioread32(i2c->base + REG_SM0D0_REG),
+ ioread32(i2c->base + 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)
+{
+ iowrite32(SM0CTL1_START | SM0CTL1_TRI, i2c->base + REG_SM0CTL1_REG);
+ return mtk_i2c_wait_idle(i2c);
+}
+
+static int mtk_i2c_master_stop(struct mtk_i2c *i2c)
+{
+ iowrite32(SM0CTL1_STOP | SM0CTL1_TRI, i2c->base + REG_SM0CTL1_REG);
+ return mtk_i2c_wait_idle(i2c);
+}
+
+static int mtk_i2c_master_cmd(struct mtk_i2c *i2c, u32 cmd, int page_len)
+{
+ iowrite32(cmd | SM0CTL1_TRI | SM0CTL1_PGLEN(page_len),
+ i2c->base + 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];
+
+ /* wait hardware idle */
+ ret = mtk_i2c_wait_idle(i2c);
+ if (ret)
+ goto err_timeout;
+
+ /* start sequence */
+ ret = mtk_i2c_master_start(i2c);
+ if (ret)
+ 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;
+ iowrite32(addr, i2c->base + REG_SM0D0_REG);
+ ret = mtk_i2c_master_cmd(i2c, SM0CTL1_WRITE, 2);
+ if (ret)
+ goto err_timeout;
+ } else {
+ /* 7 bits address */
+ addr = i2c_8bit_addr_from_msg(pmsg);
+ iowrite32(addr, i2c->base + REG_SM0D0_REG);
+ ret = mtk_i2c_master_cmd(i2c, SM0CTL1_WRITE, 1);
+ if (ret)
+ goto err_timeout;
+ }
+
+ /* check address ACK */
+ if (!(pmsg->flags & I2C_M_IGNORE_NAK)) {
+ ret = mtk_i2c_check_ack(i2c, BIT(0));
+ if (ret)
+ goto err_ack;
+ }
+
+ /* transfer data */
+ for (len = pmsg->len, j = 0; len > 0; len -= 8, j += 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);
+ iowrite32(data[0], i2c->base + REG_SM0D0_REG);
+ iowrite32(data[1], i2c->base + REG_SM0D1_REG);
+ cmd = SM0CTL1_WRITE;
+ }
+
+ ret = mtk_i2c_master_cmd(i2c, cmd, page_len);
+ if (ret)
+ goto err_timeout;
+
+ if (pmsg->flags & I2C_M_RD) {
+ data[0] = ioread32(i2c->base + REG_SM0D0_REG);
+ data[1] = ioread32(i2c->base + REG_SM0D1_REG);
+ memcpy(&pmsg->buf[j], data, page_len);
+ } else {
+ if (!(pmsg->flags & I2C_M_IGNORE_NAK)) {
+ ret = mtk_i2c_check_ack(i2c,
+ (1 << page_len)
+ - 1);
+ if (ret)
+ goto err_ack;
+ }
+ }
+ }
+ }
+
+ ret = mtk_i2c_master_stop(i2c);
+ if (ret)
+ goto err_timeout;
+
+ /* the return value is number of executed messages */
+ return i;
+
+err_ack:
+ ret = mtk_i2c_master_stop(i2c);
+ if (ret)
+ 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 | I2C_FUNC_PROTOCOL_MANGLING;
+}
+
+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 void mtk_i2c_init(struct mtk_i2c *i2c)
+{
+ i2c->clk_div = MT76XX_I2C_INPUT_CLOCK / i2c->bus_freq - 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;
+ int ret;
+
+ res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+
+ i2c = devm_kzalloc(&pdev->dev, sizeof(struct mtk_i2c), GFP_KERNEL);
+ if (!i2c)
+ 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->bus_freq))
+ i2c->bus_freq = 100000;
+
+ if (i2c->bus_freq == 0) {
+ dev_warn(i2c->dev,
+ "clock-frequency 0 not supported, using 1\n");
+ i2c->bus_freq = 1;
+ }
+
+ adap = &i2c->adap;
+ adap->owner = THIS_MODULE;
+ 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)
+ return ret;
+
+ dev_info(&pdev->dev, "clock %u kHz\n", i2c->bus_freq / 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,
+ },
+};
+
+module_platform_driver(mtk_i2c_driver);
+
+MODULE_AUTHOR("Steven Liu <steven_liu@xxxxxxxxxxxx>");
+MODULE_DESCRIPTION("MT7621 I2C host driver");
+MODULE_LICENSE("GPL v2");
+MODULE_ALIAS("platform:MT7621-I2C");
--
2.21.0
