OpenWrt – Rev 1
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From 723b8beaabf3c3c4b1ce69480141f1e926f3f3b2 Mon Sep 17 00:00:00 2001
From: John Crispin <blogic@openwrt.org>
Date: Sun, 27 Jul 2014 09:52:56 +0100
Subject: [PATCH 44/53] i2c: MIPS: adds ralink I2C driver
Signed-off-by: John Crispin <blogic@openwrt.org>
---
.../devicetree/bindings/i2c/i2c-ralink.txt | 27 ++
drivers/i2c/busses/Kconfig | 4 +
drivers/i2c/busses/Makefile | 1 +
drivers/i2c/busses/i2c-ralink.c | 327 ++++++++++++++++++++
4 files changed, 359 insertions(+)
create mode 100644 Documentation/devicetree/bindings/i2c/i2c-ralink.txt
create mode 100644 drivers/i2c/busses/i2c-ralink.c
--- /dev/null
+++ b/Documentation/devicetree/bindings/i2c/i2c-ralink.txt
@@ -0,0 +1,27 @@
+I2C for Ralink platforms
+
+Required properties :
+- compatible : Must be "link,rt3052-i2c"
+- reg: physical base address of the controller and length of memory mapped
+ region.
+- #address-cells = <1>;
+- #size-cells = <0>;
+
+Optional properties:
+- Child nodes conforming to i2c bus binding
+
+Example :
+
+palmbus@10000000 {
+ i2c@900 {
+ compatible = "link,rt3052-i2c";
+ reg = <0x900 0x100>;
+ #address-cells = <1>;
+ #size-cells = <0>;
+
+ hwmon@4b {
+ compatible = "national,lm92";
+ reg = <0x4b>;
+ };
+ };
+};
--- a/drivers/i2c/busses/Kconfig
+++ b/drivers/i2c/busses/Kconfig
@@ -863,6 +863,11 @@ config I2C_RK3X
This driver can also be built as a module. If so, the module will
be called i2c-rk3x.
+config I2C_RALINK
+ tristate "Ralink I2C Controller"
+ depends on RALINK && !SOC_MT7621
+ select OF_I2C
+
config HAVE_S3C2410_I2C
bool
help
--- a/drivers/i2c/busses/Makefile
+++ b/drivers/i2c/busses/Makefile
@@ -84,6 +84,7 @@ obj-$(CONFIG_I2C_PNX) += i2c-pnx.o
obj-$(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_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-ralink.c
@@ -0,0 +1,435 @@
+/*
+ * drivers/i2c/busses/i2c-ralink.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_CONFIG_REG 0x00
+#define REG_CLKDIV_REG 0x04
+#define REG_DEVADDR_REG 0x08
+#define REG_ADDR_REG 0x0C
+#define REG_DATAOUT_REG 0x10
+#define REG_DATAIN_REG 0x14
+#define REG_STATUS_REG 0x18
+#define REG_STARTXFR_REG 0x1C
+#define REG_BYTECNT_REG 0x20
+
+/* REG_CONFIG_REG */
+#define I2C_ADDRLEN_OFFSET 5
+#define I2C_DEVADLEN_OFFSET 2
+#define I2C_ADDRLEN_MASK 0x3
+#define I2C_ADDR_DIS BIT(1)
+#define I2C_DEVADDR_DIS BIT(0)
+#define I2C_ADDRLEN_8 (7 << I2C_ADDRLEN_OFFSET)
+#define I2C_DEVADLEN_7 (6 << I2C_DEVADLEN_OFFSET)
+#define I2C_CONF_DEFAULT (I2C_ADDRLEN_8 | I2C_DEVADLEN_7)
+
+/* REG_CLKDIV_REG */
+#define I2C_CLKDIV_MASK 0xffff
+
+/* REG_DEVADDR_REG */
+#define I2C_DEVADDR_MASK 0x7f
+
+/* REG_ADDR_REG */
+#define I2C_ADDR_MASK 0xff
+
+/* REG_STATUS_REG */
+#define I2C_STARTERR BIT(4)
+#define I2C_ACKERR BIT(3)
+#define I2C_DATARDY BIT(2)
+#define I2C_SDOEMPTY BIT(1)
+#define I2C_BUSY BIT(0)
+
+/* REG_STARTXFR_REG */
+#define NOSTOP_CMD BIT(2)
+#define NODATA_CMD BIT(1)
+#define READ_CMD BIT(0)
+
+/* REG_BYTECNT_REG */
+#define BYTECNT_MAX 64
+#define SET_BYTECNT(x) (x - 1)
+
+/* timeout waiting for I2C devices to respond (clock streching) */
+#define TIMEOUT_MS 1000
+#define DELAY_INTERVAL_US 100
+
+struct rt_i2c {
+ void __iomem *base;
+ struct clk *clk;
+ struct device *dev;
+ struct i2c_adapter adap;
+ u32 cur_clk;
+ u32 clk_div;
+ u32 flags;
+};
+
+static void rt_i2c_w32(struct rt_i2c *i2c, u32 val, unsigned reg)
+{
+ iowrite32(val, i2c->base + reg);
+}
+
+static u32 rt_i2c_r32(struct rt_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 rt_i2c_wait_idle(struct rt_i2c *i2c)
+{
+ int ret;
+
+ ret = poll_down_timeout(i2c->base + REG_STATUS_REG, 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);
+
+ /* check error status */
+ if (status & I2C_STARTERR)
+ return -EAGAIN;
+ else if (status & I2C_ACKERR)
+ return -ENXIO;
+ else if (status & mask)
+ return 0;
+
+ usleep_range(DELAY_INTERVAL_US, DELAY_INTERVAL_US + 50);
+ } while (time_before(jiffies, timeout));
+
+ return -ETIMEDOUT;
+}
+
+static int rt_i2c_wait_rx_done(struct rt_i2c *i2c)
+{
+ int ret;
+
+ ret = poll_up_timeout(i2c->base + REG_STATUS_REG, I2C_DATARDY);
+ if (ret < 0)
+ dev_dbg(i2c->dev, "rx err(%d)\n", ret);
+
+ return ret;
+}
+
+static int rt_i2c_wait_tx_done(struct rt_i2c *i2c)
+{
+ int ret;
+
+ ret = poll_up_timeout(i2c->base + REG_STATUS_REG, I2C_SDOEMPTY);
+ if (ret < 0)
+ dev_dbg(i2c->dev, "tx err(%d)\n", ret);
+
+ return ret;
+}
+
+static void rt_i2c_reset(struct rt_i2c *i2c)
+{
+ device_reset(i2c->adap.dev.parent);
+ barrier();
+ rt_i2c_w32(i2c, i2c->clk_div, REG_CLKDIV_REG);
+}
+
+static void rt_i2c_dump_reg(struct rt_i2c *i2c)
+{
+ dev_dbg(i2c->dev, "conf %08x, clkdiv %08x, devaddr %08x, " \
+ "addr %08x, dataout %08x, datain %08x, " \
+ "status %08x, startxfr %08x, bytecnt %08x\n",
+ rt_i2c_r32(i2c, REG_CONFIG_REG),
+ rt_i2c_r32(i2c, REG_CLKDIV_REG),
+ rt_i2c_r32(i2c, REG_DEVADDR_REG),
+ rt_i2c_r32(i2c, REG_ADDR_REG),
+ rt_i2c_r32(i2c, REG_DATAOUT_REG),
+ rt_i2c_r32(i2c, REG_DATAIN_REG),
+ rt_i2c_r32(i2c, REG_STATUS_REG),
+ rt_i2c_r32(i2c, REG_STARTXFR_REG),
+ rt_i2c_r32(i2c, REG_BYTECNT_REG));
+}
+
+static int rt_i2c_master_xfer(struct i2c_adapter *adap, struct i2c_msg *msgs,
+ int num)
+{
+ struct rt_i2c *i2c;
+ struct i2c_msg *pmsg;
+ unsigned char addr;
+ int i, j, ret;
+ u32 cmd;
+
+ i2c = i2c_get_adapdata(adap);
+
+ for (i = 0; i < num; i++) {
+ pmsg = &msgs[i];
+ if (i == (num - 1))
+ cmd = 0;
+ else
+ cmd = NOSTOP_CMD;
+
+ dev_dbg(i2c->dev, "addr: 0x%x, len: %d, flags: 0x%x, stop: %d\n",
+ pmsg->addr, pmsg->len, pmsg->flags,
+ (cmd == 0)? 1 : 0);
+
+ /* wait hardware idle */
+ if ((ret = rt_i2c_wait_idle(i2c)))
+ goto err_timeout;
+
+ if (pmsg->flags & I2C_M_TEN) {
+ rt_i2c_w32(i2c, I2C_CONF_DEFAULT, REG_CONFIG_REG);
+ /* 10 bits address */
+ addr = 0x78 | ((pmsg->addr >> 8) & 0x03);
+ rt_i2c_w32(i2c, addr & I2C_DEVADDR_MASK,
+ REG_DEVADDR_REG);
+ rt_i2c_w32(i2c, pmsg->addr & I2C_ADDR_MASK,
+ REG_ADDR_REG);
+ } else {
+ rt_i2c_w32(i2c, I2C_CONF_DEFAULT | I2C_ADDR_DIS,
+ REG_CONFIG_REG);
+ /* 7 bits address */
+ rt_i2c_w32(i2c, pmsg->addr & I2C_DEVADDR_MASK,
+ REG_DEVADDR_REG);
+ }
+
+ /* buffer length */
+ if (pmsg->len == 0)
+ cmd |= NODATA_CMD;
+ else
+ rt_i2c_w32(i2c, SET_BYTECNT(pmsg->len),
+ REG_BYTECNT_REG);
+
+ j = 0;
+ if (pmsg->flags & I2C_M_RD) {
+ cmd |= READ_CMD;
+ /* start transfer */
+ barrier();
+ rt_i2c_w32(i2c, cmd, REG_STARTXFR_REG);
+ do {
+ /* wait */
+ if ((ret = rt_i2c_wait_rx_done(i2c)))
+ goto err_timeout;
+ /* read data */
+ if (pmsg->len)
+ pmsg->buf[j] = rt_i2c_r32(i2c,
+ REG_DATAIN_REG);
+ j++;
+ } while (j < pmsg->len);
+ } else {
+ do {
+ /* write data */
+ if (pmsg->len)
+ rt_i2c_w32(i2c, pmsg->buf[j],
+ REG_DATAOUT_REG);
+ /* start transfer */
+ if (j == 0) {
+ barrier();
+ rt_i2c_w32(i2c, cmd, REG_STARTXFR_REG);
+ }
+ /* wait */
+ if ((ret = rt_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:
+ rt_i2c_dump_reg(i2c);
+ rt_i2c_reset(i2c);
+ return ret;
+}
+
+static u32 rt_i2c_func(struct i2c_adapter *a)
+{
+ return I2C_FUNC_I2C | I2C_FUNC_SMBUS_EMUL;
+}
+
+static const struct i2c_algorithm rt_i2c_algo = {
+ .master_xfer = rt_i2c_master_xfer,
+ .functionality = rt_i2c_func,
+};
+
+static const struct of_device_id i2c_rt_dt_ids[] = {
+ { .compatible = "ralink,rt2880-i2c" },
+ { /* sentinel */ }
+};
+
+MODULE_DEVICE_TABLE(of, i2c_rt_dt_ids);
+
+static struct i2c_adapter_quirks rt_i2c_quirks = {
+ .max_write_len = BYTECNT_MAX,
+ .max_read_len = BYTECNT_MAX,
+};
+
+static int rt_i2c_init(struct rt_i2c *i2c)
+{
+ u32 reg;
+
+ /* i2c_sclk = periph_clk / ((2 * clk_div) + 5) */
+ i2c->clk_div = (clk_get_rate(i2c->clk) - (5 * i2c->cur_clk)) /
+ (2 * i2c->cur_clk);
+ if (i2c->clk_div < 8)
+ i2c->clk_div = 8;
+ if (i2c->clk_div > I2C_CLKDIV_MASK)
+ i2c->clk_div = I2C_CLKDIV_MASK;
+
+ /* check support combinde/repeated start message */
+ rt_i2c_w32(i2c, NOSTOP_CMD, REG_STARTXFR_REG);
+ reg = rt_i2c_r32(i2c, REG_STARTXFR_REG) & NOSTOP_CMD;
+
+ rt_i2c_reset(i2c);
+
+ return reg;
+}
+
+static int rt_i2c_probe(struct platform_device *pdev)
+{
+ struct resource *res;
+ struct rt_i2c *i2c;
+ struct i2c_adapter *adap;
+ const struct of_device_id *match;
+ int ret, restart;
+
+ match = of_match_device(i2c_rt_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 rt_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 = &rt_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 = &rt_i2c_quirks;
+
+ platform_set_drvdata(pdev, i2c);
+
+ restart = rt_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 %ssupport\n",
+ i2c->cur_clk/1000, restart ? "" : "not ");
+
+ return ret;
+}
+
+static int rt_i2c_remove(struct platform_device *pdev)
+{
+ struct rt_i2c *i2c = platform_get_drvdata(pdev);
+
+ i2c_del_adapter(&i2c->adap);
+ clk_disable_unprepare(i2c->clk);
+
+ return 0;
+}
+
+static struct platform_driver rt_i2c_driver = {
+ .probe = rt_i2c_probe,
+ .remove = rt_i2c_remove,
+ .driver = {
+ .owner = THIS_MODULE,
+ .name = "i2c-ralink",
+ .of_match_table = i2c_rt_dt_ids,
+ },
+};
+
+static int __init i2c_rt_init (void)
+{
+ return platform_driver_register(&rt_i2c_driver);
+}
+subsys_initcall(i2c_rt_init);
+
+static void __exit i2c_rt_exit (void)
+{
+ platform_driver_unregister(&rt_i2c_driver);
+}
+module_exit(i2c_rt_exit);
+
+MODULE_AUTHOR("Steven Liu <steven_liu@mediatek.com>");
+MODULE_DESCRIPTION("Ralink I2c host driver");
+MODULE_LICENSE("GPL");
+MODULE_ALIAS("platform:Ralink-I2C");
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