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openwrt/target/linux/ramips/patches-3.10/0125-i2c-MIPS-adds-ralink-I...

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From 701cd2fb0513d17f248048b3a6f2c7d1ea294681 Mon Sep 17 00:00:00 2001
From: John Crispin <blogic@openwrt.org>
Date: Mon, 29 Apr 2013 14:40:43 +0200
Subject: [PATCH 125/133] 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 | 274 ++++++++++++++++++++
4 files changed, 306 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
@@ -632,6 +632,10 @@ config I2C_PXA_SLAVE
is necessary for systems where the PXA may be a target on the
I2C bus.
+config I2C_RALINK
+ tristate "Ralink I2C Controller"
+ select OF_I2C
+
config HAVE_S3C2410_I2C
bool
help
--- a/drivers/i2c/busses/Makefile
+++ b/drivers/i2c/busses/Makefile
@@ -62,6 +62,7 @@ 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_S3C2410) += i2c-s3c2410.o
obj-$(CONFIG_I2C_S6000) += i2c-s6000.o
obj-$(CONFIG_I2C_SH7760) += i2c-sh7760.o
--- /dev/null
+++ b/drivers/i2c/busses/i2c-ralink.c
@@ -0,0 +1,274 @@
+/*
+ * drivers/i2c/busses/i2c-ralink.c
+ *
+ * Copyright (C) 2013 Steven Liu <steven_liu@mediatek.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/i2c.h>
+#include <linux/io.h>
+#include <linux/of_i2c.h>
+#include <linux/err.h>
+
+#include <asm/mach-ralink/ralink_regs.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
+
+#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)
+
+#define I2C_DEVADLEN_7 (6 << 2)
+#define I2C_ADDRDIS BIT(1)
+
+#define I2C_RETRY 0x400
+
+#define CLKDIV_VALUE 200 // clock rate is 40M, 40M / (200*2) = 100k (standard i2c bus rate).
+//#define CLKDIV_VALUE 50 // clock rate is 40M, 40M / (50*2) = 400k (fast i2c bus rate).
+
+#define READ_CMD 0x01
+#define WRITE_CMD 0x00
+#define READ_BLOCK 64
+
+static void __iomem *membase;
+static struct i2c_adapter *adapter;
+
+static void rt_i2c_w32(u32 val, unsigned reg)
+{
+ iowrite32(val, membase + reg);
+}
+
+static u32 rt_i2c_r32(unsigned reg)
+{
+ return ioread32(membase + reg);
+}
+
+static inline int rt_i2c_wait_rx_done(void)
+{
+ int retries = I2C_RETRY;
+
+ do {
+ if (!retries--)
+ break;
+ } while(!(rt_i2c_r32(REG_STATUS_REG) & I2C_DATARDY));
+
+ return (retries < 0);
+}
+
+static inline int rt_i2c_wait_idle(void)
+{
+ int retries = I2C_RETRY;
+
+ do {
+ if (!retries--)
+ break;
+ } while(rt_i2c_r32(REG_STATUS_REG) & I2C_BUSY);
+
+ return (retries < 0);
+}
+
+static inline int rt_i2c_wait_tx_done(void)
+{
+ int retries = I2C_RETRY;
+
+ do {
+ if (!retries--)
+ break;
+ } while(!(rt_i2c_r32(REG_STATUS_REG) & I2C_SDOEMPTY));
+
+ return (retries < 0);
+}
+
+static int rt_i2c_handle_msg(struct i2c_adapter *a, struct i2c_msg* msg)
+{
+ int i = 0, j = 0, pos = 0;
+ int nblock = msg->len / READ_BLOCK;
+ int rem = msg->len % READ_BLOCK;
+
+ if (msg->flags & I2C_M_TEN) {
+ printk("10 bits addr not supported\n");
+ return -EINVAL;
+ }
+
+ if (msg->flags & I2C_M_RD) {
+ for (i = 0; i < nblock; i++) {
+ rt_i2c_wait_idle();
+ rt_i2c_w32(READ_BLOCK - 1, REG_BYTECNT_REG);
+ rt_i2c_w32(READ_CMD, REG_STARTXFR_REG);
+ for (j = 0; j < READ_BLOCK; j++) {
+ if (rt_i2c_wait_rx_done())
+ return -1;
+ msg->buf[pos++] = rt_i2c_r32(REG_DATAIN_REG);
+ }
+ }
+
+ rt_i2c_wait_idle();
+ rt_i2c_w32(rem - 1, REG_BYTECNT_REG);
+ rt_i2c_w32(READ_CMD, REG_STARTXFR_REG);
+ for (i = 0; i < rem; i++) {
+ if (rt_i2c_wait_rx_done())
+ return -1;
+ msg->buf[pos++] = rt_i2c_r32(REG_DATAIN_REG);
+ }
+ } else {
+ rt_i2c_wait_idle();
+ rt_i2c_w32(msg->len - 1, REG_BYTECNT_REG);
+ for (i = 0; i < msg->len; i++) {
+ rt_i2c_w32(msg->buf[i], REG_DATAOUT_REG);
+ rt_i2c_w32(WRITE_CMD, REG_STARTXFR_REG);
+ if (rt_i2c_wait_tx_done())
+ return -1;
+ }
+ }
+
+ return 0;
+}
+
+static int rt_i2c_master_xfer(struct i2c_adapter *a, struct i2c_msg *m, int n)
+{
+ int i = 0;
+ int ret = 0;
+
+ if (rt_i2c_wait_idle()) {
+ printk("i2c transfer failed\n");
+ return 0;
+ }
+
+ device_reset(a->dev.parent);
+
+ rt_i2c_w32(m->addr, REG_DEVADDR_REG);
+ rt_i2c_w32(I2C_DEVADLEN_7 | I2C_ADDRDIS, REG_CONFIG_REG);
+ rt_i2c_w32(CLKDIV_VALUE, REG_CLKDIV_REG);
+
+ for (i = 0; i < n && !ret; i++)
+ ret = rt_i2c_handle_msg(a, &m[i]);
+
+ if (ret) {
+ printk("i2c transfer failed\n");
+ return 0;
+ }
+
+ return n;
+}
+
+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 int rt_i2c_probe(struct platform_device *pdev)
+{
+ struct resource *res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+ int ret;
+
+ if (!res) {
+ dev_err(&pdev->dev, "no memory resource found\n");
+ return -ENODEV;
+ }
+
+ adapter = devm_kzalloc(&pdev->dev, sizeof(struct i2c_adapter), GFP_KERNEL);
+ if (!adapter) {
+ dev_err(&pdev->dev, "failed to allocate i2c_adapter\n");
+ return -ENOMEM;
+ }
+
+ membase = devm_request_and_ioremap(&pdev->dev, res);
+ if (IS_ERR(membase))
+ return PTR_ERR(membase);
+
+ strlcpy(adapter->name, dev_name(&pdev->dev), sizeof(adapter->name));
+ adapter->owner = THIS_MODULE;
+ adapter->nr = pdev->id;
+ adapter->timeout = HZ;
+ adapter->algo = &rt_i2c_algo;
+ adapter->class = I2C_CLASS_HWMON | I2C_CLASS_SPD;
+ adapter->dev.parent = &pdev->dev;
+ adapter->dev.of_node = pdev->dev.of_node;
+
+ ret = i2c_add_numbered_adapter(adapter);
+ if (ret)
+ return ret;
+
+ of_i2c_register_devices(adapter);
+
+ platform_set_drvdata(pdev, adapter);
+
+ dev_info(&pdev->dev, "loaded\n");
+
+ return 0;
+}
+
+static int rt_i2c_remove(struct platform_device *pdev)
+{
+ platform_set_drvdata(pdev, NULL);
+
+ return 0;
+}
+
+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 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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