Add a driver for the i2c core found on various mediatek/ralink SoCs.
This driver is based on the code found inside the SDK.
Signed-off-by: Michele Mogioni <michele.mogioni@xxxxxxxx>
Signed-off-by: John Crispin <blogic@xxxxxxxxxxx>
---
.../devicetree/bindings/i2c/i2c-rt2880.txt | 27 ++
drivers/i2c/busses/Kconfig | 10 +
drivers/i2c/busses/Makefile | 1 +
drivers/i2c/busses/i2c-rt2880.c | 300 ++++++++++++++++++++
4 files changed, 338 insertions(+)
create mode 100644 Documentation/devicetree/bindings/i2c/i2c-rt2880.txt
create mode 100644 drivers/i2c/busses/i2c-rt2880.c
diff --git a/Documentation/devicetree/bindings/i2c/i2c-rt2880.txt b/Documentation/devicetree/bindings/i2c/i2c-rt2880.txt
new file mode 100644
index 0000000..fa4588b
--- /dev/null
+++ b/Documentation/devicetree/bindings/i2c/i2c-rt2880.txt
@@ -0,0 +1,27 @@
+I2C for Ralink platforms
+
+Required properties :
+- compatible : Must be "ralink,rt2880-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 = "ralink,rt2880-i2c";
+ reg = <0x900 0x100>;
+ #address-cells = <1>;
+ #size-cells = <0>;
+
+ hwmon@4b {
+ compatible = "national,lm92";
+ reg = <0x4b>;
+ };
+ };
+};
diff --git a/drivers/i2c/busses/Kconfig b/drivers/i2c/busses/Kconfig
index 2ac87fa..2e4b4d5 100644
--- a/drivers/i2c/busses/Kconfig
+++ b/drivers/i2c/busses/Kconfig
@@ -687,6 +687,16 @@ config I2C_RK3X
This driver can also be built as a module. If so, the module will
be called i2c-rk3x.
+config I2C_RT2880
+ tristate "Ralink RT2880 I2C Controller"
+ depends on MIPS && RALINK
+ help
+ Say Y here to include support for the I2C adapter in Ralink RT2880
+ SoCs.
+
+ This driver can also be built as a module. If so, the module will
+ be called i2c-rt2880.
+
config HAVE_S3C2410_I2C
bool
help
diff --git a/drivers/i2c/busses/Makefile b/drivers/i2c/busses/Makefile
index 49bf07e..967e9f5 100644
--- a/drivers/i2c/busses/Makefile
+++ b/drivers/i2c/busses/Makefile
@@ -67,6 +67,7 @@ obj-$(CONFIG_I2C_PXA_PCI) += i2c-pxa-pci.o
obj-$(CONFIG_I2C_QUP) += i2c-qup.o
obj-$(CONFIG_I2C_RIIC) += i2c-riic.o
obj-$(CONFIG_I2C_RK3X) += i2c-rk3x.o
+obj-$(CONFIG_I2C_RT2880) += i2c-rt2880.o
obj-$(CONFIG_I2C_S3C2410) += i2c-s3c2410.o
obj-$(CONFIG_I2C_SH7760) += i2c-sh7760.o
obj-$(CONFIG_I2C_SH_MOBILE) += i2c-sh_mobile.o
diff --git a/drivers/i2c/busses/i2c-rt2880.c b/drivers/i2c/busses/i2c-rt2880.c
new file mode 100644
index 0000000..b4803e6
--- /dev/null
+++ b/drivers/i2c/busses/i2c-rt2880.c
@@ -0,0 +1,300 @@
+/*
+ * drivers/i2c/busses/i2c-ralink.c
+ *
+ * Copyright (C) 2013 Steven Liu <steven_liu@xxxxxxxxxxxx>
+ *
+ * Improve driver for i2cdetect from i2c-tools to detect i2c devices on the bus.
+ * (C) 2014 Sittisak <sittisaks@xxxxxxxxxxx>
+ * (C) 2014 Michele Mogioni <michele.mogioni@xxxxxxxx>
+ *
+ * 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/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 0x1000
+
+/* clock rate is 40M, 40M / (200*2) = 100k (standard i2c bus rate). */
+#define CLKDIV_VALUE 200
+/* clock rate is 40M, 40M / (50*2) = 400k (fast i2c bus rate). */
+/* #define CLKDIV_VALUE 50 */
+
+#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_get_ack(void)
+{
+ return (rt_i2c_r32(REG_STATUS_REG) & I2C_ACKERR) ? -EIO : 0;
+}
+
+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) ? -ETIMEDOUT : 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) ? -ETIMEDOUT : 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;
+ int ret = 0;
+
+ if (msg->flags & I2C_M_TEN) {
+ dev_err(a->dev.parent, "10 bits addr not supported\n");
+ return -EINVAL;
+ }
+
+ if (msg->flags & I2C_M_RD) {
+ for (i = 0; i < nblock; i++) {
+ if (rt_i2c_wait_idle()) {
+ dev_err(a->dev.parent, "i2c-read line busy\n");
+ return -ETIMEDOUT;
+ }
+ 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() < 0)
+ ret = rt_i2c_wait_rx_done();
+ if (rt_i2c_get_ack() < 0)
+ ret = rt_i2c_get_ack();
+ msg->buf[pos++] = rt_i2c_r32(REG_DATAIN_REG);
+ }
+ }
+
+ if (rt_i2c_wait_idle()) {
+ dev_err(a->dev.parent, "i2c-read line busy\n");
+ return -ETIMEDOUT;
+ }
+ if (rem) {
+ 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() < 0)
+ ret = rt_i2c_wait_rx_done();
+ if (rt_i2c_get_ack() < 0)
+ ret = rt_i2c_get_ack();
+
+ msg->buf[pos++] = rt_i2c_r32(REG_DATAIN_REG);
+ }
+ } else {
+ if (rt_i2c_wait_idle()) {
+ dev_err(a->dev.parent, "i2c-write line busy\n");
+ return -ETIMEDOUT;
+ }
+ 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() < 0)
+ ret = rt_i2c_wait_tx_done();
+ if (rt_i2c_get_ack() < 0)
+ ret = rt_i2c_get_ack();
+ }
+ }
+
+ return ret;
+}
+
+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()) {
+ dev_err(a->dev.parent, "i2c-master_xfer line busy\n");
+ return -ETIMEDOUT;
+ }
+
+ 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 < 0)
+ return ret;
+ }
+
+ 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)
+ return -ENOMEM;
+
+ membase = devm_ioremap_resource(&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;
+
+ 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@xxxxxxxxxxxx>");
+MODULE_DESCRIPTION("Ralink I2c host driver");
+MODULE_LICENSE("GPL");
+MODULE_ALIAS("platform:Ralink-I2C");
--
1.7.10.4
--
To unsubscribe from this list: send the line "unsubscribe linux-i2c" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
