Add support for the I2C bus functionality of the TI SM-USB-DIG.

Signed-off-by: Andrew F. Davis <a...@ti.com>
---
 drivers/i2c/busses/Kconfig           |  10 ++
 drivers/i2c/busses/Makefile          |   1 +
 drivers/i2c/busses/i2c-ti-smusbdig.c | 189 +++++++++++++++++++++++++++++++++++
 3 files changed, 200 insertions(+)
 create mode 100644 drivers/i2c/busses/i2c-ti-smusbdig.c

diff --git a/drivers/i2c/busses/Kconfig b/drivers/i2c/busses/Kconfig
index f167021..82be651 100644
--- a/drivers/i2c/busses/Kconfig
+++ b/drivers/i2c/busses/Kconfig
@@ -1076,6 +1076,16 @@ config I2C_ROBOTFUZZ_OSIF
          This driver can also be built as a module.  If so, the module
          will be called i2c-osif.
 
+config I2C_TI_SMUSBDIG
+       tristate "Texas Instruments SM-USB-DIG I2C interface"
+       depends on MFD_TI_SMUSBDIG
+       help
+         This adds support for the I2C bus functionality of the
+         TI SM-USB-DIG USB interface adapter.
+
+         This driver can also be built as a module.  If so, the module
+         will be called i2c-ti-smusbdig.
+
 config I2C_TAOS_EVM
        tristate "TAOS evaluation module"
        depends on TTY
diff --git a/drivers/i2c/busses/Makefile b/drivers/i2c/busses/Makefile
index 37f2819..38c0d87 100644
--- a/drivers/i2c/busses/Makefile
+++ b/drivers/i2c/busses/Makefile
@@ -103,6 +103,7 @@ obj-$(CONFIG_I2C_DLN2)              += i2c-dln2.o
 obj-$(CONFIG_I2C_PARPORT)      += i2c-parport.o
 obj-$(CONFIG_I2C_PARPORT_LIGHT)        += i2c-parport-light.o
 obj-$(CONFIG_I2C_ROBOTFUZZ_OSIF)       += i2c-robotfuzz-osif.o
+obj-$(CONFIG_I2C_TI_SMUSBDIG)  += i2c-ti-smusbdig.o
 obj-$(CONFIG_I2C_TAOS_EVM)     += i2c-taos-evm.o
 obj-$(CONFIG_I2C_TINY_USB)     += i2c-tiny-usb.o
 obj-$(CONFIG_I2C_VIPERBOARD)   += i2c-viperboard.o
diff --git a/drivers/i2c/busses/i2c-ti-smusbdig.c 
b/drivers/i2c/busses/i2c-ti-smusbdig.c
new file mode 100644
index 0000000..dfd3ca0
--- /dev/null
+++ b/drivers/i2c/busses/i2c-ti-smusbdig.c
@@ -0,0 +1,189 @@
+/*
+ * I2C bus driver for TI SM-USB-DIG
+ *
+ * Copyright (C) 2016 Texas Instruments Incorporated - http://www.ti.com/
+ *     Andrew F. Davis <a...@ti.com>
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ *
+ * This program is distributed "as is" WITHOUT ANY WARRANTY of any
+ * kind, whether expressed or implied; without even the implied warranty
+ * of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License version 2 for more details.
+ */
+
+#include <linux/i2c.h>
+#include <linux/mfd/ti-smusbdig.h>
+#include <linux/module.h>
+#include <linux/platform_device.h>
+
+/* (data size - start condition - address - ACK) / ACK after data byte */
+#define TI_SMUSBDIG_I2C_MAX_MSG ((TI_SMUSBDIG_DATA_SIZE - 3) / 2)
+
+struct ti_smusbdig_i2c {
+       struct device *dev;
+       struct ti_smusbdig_device *ti_smusbdig;
+       struct i2c_adapter adapter;
+};
+
+enum ti_smusbdig_i2c_command {
+       TI_SMUSBDIG_I2C_START = 0x3,
+       TI_SMUSBDIG_I2C_STOP = 0x4,
+       TI_SMUSBDIG_I2C_ACKM = 0x5,
+       TI_SMUSBDIG_I2C_ACKS = 0x6,
+};
+
+static void ti_smusbdig_i2c_packet_init(struct ti_smusbdig_packet *packet)
+{
+       memset(packet, 0, sizeof(*packet));
+       packet->function = TI_SMUSBDIG_I2C;
+       packet->channel = 0x1;
+}
+
+static int ti_smusbdig_i2c_xfer(struct i2c_adapter *adapter,
+                               struct i2c_msg *msgs, int num)
+{
+       struct ti_smusbdig_i2c *ti_smusbdig_i2c = i2c_get_adapdata(adapter);
+       struct ti_smusbdig_packet packet;
+       int i, j, k, ret;
+
+       for (i = 0; i < num; i++) {
+               ti_smusbdig_i2c_packet_init(&packet);
+               ti_smusbdig_packet_add_command(&packet, TI_SMUSBDIG_I2C_START);
+               /* add read bit to address if needed */
+               msgs[i].addr <<= 1;
+               if (msgs[i].flags & I2C_M_RD)
+                       msgs[i].addr |= BIT(0);
+               ti_smusbdig_packet_add_data(&packet, msgs[i].addr);
+               ti_smusbdig_packet_add_command(&packet, TI_SMUSBDIG_I2C_ACKS);
+               if (msgs[i].flags & I2C_M_RD) {
+                       for (j = 0; j < msgs[i].len; j++) {
+                               ti_smusbdig_packet_add_data(&packet, 0xff);
+                               ti_smusbdig_packet_add_command(&packet, 
TI_SMUSBDIG_I2C_ACKM);
+                       }
+               } else {
+                       for (j = 0; j < msgs[i].len; j++) {
+                               ti_smusbdig_packet_add_data(&packet, 
msgs[i].buf[j]);
+                               ti_smusbdig_packet_add_command(&packet, 
TI_SMUSBDIG_I2C_ACKS);
+                       }
+               }
+
+               ret = ti_smusbdig_xfer(ti_smusbdig_i2c->ti_smusbdig,
+                                      (u8 *)&packet, sizeof(packet));
+               if (ret)
+                       return ret;
+
+               /*
+                * now we read in any data we got during read MSGs
+                * and check ACKS
+                */
+               if (((u8 *)&packet)[2]) {
+                       num = -EPROTO;
+                       goto stop;
+               }
+               for (j = 0, k = 3; j < msgs[i].len; j++, k += 2) {
+                       if (msgs[i].flags & I2C_M_RD) {
+                               msgs[i].buf[j] = ((u8 *)&packet)[k];
+                       } else if (((u8 *)&packet)[k + 1]) {
+                               num = -EPROTO;
+                               goto stop;
+                       }
+               }
+       }
+
+stop:
+       /* send stop condition */
+       ti_smusbdig_i2c_packet_init(&packet);
+       ti_smusbdig_packet_add_command(&packet, TI_SMUSBDIG_I2C_STOP);
+       ret = ti_smusbdig_xfer(ti_smusbdig_i2c->ti_smusbdig,
+                              (u8 *)&packet, sizeof(packet));
+       if (ret)
+               return ret;
+
+       return num;
+}
+
+static u32 ti_smusbdig_i2c_func(struct i2c_adapter *adapter)
+{
+       return I2C_FUNC_I2C | I2C_FUNC_SMBUS_EMUL;
+}
+
+static const struct i2c_algorithm ti_smusbdig_i2c_algo = {
+       .master_xfer = ti_smusbdig_i2c_xfer,
+       .functionality = ti_smusbdig_i2c_func,
+};
+
+static struct i2c_adapter ti_smusbdig_i2c_adapter = {
+       .owner = THIS_MODULE,
+       .class = I2C_CLASS_HWMON,
+       .algo = &ti_smusbdig_i2c_algo,
+};
+
+static struct i2c_adapter_quirks dln2_i2c_quirks = {
+       .max_read_len = TI_SMUSBDIG_I2C_MAX_MSG,
+       .max_write_len = TI_SMUSBDIG_I2C_MAX_MSG,
+};
+
+static int ti_smusbdig_i2c_probe(struct platform_device *pdev)
+{
+       struct ti_smusbdig_i2c *ti_smusbdig_i2c;
+       struct device *dev = &pdev->dev;
+       int ret;
+
+       ti_smusbdig_i2c = devm_kzalloc(dev, sizeof(*ti_smusbdig_i2c), 
GFP_KERNEL);
+       if (!ti_smusbdig_i2c)
+               return -ENOMEM;
+
+       ti_smusbdig_i2c->dev = dev;
+       ti_smusbdig_i2c->ti_smusbdig = dev_get_drvdata(dev->parent);
+       ti_smusbdig_i2c->adapter = ti_smusbdig_i2c_adapter;
+       strlcpy(ti_smusbdig_i2c->adapter.name, dev_name(dev),
+               sizeof(ti_smusbdig_i2c->adapter.name));
+       ti_smusbdig_i2c->adapter.quirks = &dln2_i2c_quirks;
+       ti_smusbdig_i2c->adapter.dev.parent = dev;
+       ti_smusbdig_i2c->adapter.dev.of_node = dev->of_node;
+
+       i2c_set_adapdata(&ti_smusbdig_i2c->adapter, ti_smusbdig_i2c);
+       platform_set_drvdata(pdev, ti_smusbdig_i2c);
+
+       ret = i2c_add_adapter(&ti_smusbdig_i2c->adapter);
+       if (ret) {
+               dev_err(dev, "unable to add I2C adapter\n");
+               return ret;
+       }
+
+       dev_info(dev, "TI SM-USB-DIG Added: I2C Bus\n");
+
+       return 0;
+}
+
+static int ti_smusbdig_i2c_remove(struct platform_device *pdev)
+{
+       struct ti_smusbdig_i2c *ti_smusbdig_i2c = platform_get_drvdata(pdev);
+
+       i2c_del_adapter(&ti_smusbdig_i2c->adapter);
+
+       return 0;
+}
+
+static const struct platform_device_id ti_smusbdig_i2c_id_table[] = {
+       { "ti-sm-usb-dig-i2c", },
+       { /* sentinel */ }
+};
+MODULE_DEVICE_TABLE(platform, ti_smusbdig_i2c_id_table);
+
+static struct platform_driver ti_smusbdig_i2c_driver = {
+       .driver = {
+               .name = "ti-sm-usb-dig-i2c",
+       },
+       .probe = ti_smusbdig_i2c_probe,
+       .remove = ti_smusbdig_i2c_remove,
+       .id_table = ti_smusbdig_i2c_id_table,
+};
+module_platform_driver(ti_smusbdig_i2c_driver);
+
+MODULE_AUTHOR("Andrew F. Davis <a...@ti.com>");
+MODULE_DESCRIPTION("I2C bus driver for TI SM-USB-DIG interface adapter");
+MODULE_LICENSE("GPL v2");
-- 
2.8.3

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