3 files changed, 306 insertions, 0 deletions

diff --git a/drivers/i2c/busses/Kconfig b/drivers/i2c/busses/Kconfig
index 917c3585f45b..71ad6e11efb7 100644
--- a/drivers/i2c/busses/Kconfig
+++ b/drivers/i2c/busses/Kconfig
@@ -1044,4 +1044,15 @@ config SCx200_ACB
           This support is also available as a module.  If so, the module
           will be called scx200_acb.
 
+config I2C_OPAL
+        tristate "IBM OPAL I2C driver"
+        depends on PPC_POWERNV
+        default y
+        help
+          This exposes the PowerNV platform i2c busses to the linux i2c layer,
+          the driver is based on the OPAL interfaces.
+
+          This driver can also be built as a module. If so, the module will be
+          called as i2c-opal.
+
 endmenu
diff --git a/drivers/i2c/busses/Makefile b/drivers/i2c/busses/Makefile
index 78d56c54ba2b..e23ec815e21f 100644
--- a/drivers/i2c/busses/Makefile
+++ b/drivers/i2c/busses/Makefile
@@ -99,6 +99,7 @@ obj-$(CONFIG_I2C_ACORN)		+= i2c-acorn.o
 obj-$(CONFIG_I2C_BCM_KONA)      += i2c-bcm-kona.o
 obj-$(CONFIG_I2C_CROS_EC_TUNNEL)        += i2c-cros-ec-tunnel.o
 obj-$(CONFIG_I2C_ELEKTOR)       += i2c-elektor.o
+obj-$(CONFIG_I2C_OPAL)          += i2c-opal.o
 obj-$(CONFIG_I2C_PCA_ISA)       += i2c-pca-isa.o
 obj-$(CONFIG_I2C_SIBYTE)        += i2c-sibyte.o
 obj-$(CONFIG_SCx200_ACB)        += scx200_acb.o
diff --git a/drivers/i2c/busses/i2c-opal.c b/drivers/i2c/busses/i2c-opal.c
new file mode 100644
index 000000000000..16f90b1a7508
--- /dev/null
+++ b/drivers/i2c/busses/i2c-opal.c
@@ -0,0 +1,294 @@
+/*
+ * IBM OPAL I2C driver
+ * Copyright (C) 2014 IBM
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * 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.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.
+ */
+
+#include <linux/device.h>
+#include <linux/i2c.h>
+#include <linux/kernel.h>
+#include <linux/mm.h>
+#include <linux/module.h>
+#include <linux/of.h>
+#include <linux/platform_device.h>
+#include <linux/slab.h>
+
+#include <asm/firmware.h>
+#include <asm/opal.h>
+
+static int i2c_opal_translate_error(int rc)
+{
+        switch (rc) {
+        case OPAL_NO_MEM:
+                return -ENOMEM;
+        case OPAL_PARAMETER:
+                return -EINVAL;
+        case OPAL_I2C_ARBT_LOST:
+                return -EAGAIN;
+        case OPAL_I2C_TIMEOUT:
+                return -ETIMEDOUT;
+        case OPAL_I2C_NACK_RCVD:
+                return -ENXIO;
+        case OPAL_I2C_STOP_ERR:
+                return -EBUSY;
+        default:
+                return -EIO;
+        }
+}
+
+static int i2c_opal_send_request(u32 bus_id, struct opal_i2c_request *req)
+{
+        struct opal_msg msg;
+        int token, rc;
+
+        token = opal_async_get_token_interruptible();
+        if (token < 0) {
+                if (token != -ERESTARTSYS)
+                        pr_err("Failed to get the async token\n");
+
+                return token;
+        }
+
+        rc = opal_i2c_request(token, bus_id, req);
+        if (rc != OPAL_ASYNC_COMPLETION) {
+                rc = i2c_opal_translate_error(rc);
+                goto exit;
+        }
+
+        rc = opal_async_wait_response(token, &msg);
+        if (rc)
+                goto exit;
+
+        rc = be64_to_cpu(msg.params[1]);
+        if (rc != OPAL_SUCCESS) {
+                rc = i2c_opal_translate_error(rc);
+                goto exit;
+        }
+
+exit:
+        opal_async_release_token(token);
+        return rc;
+}
+
+static int i2c_opal_master_xfer(struct i2c_adapter *adap, struct i2c_msg *msgs,
+                                int num)
+{
+        unsigned long opal_id = (unsigned long)adap->algo_data;
+        struct opal_i2c_request req;
+        int rc, i;
+
+        /* We only support fairly simple combinations here of one
+         * or two messages
+         */
+        memset(&req, 0, sizeof(req));
+        switch(num) {
+        case 0:
+                return 0;
+        case 1:
+                req.type = (msgs[0].flags & I2C_M_RD) ?
+                        OPAL_I2C_RAW_READ : OPAL_I2C_RAW_WRITE;
+                req.addr = cpu_to_be16(msgs[0].addr);
+                req.size = cpu_to_be32(msgs[0].len);
+                req.buffer_ra = cpu_to_be64(__pa(msgs[0].buf));
+                break;
+        case 2:
+                /* For two messages, we basically support only simple
+                 * smbus transactions of a write plus a read. We might
+                 * want to allow also two writes but we'd have to bounce
+                 * the data into a single buffer.
+                 */
+                if ((msgs[0].flags & I2C_M_RD) || !(msgs[1].flags & I2C_M_RD))
+                        return -EOPNOTSUPP;
+                if (msgs[0].len > 4)
+                        return -EOPNOTSUPP;
+                if (msgs[0].addr != msgs[1].addr)
+                        return -EOPNOTSUPP;
+                req.type = OPAL_I2C_SM_READ;
+                req.addr = cpu_to_be16(msgs[0].addr);
+                req.subaddr_sz = msgs[0].len;
+                for (i = 0; i < msgs[0].len; i++)
+                        req.subaddr = (req.subaddr << 8) | msgs[0].buf[i];
+                req.subaddr = cpu_to_be32(req.subaddr);
+                req.size = cpu_to_be32(msgs[1].len);
+                req.buffer_ra = cpu_to_be64(__pa(msgs[1].buf));
+                break;
+        default:
+                return -EOPNOTSUPP;
+        }
+
+        rc = i2c_opal_send_request(opal_id, &req);
+        if (rc)
+                return rc;
+
+        return num;
+}
+
+static int i2c_opal_smbus_xfer(struct i2c_adapter *adap, u16 addr,
+                               unsigned short flags, char read_write,
+                               u8 command, int size, union i2c_smbus_data *data)
+{
+        unsigned long opal_id = (unsigned long)adap->algo_data;
+        struct opal_i2c_request req;
+        u8 local[2];
+        int rc;
+
+        memset(&req, 0, sizeof(req));
+
+        req.addr = cpu_to_be16(addr);
+        switch (size) {
+        case I2C_SMBUS_BYTE:
+                req.buffer_ra = cpu_to_be64(__pa(&data->byte));
+                req.size = cpu_to_be32(1);
+                /* Fall through */
+        case I2C_SMBUS_QUICK:
+                req.type = (read_write == I2C_SMBUS_READ) ?
+                        OPAL_I2C_RAW_READ : OPAL_I2C_RAW_WRITE;
+                break;
+        case I2C_SMBUS_BYTE_DATA:
+                req.buffer_ra = cpu_to_be64(__pa(&data->byte));
+                req.size = cpu_to_be32(1);
+                req.subaddr = cpu_to_be32(command);
+                req.subaddr_sz = 1;
+                req.type = (read_write == I2C_SMBUS_READ) ?
+                        OPAL_I2C_SM_READ : OPAL_I2C_SM_WRITE;
+                break;
+        case I2C_SMBUS_WORD_DATA:
+                if (!read_write) {
+                        local[0] = data->word & 0xff;
+                        local[1] = (data->word >> 8) & 0xff;
+                }
+                req.buffer_ra = cpu_to_be64(__pa(local));
+                req.size = cpu_to_be32(2);
+                req.subaddr = cpu_to_be32(command);
+                req.subaddr_sz = 1;
+                req.type = (read_write == I2C_SMBUS_READ) ?
+                        OPAL_I2C_SM_READ : OPAL_I2C_SM_WRITE;
+                break;
+        case I2C_SMBUS_I2C_BLOCK_DATA:
+                req.buffer_ra = cpu_to_be64(__pa(&data->block[1]));
+                req.size = cpu_to_be32(data->block[0]);
+                req.subaddr = cpu_to_be32(command);
+                req.subaddr_sz = 1;
+                req.type = (read_write == I2C_SMBUS_READ) ?
+                        OPAL_I2C_SM_READ : OPAL_I2C_SM_WRITE;
+                break;
+        default:
+                return -EINVAL;
+        }
+
+        rc = i2c_opal_send_request(opal_id, &req);
+        if (!rc && read_write && size == I2C_SMBUS_WORD_DATA) {
+                data->word = ((u16)local[1]) << 8;
+                data->word |= local[0];
+        }
+
+        return rc;
+}
+
+static u32 i2c_opal_func(struct i2c_adapter *adapter)
+{
+        return I2C_FUNC_I2C | I2C_FUNC_SMBUS_QUICK | I2C_FUNC_SMBUS_BYTE |
+               I2C_FUNC_SMBUS_BYTE_DATA | I2C_FUNC_SMBUS_WORD_DATA |
+               I2C_FUNC_SMBUS_I2C_BLOCK;
+}
+
+static const struct i2c_algorithm i2c_opal_algo = {
+        .master_xfer    = i2c_opal_master_xfer,
+        .smbus_xfer     = i2c_opal_smbus_xfer,
+        .functionality  = i2c_opal_func,
+};
+
+static int i2c_opal_probe(struct platform_device *pdev)
+{
+        struct i2c_adapter      *adapter;
+        const char              *pname;
+        u32                     opal_id;
+        int                     rc;
+
+        if (!pdev->dev.of_node)
+                return -ENODEV;
+
+        rc = of_property_read_u32(pdev->dev.of_node, "ibm,opal-id", &opal_id);
+        if (rc) {
+                dev_err(&pdev->dev, "Missing ibm,opal-id property !\n");
+                return -EIO;
+        }
+
+        adapter = devm_kzalloc(&pdev->dev, sizeof(*adapter), GFP_KERNEL);
+        if (!adapter)
+                return -ENOMEM;
+
+        adapter->algo = &i2c_opal_algo;
+        adapter->algo_data = (void *)(unsigned long)opal_id;
+        adapter->dev.parent = &pdev->dev;
+        adapter->dev.of_node = of_node_get(pdev->dev.of_node);
+        pname = of_get_property(pdev->dev.of_node, "ibm,port-name", NULL);
+        if (pname)
+                strlcpy(adapter->name, pname, sizeof(adapter->name));
+        else
+                strlcpy(adapter->name, "opal", sizeof(adapter->name));
+
+        platform_set_drvdata(pdev, adapter);
+        rc = i2c_add_adapter(adapter);
+        if (rc)
+                dev_err(&pdev->dev, "Failed to register the i2c adapter\n");
+
+        return rc;
+}
+
+static int i2c_opal_remove(struct platform_device *pdev)
+{
+        struct i2c_adapter *adapter = platform_get_drvdata(pdev);
+
+        i2c_del_adapter(adapter);
+
+        return 0;
+}
+
+static const struct of_device_id i2c_opal_of_match[] = {
+        {
+                .compatible = "ibm,opal-i2c",
+        },
+        { }
+};
+MODULE_DEVICE_TABLE(of, i2c_opal_of_match);
+
+static struct platform_driver i2c_opal_driver = {
+        .probe  = i2c_opal_probe,
+        .remove = i2c_opal_remove,
+        .driver = {
+                .name           = "i2c-opal",
+                .of_match_table = i2c_opal_of_match,
+        },
+};
+
+static int __init i2c_opal_init(void)
+{
+        if (!firmware_has_feature(FW_FEATURE_OPAL))
+                return -ENODEV;
+
+        return platform_driver_register(&i2c_opal_driver);
+}
+module_init(i2c_opal_init);
+
+static void __exit i2c_opal_exit(void)
+{
+        return platform_driver_unregister(&i2c_opal_driver);
+}
+module_exit(i2c_opal_exit);
+
+MODULE_AUTHOR("Neelesh Gupta <neelegup@linux.vnet.ibm.com>");
+MODULE_DESCRIPTION("IBM OPAL I2C driver");
+MODULE_LICENSE("GPL");