diff options
Diffstat (limited to '')
| -rw-r--r-- | drivers/i2c/busses/i2c-opal.c | 278 |
1 files changed, 278 insertions, 0 deletions
diff --git a/drivers/i2c/busses/i2c-opal.c b/drivers/i2c/busses/i2c-opal.c new file mode 100644 index 000000000..9f773b4f5 --- /dev/null +++ b/drivers/i2c/busses/i2c-opal.c @@ -0,0 +1,278 @@ +// SPDX-License-Identifier: GPL-2.0-or-later +/* + * IBM OPAL I2C driver + * Copyright (C) 2014 IBM + */ + +#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 = opal_get_async_rc(msg); + 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 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: + req.type = (msgs[1].flags & I2C_M_RD) ? + OPAL_I2C_SM_READ : OPAL_I2C_SM_WRITE; + 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; + } + + 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); + fallthrough; + 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, +}; + +/* + * For two messages, we basically support simple smbus transactions of a + * write-then-anything. + */ +static const struct i2c_adapter_quirks i2c_opal_quirks = { + .flags = I2C_AQ_COMB | I2C_AQ_COMB_WRITE_FIRST | I2C_AQ_COMB_SAME_ADDR, + .max_comb_1st_msg_len = 4, +}; + +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->quirks = &i2c_opal_quirks; + 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) + strscpy(adapter->name, pname, sizeof(adapter->name)); + else + strscpy(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"); |