[PATCH] optee: simplify i2c access

[Arnd Bergmann]

From: Arnd Bergmann <a...@arndb.de>

Storing a bogus i2c_client structure on the stack adds overhead and
causes a compile-time warning:

drivers/tee/optee/rpc.c:493:6: error: stack frame size of 1056 bytes in 
function 'optee_handle_rpc' [-Werror,-Wframe-larger-than=]
void optee_handle_rpc(struct tee_context *ctx, struct optee_rpc_param *param,

Change the implementation of handle_rpc_func_cmd_i2c_transfer() to
open-code the i2c_transfer() call, which makes it easier to read
and avoids the warning.

Fixes: c05210ab9757 ("drivers: optee: allow op-tee to access devices on the i2c 
bus")
Signed-off-by: Arnd Bergmann <a...@arndb.de>
---
 drivers/tee/optee/rpc.c | 31 ++++++++++++++++---------------
 1 file changed, 16 insertions(+), 15 deletions(-)

diff --git a/drivers/tee/optee/rpc.c b/drivers/tee/optee/rpc.c
index 1e3614e4798f..6cbb3643c6c4 100644
--- a/drivers/tee/optee/rpc.c
+++ b/drivers/tee/optee/rpc.c
@@ -54,8 +54,9 @@ static void handle_rpc_func_cmd_get_time(struct optee_msg_arg 
*arg)
 static void handle_rpc_func_cmd_i2c_transfer(struct tee_context *ctx,
                                             struct optee_msg_arg *arg)
 {
-       struct i2c_client client = { 0 };
        struct tee_param *params;
+       struct i2c_adapter *adapter;
+       struct i2c_msg msg = { };
        size_t i;
        int ret = -EOPNOTSUPP;
        u8 attr[] = {
@@ -85,48 +86,48 @@ static void handle_rpc_func_cmd_i2c_transfer(struct 
tee_context *ctx,
                        goto bad;
        }
 
-       client.adapter = i2c_get_adapter(params[0].u.value.b);
-       if (!client.adapter)
+       adapter = i2c_get_adapter(params[0].u.value.b);
+       if (!adapter)
                goto bad;
 
        if (params[1].u.value.a & OPTEE_MSG_RPC_CMD_I2C_FLAGS_TEN_BIT) {
-               if (!i2c_check_functionality(client.adapter,
+               if (!i2c_check_functionality(adapter,
                                             I2C_FUNC_10BIT_ADDR)) {
-                       i2c_put_adapter(client.adapter);
+                       i2c_put_adapter(adapter);
                        goto bad;
                }
 
-               client.flags = I2C_CLIENT_TEN;
+               msg.flags = I2C_M_TEN;
        }
 
-       client.addr = params[0].u.value.c;
-       snprintf(client.name, I2C_NAME_SIZE, "i2c%d", client.adapter->nr);
+       msg.addr = params[0].u.value.c;
+       msg.buf  = params[2].u.memref.shm->kaddr;
+       msg.len  = params[2].u.memref.size;
 
        switch (params[0].u.value.a) {
        case OPTEE_MSG_RPC_CMD_I2C_TRANSFER_RD:
-               ret = i2c_master_recv(&client, params[2].u.memref.shm->kaddr,
-                                     params[2].u.memref.size);
+               msg.flags |= I2C_M_RD;
                break;
        case OPTEE_MSG_RPC_CMD_I2C_TRANSFER_WR:
-               ret = i2c_master_send(&client, params[2].u.memref.shm->kaddr,
-                                     params[2].u.memref.size);
                break;
        default:
-               i2c_put_adapter(client.adapter);
+               i2c_put_adapter(adapter);
                goto bad;
        }
 
+       ret = i2c_transfer(adapter, &msg, 1);
+
        if (ret < 0) {
                arg->ret = TEEC_ERROR_COMMUNICATION;
        } else {
-               params[3].u.value.a = ret;
+               params[3].u.value.a = msg.len;
                if (optee_to_msg_param(arg->params, arg->num_params, params))
                        arg->ret = TEEC_ERROR_BAD_PARAMETERS;
                else
                        arg->ret = TEEC_SUCCESS;
        }
 
-       i2c_put_adapter(client.adapter);
+       i2c_put_adapter(adapter);
        kfree(params);
        return;
 bad:
-- 
2.29.2