From b7f625840267b18ef1011cba0085bb7e237d76f7 Mon Sep 17 00:00:00 2001 From: Wolfram Sang Date: Mon, 5 Jan 2015 23:45:59 +0100 Subject: [PATCH] i2c: add quirk checks to core Let the core do the checks if HW quirks prevent a transfer. Saves code from drivers and adds consistency. Signed-off-by: Wolfram Sang Tested-by: Ray Jui Tested-by: Ivan T. Ivanov Tested-by: Neelesh Gupta Tested-By: Ludovic Desroches --- drivers/i2c/i2c-core.c | 62 ++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 62 insertions(+) diff --git a/drivers/i2c/i2c-core.c b/drivers/i2c/i2c-core.c index 210cf4874cb7..57a86f4aab43 100644 --- a/drivers/i2c/i2c-core.c +++ b/drivers/i2c/i2c-core.c @@ -1929,6 +1929,65 @@ module_exit(i2c_exit); * ---------------------------------------------------- */ +/* Check if val is exceeding the quirk IFF quirk is non 0 */ +#define i2c_quirk_exceeded(val, quirk) ((quirk) && ((val) > (quirk))) + +static int i2c_quirk_error(struct i2c_adapter *adap, struct i2c_msg *msg, char *err_msg) +{ + dev_err_ratelimited(&adap->dev, "adapter quirk: %s (addr 0x%04x, size %u, %s)\n", + err_msg, msg->addr, msg->len, + msg->flags & I2C_M_RD ? "read" : "write"); + return -EOPNOTSUPP; +} + +static int i2c_check_for_quirks(struct i2c_adapter *adap, struct i2c_msg *msgs, int num) +{ + const struct i2c_adapter_quirks *q = adap->quirks; + int max_num = q->max_num_msgs, i; + bool do_len_check = true; + + if (q->flags & I2C_AQ_COMB) { + max_num = 2; + + /* special checks for combined messages */ + if (num == 2) { + if (q->flags & I2C_AQ_COMB_WRITE_FIRST && msgs[0].flags & I2C_M_RD) + return i2c_quirk_error(adap, &msgs[0], "1st comb msg must be write"); + + if (q->flags & I2C_AQ_COMB_READ_SECOND && !(msgs[1].flags & I2C_M_RD)) + return i2c_quirk_error(adap, &msgs[1], "2nd comb msg must be read"); + + if (q->flags & I2C_AQ_COMB_SAME_ADDR && msgs[0].addr != msgs[1].addr) + return i2c_quirk_error(adap, &msgs[0], "comb msg only to same addr"); + + if (i2c_quirk_exceeded(msgs[0].len, q->max_comb_1st_msg_len)) + return i2c_quirk_error(adap, &msgs[0], "msg too long"); + + if (i2c_quirk_exceeded(msgs[1].len, q->max_comb_2nd_msg_len)) + return i2c_quirk_error(adap, &msgs[1], "msg too long"); + + do_len_check = false; + } + } + + if (i2c_quirk_exceeded(num, max_num)) + return i2c_quirk_error(adap, &msgs[0], "too many messages"); + + for (i = 0; i < num; i++) { + u16 len = msgs[i].len; + + if (msgs[i].flags & I2C_M_RD) { + if (do_len_check && i2c_quirk_exceeded(len, q->max_read_len)) + return i2c_quirk_error(adap, &msgs[i], "msg too long"); + } else { + if (do_len_check && i2c_quirk_exceeded(len, q->max_write_len)) + return i2c_quirk_error(adap, &msgs[i], "msg too long"); + } + } + + return 0; +} + /** * __i2c_transfer - unlocked flavor of i2c_transfer * @adap: Handle to I2C bus @@ -1946,6 +2005,9 @@ int __i2c_transfer(struct i2c_adapter *adap, struct i2c_msg *msgs, int num) unsigned long orig_jiffies; int ret, try; + if (adap->quirks && i2c_check_for_quirks(adap, msgs, num)) + return -EOPNOTSUPP; + /* i2c_trace_msg gets enabled when tracepoint i2c_transfer gets * enabled. This is an efficient way of keeping the for-loop from * being executed when not needed. -- GitLab