summaryrefslogtreecommitdiff
path: root/drivers/i2c/i2c-core.c
diff options
context:
space:
mode:
authorWolfram Sang <wsa@the-dreams.de>2015-01-06 01:45:59 +0300
committerWolfram Sang <wsa@the-dreams.de>2015-03-13 17:10:44 +0300
commitb7f625840267b18ef1011cba0085bb7e237d76f7 (patch)
treeabc1b0d0ed98c147c6a0bc60f3fd30ed89ec3c73 /drivers/i2c/i2c-core.c
parent2187f03a9576c4fb8342deed912b5ba6fcf98cba (diff)
downloadlinux-b7f625840267b18ef1011cba0085bb7e237d76f7.tar.xz
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 <wsa@the-dreams.de> Tested-by: Ray Jui <rjui@broadcom.com> Tested-by: Ivan T. Ivanov <iivanov@mm-sol.com> Tested-by: Neelesh Gupta <neelegup@linux.vnet.ibm.com> Tested-By: Ludovic Desroches <ludovic.desroches@atmel.com>
Diffstat (limited to 'drivers/i2c/i2c-core.c')
-rw-r--r--drivers/i2c/i2c-core.c62
1 files changed, 62 insertions, 0 deletions
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.