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>

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.