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Commit b7f62584 authored by Wolfram Sang's avatar Wolfram Sang
Browse files

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: default avatarWolfram Sang <wsa@the-dreams.de>
Tested-by: default avatarRay Jui <rjui@broadcom.com>
Tested-by: default avatarIvan T. Ivanov <iivanov@mm-sol.com>
Tested-by: default avatarNeelesh Gupta <neelegup@linux.vnet.ibm.com>
Tested-By: default avatarLudovic Desroches <ludovic.desroches@atmel.com>
parent 2187f03a

drivers/i2c/i2c-core.c

+62 −0
Original line number Diff line number Diff line
@@ -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.