Merge branch 'i2c/for-4.19' of git://git.kernel.org/pub/scm/linux/kernel/git/wsa/linux

Pull i2c updates from Wolfram Sang:

 - the core has now a lockless variant of i2c_smbus_xfer. Some open
   coded versions of this got removed in drivers. This also enables
   proper SCCB support in regmap.

 - locking got a more precise naming. i2c_{un}lock_adapter() had to go,
   and we know use i2c_lock_bus() consistently with flags like
   I2C_LOCK_ROOT_ADAPTER and I2C_LOCK_SEGMENT to avoid ambiguity.

 - the gpio fault injector got a new delicate testcase

 - the bus recovery procedure got fixed to handle the new testcase
   correctly

 - a new quirk flag for controllers not able to handle zero length
   messages together with driver updates to use it

 - new drivers: FSI bus attached I2C masters, GENI I2C controller, Owl
   family S900

 - and a good set of driver improvements and bugfixes

* 'i2c/for-4.19' of git://git.kernel.org/pub/scm/linux/kernel/git/wsa/linux: (77 commits)
  i2c: rcar: implement STOP and REP_START according to docs
  i2c: rcar: refactor private flags
  i2c: core: ACPI: Make acpi_gsb_i2c_read_bytes() check i2c_transfer return value
  i2c: core: ACPI: Properly set status byte to 0 for multi-byte writes
  dt-bindings: i2c: rcar: Add r8a774a1 support
  dt-bindings: i2c: sh_mobile: Add r8a774a1 support
  i2c: imx: Simplify stopped state tracking
  i2c: imx: Fix race condition in dma read
  i2c: pasemi: remove hardcoded bus numbers on smbus
  i2c: designware: Add SPDX license tag
  i2c: designware: Convert to use struct i2c_timings
  i2c: core: Parse SDA hold time from firmware
  i2c: designware-pcidrv: Mark expected switch fall-through
  i2c: amd8111: Mark expected switch fall-through
  i2c: sh_mobile: use core to detect 'no zero length read' quirk
  i2c: xlr: use core to detect 'no zero length' quirk
  i2c: rcar: use core to detect 'no zero length' quirk
  i2c: stu300: use core to detect 'no zero length' quirk
  i2c: pmcmsp: use core to detect 'no zero length' quirk
  i2c: mxs: use core to detect 'no zero length' quirk
  ...

1 files changed, 5 insertions, 6 deletions

diff --git a/drivers/i2c/busses/i2c-xlr.c b/drivers/i2c/busses/i2c-xlr.c
index 484bfa15d58e..34cd4b308540 100644
--- a/drivers/i2c/busses/i2c-xlr.c
+++ b/drivers/i2c/busses/i2c-xlr.c
@@ -173,9 +173,6 @@ static int xlr_i2c_tx(struct xlr_i2c_private *priv,  u16 len,
 	u8 offset;
 	u32 xfer;
 
-	if (!len)
-		return -EOPNOTSUPP;
-
 	offset = buf[0];
 	xlr_i2c_wreg(priv->iobase, XLR_I2C_ADDR, offset);
 	xlr_i2c_wreg(priv->iobase, XLR_I2C_DEVADDR, addr);
@@ -241,9 +238,6 @@ static int xlr_i2c_rx(struct xlr_i2c_private *priv, u16 len, u8 *buf, u16 addr)
 	unsigned long timeout, stoptime, checktime;
 	int nbytes, timedout;
 
-	if (!len)
-		return -EOPNOTSUPP;
-
 	xlr_i2c_wreg(priv->iobase, XLR_I2C_CFG,
 			XLR_I2C_CFG_NOADDR | priv->cfg->cfg_extra);
 	xlr_i2c_wreg(priv->iobase, XLR_I2C_BYTECNT, len - 1);
@@ -340,6 +334,10 @@ static const struct i2c_algorithm xlr_i2c_algo = {
 	.functionality	= xlr_func,
 };
 
+static const struct i2c_adapter_quirks xlr_i2c_quirks = {
+	.flags = I2C_AQ_NO_ZERO_LEN,
+};
+
 static const struct xlr_i2c_config xlr_i2c_config_default = {
 	.status_busy	= XLR_I2C_BUS_BUSY,
 	.cfg_extra	= 0,
@@ -427,6 +425,7 @@ static int xlr_i2c_probe(struct platform_device *pdev)
 	priv->adap.owner	= THIS_MODULE;
 	priv->adap.algo_data	= priv;
 	priv->adap.algo		= &xlr_i2c_algo;
+	priv->adap.quirks	= &xlr_i2c_quirks;
 	priv->adap.nr		= pdev->id;
 	priv->adap.class	= I2C_CLASS_HWMON;
 	snprintf(priv->adap.name, sizeof(priv->adap.name), "xlr-i2c");