[PATCHv2 1/2] i2c: add dm_i2c_reg_clrset

[Sebastian Reichel]

Add function to apply a bitmask to an i2c register, so
that specific bits can be cleared and/or set.

Suggested-by: Simon Glass <sjg at chromium.org>
Signed-off-by: Sebastian Reichel <sebastian.reichel at collabora.com>
---
 drivers/i2c/i2c-uclass.c | 15 +++++++++++++++
 include/i2c.h            | 14 ++++++++++++++
 test/dm/i2c.c            | 29 +++++++++++++++++++++++++++++
 3 files changed, 58 insertions(+)

diff --git a/drivers/i2c/i2c-uclass.c b/drivers/i2c/i2c-uclass.c
index be56785217c3..8adcdaf86411 100644
--- a/drivers/i2c/i2c-uclass.c
+++ b/drivers/i2c/i2c-uclass.c
@@ -245,6 +245,21 @@ int dm_i2c_reg_write(struct udevice *dev, uint offset, uint value)
 	return dm_i2c_write(dev, offset, &val, 1);
 }
 
+int dm_i2c_reg_clrset(struct udevice *dev, uint offset, u32 clr, u32 set)
+{
+	uint8_t val;
+	int ret;
+
+	ret = dm_i2c_read(dev, offset, &val, 1);
+	if (ret < 0)
+		return ret;
+
+	val &= ~clr;
+	val |= set;
+
+	return dm_i2c_write(dev, offset, &val, 1);
+}
+
 /**
  * i2c_probe_chip() - probe for a chip on a bus
  *
diff --git a/include/i2c.h b/include/i2c.h
index c0fe94c1f333..4fa2222a15ae 100644
--- a/include/i2c.h
+++ b/include/i2c.h
@@ -242,6 +242,20 @@ int dm_i2c_reg_read(struct udevice *dev, uint offset);
  */
 int dm_i2c_reg_write(struct udevice *dev, uint offset, unsigned int val);
 
+/**
+ * dm_i2c_reg_clrset() - Apply bitmask to an I2C register
+ *
+ * Read value, apply bitmask and write modified value back to the
+ * given address in an I2C chip
+ *
+ * @dev:	Device to use for transfer
+ * @offset:	Address for the R/W operation
+ * @clr:	Bitmask of bits that should be cleared
+ * @set:	Bitmask of bits that should be set
+ * @return 0 on success, -ve on error
+ */
+int dm_i2c_reg_clrset(struct udevice *dev, uint offset, u32 clr, u32 set);
+
 /**
  * dm_i2c_xfer() - Transfer messages over I2C
  *
diff --git a/test/dm/i2c.c b/test/dm/i2c.c
index d74f5f9fbc7c..74b209719560 100644
--- a/test/dm/i2c.c
+++ b/test/dm/i2c.c
@@ -304,3 +304,32 @@ static int dm_test_i2c_addr_offset(struct unit_test_state *uts)
 }
 
 DM_TEST(dm_test_i2c_addr_offset, UT_TESTF_SCAN_PDATA | UT_TESTF_SCAN_FDT);
+
+static int dm_test_i2c_reg_clrset(struct unit_test_state *uts)
+{
+	struct udevice *eeprom;
+	struct udevice *dev;
+	u8 buf[5];
+
+	ut_assertok(i2c_get_chip_for_busnum(busnum, chip, 1, &dev));
+
+	/* Do a transfer so we can find the emulator */
+	ut_assertok(dm_i2c_read(dev, 0, buf, 5));
+	ut_assertok(uclass_first_device(UCLASS_I2C_EMUL, &eeprom));
+
+	/* Dummy data for the test */
+	ut_assertok(dm_i2c_write(dev, 0, "\xff\x00\xff\x00\x10", 5));
+
+	/* Do some clrset tests */
+	ut_assertok(dm_i2c_reg_clrset(dev, 0, 0xff, 0x10));
+	ut_assertok(dm_i2c_reg_clrset(dev, 1, 0x00, 0x11));
+	ut_assertok(dm_i2c_reg_clrset(dev, 2, 0xed, 0x00));
+	ut_assertok(dm_i2c_reg_clrset(dev, 3, 0xff, 0x13));
+	ut_assertok(dm_i2c_reg_clrset(dev, 4, 0x00, 0x14));
+
+	ut_assertok(dm_i2c_read(dev, 0, buf, 5));
+	ut_asserteq_mem("\x10\x11\x12\x13\x14", buf, sizeof(buf));
+
+	return 0;
+}
+DM_TEST(dm_test_i2c_reg_clrset, UT_TESTF_SCAN_PDATA | UT_TESTF_SCAN_FDT);
-- 
2.30.2