1 files changed, 62 insertions, 3 deletions

diff --git a/drivers/clk/clk-renesas-pcie.c b/drivers/clk/clk-renesas-pcie.c
index 4f5df1fc74b4..e6247141d0c0 100644
--- a/drivers/clk/clk-renesas-pcie.c
+++ b/drivers/clk/clk-renesas-pcie.c
@@ -90,13 +90,66 @@ static const struct regmap_access_table rs9_writeable_table = {
 	.n_yes_ranges = ARRAY_SIZE(rs9_writeable_ranges),
 };
 
+static int rs9_regmap_i2c_write(void *context,
+				unsigned int reg, unsigned int val)
+{
+	struct i2c_client *i2c = context;
+	const u8 data[3] = { reg, 1, val };
+	const int count = ARRAY_SIZE(data);
+	int ret;
+
+	ret = i2c_master_send(i2c, data, count);
+	if (ret == count)
+		return 0;
+	else if (ret < 0)
+		return ret;
+	else
+		return -EIO;
+}
+
+static int rs9_regmap_i2c_read(void *context,
+			       unsigned int reg, unsigned int *val)
+{
+	struct i2c_client *i2c = context;
+	struct i2c_msg xfer[2];
+	u8 txdata = reg;
+	u8 rxdata[2];
+	int ret;
+
+	xfer[0].addr = i2c->addr;
+	xfer[0].flags = 0;
+	xfer[0].len = 1;
+	xfer[0].buf = (void *)&txdata;
+
+	xfer[1].addr = i2c->addr;
+	xfer[1].flags = I2C_M_RD;
+	xfer[1].len = 2;
+	xfer[1].buf = (void *)rxdata;
+
+	ret = i2c_transfer(i2c->adapter, xfer, 2);
+	if (ret < 0)
+		return ret;
+	if (ret != 2)
+		return -EIO;
+
+	/*
+	 * Byte 0 is transfer length, which is always 1 due
+	 * to BCP register programming to 1 in rs9_probe(),
+	 * ignore it and use data from Byte 1.
+	 */
+	*val = rxdata[1];
+	return 0;
+}
+
 static const struct regmap_config rs9_regmap_config = {
 	.reg_bits = 8,
 	.val_bits = 8,
-	.cache_type = REGCACHE_FLAT,
-	.max_register = 0x8,
+	.cache_type = REGCACHE_NONE,
+	.max_register = RS9_REG_BCP,
 	.rd_table = &rs9_readable_table,
 	.wr_table = &rs9_writeable_table,
+	.reg_write = rs9_regmap_i2c_write,
+	.reg_read = rs9_regmap_i2c_read,
 };
 
 static int rs9_get_output_config(struct rs9_driver_data *rs9, int idx)
@@ -242,11 +295,17 @@ static int rs9_probe(struct i2c_client *client)
 			return ret;
 	}
 
-	rs9->regmap = devm_regmap_init_i2c(client, &rs9_regmap_config);
+	rs9->regmap = devm_regmap_init(&client->dev, NULL,
+				       client, &rs9_regmap_config);
 	if (IS_ERR(rs9->regmap))
 		return dev_err_probe(&client->dev, PTR_ERR(rs9->regmap),
 				     "Failed to allocate register map\n");
 
+	/* Always read back 1 Byte via I2C */
+	ret = regmap_write(rs9->regmap, RS9_REG_BCP, 1);
+	if (ret < 0)
+		return ret;
+
 	/* Register clock */
 	for (i = 0; i < rs9->chip_info->num_clks; i++) {
 		snprintf(name, 5, "DIF%d", i);