From 611b7eb19d0a305d4de00280e4a71a1b15c507fc Mon Sep 17 00:00:00 2001 From: Jim Wylder Date: Thu, 23 May 2024 16:14:36 -0500 Subject: regmap-i2c: Subtract reg size from max_write Currently, when an adapter defines a max_write_len quirk, the data will be chunked into data sizes equal to the max_write_len quirk value. But the payload will be increased by the size of the register address before transmission. The resulting value always ends up larger than the limit set by the quirk. Avoid this error by setting regmap's max_write to the quirk's max_write_len minus the number of bytes for the register and padding. This allows the chunking to work correctly for this limited case without impacting other use-cases. Signed-off-by: Jim Wylder Link: https://msgid.link/r/20240523211437.2839942-1-jwylder@google.com Signed-off-by: Mark Brown --- drivers/base/regmap/regmap-i2c.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) (limited to 'drivers') diff --git a/drivers/base/regmap/regmap-i2c.c b/drivers/base/regmap/regmap-i2c.c index 3ec611dc0c09..a905e955bbfc 100644 --- a/drivers/base/regmap/regmap-i2c.c +++ b/drivers/base/regmap/regmap-i2c.c @@ -350,7 +350,8 @@ static const struct regmap_bus *regmap_get_i2c_bus(struct i2c_client *i2c, if (quirks->max_write_len && (bus->max_raw_write == 0 || bus->max_raw_write > quirks->max_write_len)) - max_write = quirks->max_write_len; + max_write = quirks->max_write_len - + (config->reg_bits + config->pad_bits) / BITS_PER_BYTE; if (max_read || max_write) { ret_bus = kmemdup(bus, sizeof(*bus), GFP_KERNEL); -- cgit v1.2.3