diff --git a/drivers/i2c/busses/i2c-designware-core.h b/drivers/i2c/busses/i2c-designware-core.h index 347843b4f5dd..6ecd8b1aab56 100644 --- a/drivers/i2c/busses/i2c-designware-core.h +++ b/drivers/i2c/busses/i2c-designware-core.h @@ -123,7 +123,9 @@ #define DW_IC_ERR_TX_ABRT 0x1 +#define DW_IC_TAR_SPECIAL BIT(11) #define DW_IC_TAR_10BITADDR_MASTER BIT(12) +#define DW_IC_TAR_SMBUS_QUICK_CMD BIT(16) #define DW_IC_COMP_PARAM_1_SPEED_MODE_HIGH (BIT(2) | BIT(3)) #define DW_IC_COMP_PARAM_1_SPEED_MODE_MASK GENMASK(3, 2) diff --git a/drivers/i2c/busses/i2c-designware-master.c b/drivers/i2c/busses/i2c-designware-master.c index 41e9b5ecad20..38f1ecbbe98f 100644 --- a/drivers/i2c/busses/i2c-designware-master.c +++ b/drivers/i2c/busses/i2c-designware-master.c @@ -265,6 +265,10 @@ static void i2c_dw_xfer_init(struct dw_i2c_dev *dev) ic_tar = DW_IC_TAR_10BITADDR_MASTER; } + /* Convert a zero-length read into an SMBUS quick command */ + if (!msgs[dev->msg_write_idx].len) + ic_tar = DW_IC_TAR_SPECIAL | DW_IC_TAR_SMBUS_QUICK_CMD; + regmap_update_bits(dev->map, DW_IC_CON, DW_IC_CON_10BITADDR_MASTER, ic_con); @@ -475,6 +479,14 @@ i2c_dw_xfer_msg(struct dw_i2c_dev *dev) regmap_read(dev->map, DW_IC_RXFLR, &flr); rx_limit = dev->rx_fifo_depth - flr; + /* Handle SMBUS quick commands */ + if (!buf_len) { + if (msgs[dev->msg_write_idx].flags & I2C_M_RD) + regmap_write(dev->map, DW_IC_DATA_CMD, 0x300); + else + regmap_write(dev->map, DW_IC_DATA_CMD, 0x200); + } + while (buf_len > 0 && tx_limit > 0 && rx_limit > 0) { u32 cmd = 0; @@ -912,14 +924,15 @@ static const struct i2c_algorithm i2c_dw_algo = { }; static const struct i2c_adapter_quirks i2c_dw_quirks = { - .flags = I2C_AQ_NO_ZERO_LEN, + .flags = 0, }; void i2c_dw_configure_master(struct dw_i2c_dev *dev) { struct i2c_timings *t = &dev->timings; - dev->functionality = I2C_FUNC_10BIT_ADDR | DW_IC_DEFAULT_FUNCTIONALITY; + dev->functionality = I2C_FUNC_10BIT_ADDR | I2C_FUNC_SMBUS_QUICK | + DW_IC_DEFAULT_FUNCTIONALITY; dev->master_cfg = DW_IC_CON_MASTER | DW_IC_CON_SLAVE_DISABLE | DW_IC_CON_RESTART_EN;