Remove __omap24_i2c_read/write() usage from omap_i2c_xfer() in favour of the more flexible __omap24_i2c_xfer_msg(). Consequently, these are also no longer needed when DM_I2C is enabled.
New function __omap24_i2c_xfer_msg() will take care of individual read OR write transfers with a target device. It goes through below sequence: - Program the provided Target Chip address (OMAP_I2C_SA_REG) - Program the provided Data len (OMAP_I2C_CNT_REG) - Program the provided Control register flags (OMAP_I2C_CON_REG) - Read from or Write to the provided Data buffer (OMAP_I2C_DATA_REG) For a detailed programming guide, refer to the TRM[0] (12.1.3.4 I2C Programming Guide). This patch by itself should be a transparent change. However this is needed for implementing a proper Repeated Start (Sr) functionality for i2c_msgs. Previous implementation for omap_i2c_xfer called __omap24_i2c_read/write functions, with hardcoded addr=0 and alen=0 for each i2c_msg. Each of these calls would program the registers always with a Stop bit set, not allowing for a repeated start between i2c_msgs in the same xfer(). [0]: https://www.ti.com/lit/zip/spruj28 (TRM) Signed-off-by: Aniket Limaye <a-lim...@ti.com> --- v2: - Use proper error codes in __omap24_i2c_xfer_msg() - Use proper error prints to indicate omap24xx i2c driver - Link to v1: https://lore.kernel.org/u-boot/20250304220546.866602-2-a-lim...@ti.com/ --- drivers/i2c/omap24xx_i2c.c | 143 +++++++++++++++++++++++++++++++------ 1 file changed, 123 insertions(+), 20 deletions(-) diff --git a/drivers/i2c/omap24xx_i2c.c b/drivers/i2c/omap24xx_i2c.c index 1fd5f5cc224..7c5d786e8e9 100644 --- a/drivers/i2c/omap24xx_i2c.c +++ b/drivers/i2c/omap24xx_i2c.c @@ -535,6 +535,107 @@ pr_exit: return res; } +static int __omap24_i2c_xfer_msg(void __iomem *i2c_base, int ip_rev, int waitdelay, + uchar chip, uchar *buffer, int len, u16 i2c_con_reg) +{ + int i; + u16 status; + int i2c_error = 0; + int timeout = I2C_TIMEOUT; + + if (len < 0) { + printf("%s: data len < 0\n", __func__); + return -EINVAL; + } + + if (!buffer) { + printf("%s: NULL pointer passed\n", __func__); + return -EINVAL; + } + + if (!(i2c_con_reg & I2C_CON_EN)) { + printf("%s: I2C_CON_EN not set\n", __func__); + return -EINVAL; + } + + /* Set slave address */ + omap_i2c_write_reg(i2c_base, ip_rev, chip, OMAP_I2C_SA_REG); + /* Read/Write len bytes data */ + omap_i2c_write_reg(i2c_base, ip_rev, len, OMAP_I2C_CNT_REG); + /* Configure the I2C_CON register */ + omap_i2c_write_reg(i2c_base, ip_rev, i2c_con_reg, OMAP_I2C_CON_REG); + + /* read/write data bytewise */ + for (i = 0; i < len; i++) { + status = wait_for_event(i2c_base, ip_rev, waitdelay); + /* Ignore I2C_STAT_RRDY in transmitter mode */ + if (i2c_con_reg & I2C_CON_TRX) + status &= ~I2C_STAT_RRDY; + else + status &= ~I2C_STAT_XRDY; + + /* Try to identify bus that is not padconf'd for I2C */ + if (status == I2C_STAT_XRDY) { + i2c_error = -EREMOTEIO; + printf("%s: pads on bus probably not configured (status=0x%x)\n", + __func__, status); + goto xfer_exit; + } + if (status == 0 || (status & I2C_STAT_NACK)) { + i2c_error = -EREMOTEIO; + printf("%s: error waiting for ACK (status=0x%x)\n", + __func__, status); + goto xfer_exit; + } + if (status & I2C_STAT_XRDY) { + /* Transmit data */ + omap_i2c_write_reg(i2c_base, ip_rev, + buffer[i], OMAP_I2C_DATA_REG); + omap_i2c_write_reg(i2c_base, ip_rev, + I2C_STAT_XRDY, OMAP_I2C_STAT_REG); + } + if (status & I2C_STAT_RRDY) { + /* Receive data */ + *buffer++ = omap_i2c_read_reg(i2c_base, ip_rev, + OMAP_I2C_DATA_REG); + omap_i2c_write_reg(i2c_base, ip_rev, + I2C_STAT_RRDY, OMAP_I2C_STAT_REG); + } + } + + /* + * poll ARDY bit for making sure that last byte really has been + * transferred on the bus. + */ + do { + status = wait_for_event(i2c_base, ip_rev, waitdelay); + } while (!(status & I2C_STAT_ARDY) && timeout--); + if (timeout <= 0) { + printf("%s: timed out on last byte!\n", __func__); + i2c_error = -EREMOTEIO; + goto xfer_exit; + } else { + omap_i2c_write_reg(i2c_base, ip_rev, I2C_STAT_ARDY, OMAP_I2C_STAT_REG); + } + + /* If Stop bit set, flush FIFO. */ + if (i2c_con_reg & I2C_CON_STP) + goto xfer_exit; + + return 0; + +xfer_exit: + flush_fifo(i2c_base, ip_rev); + omap_i2c_write_reg(i2c_base, ip_rev, 0xFFFF, OMAP_I2C_STAT_REG); + return i2c_error; +} + +#if !CONFIG_IS_ENABLED(DM_I2C) +/* + * The legacy I2C functions. These need to get removed once + * all users of this driver are converted to DM. + */ + /* * i2c_read: Function now uses a single I2C read transaction with bulk transfer * of the requested number of bytes (note that the 'i2c md' command @@ -828,11 +929,6 @@ wr_exit: return i2c_error; } -#if !CONFIG_IS_ENABLED(DM_I2C) -/* - * The legacy I2C functions. These need to get removed once - * all users of this driver are converted to DM. - */ static void __iomem *omap24_get_base(struct i2c_adapter *adap) { switch (adap->hwadapnr) { @@ -967,24 +1063,31 @@ static int omap_i2c_xfer(struct udevice *bus, struct i2c_msg *msg, int nmsgs) { struct omap_i2c *priv = dev_get_priv(bus); int ret; + u16 i2c_con_reg = 0; - debug("i2c_xfer: %d messages\n", nmsgs); + debug("%s: %d messages\n", __func__, nmsgs); for (; nmsgs > 0; nmsgs--, msg++) { - debug("i2c_xfer: chip=0x%x, len=0x%x\n", msg->addr, msg->len); - if (msg->flags & I2C_M_RD) { - ret = __omap24_i2c_read(priv->regs, priv->ip_rev, - priv->waitdelay, - msg->addr, 0, 0, msg->buf, - msg->len); - } else { - ret = __omap24_i2c_write(priv->regs, priv->ip_rev, - priv->waitdelay, - msg->addr, 0, 0, msg->buf, - msg->len); - } - if (ret) { - debug("i2c_write: error sending\n"); + /* Wait until bus not busy */ + if (wait_for_bb(priv->regs, priv->ip_rev, priv->waitdelay)) return -EREMOTEIO; + + /* Set Controller mode with Start and Stop bit */ + i2c_con_reg = I2C_CON_EN | I2C_CON_MST | I2C_CON_STT | I2C_CON_STP; + /* Set Transmitter/Receiver mode if it is a write/read msg */ + if (msg->flags & I2C_M_RD) + i2c_con_reg &= ~I2C_CON_TRX; + else + i2c_con_reg |= I2C_CON_TRX; + + debug("%s: chip=0x%x, len=0x%x, i2c_con_reg=0x%x\n", + __func__, msg->addr, msg->len, i2c_con_reg); + + ret = __omap24_i2c_xfer_msg(priv->regs, priv->ip_rev, priv->waitdelay, + msg->addr, msg->buf, msg->len, + i2c_con_reg); + if (ret) { + printf("%s: errored out at msg %d: %d\n", __func__, i, ret); + return ret; } } -- 2.48.1
