Hi,
On Thu, Aug 08, 2019 at 11:53:43AM +0800, Biwen Li wrote:
> The patch supports slave mode for imx I2C driver
>
> Signed-off-by: Biwen Li <biwen.li@xxxxxxx>
> ---
> drivers/i2c/busses/i2c-imx.c | 199 ++++++++++++++++++++++++++++++++---
> 1 file changed, 185 insertions(+), 14 deletions(-)
>
> diff --git a/drivers/i2c/busses/i2c-imx.c b/drivers/i2c/busses/i2c-imx.c
> index b1b8b938d7f4..f7583a9fa56f 100644
> --- a/drivers/i2c/busses/i2c-imx.c
> +++ b/drivers/i2c/busses/i2c-imx.c
> @@ -202,6 +202,9 @@ struct imx_i2c_struct {
> struct pinctrl_state *pinctrl_pins_gpio;
>
> struct imx_i2c_dma *dma;
> +#if IS_ENABLED(CONFIG_I2C_SLAVE)
> + struct i2c_client *slave;
> +#endif /* CONFIG_I2C_SLAVE */
Other drivers just do a "select I2C_SLAVE" in Kconfig to get rid of
these #ifs. We should do the same.
> };
>
> static const struct imx_i2c_hwdata imx1_i2c_hwdata = {
> @@ -583,23 +586,40 @@ static void i2c_imx_stop(struct imx_i2c_struct *i2c_imx)
> imx_i2c_write_reg(temp, i2c_imx, IMX_I2C_I2CR);
> }
>
> -static irqreturn_t i2c_imx_isr(int irq, void *dev_id)
> +/* Clear interrupt flag bit */
> +static void i2c_imx_clr_if_bit(struct imx_i2c_struct *i2c_imx)
> {
> - struct imx_i2c_struct *i2c_imx = dev_id;
> - unsigned int temp;
> + unsigned int status;
>
> - temp = imx_i2c_read_reg(i2c_imx, IMX_I2C_I2SR);
> - if (temp & I2SR_IIF) {
> - /* save status register */
> - i2c_imx->i2csr = temp;
> - temp &= ~I2SR_IIF;
> - temp |= (i2c_imx->hwdata->i2sr_clr_opcode & I2SR_IIF);
> - imx_i2c_write_reg(temp, i2c_imx, IMX_I2C_I2SR);
> - wake_up(&i2c_imx->queue);
> - return IRQ_HANDLED;
> - }
> + status = imx_i2c_read_reg(i2c_imx, IMX_I2C_I2SR);
> + status &= ~I2SR_IIF;
> + status |= (i2c_imx->hwdata->i2sr_clr_opcode & I2SR_IIF);
> + imx_i2c_write_reg(status, i2c_imx, IMX_I2C_I2SR);
> +}
> +
> +/* Clear arbitration lost bit */
> +static void i2c_imx_clr_al_bit(struct imx_i2c_struct *i2c_imx)
> +{
> + unsigned int status;
> +
> + status = imx_i2c_read_reg(i2c_imx, IMX_I2C_I2SR);
> + status &= ~I2SR_IAL;
> + imx_i2c_write_reg(status, i2c_imx, IMX_I2C_I2SR);
> +}
>
> - return IRQ_NONE;
> +static irqreturn_t i2c_imx_master_isr(struct imx_i2c_struct *i2c_imx)
> +{
> + unsigned int status;
> +
> + dev_dbg(&i2c_imx->adapter.dev, "<%s>: master interrupt\n", __func__);
Generally this driver has way too many dev_dbg spread around in hot
pathes already. IMO adding more doesn't make the output more useful.
> +
> + /* Save status register */
> + status = imx_i2c_read_reg(i2c_imx, IMX_I2C_I2SR);
> + i2c_imx->i2csr = status | I2SR_IIF;
> +
> + wake_up(&i2c_imx->queue);
> +
> + return IRQ_HANDLED;
> }
>
> static int i2c_imx_dma_write(struct imx_i2c_struct *i2c_imx,
> @@ -1043,11 +1063,162 @@ static u32 i2c_imx_func(struct i2c_adapter *adapter)
> | I2C_FUNC_SMBUS_READ_BLOCK_DATA;
> }
>
> +#if IS_ENABLED(CONFIG_I2C_SLAVE)
> +static void i2c_imx_slave_init(struct imx_i2c_struct *i2c_imx)
> +{
> + unsigned int temp;
> +
> + dev_dbg(&i2c_imx->adapter.dev, "<%s>\n", __func__);
> +
> + /* Set slave addr. */
> + imx_i2c_write_reg((i2c_imx->slave->addr << 1), i2c_imx, IMX_I2C_IADR);
> +
> + /* Disable i2c module */
> + temp = i2c_imx->hwdata->i2cr_ien_opcode
> + ^ I2CR_IEN;
unnecessary line break.
> + imx_i2c_write_reg(temp, i2c_imx, IMX_I2C_I2CR);
> +
> + /* Reset status register */
> + imx_i2c_write_reg(i2c_imx->hwdata->i2sr_clr_opcode, i2c_imx,
> + IMX_I2C_I2SR);
> +
> + /* Enable module and enable interrupt from i2c module */
> + temp = i2c_imx->hwdata->i2cr_ien_opcode
> + | I2CR_IIEN;
ditto.
> + imx_i2c_write_reg(temp, i2c_imx, IMX_I2C_I2CR);
> +
> + /* Wait controller to be stable */
> + usleep_range(50, 150);
> +}
> +
> +static irqreturn_t i2c_imx_slave_isr(struct imx_i2c_struct *i2c_imx)
> +{
> + unsigned int status, ctl;
> + u8 value;
> +
> + if (!i2c_imx->slave) {
> + dev_err(&i2c_imx->adapter.dev, "cannot deal with slave irq,i2c_imx->slave is null");
> + return IRQ_NONE;
> + }
> +
> + status = imx_i2c_read_reg(i2c_imx, IMX_I2C_I2SR);
> + ctl = imx_i2c_read_reg(i2c_imx, IMX_I2C_I2CR);
> + if (status & I2SR_IAL) { /* Arbitration lost */
> + i2c_imx_clr_al_bit(i2c_imx);
> + } else if (status & I2SR_IAAS) { /* Addressed as a slave */
> + if (status & I2SR_SRW) { /* Master wants to read from us*/
> + dev_dbg(&i2c_imx->adapter.dev, "read requested");
> + i2c_slave_event(i2c_imx->slave, I2C_SLAVE_READ_REQUESTED, &value);
> +
> + /* Slave transimt */
s/transimt/transmit/
> + ctl |= I2CR_MTX;
> + imx_i2c_write_reg(ctl, i2c_imx, IMX_I2C_I2CR);
> +
> + /* Send data */
> + imx_i2c_write_reg(value, i2c_imx, IMX_I2C_I2DR);
> + } else { /* Master wants to write to us */
> + dev_dbg(&i2c_imx->adapter.dev, "write requested");
> + i2c_slave_event(i2c_imx->slave, I2C_SLAVE_WRITE_REQUESTED, &value);
> +
> + /* Slave receive */
> + ctl &= ~I2CR_MTX;
> + imx_i2c_write_reg(ctl, i2c_imx, IMX_I2C_I2CR);
> + /* Dummy read */
> + value = imx_i2c_read_reg(i2c_imx, IMX_I2C_I2DR);
value is unused, no need to assign a value to it.
> + }
> + } else {
> + if (!(ctl & I2CR_MTX)) { /* Receive mode */
Since you have an 'else' path please convert this to positive logic.
This makes it easier to read.
> + if (status & I2SR_IBB) { /* No STOP signal detected */
> + ctl &= ~I2CR_MTX;
> + imx_i2c_write_reg(ctl, i2c_imx, IMX_I2C_I2CR);
> +
> + value = imx_i2c_read_reg(i2c_imx, IMX_I2C_I2DR);
> + i2c_slave_event(i2c_imx->slave, I2C_SLAVE_WRITE_RECEIVED, &value);
> + } else { /* STOP signal is detected */
> + dev_dbg(&i2c_imx->adapter.dev,
> + "STOP signal detected");
> + i2c_slave_event(i2c_imx->slave, I2C_SLAVE_STOP, &value);
> + }
> + } else { /* Transmit mode */
> + if (!(status & I2SR_RXAK)) { /* Received ACK */
Same here.
> + ctl |= I2CR_MTX;
> + imx_i2c_write_reg(ctl, i2c_imx, IMX_I2C_I2CR);
> +
> + i2c_slave_event(i2c_imx->slave, I2C_SLAVE_READ_PROCESSED, &value);
> +
> + imx_i2c_write_reg(value, i2c_imx, IMX_I2C_I2DR);
> + } else { /* Received NAK */
> + ctl &= ~I2CR_MTX;
> + imx_i2c_write_reg(ctl, i2c_imx, IMX_I2C_I2CR);
> + value = imx_i2c_read_reg(i2c_imx, IMX_I2C_I2DR);
Also value unused.
> + }
> + }
> + }
> + return IRQ_HANDLED;
> +}
> +
> +static int i2c_imx_reg_slave(struct i2c_client *client)
> +{
> + struct imx_i2c_struct *i2c_imx = i2c_get_adapdata(client->adapter);
> +
> + if (i2c_imx->slave)
> + return -EINVAL;
Better -EBUSY?
Sascha
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