Hi Kevin Paul,
On Tue, Dec 22, 2020 at 11:48:50AM -0800, Kevin Paul Herbert wrote:
> Only the Layerscape SoCs have interrupts on bus idle, which facilitate
> sending events which complete slave bus transactions.
>
> Add support for synthesizing missing events. If we see a master request,
> or a newly addressed slave request, if the last event sent to the backend
> was I2C_SLAVE_READ_REQUESTED, send the backend a I2C_SLAVE_READ_PROCESSED
> followed by I2C_SLAVE_STOP. For all other events, send an I2C_SLAVE_STOP.
>
> Signed-off-by: Kevin Paul Herbert <kph@xxxxxxxxxxxxxxxxxx>
> ---
> drivers/i2c/busses/i2c-imx.c | 59 +++++++++++++++++++++++++++++++-----
> 1 file changed, 52 insertions(+), 7 deletions(-)
>
> diff --git a/drivers/i2c/busses/i2c-imx.c b/drivers/i2c/busses/i2c-imx.c
> index b444fbf1a262..b3e2a6a7fc19 100644
> --- a/drivers/i2c/busses/i2c-imx.c
> +++ b/drivers/i2c/busses/i2c-imx.c
> @@ -209,6 +209,7 @@ struct imx_i2c_struct {
>
> struct imx_i2c_dma *dma;
> struct i2c_client *slave;
> + enum i2c_slave_event last_slave_event;
> };
>
> static const struct imx_i2c_hwdata imx1_i2c_hwdata = {
> @@ -662,6 +663,36 @@ static void i2c_imx_enable_bus_idle(struct imx_i2c_struct *i2c_imx)
> }
> }
>
> +static void i2c_imx_slave_event(struct imx_i2c_struct *i2c_imx,
> + enum i2c_slave_event event, u8 *val)
> +{
> + i2c_slave_event(i2c_imx->slave, event, val);
> + i2c_imx->last_slave_event = event;
> +}
> +
> +static void i2c_imx_slave_finish_op(struct imx_i2c_struct *i2c_imx)
> +{
> + u8 val;
> +
> + while (i2c_imx->last_slave_event != I2C_SLAVE_STOP) {
> + switch (i2c_imx->last_slave_event) {
> + case I2C_SLAVE_READ_REQUESTED:
> + i2c_imx_slave_event(i2c_imx, I2C_SLAVE_READ_PROCESSED,
> + &val);
> + break;
> +
> + case I2C_SLAVE_WRITE_REQUESTED:
> + case I2C_SLAVE_READ_PROCESSED:
> + case I2C_SLAVE_WRITE_RECEIVED:
> + i2c_imx_slave_event(i2c_imx, I2C_SLAVE_STOP, &val);
> + break;
> +
> + case I2C_SLAVE_STOP:
> + break;
> + }
> + }
> +}
Is it really working code?
The i2c_imx_slave_finish_op() is a waiting busy loop withing an IRQ! And
it is waiting for an event, which is updated in the same IRQ callback.
Or am i missing some thing?
Regards,
Oleksij
> static irqreturn_t i2c_imx_slave_isr(struct imx_i2c_struct *i2c_imx,
> unsigned int status, unsigned int ctl)
> {
> @@ -674,9 +705,11 @@ static irqreturn_t i2c_imx_slave_isr(struct imx_i2c_struct *i2c_imx,
> }
>
> if (status & I2SR_IAAS) { /* Addressed as a slave */
> + i2c_imx_slave_finish_op(i2c_imx);
> 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);
> + i2c_imx_slave_event(i2c_imx,
> + I2C_SLAVE_READ_REQUESTED, &value);
>
> /* Slave transmit */
> ctl |= I2CR_MTX;
> @@ -686,7 +719,8 @@ static irqreturn_t i2c_imx_slave_isr(struct imx_i2c_struct *i2c_imx,
> 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);
> + i2c_imx_slave_event(i2c_imx,
> + I2C_SLAVE_WRITE_REQUESTED, &value);
>
> /* Slave receive */
> ctl &= ~I2CR_MTX;
> @@ -697,17 +731,20 @@ static irqreturn_t i2c_imx_slave_isr(struct imx_i2c_struct *i2c_imx,
> } else if (!(ctl & I2CR_MTX)) { /* Receive mode */
> if (status & I2SR_IBB) { /* No STOP signal detected */
> value = imx_i2c_read_reg(i2c_imx, IMX_I2C_I2DR);
> - i2c_slave_event(i2c_imx->slave, I2C_SLAVE_WRITE_RECEIVED, &value);
> + i2c_imx_slave_event(i2c_imx,
> + 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);
> + i2c_imx_slave_event(i2c_imx,
> + I2C_SLAVE_STOP, &value);
> }
> } else if (!(status & I2SR_RXAK)) { /* Transmit mode received ACK */
> ctl |= I2CR_MTX;
> imx_i2c_write_reg(ctl, i2c_imx, IMX_I2C_I2CR);
>
> - i2c_slave_event(i2c_imx->slave, I2C_SLAVE_READ_PROCESSED, &value);
> + i2c_imx_slave_event(i2c_imx,
> + I2C_SLAVE_READ_PROCESSED, &value);
>
> imx_i2c_write_reg(value, i2c_imx, IMX_I2C_I2DR);
> } else { /* Transmit mode received NAK */
> @@ -748,6 +785,7 @@ static int i2c_imx_reg_slave(struct i2c_client *client)
> return -EBUSY;
>
> i2c_imx->slave = client;
> + i2c_imx->last_slave_event = I2C_SLAVE_STOP;
>
> /* Resume */
> ret = pm_runtime_get_sync(i2c_imx->adapter.dev.parent);
> @@ -800,10 +838,17 @@ static irqreturn_t i2c_imx_isr(int irq, void *dev_id)
>
> status = imx_i2c_read_reg(i2c_imx, IMX_I2C_I2SR);
> ctl = imx_i2c_read_reg(i2c_imx, IMX_I2C_I2CR);
> +
> if (status & I2SR_IIF) {
> i2c_imx_clear_irq(i2c_imx, I2SR_IIF);
> - if (i2c_imx->slave && !(ctl & I2CR_MSTA))
> - return i2c_imx_slave_isr(i2c_imx, status, ctl);
> + if (i2c_imx->slave) {
> + if (!(ctl & I2CR_MSTA)) {
> + return i2c_imx_slave_isr(i2c_imx, status, ctl);
> + } else if (i2c_imx->last_slave_event !=
> + I2C_SLAVE_STOP) {
> + i2c_imx_slave_finish_op(i2c_imx);
> + }
> + }
> return i2c_imx_master_isr(i2c_imx, status);
> }
>
> --
> 2.25.1
>
>
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>
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