Hi Andrew, My patch for this (that is waiting since October 2018) has been reviewed by Peter at least once, and we agreed to make it ready for a master_xfer_irq_less() proposal. In case that proposal evolves in an actual change, then the driver will be ready for it with minimal changes. If you have improvements or comments can you do it on the patch (V2) I sent https://patchwork.ozlabs.org/patch/990283/ @Wolfram how seriously should we consider the possibility of having IRQ less and atomic safe transfers? (add Peter in CC) On Friday, February 8, 2019 2:05:07 AM CET Andrew Lunn wrote: > Not all implementations of the OCORES i2c bus master support > generating interrupts. Add support for polling the interrupt status > bit when no interrupt is defined. > > Signed-off-by: Andrew Lunn <andrew@xxxxxxx> > --- > drivers/i2c/busses/i2c-ocores.c | 64 ++++++++++++++++++++++++++------- > 1 file changed, 51 insertions(+), 13 deletions(-) > > diff --git a/drivers/i2c/busses/i2c-ocores.c > b/drivers/i2c/busses/i2c-ocores.c index d2730efe6bec..9576e842e557 100644 > --- a/drivers/i2c/busses/i2c-ocores.c > +++ b/drivers/i2c/busses/i2c-ocores.c > @@ -13,6 +13,7 @@ > */ > > #include <linux/clk.h> > +#include <linux/delay.h> > #include <linux/err.h> > #include <linux/kernel.h> > #include <linux/module.h> > @@ -40,10 +41,14 @@ struct ocores_i2c { > struct clk *clk; > int ip_clock_khz; > int bus_clock_khz; > + int flags; > void (*setreg)(struct ocores_i2c *i2c, int reg, u8 value); > u8 (*getreg)(struct ocores_i2c *i2c, int reg); > }; > > +/* flags */ > +#define I2C_FLAG_NOIRQ BIT(0) > + > /* registers */ > #define OCI2C_PRELOW 0 > #define OCI2C_PREHIGH 1 > @@ -224,6 +229,27 @@ static irqreturn_t ocores_isr(int irq, void *dev_id) > return IRQ_HANDLED; > } > > +static void ocores_poll_irq(struct ocores_i2c *i2c) > +{ > + int timeout = 500; > + u8 stat; > + > + do { > + /* delay 2-3 SCL (5-7usec for 400KHz) */ > + usleep_range(5, 7); > + stat = oc_getreg(i2c, OCI2C_STATUS); > + } while ((stat & OCI2C_STAT_TIP) && timeout--); > + > + > + if (!(stat & OCI2C_STAT_TIP)) { > + ocores_process(i2c); > + } else { > + i2c->state = STATE_ERROR; > + dev_dbg(&i2c->adap.dev, "Timeout while polling %02x\n", stat); > + oc_setreg(i2c, OCI2C_CMD, OCI2C_CMD_STOP); > + } > +} > + > static int ocores_xfer(struct i2c_adapter *adap, struct i2c_msg *msgs, int > num) { > struct ocores_i2c *i2c = i2c_get_adapdata(adap); > @@ -236,11 +262,18 @@ static int ocores_xfer(struct i2c_adapter *adap, > struct i2c_msg *msgs, int num) oc_setreg(i2c, OCI2C_DATA, > i2c_8bit_addr_from_msg(i2c->msg)); > oc_setreg(i2c, OCI2C_CMD, OCI2C_CMD_START); > > - if (wait_event_timeout(i2c->wait, (i2c->state == STATE_ERROR) || > - (i2c->state == STATE_DONE), HZ)) > + if (i2c->flags & I2C_FLAG_NOIRQ) { > + while (!((i2c->state == STATE_DONE) || > + (i2c->state == STATE_ERROR))) > + ocores_poll_irq(i2c); > return (i2c->state == STATE_DONE) ? num : -EIO; > - else > - return -ETIMEDOUT; > + } else { > + if (wait_event_timeout(i2c->wait, > + (i2c->state == STATE_ERROR) || > + (i2c->state == STATE_DONE), HZ)) > + return (i2c->state == STATE_DONE) ? num : -EIO; > + } > + return -ETIMEDOUT; > } > > static int ocores_init(struct device *dev, struct ocores_i2c *i2c) > @@ -425,14 +458,17 @@ static int ocores_i2c_probe(struct platform_device > *pdev) int ret; > int i; > > - irq = platform_get_irq(pdev, 0); > - if (irq < 0) > - return irq; > - > i2c = devm_kzalloc(&pdev->dev, sizeof(*i2c), GFP_KERNEL); > if (!i2c) > return -ENOMEM; > > + irq = platform_get_irq(pdev, 0); > + if (irq == -ENXIO) > + i2c->flags |= I2C_FLAG_NOIRQ; > + else > + if (irq < 0) > + return irq; > + > res = platform_get_resource(pdev, IORESOURCE_MEM, 0); > if (res) { > i2c->base = devm_ioremap_resource(&pdev->dev, res); > @@ -504,11 +540,13 @@ static int ocores_i2c_probe(struct platform_device > *pdev) goto err_clk; > > init_waitqueue_head(&i2c->wait); > - ret = devm_request_irq(&pdev->dev, irq, ocores_isr, 0, > - pdev->name, i2c); > - if (ret) { > - dev_err(&pdev->dev, "Cannot claim IRQ\n"); > - goto err_clk; > + if (!(i2c->flags & I2C_FLAG_NOIRQ)) { > + ret = devm_request_irq(&pdev->dev, irq, ocores_isr, 0, > + pdev->name, i2c); > + if (ret) { > + dev_err(&pdev->dev, "Cannot claim IRQ\n"); > + goto err_clk; > + } > } > > /* hook up driver to tree */
