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> Wow, this is much simpler than the other approach flying around: http://patchwork.ozlabs.org/patch/1124048/ Can this one be master and slave on the same bus, too? CCing the author of the other patch. > --- > 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 */ > }; > > 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__); > + > + /* 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; > + 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; > + 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 */ > + 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); > + } > + } else { > + if (!(ctl & I2CR_MTX)) { /* Receive mode */ > + 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 */ > + 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); > + } > + } > + } > + 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; > + > + dev_dbg(&i2c_imx->adapter.dev, "<%s>\n", __func__); > + i2c_imx->slave = client; > + > + i2c_imx_slave_init(i2c_imx); > + > + return 0; > +} > + > +static int i2c_imx_unreg_slave(struct i2c_client *client) > +{ > + struct imx_i2c_struct *i2c_imx = i2c_get_adapdata(client->adapter); > + > + if (!i2c_imx->slave) > + return -EINVAL; > + > + i2c_imx->slave = NULL; > + > + return 0; > +} > +#endif /* CONFIG_I2C_SLAVE */ > + > static const struct i2c_algorithm i2c_imx_algo = { > .master_xfer = i2c_imx_xfer, > .functionality = i2c_imx_func, > +#if IS_ENABLED(CONFIG_I2C_SLAVE) > + .reg_slave = i2c_imx_reg_slave, > + .unreg_slave = i2c_imx_unreg_slave, > +#endif /* CONFIG_I2C_SLAVE */ > }; > > +static irqreturn_t i2c_imx_isr(int irq, void *dev_id) > +{ > + struct imx_i2c_struct *i2c_imx = dev_id; > + unsigned int status, ctl; > + irqreturn_t irq_status = 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_IIF) { > + i2c_imx_clr_if_bit(i2c_imx); > +#if IS_ENABLED(CONFIG_I2C_SLAVE) > + if (ctl & I2CR_MSTA) > + irq_status = i2c_imx_master_isr(i2c_imx); > + else > + irq_status = i2c_imx_slave_isr(i2c_imx); > +#else > + irq_status = i2c_imx_master_isr(i2c_imx); > + > +#endif /* CONFIG_I2C_SLAVE */ > + } > + > + return irq_status; > +} > + > static int i2c_imx_probe(struct platform_device *pdev) > { > const struct of_device_id *of_id = of_match_device(i2c_imx_dt_ids, > -- > 2.17.1 >
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