From 865433df5d11aef7cfe5d51b362b6276bddb7a15 Mon Sep 17 00:00:00 2001 From: Biwen Li Date: Fri, 2 Aug 2019 17:45:56 +0800 Subject: [PATCH] i2c: imx: support slave mode for imx I2C driver The patch supports slave mode for imx I2C driver Reviewed-by: Clark Wang Signed-off-by: Biwen Li --- drivers/i2c/busses/i2c-imx.c | 219 +++++++++++++++++++++++++++++++++++++++---- 1 file changed, 201 insertions(+), 18 deletions(-) --- a/drivers/i2c/busses/i2c-imx.c +++ b/drivers/i2c/busses/i2c-imx.c @@ -265,6 +265,9 @@ struct imx_i2c_struct { int pmuxcr_set; int pmuxcr_endian; void __iomem *pmuxcr_addr; +#if IS_ENABLED(CONFIG_I2C_SLAVE) + struct i2c_client *slave; +#endif }; static const struct imx_i2c_hwdata imx1_i2c_hwdata = { @@ -357,6 +360,14 @@ static inline unsigned char imx_i2c_read return readb(i2c_imx->base + (reg << i2c_imx->hwdata->regshift)); } +/* Set up i2c controller register and i2c status register to default value. */ +static void i2c_imx_reset_regs(struct imx_i2c_struct *i2c_imx) +{ + imx_i2c_write_reg(i2c_imx->hwdata->i2cr_ien_opcode ^ I2CR_IEN, + i2c_imx, IMX_I2C_I2CR); + imx_i2c_write_reg(i2c_imx->hwdata->i2sr_clr_opcode, i2c_imx, IMX_I2C_I2SR); +} + /* Functions for DMA support */ static void i2c_imx_dma_request(struct imx_i2c_struct *i2c_imx, dma_addr_t phy_addr) @@ -705,21 +716,33 @@ static void i2c_imx_stop(struct imx_i2c_ 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(unsigned int status, struct imx_i2c_struct *i2c_imx) { - struct imx_i2c_struct *i2c_imx = dev_id; - unsigned int temp; + status &= ~I2SR_IIF; + status |= (i2c_imx->hwdata->i2sr_clr_opcode & I2SR_IIF); + imx_i2c_write_reg(status, i2c_imx, IMX_I2C_I2SR); +} - temp = imx_i2c_read_reg(i2c_imx, IMX_I2C_I2SR); - if (temp & I2SR_IIF) { - /* save status register */ - i2c_imx->i2csr = temp; - i2c_imx_clear_irq(i2c_imx, I2SR_IIF); - wake_up(&i2c_imx->queue); - return IRQ_HANDLED; - } +/* Clear arbitration lost bit */ +static void i2c_imx_clr_al_bit(unsigned int status, struct imx_i2c_struct *i2c_imx) +{ + status &= ~I2SR_IAL; + status |= (i2c_imx->hwdata->i2sr_clr_opcode & I2SR_IAL); + imx_i2c_write_reg(status, i2c_imx, IMX_I2C_I2SR); +} + +static irqreturn_t i2c_imx_master_isr(struct imx_i2c_struct *i2c_imx) +{ + unsigned int status; + + /* 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_NONE; + return IRQ_HANDLED; } static int i2c_imx_dma_write(struct imx_i2c_struct *i2c_imx, @@ -1094,6 +1117,13 @@ static int i2c_imx_xfer(struct i2c_adapt dev_dbg(&i2c_imx->adapter.dev, "<%s>\n", __func__); +#if IS_ENABLED(CONFIG_I2C_SLAVE) + if (i2c_imx->slave) { + dev_err(&i2c_imx->adapter.dev, "Please not do operations of master mode in slave mode"); + return -EBUSY; + } +#endif + if (!pm_runtime_enabled(i2c_imx->adapter.dev.parent)) { pm_runtime_enable(i2c_imx->adapter.dev.parent); enable_runtime_pm = true; @@ -1307,11 +1337,169 @@ static u32 i2c_imx_func(struct i2c_adapt | I2C_FUNC_SMBUS_READ_BLOCK_DATA; } +#if IS_ENABLED(CONFIG_I2C_SLAVE) +static int i2c_imx_slave_init(struct imx_i2c_struct *i2c_imx) +{ + int temp; + + /* Resume */ + temp = pm_runtime_get_sync(i2c_imx->adapter.dev.parent); + if (temp < 0) { + dev_err(&i2c_imx->adapter.dev, "failed to resume i2c controller"); + return temp; + } + + /* Set slave addr. */ + imx_i2c_write_reg((i2c_imx->slave->addr << 1), i2c_imx, IMX_I2C_IADR); + + i2c_imx_reset_regs(i2c_imx); + + /* Enable module */ + temp = i2c_imx->hwdata->i2cr_ien_opcode; + imx_i2c_write_reg(temp, i2c_imx, IMX_I2C_I2CR); + + /* Enable interrupt from i2c module */ + temp |= I2CR_IIEN; + imx_i2c_write_reg(temp, i2c_imx, IMX_I2C_I2CR); + + /* Wait controller to be stable */ + usleep_range(50, 150); + return 0; +} + +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(status, 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 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 */ + 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 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); + + imx_i2c_write_reg(value, i2c_imx, IMX_I2C_I2DR); + } else { /* Transmit mode received NAK */ + ctl &= ~I2CR_MTX; + imx_i2c_write_reg(ctl, i2c_imx, IMX_I2C_I2CR); + 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); + int ret; + if (i2c_imx->slave) + return -EBUSY; + + i2c_imx->slave = client; + + ret = i2c_imx_slave_init(i2c_imx); + if (ret < 0) + dev_err(&i2c_imx->adapter.dev, "failed to switch to slave mode"); + + return ret; +} + +static int i2c_imx_unreg_slave(struct i2c_client *client) +{ + struct imx_i2c_struct *i2c_imx = i2c_get_adapdata(client->adapter); + int ret; + + if (!i2c_imx->slave) + return -EINVAL; + + /* Reset slave address. */ + imx_i2c_write_reg(0, i2c_imx, IMX_I2C_IADR); + + i2c_imx_reset_regs(i2c_imx); + + i2c_imx->slave = NULL; + + /* Suspend */ + ret = pm_runtime_put_sync(i2c_imx->adapter.dev.parent); + if (ret < 0) + dev_err(&i2c_imx->adapter.dev, "failed to suspend i2c controller"); + + return ret; +} +#endif + 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 }; +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(status, i2c_imx); + if (ctl & I2CR_MSTA) + irq_status = i2c_imx_master_isr(i2c_imx); +#if IS_ENABLED(CONFIG_I2C_SLAVE) + else + irq_status = i2c_imx_slave_isr(i2c_imx); +#endif + } + + return irq_status; +} + static int i2c_imx_probe(struct platform_device *pdev) { struct imx_i2c_struct *i2c_imx; @@ -1420,10 +1608,7 @@ static int i2c_imx_probe(struct platform if (is_imx7d_i2c(i2c_imx) && i2c_imx->bitrate > IMX_I2C_MAX_E_BIT_RATE) i2c_imx->bitrate = IMX_I2C_MAX_E_BIT_RATE; - /* Set up chip registers to defaults */ - imx_i2c_write_reg(i2c_imx->hwdata->i2cr_ien_opcode ^ I2CR_IEN, - i2c_imx, IMX_I2C_I2CR); - imx_i2c_write_reg(i2c_imx->hwdata->i2sr_clr_opcode, i2c_imx, IMX_I2C_I2SR); + i2c_imx_reset_regs(i2c_imx); /* Init optional bus recovery */ if (of_match_node(pinmux_of_match, pdev->dev.of_node))