From: Biwen Li <biwen.li@xxxxxxx> The patch supports slave mode for imx I2C driver Signed-off-by: Biwen Li <biwen.li@xxxxxxx> --- Change in v10: - totally remove CONFIG_I2C_SLAVE - replace api with i2c_imx_clart_irq() - remove robust code - place pm_runtime_get in i2c_imx_slave_init() to i2c_imx_reg_slave() - apply the patch on top of this patch set: [PATCH v6 0/3] i2c: imx: Fix handling of arbitration loss https://lkml.org/lkml/2020/10/9/407 Change in v9: - remove #ifdef after select I2C_SLAVE by default Change in v8: - fix build issue Change in v7: - support auto switch mode between master and slave - enable interrupt when idle in slave mode - remove #ifdef Change in v6: - delete robust logs and comments - not read status register again in master isr. Change in v5: - fix a bug that cannot determine in what mode(master mode or slave mode) Change in v4: - add MACRO CONFIG_I2C_SLAVE to fix compilation issue Change in v3: - support layerscape and i.mx platform Change in v2: - remove MACRO CONFIG_I2C_SLAVE drivers/i2c/busses/Kconfig | 1 + drivers/i2c/busses/i2c-imx.c | 219 +++++++++++++++++++++++++++++++---- 2 files changed, 196 insertions(+), 24 deletions(-) diff --git a/drivers/i2c/busses/Kconfig b/drivers/i2c/busses/Kconfig index a97a9d058198..e2ad62481f25 100644 --- a/drivers/i2c/busses/Kconfig +++ b/drivers/i2c/busses/Kconfig @@ -675,6 +675,7 @@ config I2C_IMG config I2C_IMX tristate "IMX I2C interface" depends on ARCH_MXC || ARCH_LAYERSCAPE || COLDFIRE + select I2C_SLAVE help Say Y here if you want to use the IIC bus controller on the Freescale i.MX/MXC, Layerscape or ColdFire processors. diff --git a/drivers/i2c/busses/i2c-imx.c b/drivers/i2c/busses/i2c-imx.c index e6f8d6e45a15..a8e8af57e33f 100644 --- a/drivers/i2c/busses/i2c-imx.c +++ b/drivers/i2c/busses/i2c-imx.c @@ -17,6 +17,7 @@ * Copyright (C) 2008 Darius Augulis <darius.augulis at teltonika.lt> * * Copyright 2013 Freescale Semiconductor, Inc. + * Copyright 2020 NXP * */ @@ -73,6 +74,11 @@ #define IMX_I2C_I2SR 0x03 /* i2c status */ #define IMX_I2C_I2DR 0x04 /* i2c transfer data */ +/* + * All of the layerscape series SoCs support IBIC register. + */ +#define IMX_I2C_IBIC 0x05 /* i2c bus interrupt config */ + #define IMX_I2C_REGSHIFT 2 #define VF610_I2C_REGSHIFT 0 @@ -91,6 +97,7 @@ #define I2CR_MSTA 0x20 #define I2CR_IIEN 0x40 #define I2CR_IEN 0x80 +#define IBIC_BIIE 0x80 /* Bus idle interrupt enable */ /* register bits different operating codes definition: * 1) I2SR: Interrupt flags clear operation differ between SoCs: @@ -201,6 +208,7 @@ struct imx_i2c_struct { struct pinctrl_state *pinctrl_pins_gpio; struct imx_i2c_dma *dma; + struct i2c_client *slave; }; static const struct imx_i2c_hwdata imx1_i2c_hwdata = { @@ -265,6 +273,11 @@ static inline int is_imx1_i2c(struct imx_i2c_struct *i2c_imx) return i2c_imx->hwdata->devtype == IMX1_I2C; } +static inline int is_vf610_i2c(struct imx_i2c_struct *i2c_imx) +{ + return i2c_imx->hwdata->devtype == VF610_I2C; +} + static inline void imx_i2c_write_reg(unsigned int val, struct imx_i2c_struct *i2c_imx, unsigned int reg) { @@ -277,6 +290,27 @@ static inline unsigned char imx_i2c_read_reg(struct imx_i2c_struct *i2c_imx, return readb(i2c_imx->base + (reg << i2c_imx->hwdata->regshift)); } +static void i2c_imx_clear_irq(struct imx_i2c_struct *i2c_imx, unsigned int bits) +{ + unsigned int temp; + + /* + * i2sr_clr_opcode is the value to clear all interrupts. Here we want to + * clear only <bits>, so we write ~i2sr_clr_opcode with just <bits> + * toggled. This is required because i.MX needs W0C and Vybrid uses W1C. + */ + temp = ~i2c_imx->hwdata->i2sr_clr_opcode ^ bits; + imx_i2c_write_reg(temp, i2c_imx, IMX_I2C_I2SR); +} + +/* 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); + i2c_imx_clear_irq(i2c_imx, I2SR_IIF | I2SR_IAL); +} + /* Functions for DMA support */ static void i2c_imx_dma_request(struct imx_i2c_struct *i2c_imx, dma_addr_t phy_addr) @@ -412,19 +446,6 @@ static void i2c_imx_dma_free(struct imx_i2c_struct *i2c_imx) dma->chan_using = NULL; } -static void i2c_imx_clear_irq(struct imx_i2c_struct *i2c_imx, unsigned int bits) -{ - unsigned int temp; - - /* - * i2sr_clr_opcode is the value to clear all interrupts. Here we want to - * clear only <bits>, so we write ~i2sr_clr_opcode with just <bits> - * toggled. This is required because i.MX needs W0C and Vybrid uses W1C. - */ - temp = ~i2c_imx->hwdata->i2sr_clr_opcode ^ bits; - imx_i2c_write_reg(temp, i2c_imx, IMX_I2C_I2SR); -} - static int i2c_imx_bus_busy(struct imx_i2c_struct *i2c_imx, int for_busy, bool atomic) { unsigned long orig_jiffies = jiffies; @@ -638,18 +659,165 @@ static void i2c_imx_stop(struct imx_i2c_struct *i2c_imx, bool atomic) imx_i2c_write_reg(temp, i2c_imx, IMX_I2C_I2CR); } +/* + * Enable bus idle interrupts + * Note: IBIC register will be cleared after disabled i2c module. + * All of layerscape series SoCs support IBIC register. + */ +static void i2c_imx_enable_bus_idle(struct imx_i2c_struct *i2c_imx) +{ + if (is_vf610_i2c(i2c_imx)) { + unsigned int temp; + + temp = imx_i2c_read_reg(i2c_imx, IMX_I2C_IBIC); + temp |= IBIC_BIIE; + imx_i2c_write_reg(temp, i2c_imx, IMX_I2C_IBIC); + } +} + +static irqreturn_t i2c_imx_slave_isr(struct imx_i2c_struct *i2c_imx, + unsigned int status, unsigned int ctl) +{ + u8 value; + + if (status & I2SR_IAL) { /* Arbitration lost */ + i2c_imx_clear_irq(i2c_imx, I2SR_IAL); + if (!(status & I2SR_IAAS)) + return IRQ_HANDLED; + } + + 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 */ + 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 void i2c_imx_slave_init(struct imx_i2c_struct *i2c_imx) +{ + int 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); + + i2c_imx_enable_bus_idle(i2c_imx); +} + +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; + + /* Resume */ + ret = pm_runtime_get_sync(i2c_imx->adapter.dev.parent); + if (ret < 0) { + dev_err(&i2c_imx->adapter.dev, "failed to resume i2c controller"); + return ret; + } + + 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); + 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; +} + +static irqreturn_t i2c_imx_master_isr(struct imx_i2c_struct *i2c_imx, unsigned int status) +{ + /* save status register */ + i2c_imx->i2csr = status; + wake_up(&i2c_imx->queue); + + return IRQ_HANDLED; +} + static irqreturn_t i2c_imx_isr(int irq, void *dev_id) { struct imx_i2c_struct *i2c_imx = dev_id; - unsigned int temp; + unsigned int ctl, status; - temp = imx_i2c_read_reg(i2c_imx, IMX_I2C_I2SR); - if (temp & I2SR_IIF) { - /* save status register */ - i2c_imx->i2csr = temp; + 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); - wake_up(&i2c_imx->queue); - return IRQ_HANDLED; + if (i2c_imx->slave && !(ctl & I2CR_MSTA)) + return i2c_imx_slave_isr(i2c_imx, status, ctl); + return i2c_imx_master_isr(i2c_imx, status); } return IRQ_NONE; @@ -1027,6 +1195,10 @@ static int i2c_imx_xfer_common(struct i2c_adapter *adapter, dev_dbg(&i2c_imx->adapter.dev, "<%s> exit with: %s: %d\n", __func__, (result < 0) ? "error" : "success msg", (result < 0) ? result : num); + /* After data is transferred, switch to slave mode(as a receiver) */ + if (i2c_imx->slave) + i2c_imx_slave_init(i2c_imx); + return (result < 0) ? result : num; } @@ -1140,6 +1312,8 @@ static const struct i2c_algorithm i2c_imx_algo = { .master_xfer = i2c_imx_xfer, .master_xfer_atomic = i2c_imx_xfer_atomic, .functionality = i2c_imx_func, + .reg_slave = i2c_imx_reg_slave, + .unreg_slave = i2c_imx_unreg_slave, }; static int i2c_imx_probe(struct platform_device *pdev) @@ -1233,10 +1407,7 @@ static int i2c_imx_probe(struct platform_device *pdev) clk_notifier_register(i2c_imx->clk, &i2c_imx->clk_change_nb); i2c_imx_set_clk(i2c_imx, clk_get_rate(i2c_imx->clk)); - /* 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 function */ ret = i2c_imx_init_recovery_info(i2c_imx, pdev); -- 2.17.1
