From f34b8d9093d7b82b0dbe47825ef15565c5be7aff Mon Sep 17 00:00:00 2001 From: Shreesha Rajashekar Date: Tue, 2 Apr 2019 18:18:23 -0700 Subject: [PATCH] i2c: iproc: Add slave mode support Add slave mode support to the iProc I2C driver. Signed-off-by: Rayagonda Kokatanur Signed-off-by: Michael Cheng Signed-off-by: Shreesha Rajashekar Signed-off-by: Ray Jui Signed-off-by: Wolfram Sang --- drivers/i2c/busses/Kconfig | 1 + drivers/i2c/busses/i2c-bcm-iproc.c | 304 ++++++++++++++++++++++++++++++++++++- 2 files changed, 299 insertions(+), 6 deletions(-) diff --git a/drivers/i2c/busses/Kconfig b/drivers/i2c/busses/Kconfig index 2a978ec..690f0d3 100644 --- a/drivers/i2c/busses/Kconfig +++ b/drivers/i2c/busses/Kconfig @@ -447,6 +447,7 @@ config I2C_BCM_IPROC tristate "Broadcom iProc I2C controller" depends on ARCH_BCM_IPROC || COMPILE_TEST default ARCH_BCM_IPROC + select I2C_SLAVE help If you say yes to this option, support will be included for the Broadcom iProc I2C controller. diff --git a/drivers/i2c/busses/i2c-bcm-iproc.c b/drivers/i2c/busses/i2c-bcm-iproc.c index 4c31f4e..915c1b5 100644 --- a/drivers/i2c/busses/i2c-bcm-iproc.c +++ b/drivers/i2c/busses/i2c-bcm-iproc.c @@ -23,11 +23,30 @@ #define CFG_OFFSET 0x00 #define CFG_RESET_SHIFT 31 #define CFG_EN_SHIFT 30 +#define CFG_SLAVE_ADDR_0_SHIFT 28 #define CFG_M_RETRY_CNT_SHIFT 16 #define CFG_M_RETRY_CNT_MASK 0x0f #define TIM_CFG_OFFSET 0x04 #define TIM_CFG_MODE_400_SHIFT 31 +#define TIM_RAND_SLAVE_STRETCH_SHIFT 24 +#define TIM_RAND_SLAVE_STRETCH_MASK 0x7f +#define TIM_PERIODIC_SLAVE_STRETCH_SHIFT 16 +#define TIM_PERIODIC_SLAVE_STRETCH_MASK 0x7f + +#define S_CFG_SMBUS_ADDR_OFFSET 0x08 +#define S_CFG_EN_NIC_SMB_ADDR3_SHIFT 31 +#define S_CFG_NIC_SMB_ADDR3_SHIFT 24 +#define S_CFG_NIC_SMB_ADDR3_MASK 0x7f +#define S_CFG_EN_NIC_SMB_ADDR2_SHIFT 23 +#define S_CFG_NIC_SMB_ADDR2_SHIFT 16 +#define S_CFG_NIC_SMB_ADDR2_MASK 0x7f +#define S_CFG_EN_NIC_SMB_ADDR1_SHIFT 15 +#define S_CFG_NIC_SMB_ADDR1_SHIFT 8 +#define S_CFG_NIC_SMB_ADDR1_MASK 0x7f +#define S_CFG_EN_NIC_SMB_ADDR0_SHIFT 7 +#define S_CFG_NIC_SMB_ADDR0_SHIFT 0 +#define S_CFG_NIC_SMB_ADDR0_MASK 0x7f #define M_FIFO_CTRL_OFFSET 0x0c #define M_FIFO_RX_FLUSH_SHIFT 31 @@ -37,6 +56,14 @@ #define M_FIFO_RX_THLD_SHIFT 8 #define M_FIFO_RX_THLD_MASK 0x3f +#define S_FIFO_CTRL_OFFSET 0x10 +#define S_FIFO_RX_FLUSH_SHIFT 31 +#define S_FIFO_TX_FLUSH_SHIFT 30 +#define S_FIFO_RX_CNT_SHIFT 16 +#define S_FIFO_RX_CNT_MASK 0x7f +#define S_FIFO_RX_THLD_SHIFT 8 +#define S_FIFO_RX_THLD_MASK 0x3f + #define M_CMD_OFFSET 0x30 #define M_CMD_START_BUSY_SHIFT 31 #define M_CMD_STATUS_SHIFT 25 @@ -54,17 +81,36 @@ #define M_CMD_RD_CNT_SHIFT 0 #define M_CMD_RD_CNT_MASK 0xff +#define S_CMD_OFFSET 0x34 +#define S_CMD_START_BUSY_SHIFT 31 +#define S_CMD_STATUS_SHIFT 23 +#define S_CMD_STATUS_MASK 0x07 +#define S_CMD_STATUS_SUCCESS 0x0 +#define S_CMD_STATUS_TIMEOUT 0x5 + #define IE_OFFSET 0x38 #define IE_M_RX_FIFO_FULL_SHIFT 31 #define IE_M_RX_THLD_SHIFT 30 #define IE_M_START_BUSY_SHIFT 28 #define IE_M_TX_UNDERRUN_SHIFT 27 +#define IE_S_RX_FIFO_FULL_SHIFT 26 +#define IE_S_RX_THLD_SHIFT 25 +#define IE_S_RX_EVENT_SHIFT 24 +#define IE_S_START_BUSY_SHIFT 23 +#define IE_S_TX_UNDERRUN_SHIFT 22 +#define IE_S_RD_EVENT_SHIFT 21 #define IS_OFFSET 0x3c #define IS_M_RX_FIFO_FULL_SHIFT 31 #define IS_M_RX_THLD_SHIFT 30 #define IS_M_START_BUSY_SHIFT 28 #define IS_M_TX_UNDERRUN_SHIFT 27 +#define IS_S_RX_FIFO_FULL_SHIFT 26 +#define IS_S_RX_THLD_SHIFT 25 +#define IS_S_RX_EVENT_SHIFT 24 +#define IS_S_START_BUSY_SHIFT 23 +#define IS_S_TX_UNDERRUN_SHIFT 22 +#define IS_S_RD_EVENT_SHIFT 21 #define M_TX_OFFSET 0x40 #define M_TX_WR_STATUS_SHIFT 31 @@ -78,6 +124,18 @@ #define M_RX_DATA_SHIFT 0 #define M_RX_DATA_MASK 0xff +#define S_TX_OFFSET 0x48 +#define S_TX_WR_STATUS_SHIFT 31 +#define S_TX_DATA_SHIFT 0 +#define S_TX_DATA_MASK 0xff + +#define S_RX_OFFSET 0x4c +#define S_RX_STATUS_SHIFT 30 +#define S_RX_STATUS_MASK 0x03 +#define S_RX_PEC_ERR_SHIFT 29 +#define S_RX_DATA_SHIFT 0 +#define S_RX_DATA_MASK 0xff + #define I2C_TIMEOUT_MSEC 50000 #define M_TX_RX_FIFO_SIZE 64 #define M_RX_FIFO_MAX_THLD_VALUE (M_TX_RX_FIFO_SIZE - 1) @@ -85,6 +143,30 @@ #define M_RX_MAX_READ_LEN 255 #define M_RX_FIFO_THLD_VALUE 50 +#define IE_M_ALL_INTERRUPT_SHIFT 27 +#define IE_M_ALL_INTERRUPT_MASK 0x1e + +#define SLAVE_READ_WRITE_BIT_MASK 0x1 +#define SLAVE_READ_WRITE_BIT_SHIFT 0x1 +#define SLAVE_MAX_SIZE_TRANSACTION 64 +#define SLAVE_CLOCK_STRETCH_TIME 25 + +#define IE_S_ALL_INTERRUPT_SHIFT 21 +#define IE_S_ALL_INTERRUPT_MASK 0x3f + +enum i2c_slave_read_status { + I2C_SLAVE_RX_FIFO_EMPTY = 0, + I2C_SLAVE_RX_START, + I2C_SLAVE_RX_DATA, + I2C_SLAVE_RX_END, +}; + +enum i2c_slave_xfer_dir { + I2C_SLAVE_DIR_READ = 0, + I2C_SLAVE_DIR_WRITE, + I2C_SLAVE_DIR_NONE, +}; + enum bus_speed_index { I2C_SPD_100K = 0, I2C_SPD_400K, @@ -104,6 +186,9 @@ struct bcm_iproc_i2c_dev { struct i2c_msg *msg; + struct i2c_client *slave; + enum i2c_slave_xfer_dir xfer_dir; + /* bytes that have been transferred */ unsigned int tx_bytes; /* bytes that have been read */ @@ -117,6 +202,156 @@ struct bcm_iproc_i2c_dev { #define ISR_MASK (BIT(IS_M_START_BUSY_SHIFT) | BIT(IS_M_TX_UNDERRUN_SHIFT)\ | BIT(IS_M_RX_THLD_SHIFT)) +#define ISR_MASK_SLAVE (BIT(IS_S_START_BUSY_SHIFT)\ + | BIT(IS_S_RX_EVENT_SHIFT) | BIT(IS_S_RD_EVENT_SHIFT)) + +static int bcm_iproc_i2c_reg_slave(struct i2c_client *slave); +static int bcm_iproc_i2c_unreg_slave(struct i2c_client *slave); +static void bcm_iproc_i2c_enable_disable(struct bcm_iproc_i2c_dev *iproc_i2c, + bool enable); + +static void bcm_iproc_i2c_slave_init( + struct bcm_iproc_i2c_dev *iproc_i2c, bool need_reset) +{ + u32 val; + + if (need_reset) { + /* put controller in reset */ + val = readl(iproc_i2c->base + CFG_OFFSET); + val |= BIT(CFG_RESET_SHIFT); + writel(val, iproc_i2c->base + CFG_OFFSET); + + /* wait 100 usec per spec */ + udelay(100); + + /* bring controller out of reset */ + val &= ~(BIT(CFG_RESET_SHIFT)); + writel(val, iproc_i2c->base + CFG_OFFSET); + } + + /* flush TX/RX FIFOs */ + val = (BIT(S_FIFO_RX_FLUSH_SHIFT) | BIT(S_FIFO_TX_FLUSH_SHIFT)); + writel(val, iproc_i2c->base + S_FIFO_CTRL_OFFSET); + + /* Maximum slave stretch time */ + val = readl(iproc_i2c->base + TIM_CFG_OFFSET); + val &= ~(TIM_RAND_SLAVE_STRETCH_MASK << TIM_RAND_SLAVE_STRETCH_SHIFT); + val |= (SLAVE_CLOCK_STRETCH_TIME << TIM_RAND_SLAVE_STRETCH_SHIFT); + writel(val, iproc_i2c->base + TIM_CFG_OFFSET); + + /* Configure the slave address */ + val = readl(iproc_i2c->base + S_CFG_SMBUS_ADDR_OFFSET); + val |= BIT(S_CFG_EN_NIC_SMB_ADDR3_SHIFT); + val &= ~(S_CFG_NIC_SMB_ADDR3_MASK << S_CFG_NIC_SMB_ADDR3_SHIFT); + val |= (iproc_i2c->slave->addr << S_CFG_NIC_SMB_ADDR3_SHIFT); + writel(val, iproc_i2c->base + S_CFG_SMBUS_ADDR_OFFSET); + + /* clear all pending slave interrupts */ + writel(ISR_MASK_SLAVE, iproc_i2c->base + IS_OFFSET); + + /* Enable interrupt register for any READ event */ + val = BIT(IE_S_RD_EVENT_SHIFT); + /* Enable interrupt register to indicate a valid byte in receive fifo */ + val |= BIT(IE_S_RX_EVENT_SHIFT); + /* Enable interrupt register for the Slave BUSY command */ + val |= BIT(IE_S_START_BUSY_SHIFT); + writel(val, iproc_i2c->base + IE_OFFSET); + + iproc_i2c->xfer_dir = I2C_SLAVE_DIR_NONE; +} + +static void bcm_iproc_i2c_check_slave_status( + struct bcm_iproc_i2c_dev *iproc_i2c) +{ + u32 val; + + val = readl(iproc_i2c->base + S_CMD_OFFSET); + val = (val >> S_CMD_STATUS_SHIFT) & S_CMD_STATUS_MASK; + + if (val == S_CMD_STATUS_TIMEOUT) { + dev_err(iproc_i2c->device, "slave random stretch time timeout\n"); + + /* re-initialize i2c for recovery */ + bcm_iproc_i2c_enable_disable(iproc_i2c, false); + bcm_iproc_i2c_slave_init(iproc_i2c, true); + bcm_iproc_i2c_enable_disable(iproc_i2c, true); + } +} + +static bool bcm_iproc_i2c_slave_isr(struct bcm_iproc_i2c_dev *iproc_i2c, + u32 status) +{ + u8 value; + u32 val; + u32 rd_status; + u32 tmp; + + /* Start of transaction. check address and populate the direction */ + if (iproc_i2c->xfer_dir == I2C_SLAVE_DIR_NONE) { + tmp = readl(iproc_i2c->base + S_RX_OFFSET); + rd_status = (tmp >> S_RX_STATUS_SHIFT) & S_RX_STATUS_MASK; + /* This condition checks whether the request is a new request */ + if (((rd_status == I2C_SLAVE_RX_START) && + (status & BIT(IS_S_RX_EVENT_SHIFT))) || + ((rd_status == I2C_SLAVE_RX_END) && + (status & BIT(IS_S_RD_EVENT_SHIFT)))) { + + /* Last bit is W/R bit. + * If 1 then its a read request(by master). + */ + iproc_i2c->xfer_dir = tmp & SLAVE_READ_WRITE_BIT_MASK; + if (iproc_i2c->xfer_dir == I2C_SLAVE_DIR_WRITE) + i2c_slave_event(iproc_i2c->slave, + I2C_SLAVE_READ_REQUESTED, &value); + else + i2c_slave_event(iproc_i2c->slave, + I2C_SLAVE_WRITE_REQUESTED, &value); + } + } + + /* read request from master */ + if ((status & BIT(IS_S_RD_EVENT_SHIFT)) && + (iproc_i2c->xfer_dir == I2C_SLAVE_DIR_WRITE)) { + i2c_slave_event(iproc_i2c->slave, + I2C_SLAVE_READ_PROCESSED, &value); + writel(value, iproc_i2c->base + S_TX_OFFSET); + + val = BIT(S_CMD_START_BUSY_SHIFT); + writel(val, iproc_i2c->base + S_CMD_OFFSET); + } + + /* write request from master */ + if ((status & BIT(IS_S_RX_EVENT_SHIFT)) && + (iproc_i2c->xfer_dir == I2C_SLAVE_DIR_READ)) { + val = readl(iproc_i2c->base + S_RX_OFFSET); + /* Its a write request by Master to Slave. + * We read data present in receive FIFO + */ + value = (u8)((val >> S_RX_DATA_SHIFT) & S_RX_DATA_MASK); + i2c_slave_event(iproc_i2c->slave, + I2C_SLAVE_WRITE_RECEIVED, &value); + + /* check the status for the last byte of the transaction */ + rd_status = (val >> S_RX_STATUS_SHIFT) & S_RX_STATUS_MASK; + if (rd_status == I2C_SLAVE_RX_END) + iproc_i2c->xfer_dir = I2C_SLAVE_DIR_NONE; + + dev_dbg(iproc_i2c->device, "\nread value = 0x%x\n", value); + } + + /* Stop */ + if (status & BIT(IS_S_START_BUSY_SHIFT)) { + i2c_slave_event(iproc_i2c->slave, I2C_SLAVE_STOP, &value); + iproc_i2c->xfer_dir = I2C_SLAVE_DIR_NONE; + } + + /* clear interrupt status */ + writel(status, iproc_i2c->base + IS_OFFSET); + + bcm_iproc_i2c_check_slave_status(iproc_i2c); + return true; +} + static void bcm_iproc_i2c_read_valid_bytes(struct bcm_iproc_i2c_dev *iproc_i2c) { struct i2c_msg *msg = iproc_i2c->msg; @@ -140,6 +375,18 @@ static irqreturn_t bcm_iproc_i2c_isr(int irq, void *data) u32 status = readl(iproc_i2c->base + IS_OFFSET); u32 tmp; + + bool ret; + u32 sl_status = status & ISR_MASK_SLAVE; + + if (sl_status) { + ret = bcm_iproc_i2c_slave_isr(iproc_i2c, sl_status); + if (ret) + return IRQ_HANDLED; + else + return IRQ_NONE; + } + status &= ISR_MASK; if (!status) @@ -222,22 +469,25 @@ static int bcm_iproc_i2c_init(struct bcm_iproc_i2c_dev *iproc_i2c) /* put controller in reset */ val = readl(iproc_i2c->base + CFG_OFFSET); - val |= 1 << CFG_RESET_SHIFT; - val &= ~(1 << CFG_EN_SHIFT); + val |= BIT(CFG_RESET_SHIFT); + val &= ~(BIT(CFG_EN_SHIFT)); writel(val, iproc_i2c->base + CFG_OFFSET); /* wait 100 usec per spec */ udelay(100); /* bring controller out of reset */ - val &= ~(1 << CFG_RESET_SHIFT); + val &= ~(BIT(CFG_RESET_SHIFT)); writel(val, iproc_i2c->base + CFG_OFFSET); /* flush TX/RX FIFOs and set RX FIFO threshold to zero */ - val = (1 << M_FIFO_RX_FLUSH_SHIFT) | (1 << M_FIFO_TX_FLUSH_SHIFT); + val = (BIT(M_FIFO_RX_FLUSH_SHIFT) | BIT(M_FIFO_TX_FLUSH_SHIFT)); writel(val, iproc_i2c->base + M_FIFO_CTRL_OFFSET); /* disable all interrupts */ - writel(0, iproc_i2c->base + IE_OFFSET); + val = readl(iproc_i2c->base + IE_OFFSET); + val &= ~(IE_M_ALL_INTERRUPT_MASK << + IE_M_ALL_INTERRUPT_SHIFT); + writel(val, iproc_i2c->base + IE_OFFSET); /* clear all pending interrupts */ writel(0xffffffff, iproc_i2c->base + IS_OFFSET); @@ -440,12 +690,14 @@ static int bcm_iproc_i2c_xfer(struct i2c_adapter *adapter, static uint32_t bcm_iproc_i2c_functionality(struct i2c_adapter *adap) { - return I2C_FUNC_I2C | I2C_FUNC_SMBUS_EMUL; + return I2C_FUNC_I2C | I2C_FUNC_SMBUS_EMUL | I2C_FUNC_SLAVE; } static const struct i2c_algorithm bcm_iproc_algo = { .master_xfer = bcm_iproc_i2c_xfer, .functionality = bcm_iproc_i2c_functionality, + .reg_slave = bcm_iproc_i2c_reg_slave, + .unreg_slave = bcm_iproc_i2c_unreg_slave, }; static struct i2c_adapter_quirks bcm_iproc_i2c_quirks = { @@ -610,6 +862,46 @@ static const struct dev_pm_ops bcm_iproc_i2c_pm_ops = { #define BCM_IPROC_I2C_PM_OPS NULL #endif /* CONFIG_PM_SLEEP */ + +static int bcm_iproc_i2c_reg_slave(struct i2c_client *slave) +{ + struct bcm_iproc_i2c_dev *iproc_i2c = i2c_get_adapdata(slave->adapter); + + if (iproc_i2c->slave) + return -EBUSY; + + if (slave->flags & I2C_CLIENT_TEN) + return -EAFNOSUPPORT; + + iproc_i2c->slave = slave; + bcm_iproc_i2c_slave_init(iproc_i2c, false); + return 0; +} + +static int bcm_iproc_i2c_unreg_slave(struct i2c_client *slave) +{ + u32 tmp; + struct bcm_iproc_i2c_dev *iproc_i2c = i2c_get_adapdata(slave->adapter); + + if (!iproc_i2c->slave) + return -EINVAL; + + iproc_i2c->slave = NULL; + + /* disable all slave interrupts */ + tmp = readl(iproc_i2c->base + IE_OFFSET); + tmp &= ~(IE_S_ALL_INTERRUPT_MASK << + IE_S_ALL_INTERRUPT_SHIFT); + writel(tmp, iproc_i2c->base + IE_OFFSET); + + /* Erase the slave address programmed */ + tmp = readl(iproc_i2c->base + S_CFG_SMBUS_ADDR_OFFSET); + tmp &= ~BIT(S_CFG_EN_NIC_SMB_ADDR3_SHIFT); + writel(tmp, iproc_i2c->base + S_CFG_SMBUS_ADDR_OFFSET); + + return 0; +} + static const struct of_device_id bcm_iproc_i2c_of_match[] = { { .compatible = "brcm,iproc-i2c" }, { /* sentinel */ } -- 2.7.4