From f9eb91350bb20b3e881bc59158071e14ee4f0326 Mon Sep 17 00:00:00 2001 From: Brendan Higgins Date: Tue, 20 Jun 2017 14:15:16 -0700 Subject: [PATCH] i2c: aspeed: added slave support for Aspeed I2C driver Added slave support for Aspeed I2C controller. Supports fourteen busses present in AST24XX and AST25XX BMC SoCs by Aspeed. Signed-off-by: Brendan Higgins Signed-off-by: Wolfram Sang --- drivers/i2c/busses/i2c-aspeed.c | 201 ++++++++++++++++++++++++++++++++++++++++ 1 file changed, 201 insertions(+) diff --git a/drivers/i2c/busses/i2c-aspeed.c b/drivers/i2c/busses/i2c-aspeed.c index 55f241f..f193483 100644 --- a/drivers/i2c/busses/i2c-aspeed.c +++ b/drivers/i2c/busses/i2c-aspeed.c @@ -49,6 +49,7 @@ #define ASPEED_I2CD_SDA_DRIVE_1T_EN BIT(8) #define ASPEED_I2CD_M_SDA_DRIVE_1T_EN BIT(7) #define ASPEED_I2CD_M_HIGH_SPEED_EN BIT(6) +#define ASPEED_I2CD_SLAVE_EN BIT(1) #define ASPEED_I2CD_MASTER_EN BIT(0) /* 0x04 : I2CD Clock and AC Timing Control Register #1 */ @@ -69,6 +70,7 @@ */ #define ASPEED_I2CD_INTR_SDA_DL_TIMEOUT BIT(14) #define ASPEED_I2CD_INTR_BUS_RECOVER_DONE BIT(13) +#define ASPEED_I2CD_INTR_SLAVE_MATCH BIT(7) #define ASPEED_I2CD_INTR_SCL_TIMEOUT BIT(6) #define ASPEED_I2CD_INTR_ABNORMAL BIT(5) #define ASPEED_I2CD_INTR_NORMAL_STOP BIT(4) @@ -101,6 +103,9 @@ #define ASPEED_I2CD_M_TX_CMD BIT(1) #define ASPEED_I2CD_M_START_CMD BIT(0) +/* 0x18 : I2CD Slave Device Address Register */ +#define ASPEED_I2CD_DEV_ADDR_MASK GENMASK(6, 0) + enum aspeed_i2c_master_state { ASPEED_I2C_MASTER_START, ASPEED_I2C_MASTER_TX_FIRST, @@ -111,6 +116,15 @@ enum aspeed_i2c_master_state { ASPEED_I2C_MASTER_INACTIVE, }; +enum aspeed_i2c_slave_state { + ASPEED_I2C_SLAVE_START, + ASPEED_I2C_SLAVE_READ_REQUESTED, + ASPEED_I2C_SLAVE_READ_PROCESSED, + ASPEED_I2C_SLAVE_WRITE_REQUESTED, + ASPEED_I2C_SLAVE_WRITE_RECEIVED, + ASPEED_I2C_SLAVE_STOP, +}; + struct aspeed_i2c_bus { struct i2c_adapter adap; struct device *dev; @@ -130,6 +144,10 @@ struct aspeed_i2c_bus { int cmd_err; /* Protected only by i2c_lock_bus */ int master_xfer_result; +#if IS_ENABLED(CONFIG_I2C_SLAVE) + struct i2c_client *slave; + enum aspeed_i2c_slave_state slave_state; +#endif /* CONFIG_I2C_SLAVE */ }; static int aspeed_i2c_reset(struct aspeed_i2c_bus *bus); @@ -202,6 +220,110 @@ reset_out: return aspeed_i2c_reset(bus); } +#if IS_ENABLED(CONFIG_I2C_SLAVE) +static bool aspeed_i2c_slave_irq(struct aspeed_i2c_bus *bus) +{ + u32 command, irq_status, status_ack = 0; + struct i2c_client *slave = bus->slave; + bool irq_handled = true; + u8 value; + + spin_lock(&bus->lock); + if (!slave) { + irq_handled = false; + goto out; + } + + command = readl(bus->base + ASPEED_I2C_CMD_REG); + irq_status = readl(bus->base + ASPEED_I2C_INTR_STS_REG); + + /* Slave was requested, restart state machine. */ + if (irq_status & ASPEED_I2CD_INTR_SLAVE_MATCH) { + status_ack |= ASPEED_I2CD_INTR_SLAVE_MATCH; + bus->slave_state = ASPEED_I2C_SLAVE_START; + } + + /* Slave is not currently active, irq was for someone else. */ + if (bus->slave_state == ASPEED_I2C_SLAVE_STOP) { + irq_handled = false; + goto out; + } + + dev_dbg(bus->dev, "slave irq status 0x%08x, cmd 0x%08x\n", + irq_status, command); + + /* Slave was sent something. */ + if (irq_status & ASPEED_I2CD_INTR_RX_DONE) { + value = readl(bus->base + ASPEED_I2C_BYTE_BUF_REG) >> 8; + /* Handle address frame. */ + if (bus->slave_state == ASPEED_I2C_SLAVE_START) { + if (value & 0x1) + bus->slave_state = + ASPEED_I2C_SLAVE_READ_REQUESTED; + else + bus->slave_state = + ASPEED_I2C_SLAVE_WRITE_REQUESTED; + } + status_ack |= ASPEED_I2CD_INTR_RX_DONE; + } + + /* Slave was asked to stop. */ + if (irq_status & ASPEED_I2CD_INTR_NORMAL_STOP) { + status_ack |= ASPEED_I2CD_INTR_NORMAL_STOP; + bus->slave_state = ASPEED_I2C_SLAVE_STOP; + } + if (irq_status & ASPEED_I2CD_INTR_TX_NAK) { + status_ack |= ASPEED_I2CD_INTR_TX_NAK; + bus->slave_state = ASPEED_I2C_SLAVE_STOP; + } + + switch (bus->slave_state) { + case ASPEED_I2C_SLAVE_READ_REQUESTED: + if (irq_status & ASPEED_I2CD_INTR_TX_ACK) + dev_err(bus->dev, "Unexpected ACK on read request.\n"); + bus->slave_state = ASPEED_I2C_SLAVE_READ_PROCESSED; + + i2c_slave_event(slave, I2C_SLAVE_READ_REQUESTED, &value); + writel(value, bus->base + ASPEED_I2C_BYTE_BUF_REG); + writel(ASPEED_I2CD_S_TX_CMD, bus->base + ASPEED_I2C_CMD_REG); + break; + case ASPEED_I2C_SLAVE_READ_PROCESSED: + status_ack |= ASPEED_I2CD_INTR_TX_ACK; + if (!(irq_status & ASPEED_I2CD_INTR_TX_ACK)) + dev_err(bus->dev, + "Expected ACK after processed read.\n"); + i2c_slave_event(slave, I2C_SLAVE_READ_PROCESSED, &value); + writel(value, bus->base + ASPEED_I2C_BYTE_BUF_REG); + writel(ASPEED_I2CD_S_TX_CMD, bus->base + ASPEED_I2C_CMD_REG); + break; + case ASPEED_I2C_SLAVE_WRITE_REQUESTED: + bus->slave_state = ASPEED_I2C_SLAVE_WRITE_RECEIVED; + i2c_slave_event(slave, I2C_SLAVE_WRITE_REQUESTED, &value); + break; + case ASPEED_I2C_SLAVE_WRITE_RECEIVED: + i2c_slave_event(slave, I2C_SLAVE_WRITE_RECEIVED, &value); + break; + case ASPEED_I2C_SLAVE_STOP: + i2c_slave_event(slave, I2C_SLAVE_STOP, &value); + break; + default: + dev_err(bus->dev, "unhandled slave_state: %d\n", + bus->slave_state); + break; + } + + if (status_ack != irq_status) + dev_err(bus->dev, + "irq handled != irq. expected %x, but was %x\n", + irq_status, status_ack); + writel(status_ack, bus->base + ASPEED_I2C_INTR_STS_REG); + +out: + spin_unlock(&bus->lock); + return irq_handled; +} +#endif /* CONFIG_I2C_SLAVE */ + /* precondition: bus.lock has been acquired. */ static void aspeed_i2c_do_start(struct aspeed_i2c_bus *bus) { @@ -427,6 +549,13 @@ static irqreturn_t aspeed_i2c_bus_irq(int irq, void *dev_id) { struct aspeed_i2c_bus *bus = dev_id; +#if IS_ENABLED(CONFIG_I2C_SLAVE) + if (aspeed_i2c_slave_irq(bus)) { + dev_dbg(bus->dev, "irq handled by slave.\n"); + return IRQ_HANDLED; + } +#endif /* CONFIG_I2C_SLAVE */ + return aspeed_i2c_master_irq(bus) ? IRQ_HANDLED : IRQ_NONE; } @@ -474,9 +603,75 @@ static u32 aspeed_i2c_functionality(struct i2c_adapter *adap) return I2C_FUNC_I2C | I2C_FUNC_SMBUS_EMUL | I2C_FUNC_SMBUS_BLOCK_DATA; } +#if IS_ENABLED(CONFIG_I2C_SLAVE) +/* precondition: bus.lock has been acquired. */ +static void __aspeed_i2c_reg_slave(struct aspeed_i2c_bus *bus, u16 slave_addr) +{ + u32 addr_reg_val, func_ctrl_reg_val; + + /* Set slave addr. */ + addr_reg_val = readl(bus->base + ASPEED_I2C_DEV_ADDR_REG); + addr_reg_val &= ~ASPEED_I2CD_DEV_ADDR_MASK; + addr_reg_val |= slave_addr & ASPEED_I2CD_DEV_ADDR_MASK; + writel(addr_reg_val, bus->base + ASPEED_I2C_DEV_ADDR_REG); + + /* Turn on slave mode. */ + func_ctrl_reg_val = readl(bus->base + ASPEED_I2C_FUN_CTRL_REG); + func_ctrl_reg_val |= ASPEED_I2CD_SLAVE_EN; + writel(func_ctrl_reg_val, bus->base + ASPEED_I2C_FUN_CTRL_REG); +} + +static int aspeed_i2c_reg_slave(struct i2c_client *client) +{ + struct aspeed_i2c_bus *bus = i2c_get_adapdata(client->adapter); + unsigned long flags; + + spin_lock_irqsave(&bus->lock, flags); + if (bus->slave) { + spin_unlock_irqrestore(&bus->lock, flags); + return -EINVAL; + } + + __aspeed_i2c_reg_slave(bus, client->addr); + + bus->slave = client; + bus->slave_state = ASPEED_I2C_SLAVE_STOP; + spin_unlock_irqrestore(&bus->lock, flags); + + return 0; +} + +static int aspeed_i2c_unreg_slave(struct i2c_client *client) +{ + struct aspeed_i2c_bus *bus = i2c_get_adapdata(client->adapter); + u32 func_ctrl_reg_val; + unsigned long flags; + + spin_lock_irqsave(&bus->lock, flags); + if (!bus->slave) { + spin_unlock_irqrestore(&bus->lock, flags); + return -EINVAL; + } + + /* Turn off slave mode. */ + func_ctrl_reg_val = readl(bus->base + ASPEED_I2C_FUN_CTRL_REG); + func_ctrl_reg_val &= ~ASPEED_I2CD_SLAVE_EN; + writel(func_ctrl_reg_val, bus->base + ASPEED_I2C_FUN_CTRL_REG); + + bus->slave = NULL; + spin_unlock_irqrestore(&bus->lock, flags); + + return 0; +} +#endif /* CONFIG_I2C_SLAVE */ + static const struct i2c_algorithm aspeed_i2c_algo = { .master_xfer = aspeed_i2c_master_xfer, .functionality = aspeed_i2c_functionality, +#if IS_ENABLED(CONFIG_I2C_SLAVE) + .reg_slave = aspeed_i2c_reg_slave, + .unreg_slave = aspeed_i2c_unreg_slave, +#endif /* CONFIG_I2C_SLAVE */ }; static u32 aspeed_i2c_get_clk_reg_val(u32 divisor) @@ -551,6 +746,12 @@ static int aspeed_i2c_init(struct aspeed_i2c_bus *bus, writel(readl(bus->base + ASPEED_I2C_FUN_CTRL_REG) | fun_ctrl_reg, bus->base + ASPEED_I2C_FUN_CTRL_REG); +#if IS_ENABLED(CONFIG_I2C_SLAVE) + /* If slave has already been registered, re-enable it. */ + if (bus->slave) + __aspeed_i2c_reg_slave(bus, bus->slave->addr); +#endif /* CONFIG_I2C_SLAVE */ + /* Set interrupt generation of I2C controller */ writel(ASPEED_I2CD_INTR_ALL, bus->base + ASPEED_I2C_INTR_CTRL_REG); -- 2.7.4