From 9e48155f6bfe3d3896c8596f56cc2f76d344db3a Mon Sep 17 00:00:00 2001 From: Pierre-Yves MORDRET Date: Wed, 11 Apr 2018 15:24:55 +0200 Subject: [PATCH] i2c: i2c-stm32f7: Add initial SMBus protocols support This patch adds SMBus support for I2C controller embedded in STM32F7 Soc. All SMBus protocols are implemented except SMBus-specific protocols like SMBus Host Notification and SMBus Alert protocols. Implemented: SMBus Quick command, Send byte, Receive byte, Write byte/word, read byte/word, Process call, Block write/read and Block write-block read process call. Signed-off-by: M'boumba Cedric Madianga Signed-off-by: Pierre-Yves MORDRET Signed-off-by: Wolfram Sang --- drivers/i2c/busses/i2c-stm32f7.c | 377 ++++++++++++++++++++++++++++++- 1 file changed, 368 insertions(+), 9 deletions(-) diff --git a/drivers/i2c/busses/i2c-stm32f7.c b/drivers/i2c/busses/i2c-stm32f7.c index 9bf676ee2509..0b81b5dc2eda 100644 --- a/drivers/i2c/busses/i2c-stm32f7.c +++ b/drivers/i2c/busses/i2c-stm32f7.c @@ -37,6 +37,7 @@ #define STM32F7_I2C_CR2 0x04 #define STM32F7_I2C_OAR1 0x08 #define STM32F7_I2C_OAR2 0x0C +#define STM32F7_I2C_PECR 0x20 #define STM32F7_I2C_TIMINGR 0x10 #define STM32F7_I2C_ISR 0x18 #define STM32F7_I2C_ICR 0x1C @@ -44,6 +45,7 @@ #define STM32F7_I2C_TXDR 0x28 /* STM32F7 I2C control 1 */ +#define STM32F7_I2C_CR1_PECEN BIT(23) #define STM32F7_I2C_CR1_SBC BIT(16) #define STM32F7_I2C_CR1_ANFOFF BIT(12) #define STM32F7_I2C_CR1_ERRIE BIT(7) @@ -67,6 +69,7 @@ | STM32F7_I2C_CR1_TXIE) /* STM32F7 I2C control 2 */ +#define STM32F7_I2C_CR2_PECBYTE BIT(26) #define STM32F7_I2C_CR2_RELOAD BIT(24) #define STM32F7_I2C_CR2_NBYTES_MASK GENMASK(23, 16) #define STM32F7_I2C_CR2_NBYTES(n) (((n) & 0xff) << 16) @@ -111,6 +114,7 @@ (((n) & STM32F7_I2C_ISR_ADDCODE_MASK) >> 17) #define STM32F7_I2C_ISR_DIR BIT(16) #define STM32F7_I2C_ISR_BUSY BIT(15) +#define STM32F7_I2C_ISR_PECERR BIT(11) #define STM32F7_I2C_ISR_ARLO BIT(9) #define STM32F7_I2C_ISR_BERR BIT(8) #define STM32F7_I2C_ISR_TCR BIT(7) @@ -123,6 +127,7 @@ #define STM32F7_I2C_ISR_TXE BIT(0) /* STM32F7 I2C Interrupt Clear */ +#define STM32F7_I2C_ICR_PECCF BIT(11) #define STM32F7_I2C_ICR_ARLOCF BIT(9) #define STM32F7_I2C_ICR_BERRCF BIT(8) #define STM32F7_I2C_ICR_STOPCF BIT(5) @@ -225,6 +230,14 @@ struct stm32f7_i2c_timings { * @buf: data buffer * @result: result of the transfer * @stop: last I2C msg to be sent, i.e. STOP to be generated + * @smbus: boolean to know if the I2C IP is used in SMBus mode + * @size: type of SMBus protocol + * @read_write: direction of SMBus protocol + * SMBus block read and SMBus block write - block read process call protocols + * @smbus_buff: buffer to be used for SMBus protocol transfer. It will + * contain a maximum of 32 bytes of data + byte command + byte count + PEC + * This buffer has to be 32-bit aligned to be compliant with memory address + * register in DMA mode. */ struct stm32f7_i2c_msg { u16 addr; @@ -232,6 +245,10 @@ struct stm32f7_i2c_msg { u8 *buf; int result; bool stop; + bool smbus; + int size; + char read_write; + u8 smbus_buf[I2C_SMBUS_BLOCK_MAX + 3] __aligned(4); }; /** @@ -649,6 +666,29 @@ static void stm32f7_i2c_reload(struct stm32f7_i2c_dev *i2c_dev) writel_relaxed(cr2, i2c_dev->base + STM32F7_I2C_CR2); } +static void stm32f7_i2c_smbus_reload(struct stm32f7_i2c_dev *i2c_dev) +{ + struct stm32f7_i2c_msg *f7_msg = &i2c_dev->f7_msg; + u32 cr2; + u8 *val; + + /* + * For I2C_SMBUS_BLOCK_DATA && I2C_SMBUS_BLOCK_PROC_CALL, the first + * data received inform us how many data will follow. + */ + stm32f7_i2c_read_rx_data(i2c_dev); + + /* + * Update NBYTES with the value read to continue the transfer + */ + val = f7_msg->buf - sizeof(u8); + f7_msg->count = *val; + cr2 = readl_relaxed(i2c_dev->base + STM32F7_I2C_CR2); + cr2 &= ~(STM32F7_I2C_CR2_NBYTES_MASK | STM32F7_I2C_CR2_RELOAD); + cr2 |= STM32F7_I2C_CR2_NBYTES(f7_msg->count); + writel_relaxed(cr2, i2c_dev->base + STM32F7_I2C_CR2); +} + static int stm32f7_i2c_wait_free_bus(struct stm32f7_i2c_dev *i2c_dev) { u32 status; @@ -732,6 +772,237 @@ static void stm32f7_i2c_xfer_msg(struct stm32f7_i2c_dev *i2c_dev, writel_relaxed(cr2, base + STM32F7_I2C_CR2); } +static int stm32f7_i2c_smbus_xfer_msg(struct stm32f7_i2c_dev *i2c_dev, + unsigned short flags, u8 command, + union i2c_smbus_data *data) +{ + struct stm32f7_i2c_msg *f7_msg = &i2c_dev->f7_msg; + struct device *dev = i2c_dev->dev; + void __iomem *base = i2c_dev->base; + u32 cr1, cr2; + int i; + + f7_msg->result = 0; + reinit_completion(&i2c_dev->complete); + + cr2 = readl_relaxed(base + STM32F7_I2C_CR2); + cr1 = readl_relaxed(base + STM32F7_I2C_CR1); + + /* Set transfer direction */ + cr2 &= ~STM32F7_I2C_CR2_RD_WRN; + if (f7_msg->read_write) + cr2 |= STM32F7_I2C_CR2_RD_WRN; + + /* Set slave address */ + cr2 &= ~(STM32F7_I2C_CR2_ADD10 | STM32F7_I2C_CR2_SADD7_MASK); + cr2 |= STM32F7_I2C_CR2_SADD7(f7_msg->addr); + + f7_msg->smbus_buf[0] = command; + switch (f7_msg->size) { + case I2C_SMBUS_QUICK: + f7_msg->stop = true; + f7_msg->count = 0; + break; + case I2C_SMBUS_BYTE: + f7_msg->stop = true; + f7_msg->count = 1; + break; + case I2C_SMBUS_BYTE_DATA: + if (f7_msg->read_write) { + f7_msg->stop = false; + f7_msg->count = 1; + cr2 &= ~STM32F7_I2C_CR2_RD_WRN; + } else { + f7_msg->stop = true; + f7_msg->count = 2; + f7_msg->smbus_buf[1] = data->byte; + } + break; + case I2C_SMBUS_WORD_DATA: + if (f7_msg->read_write) { + f7_msg->stop = false; + f7_msg->count = 1; + cr2 &= ~STM32F7_I2C_CR2_RD_WRN; + } else { + f7_msg->stop = true; + f7_msg->count = 3; + f7_msg->smbus_buf[1] = data->word & 0xff; + f7_msg->smbus_buf[2] = data->word >> 8; + } + break; + case I2C_SMBUS_BLOCK_DATA: + if (f7_msg->read_write) { + f7_msg->stop = false; + f7_msg->count = 1; + cr2 &= ~STM32F7_I2C_CR2_RD_WRN; + } else { + f7_msg->stop = true; + if (data->block[0] > I2C_SMBUS_BLOCK_MAX || + !data->block[0]) { + dev_err(dev, "Invalid block write size %d\n", + data->block[0]); + return -EINVAL; + } + f7_msg->count = data->block[0] + 2; + for (i = 1; i < f7_msg->count; i++) + f7_msg->smbus_buf[i] = data->block[i - 1]; + } + break; + case I2C_SMBUS_PROC_CALL: + f7_msg->stop = false; + f7_msg->count = 3; + f7_msg->smbus_buf[1] = data->word & 0xff; + f7_msg->smbus_buf[2] = data->word >> 8; + cr2 &= ~STM32F7_I2C_CR2_RD_WRN; + f7_msg->read_write = I2C_SMBUS_READ; + break; + case I2C_SMBUS_BLOCK_PROC_CALL: + f7_msg->stop = false; + if (data->block[0] > I2C_SMBUS_BLOCK_MAX - 1) { + dev_err(dev, "Invalid block write size %d\n", + data->block[0]); + return -EINVAL; + } + f7_msg->count = data->block[0] + 2; + for (i = 1; i < f7_msg->count; i++) + f7_msg->smbus_buf[i] = data->block[i - 1]; + cr2 &= ~STM32F7_I2C_CR2_RD_WRN; + f7_msg->read_write = I2C_SMBUS_READ; + break; + default: + dev_err(dev, "Unsupported smbus protocol %d\n", f7_msg->size); + return -EOPNOTSUPP; + } + + f7_msg->buf = f7_msg->smbus_buf; + + /* Configure PEC */ + if ((flags & I2C_CLIENT_PEC) && f7_msg->size != I2C_SMBUS_QUICK) { + cr1 |= STM32F7_I2C_CR1_PECEN; + cr2 |= STM32F7_I2C_CR2_PECBYTE; + if (!f7_msg->read_write) + f7_msg->count++; + } else { + cr1 &= ~STM32F7_I2C_CR1_PECEN; + cr2 &= ~STM32F7_I2C_CR2_PECBYTE; + } + + /* Set number of bytes to be transferred */ + cr2 &= ~(STM32F7_I2C_CR2_NBYTES_MASK | STM32F7_I2C_CR2_RELOAD); + cr2 |= STM32F7_I2C_CR2_NBYTES(f7_msg->count); + + /* Enable NACK, STOP, error and transfer complete interrupts */ + cr1 |= STM32F7_I2C_CR1_ERRIE | STM32F7_I2C_CR1_TCIE | + STM32F7_I2C_CR1_STOPIE | STM32F7_I2C_CR1_NACKIE; + + /* Clear TX/RX interrupt */ + cr1 &= ~(STM32F7_I2C_CR1_RXIE | STM32F7_I2C_CR1_TXIE); + + /* Enable RX/TX interrupt according to msg direction */ + if (cr2 & STM32F7_I2C_CR2_RD_WRN) + cr1 |= STM32F7_I2C_CR1_RXIE; + else + cr1 |= STM32F7_I2C_CR1_TXIE; + + /* Set Start bit */ + cr2 |= STM32F7_I2C_CR2_START; + + i2c_dev->master_mode = true; + + /* Write configurations registers */ + writel_relaxed(cr1, base + STM32F7_I2C_CR1); + writel_relaxed(cr2, base + STM32F7_I2C_CR2); + + return 0; +} + +static void stm32f7_i2c_smbus_rep_start(struct stm32f7_i2c_dev *i2c_dev) +{ + struct stm32f7_i2c_msg *f7_msg = &i2c_dev->f7_msg; + void __iomem *base = i2c_dev->base; + u32 cr1, cr2; + + cr2 = readl_relaxed(base + STM32F7_I2C_CR2); + cr1 = readl_relaxed(base + STM32F7_I2C_CR1); + + /* Set transfer direction */ + cr2 |= STM32F7_I2C_CR2_RD_WRN; + + switch (f7_msg->size) { + case I2C_SMBUS_BYTE_DATA: + f7_msg->count = 1; + break; + case I2C_SMBUS_WORD_DATA: + case I2C_SMBUS_PROC_CALL: + f7_msg->count = 2; + break; + case I2C_SMBUS_BLOCK_DATA: + case I2C_SMBUS_BLOCK_PROC_CALL: + f7_msg->count = 1; + cr2 |= STM32F7_I2C_CR2_RELOAD; + break; + } + + f7_msg->buf = f7_msg->smbus_buf; + f7_msg->stop = true; + + /* Add one byte for PEC if needed */ + if (cr1 & STM32F7_I2C_CR1_PECEN) + f7_msg->count++; + + /* Set number of bytes to be transferred */ + cr2 &= ~(STM32F7_I2C_CR2_NBYTES_MASK); + cr2 |= STM32F7_I2C_CR2_NBYTES(f7_msg->count); + + /* + * Configure RX/TX interrupt: + */ + cr1 &= ~(STM32F7_I2C_CR1_RXIE | STM32F7_I2C_CR1_TXIE); + cr1 |= STM32F7_I2C_CR1_RXIE; + + /* Configure Repeated Start */ + cr2 |= STM32F7_I2C_CR2_START; + + /* Write configurations registers */ + writel_relaxed(cr1, base + STM32F7_I2C_CR1); + writel_relaxed(cr2, base + STM32F7_I2C_CR2); +} + +static int stm32f7_i2c_smbus_check_pec(struct stm32f7_i2c_dev *i2c_dev) +{ + struct stm32f7_i2c_msg *f7_msg = &i2c_dev->f7_msg; + u8 count, internal_pec, received_pec; + + internal_pec = readl_relaxed(i2c_dev->base + STM32F7_I2C_PECR); + + switch (f7_msg->size) { + case I2C_SMBUS_BYTE: + case I2C_SMBUS_BYTE_DATA: + received_pec = f7_msg->smbus_buf[1]; + break; + case I2C_SMBUS_WORD_DATA: + case I2C_SMBUS_PROC_CALL: + received_pec = f7_msg->smbus_buf[2]; + break; + case I2C_SMBUS_BLOCK_DATA: + case I2C_SMBUS_BLOCK_PROC_CALL: + count = f7_msg->smbus_buf[0]; + received_pec = f7_msg->smbus_buf[count]; + break; + default: + dev_err(i2c_dev->dev, "Unsupported smbus protocol for PEC\n"); + return -EINVAL; + } + + if (internal_pec != received_pec) { + dev_err(i2c_dev->dev, "Bad PEC 0x%02x vs. 0x%02x\n", + internal_pec, received_pec); + return -EBADMSG; + } + + return 0; +} + static bool stm32f7_i2c_is_addr_match(struct i2c_client *slave, u32 addcode) { u32 addr; @@ -1023,6 +1294,8 @@ static irqreturn_t stm32f7_i2c_isr_event(int irq, void *data) if (f7_msg->stop) { mask = STM32F7_I2C_CR2_STOP; stm32f7_i2c_set_bits(base + STM32F7_I2C_CR2, mask); + } else if (f7_msg->smbus) { + stm32f7_i2c_smbus_rep_start(i2c_dev); } else { i2c_dev->msg_id++; i2c_dev->msg++; @@ -1030,13 +1303,12 @@ static irqreturn_t stm32f7_i2c_isr_event(int irq, void *data) } } - /* - * Transfer Complete Reload: 255 data bytes have been transferred - * We have to prepare the I2C controller to transfer the remaining - * data. - */ - if (status & STM32F7_I2C_ISR_TCR) - stm32f7_i2c_reload(i2c_dev); + if (status & STM32F7_I2C_ISR_TCR) { + if (f7_msg->smbus) + stm32f7_i2c_smbus_reload(i2c_dev); + else + stm32f7_i2c_reload(i2c_dev); + } return IRQ_HANDLED; } @@ -1065,6 +1337,12 @@ static irqreturn_t stm32f7_i2c_isr_error(int irq, void *data) f7_msg->result = -EAGAIN; } + if (status & STM32F7_I2C_ISR_PECERR) { + dev_err(dev, "<%s>: PEC error in reception\n", __func__); + writel_relaxed(STM32F7_I2C_ICR_PECCF, base + STM32F7_I2C_ICR); + f7_msg->result = -EINVAL; + } + /* Disable interrupts */ if (stm32f7_i2c_is_slave_registered(i2c_dev)) mask = STM32F7_I2C_XFER_IRQ_MASK; @@ -1089,6 +1367,7 @@ static int stm32f7_i2c_xfer(struct i2c_adapter *i2c_adap, i2c_dev->msg = msgs; i2c_dev->msg_num = num; i2c_dev->msg_id = 0; + f7_msg->smbus = false; ret = clk_enable(i2c_dev->clk); if (ret) { @@ -1118,6 +1397,82 @@ clk_free: return (ret < 0) ? ret : num; } +static int stm32f7_i2c_smbus_xfer(struct i2c_adapter *adapter, u16 addr, + unsigned short flags, char read_write, + u8 command, int size, + union i2c_smbus_data *data) +{ + struct stm32f7_i2c_dev *i2c_dev = i2c_get_adapdata(adapter); + struct stm32f7_i2c_msg *f7_msg = &i2c_dev->f7_msg; + struct device *dev = i2c_dev->dev; + unsigned long timeout; + int i, ret; + + f7_msg->addr = addr; + f7_msg->size = size; + f7_msg->read_write = read_write; + f7_msg->smbus = true; + + ret = clk_enable(i2c_dev->clk); + if (ret) { + dev_err(i2c_dev->dev, "Failed to enable clock\n"); + return ret; + } + + ret = stm32f7_i2c_wait_free_bus(i2c_dev); + if (ret) + goto clk_free; + + ret = stm32f7_i2c_smbus_xfer_msg(i2c_dev, flags, command, data); + if (ret) + goto clk_free; + + timeout = wait_for_completion_timeout(&i2c_dev->complete, + i2c_dev->adap.timeout); + ret = f7_msg->result; + if (ret) + goto clk_free; + + if (!timeout) { + dev_dbg(dev, "Access to slave 0x%x timed out\n", f7_msg->addr); + ret = -ETIMEDOUT; + goto clk_free; + } + + /* Check PEC */ + if ((flags & I2C_CLIENT_PEC) && size != I2C_SMBUS_QUICK && read_write) { + ret = stm32f7_i2c_smbus_check_pec(i2c_dev); + if (ret) + goto clk_free; + } + + if (read_write && size != I2C_SMBUS_QUICK) { + switch (size) { + case I2C_SMBUS_BYTE: + case I2C_SMBUS_BYTE_DATA: + data->byte = f7_msg->smbus_buf[0]; + break; + case I2C_SMBUS_WORD_DATA: + case I2C_SMBUS_PROC_CALL: + data->word = f7_msg->smbus_buf[0] | + (f7_msg->smbus_buf[1] << 8); + break; + case I2C_SMBUS_BLOCK_DATA: + case I2C_SMBUS_BLOCK_PROC_CALL: + for (i = 0; i <= f7_msg->smbus_buf[0]; i++) + data->block[i] = f7_msg->smbus_buf[i]; + break; + default: + dev_err(dev, "Unsupported smbus transaction\n"); + ret = -EINVAL; + } + } + +clk_free: + clk_disable(i2c_dev->clk); + return ret; +} + static int stm32f7_i2c_reg_slave(struct i2c_client *slave) { struct stm32f7_i2c_dev *i2c_dev = i2c_get_adapdata(slave->adapter); @@ -1229,12 +1584,16 @@ static int stm32f7_i2c_unreg_slave(struct i2c_client *slave) static u32 stm32f7_i2c_func(struct i2c_adapter *adap) { - return I2C_FUNC_I2C | I2C_FUNC_SMBUS_EMUL | I2C_FUNC_10BIT_ADDR | - I2C_FUNC_SLAVE; + return I2C_FUNC_I2C | I2C_FUNC_10BIT_ADDR | I2C_FUNC_SLAVE | + I2C_FUNC_SMBUS_QUICK | I2C_FUNC_SMBUS_BYTE | + I2C_FUNC_SMBUS_BYTE_DATA | I2C_FUNC_SMBUS_WORD_DATA | + I2C_FUNC_SMBUS_BLOCK_DATA | I2C_FUNC_SMBUS_BLOCK_PROC_CALL | + I2C_FUNC_SMBUS_PROC_CALL | I2C_FUNC_SMBUS_PEC; } static struct i2c_algorithm stm32f7_i2c_algo = { .master_xfer = stm32f7_i2c_xfer, + .smbus_xfer = stm32f7_i2c_smbus_xfer, .functionality = stm32f7_i2c_func, .reg_slave = stm32f7_i2c_reg_slave, .unreg_slave = stm32f7_i2c_unreg_slave,