// SPDX-License-Identifier: GPL-2.0 /* * Driver for STMicroelectronics STM32 I2C controller * * This I2C controller is described in the STM32F429/439 Soc reference manual. * Please see below a link to the documentation: * http://www.st.com/resource/en/reference_manual/DM00031020.pdf * * Copyright (C) M'boumba Cedric Madianga 2016 * Copyright (C) STMicroelectronics 2017 * Author: M'boumba Cedric Madianga * * This driver is based on i2c-st.c * */ #include #include #include #include #include #include #include #include #include #include #include #include #include #include "i2c-stm32.h" /* STM32F4 I2C offset registers */ #define STM32F4_I2C_CR1 0x00 #define STM32F4_I2C_CR2 0x04 #define STM32F4_I2C_DR 0x10 #define STM32F4_I2C_SR1 0x14 #define STM32F4_I2C_SR2 0x18 #define STM32F4_I2C_CCR 0x1C #define STM32F4_I2C_TRISE 0x20 #define STM32F4_I2C_FLTR 0x24 /* STM32F4 I2C control 1*/ #define STM32F4_I2C_CR1_POS BIT(11) #define STM32F4_I2C_CR1_ACK BIT(10) #define STM32F4_I2C_CR1_STOP BIT(9) #define STM32F4_I2C_CR1_START BIT(8) #define STM32F4_I2C_CR1_PE BIT(0) /* STM32F4 I2C control 2 */ #define STM32F4_I2C_CR2_FREQ_MASK GENMASK(5, 0) #define STM32F4_I2C_CR2_FREQ(n) ((n) & STM32F4_I2C_CR2_FREQ_MASK) #define STM32F4_I2C_CR2_ITBUFEN BIT(10) #define STM32F4_I2C_CR2_ITEVTEN BIT(9) #define STM32F4_I2C_CR2_ITERREN BIT(8) #define STM32F4_I2C_CR2_IRQ_MASK (STM32F4_I2C_CR2_ITBUFEN | \ STM32F4_I2C_CR2_ITEVTEN | \ STM32F4_I2C_CR2_ITERREN) /* STM32F4 I2C Status 1 */ #define STM32F4_I2C_SR1_AF BIT(10) #define STM32F4_I2C_SR1_ARLO BIT(9) #define STM32F4_I2C_SR1_BERR BIT(8) #define STM32F4_I2C_SR1_TXE BIT(7) #define STM32F4_I2C_SR1_RXNE BIT(6) #define STM32F4_I2C_SR1_BTF BIT(2) #define STM32F4_I2C_SR1_ADDR BIT(1) #define STM32F4_I2C_SR1_SB BIT(0) #define STM32F4_I2C_SR1_ITEVTEN_MASK (STM32F4_I2C_SR1_BTF | \ STM32F4_I2C_SR1_ADDR | \ STM32F4_I2C_SR1_SB) #define STM32F4_I2C_SR1_ITBUFEN_MASK (STM32F4_I2C_SR1_TXE | \ STM32F4_I2C_SR1_RXNE) #define STM32F4_I2C_SR1_ITERREN_MASK (STM32F4_I2C_SR1_AF | \ STM32F4_I2C_SR1_ARLO | \ STM32F4_I2C_SR1_BERR) /* STM32F4 I2C Status 2 */ #define STM32F4_I2C_SR2_BUSY BIT(1) /* STM32F4 I2C Control Clock */ #define STM32F4_I2C_CCR_CCR_MASK GENMASK(11, 0) #define STM32F4_I2C_CCR_CCR(n) ((n) & STM32F4_I2C_CCR_CCR_MASK) #define STM32F4_I2C_CCR_FS BIT(15) #define STM32F4_I2C_CCR_DUTY BIT(14) /* STM32F4 I2C Trise */ #define STM32F4_I2C_TRISE_VALUE_MASK GENMASK(5, 0) #define STM32F4_I2C_TRISE_VALUE(n) ((n) & STM32F4_I2C_TRISE_VALUE_MASK) #define STM32F4_I2C_MIN_STANDARD_FREQ 2U #define STM32F4_I2C_MIN_FAST_FREQ 6U #define STM32F4_I2C_MAX_FREQ 46U #define HZ_TO_MHZ 1000000 /** * struct stm32f4_i2c_msg - client specific data * @addr: 8-bit slave addr, including r/w bit * @count: number of bytes to be transferred * @buf: data buffer * @result: result of the transfer * @stop: last I2C msg to be sent, i.e. STOP to be generated */ struct stm32f4_i2c_msg { u8 addr; u32 count; u8 *buf; int result; bool stop; }; /** * struct stm32f4_i2c_dev - private data of the controller * @adap: I2C adapter for this controller * @dev: device for this controller * @base: virtual memory area * @complete: completion of I2C message * @clk: hw i2c clock * @speed: I2C clock frequency of the controller. Standard or Fast are supported * @parent_rate: I2C clock parent rate in MHz * @msg: I2C transfer information */ struct stm32f4_i2c_dev { struct i2c_adapter adap; struct device *dev; void __iomem *base; struct completion complete; struct clk *clk; int speed; int parent_rate; struct stm32f4_i2c_msg msg; }; static inline void stm32f4_i2c_set_bits(void __iomem *reg, u32 mask) { writel_relaxed(readl_relaxed(reg) | mask, reg); } static inline void stm32f4_i2c_clr_bits(void __iomem *reg, u32 mask) { writel_relaxed(readl_relaxed(reg) & ~mask, reg); } static void stm32f4_i2c_disable_irq(struct stm32f4_i2c_dev *i2c_dev) { void __iomem *reg = i2c_dev->base + STM32F4_I2C_CR2; stm32f4_i2c_clr_bits(reg, STM32F4_I2C_CR2_IRQ_MASK); } static int stm32f4_i2c_set_periph_clk_freq(struct stm32f4_i2c_dev *i2c_dev) { u32 freq; u32 cr2 = 0; i2c_dev->parent_rate = clk_get_rate(i2c_dev->clk); freq = DIV_ROUND_UP(i2c_dev->parent_rate, HZ_TO_MHZ); if (i2c_dev->speed == STM32_I2C_SPEED_STANDARD) { /* * To reach 100 kHz, the parent clk frequency should be between * a minimum value of 2 MHz and a maximum value of 46 MHz due * to hardware limitation */ if (freq < STM32F4_I2C_MIN_STANDARD_FREQ || freq > STM32F4_I2C_MAX_FREQ) { dev_err(i2c_dev->dev, "bad parent clk freq for standard mode\n"); return -EINVAL; } } else { /* * To be as close as possible to 400 kHz, the parent clk * frequency should be between a minimum value of 6 MHz and a * maximum value of 46 MHz due to hardware limitation */ if (freq < STM32F4_I2C_MIN_FAST_FREQ || freq > STM32F4_I2C_MAX_FREQ) { dev_err(i2c_dev->dev, "bad parent clk freq for fast mode\n"); return -EINVAL; } } cr2 |= STM32F4_I2C_CR2_FREQ(freq); writel_relaxed(cr2, i2c_dev->base + STM32F4_I2C_CR2); return 0; } static void stm32f4_i2c_set_rise_time(struct stm32f4_i2c_dev *i2c_dev) { u32 freq = DIV_ROUND_UP(i2c_dev->parent_rate, HZ_TO_MHZ); u32 trise; /* * These bits must be programmed with the maximum SCL rise time given in * the I2C bus specification, incremented by 1. * * In standard mode, the maximum allowed SCL rise time is 1000 ns. * If, in the I2C_CR2 register, the value of FREQ[5:0] bits is equal to * 0x08 so period = 125 ns therefore the TRISE[5:0] bits must be * programmed with 0x9. (1000 ns / 125 ns + 1) * So, for I2C standard mode TRISE = FREQ[5:0] + 1 * * In fast mode, the maximum allowed SCL rise time is 300 ns. * If, in the I2C_CR2 register, the value of FREQ[5:0] bits is equal to * 0x08 so period = 125 ns therefore the TRISE[5:0] bits must be * programmed with 0x3. (300 ns / 125 ns + 1) * So, for I2C fast mode TRISE = FREQ[5:0] * 300 / 1000 + 1 * * Function stm32f4_i2c_set_periph_clk_freq made sure that parent rate * is not higher than 46 MHz . As a result trise is at most 4 bits wide * and so fits into the TRISE bits [5:0]. */ if (i2c_dev->speed == STM32_I2C_SPEED_STANDARD) trise = freq + 1; else trise = freq * 3 / 10 + 1; writel_relaxed(STM32F4_I2C_TRISE_VALUE(trise), i2c_dev->base + STM32F4_I2C_TRISE); } static void stm32f4_i2c_set_speed_mode(struct stm32f4_i2c_dev *i2c_dev) { u32 val; u32 ccr = 0; if (i2c_dev->speed == STM32_I2C_SPEED_STANDARD) { /* * In standard mode: * t_scl_high = t_scl_low = CCR * I2C parent clk period * So to reach 100 kHz, we have: * CCR = I2C parent rate / 100 kHz >> 1 * * For example with parent rate = 2 MHz: * CCR = 2000000 / (100000 << 1) = 10 * t_scl_high = t_scl_low = 10 * (1 / 2000000) = 5000 ns * t_scl_high + t_scl_low = 10000 ns so 100 kHz is reached * * Function stm32f4_i2c_set_periph_clk_freq made sure that * parent rate is not higher than 46 MHz . As a result val * is at most 8 bits wide and so fits into the CCR bits [11:0]. */ val = i2c_dev->parent_rate / (100000 << 1); } else { /* * In fast mode, we compute CCR with duty = 0 as with low * frequencies we are not able to reach 400 kHz. * In that case: * t_scl_high = CCR * I2C parent clk period * t_scl_low = 2 * CCR * I2C parent clk period * So, CCR = I2C parent rate / (400 kHz * 3) * * For example with parent rate = 6 MHz: * CCR = 6000000 / (400000 * 3) = 5 * t_scl_high = 5 * (1 / 6000000) = 833 ns > 600 ns * t_scl_low = 2 * 5 * (1 / 6000000) = 1667 ns > 1300 ns * t_scl_high + t_scl_low = 2500 ns so 400 kHz is reached * * Function stm32f4_i2c_set_periph_clk_freq made sure that * parent rate is not higher than 46 MHz . As a result val * is at most 6 bits wide and so fits into the CCR bits [11:0]. */ val = DIV_ROUND_UP(i2c_dev->parent_rate, 400000 * 3); /* Select Fast mode */ ccr |= STM32F4_I2C_CCR_FS; } ccr |= STM32F4_I2C_CCR_CCR(val); writel_relaxed(ccr, i2c_dev->base + STM32F4_I2C_CCR); } /** * stm32f4_i2c_hw_config() - Prepare I2C block * @i2c_dev: Controller's private data */ static int stm32f4_i2c_hw_config(struct stm32f4_i2c_dev *i2c_dev) { int ret; ret = stm32f4_i2c_set_periph_clk_freq(i2c_dev); if (ret) return ret; stm32f4_i2c_set_rise_time(i2c_dev); stm32f4_i2c_set_speed_mode(i2c_dev); /* Enable I2C */ writel_relaxed(STM32F4_I2C_CR1_PE, i2c_dev->base + STM32F4_I2C_CR1); return 0; } static int stm32f4_i2c_wait_free_bus(struct stm32f4_i2c_dev *i2c_dev) { u32 status; int ret; ret = readl_relaxed_poll_timeout(i2c_dev->base + STM32F4_I2C_SR2, status, !(status & STM32F4_I2C_SR2_BUSY), 10, 1000); if (ret) { dev_dbg(i2c_dev->dev, "bus not free\n"); ret = -EBUSY; } return ret; } /** * stm32f4_i2c_write_ byte() - Write a byte in the data register * @i2c_dev: Controller's private data * @byte: Data to write in the register */ static void stm32f4_i2c_write_byte(struct stm32f4_i2c_dev *i2c_dev, u8 byte) { writel_relaxed(byte, i2c_dev->base + STM32F4_I2C_DR); } /** * stm32f4_i2c_write_msg() - Fill the data register in write mode * @i2c_dev: Controller's private data * * This function fills the data register with I2C transfer buffer */ static void stm32f4_i2c_write_msg(struct stm32f4_i2c_dev *i2c_dev) { struct stm32f4_i2c_msg *msg = &i2c_dev->msg; stm32f4_i2c_write_byte(i2c_dev, *msg->buf++); msg->count--; } static void stm32f4_i2c_read_msg(struct stm32f4_i2c_dev *i2c_dev) { struct stm32f4_i2c_msg *msg = &i2c_dev->msg; u32 rbuf; rbuf = readl_relaxed(i2c_dev->base + STM32F4_I2C_DR); *msg->buf++ = rbuf; msg->count--; } static void stm32f4_i2c_terminate_xfer(struct stm32f4_i2c_dev *i2c_dev) { struct stm32f4_i2c_msg *msg = &i2c_dev->msg; void __iomem *reg; stm32f4_i2c_disable_irq(i2c_dev); reg = i2c_dev->base + STM32F4_I2C_CR1; if (msg->stop) stm32f4_i2c_set_bits(reg, STM32F4_I2C_CR1_STOP); else stm32f4_i2c_set_bits(reg, STM32F4_I2C_CR1_START); complete(&i2c_dev->complete); } /** * stm32f4_i2c_handle_write() - Handle FIFO empty interrupt in case of write * @i2c_dev: Controller's private data */ static void stm32f4_i2c_handle_write(struct stm32f4_i2c_dev *i2c_dev) { struct stm32f4_i2c_msg *msg = &i2c_dev->msg; void __iomem *reg = i2c_dev->base + STM32F4_I2C_CR2; if (msg->count) { stm32f4_i2c_write_msg(i2c_dev); if (!msg->count) { /* * Disable buffer interrupts for RX not empty and TX * empty events */ stm32f4_i2c_clr_bits(reg, STM32F4_I2C_CR2_ITBUFEN); } } else { stm32f4_i2c_terminate_xfer(i2c_dev); } } /** * stm32f4_i2c_handle_read() - Handle FIFO empty interrupt in case of read * @i2c_dev: Controller's private data * * This function is called when a new data is received in data register */ static void stm32f4_i2c_handle_read(struct stm32f4_i2c_dev *i2c_dev) { struct stm32f4_i2c_msg *msg = &i2c_dev->msg; void __iomem *reg = i2c_dev->base + STM32F4_I2C_CR2; switch (msg->count) { case 1: stm32f4_i2c_disable_irq(i2c_dev); stm32f4_i2c_read_msg(i2c_dev); complete(&i2c_dev->complete); break; /* * For 2-byte reception, 3-byte reception and for Data N-2, N-1 and N * for N-byte reception with N > 3, we do not have to read the data * register when RX not empty event occurs as we have to wait for byte * transferred finished event before reading data. * So, here we just disable buffer interrupt in order to avoid another * system preemption due to RX not empty event. */ case 2: case 3: stm32f4_i2c_clr_bits(reg, STM32F4_I2C_CR2_ITBUFEN); break; /* * For N byte reception with N > 3 we directly read data register * until N-2 data. */ default: stm32f4_i2c_read_msg(i2c_dev); } } /** * stm32f4_i2c_handle_rx_done() - Handle byte transfer finished interrupt * in case of read * @i2c_dev: Controller's private data * * This function is called when a new data is received in the shift register * but data register has not been read yet. */ static void stm32f4_i2c_handle_rx_done(struct stm32f4_i2c_dev *i2c_dev) { struct stm32f4_i2c_msg *msg = &i2c_dev->msg; void __iomem *reg; u32 mask; int i; switch (msg->count) { case 2: /* * In order to correctly send the Stop or Repeated Start * condition on the I2C bus, the STOP/START bit has to be set * before reading the last two bytes (data N-1 and N). * After that, we could read the last two bytes, disable * remaining interrupts and notify the end of xfer to the * client */ reg = i2c_dev->base + STM32F4_I2C_CR1; if (msg->stop) stm32f4_i2c_set_bits(reg, STM32F4_I2C_CR1_STOP); else stm32f4_i2c_set_bits(reg, STM32F4_I2C_CR1_START); for (i = 2; i > 0; i--) stm32f4_i2c_read_msg(i2c_dev); reg = i2c_dev->base + STM32F4_I2C_CR2; mask = STM32F4_I2C_CR2_ITEVTEN | STM32F4_I2C_CR2_ITERREN; stm32f4_i2c_clr_bits(reg, mask); complete(&i2c_dev->complete); break; case 3: /* * In order to correctly generate the NACK pulse after the last * received data byte, we have to enable NACK before reading N-2 * data */ reg = i2c_dev->base + STM32F4_I2C_CR1; stm32f4_i2c_clr_bits(reg, STM32F4_I2C_CR1_ACK); stm32f4_i2c_read_msg(i2c_dev); break; default: stm32f4_i2c_read_msg(i2c_dev); } } /** * stm32f4_i2c_handle_rx_addr() - Handle address matched interrupt in case of * master receiver * @i2c_dev: Controller's private data */ static void stm32f4_i2c_handle_rx_addr(struct stm32f4_i2c_dev *i2c_dev) { struct stm32f4_i2c_msg *msg = &i2c_dev->msg; u32 cr1; switch (msg->count) { case 0: stm32f4_i2c_terminate_xfer(i2c_dev); /* Clear ADDR flag */ readl_relaxed(i2c_dev->base + STM32F4_I2C_SR2); break; case 1: /* * Single byte reception: * Enable NACK and reset POS (Acknowledge position). * Then, clear ADDR flag and set STOP or RepSTART. * In that way, the NACK and STOP or RepStart pulses will be * sent as soon as the byte will be received in shift register */ cr1 = readl_relaxed(i2c_dev->base + STM32F4_I2C_CR1); cr1 &= ~(STM32F4_I2C_CR1_ACK | STM32F4_I2C_CR1_POS); writel_relaxed(cr1, i2c_dev->base + STM32F4_I2C_CR1); readl_relaxed(i2c_dev->base + STM32F4_I2C_SR2); if (msg->stop) cr1 |= STM32F4_I2C_CR1_STOP; else cr1 |= STM32F4_I2C_CR1_START; writel_relaxed(cr1, i2c_dev->base + STM32F4_I2C_CR1); break; case 2: /* * 2-byte reception: * Enable NACK, set POS (NACK position) and clear ADDR flag. * In that way, NACK will be sent for the next byte which will * be received in the shift register instead of the current * one. */ cr1 = readl_relaxed(i2c_dev->base + STM32F4_I2C_CR1); cr1 &= ~STM32F4_I2C_CR1_ACK; cr1 |= STM32F4_I2C_CR1_POS; writel_relaxed(cr1, i2c_dev->base + STM32F4_I2C_CR1); readl_relaxed(i2c_dev->base + STM32F4_I2C_SR2); break; default: /* * N-byte reception: * Enable ACK, reset POS (ACK postion) and clear ADDR flag. * In that way, ACK will be sent as soon as the current byte * will be received in the shift register */ cr1 = readl_relaxed(i2c_dev->base + STM32F4_I2C_CR1); cr1 |= STM32F4_I2C_CR1_ACK; cr1 &= ~STM32F4_I2C_CR1_POS; writel_relaxed(cr1, i2c_dev->base + STM32F4_I2C_CR1); readl_relaxed(i2c_dev->base + STM32F4_I2C_SR2); break; } } /** * stm32f4_i2c_isr_event() - Interrupt routine for I2C bus event * @irq: interrupt number * @data: Controller's private data */ static irqreturn_t stm32f4_i2c_isr_event(int irq, void *data) { struct stm32f4_i2c_dev *i2c_dev = data; struct stm32f4_i2c_msg *msg = &i2c_dev->msg; u32 possible_status = STM32F4_I2C_SR1_ITEVTEN_MASK; u32 status, ien, event, cr2; cr2 = readl_relaxed(i2c_dev->base + STM32F4_I2C_CR2); ien = cr2 & STM32F4_I2C_CR2_IRQ_MASK; /* Update possible_status if buffer interrupt is enabled */ if (ien & STM32F4_I2C_CR2_ITBUFEN) possible_status |= STM32F4_I2C_SR1_ITBUFEN_MASK; status = readl_relaxed(i2c_dev->base + STM32F4_I2C_SR1); event = status & possible_status; if (!event) { dev_dbg(i2c_dev->dev, "spurious evt irq (status=0x%08x, ien=0x%08x)\n", status, ien); return IRQ_NONE; } /* Start condition generated */ if (event & STM32F4_I2C_SR1_SB) stm32f4_i2c_write_byte(i2c_dev, msg->addr); /* I2C Address sent */ if (event & STM32F4_I2C_SR1_ADDR) { if (msg->addr & I2C_M_RD) stm32f4_i2c_handle_rx_addr(i2c_dev); else readl_relaxed(i2c_dev->base + STM32F4_I2C_SR2); /* * Enable buffer interrupts for RX not empty and TX empty * events */ cr2 |= STM32F4_I2C_CR2_ITBUFEN; writel_relaxed(cr2, i2c_dev->base + STM32F4_I2C_CR2); } /* TX empty */ if ((event & STM32F4_I2C_SR1_TXE) && !(msg->addr & I2C_M_RD)) stm32f4_i2c_handle_write(i2c_dev); /* RX not empty */ if ((event & STM32F4_I2C_SR1_RXNE) && (msg->addr & I2C_M_RD)) stm32f4_i2c_handle_read(i2c_dev); /* * The BTF (Byte Transfer finished) event occurs when: * - in reception : a new byte is received in the shift register * but the previous byte has not been read yet from data register * - in transmission: a new byte should be sent but the data register * has not been written yet */ if (event & STM32F4_I2C_SR1_BTF) { if (msg->addr & I2C_M_RD) stm32f4_i2c_handle_rx_done(i2c_dev); else stm32f4_i2c_handle_write(i2c_dev); } return IRQ_HANDLED; } /** * stm32f4_i2c_isr_error() - Interrupt routine for I2C bus error * @irq: interrupt number * @data: Controller's private data */ static irqreturn_t stm32f4_i2c_isr_error(int irq, void *data) { struct stm32f4_i2c_dev *i2c_dev = data; struct stm32f4_i2c_msg *msg = &i2c_dev->msg; void __iomem *reg; u32 status; status = readl_relaxed(i2c_dev->base + STM32F4_I2C_SR1); /* Arbitration lost */ if (status & STM32F4_I2C_SR1_ARLO) { status &= ~STM32F4_I2C_SR1_ARLO; writel_relaxed(status, i2c_dev->base + STM32F4_I2C_SR1); msg->result = -EAGAIN; } /* * Acknowledge failure: * In master transmitter mode a Stop must be generated by software */ if (status & STM32F4_I2C_SR1_AF) { if (!(msg->addr & I2C_M_RD)) { reg = i2c_dev->base + STM32F4_I2C_CR1; stm32f4_i2c_set_bits(reg, STM32F4_I2C_CR1_STOP); } status &= ~STM32F4_I2C_SR1_AF; writel_relaxed(status, i2c_dev->base + STM32F4_I2C_SR1); msg->result = -EIO; } /* Bus error */ if (status & STM32F4_I2C_SR1_BERR) { status &= ~STM32F4_I2C_SR1_BERR; writel_relaxed(status, i2c_dev->base + STM32F4_I2C_SR1); msg->result = -EIO; } stm32f4_i2c_disable_irq(i2c_dev); complete(&i2c_dev->complete); return IRQ_HANDLED; } /** * stm32f4_i2c_xfer_msg() - Transfer a single I2C message * @i2c_dev: Controller's private data * @msg: I2C message to transfer * @is_first: first message of the sequence * @is_last: last message of the sequence */ static int stm32f4_i2c_xfer_msg(struct stm32f4_i2c_dev *i2c_dev, struct i2c_msg *msg, bool is_first, bool is_last) { struct stm32f4_i2c_msg *f4_msg = &i2c_dev->msg; void __iomem *reg = i2c_dev->base + STM32F4_I2C_CR1; unsigned long timeout; u32 mask; int ret; f4_msg->addr = i2c_8bit_addr_from_msg(msg); f4_msg->buf = msg->buf; f4_msg->count = msg->len; f4_msg->result = 0; f4_msg->stop = is_last; reinit_completion(&i2c_dev->complete); /* Enable events and errors interrupts */ mask = STM32F4_I2C_CR2_ITEVTEN | STM32F4_I2C_CR2_ITERREN; stm32f4_i2c_set_bits(i2c_dev->base + STM32F4_I2C_CR2, mask); if (is_first) { ret = stm32f4_i2c_wait_free_bus(i2c_dev); if (ret) return ret; /* START generation */ stm32f4_i2c_set_bits(reg, STM32F4_I2C_CR1_START); } timeout = wait_for_completion_timeout(&i2c_dev->complete, i2c_dev->adap.timeout); ret = f4_msg->result; if (!timeout) ret = -ETIMEDOUT; return ret; } /** * stm32f4_i2c_xfer() - Transfer combined I2C message * @i2c_adap: Adapter pointer to the controller * @msgs: Pointer to data to be written. * @num: Number of messages to be executed */ static int stm32f4_i2c_xfer(struct i2c_adapter *i2c_adap, struct i2c_msg msgs[], int num) { struct stm32f4_i2c_dev *i2c_dev = i2c_get_adapdata(i2c_adap); int ret, i; ret = clk_enable(i2c_dev->clk); if (ret) { dev_err(i2c_dev->dev, "Failed to enable clock\n"); return ret; } for (i = 0; i < num && !ret; i++) ret = stm32f4_i2c_xfer_msg(i2c_dev, &msgs[i], i == 0, i == num - 1); clk_disable(i2c_dev->clk); return (ret < 0) ? ret : num; } static u32 stm32f4_i2c_func(struct i2c_adapter *adap) { return I2C_FUNC_I2C | I2C_FUNC_SMBUS_EMUL; } static const struct i2c_algorithm stm32f4_i2c_algo = { .master_xfer = stm32f4_i2c_xfer, .functionality = stm32f4_i2c_func, }; static int stm32f4_i2c_probe(struct platform_device *pdev) { struct device_node *np = pdev->dev.of_node; struct stm32f4_i2c_dev *i2c_dev; struct resource *res; u32 irq_event, irq_error, clk_rate; struct i2c_adapter *adap; struct reset_control *rst; int ret; i2c_dev = devm_kzalloc(&pdev->dev, sizeof(*i2c_dev), GFP_KERNEL); if (!i2c_dev) return -ENOMEM; res = platform_get_resource(pdev, IORESOURCE_MEM, 0); i2c_dev->base = devm_ioremap_resource(&pdev->dev, res); if (IS_ERR(i2c_dev->base)) return PTR_ERR(i2c_dev->base); irq_event = irq_of_parse_and_map(np, 0); if (!irq_event) { dev_err(&pdev->dev, "IRQ event missing or invalid\n"); return -EINVAL; } irq_error = irq_of_parse_and_map(np, 1); if (!irq_error) { dev_err(&pdev->dev, "IRQ error missing or invalid\n"); return -EINVAL; } i2c_dev->clk = devm_clk_get(&pdev->dev, NULL); if (IS_ERR(i2c_dev->clk)) { dev_err(&pdev->dev, "Error: Missing controller clock\n"); return PTR_ERR(i2c_dev->clk); } ret = clk_prepare_enable(i2c_dev->clk); if (ret) { dev_err(i2c_dev->dev, "Failed to prepare_enable clock\n"); return ret; } rst = devm_reset_control_get_exclusive(&pdev->dev, NULL); if (IS_ERR(rst)) { ret = PTR_ERR(rst); if (ret != -EPROBE_DEFER) dev_err(&pdev->dev, "Error: Missing reset ctrl\n"); goto clk_free; } reset_control_assert(rst); udelay(2); reset_control_deassert(rst); i2c_dev->speed = STM32_I2C_SPEED_STANDARD; ret = of_property_read_u32(np, "clock-frequency", &clk_rate); if (!ret && clk_rate >= 400000) i2c_dev->speed = STM32_I2C_SPEED_FAST; i2c_dev->dev = &pdev->dev; ret = devm_request_irq(&pdev->dev, irq_event, stm32f4_i2c_isr_event, 0, pdev->name, i2c_dev); if (ret) { dev_err(&pdev->dev, "Failed to request irq event %i\n", irq_event); goto clk_free; } ret = devm_request_irq(&pdev->dev, irq_error, stm32f4_i2c_isr_error, 0, pdev->name, i2c_dev); if (ret) { dev_err(&pdev->dev, "Failed to request irq error %i\n", irq_error); goto clk_free; } ret = stm32f4_i2c_hw_config(i2c_dev); if (ret) goto clk_free; adap = &i2c_dev->adap; i2c_set_adapdata(adap, i2c_dev); snprintf(adap->name, sizeof(adap->name), "STM32 I2C(%pa)", &res->start); adap->owner = THIS_MODULE; adap->timeout = 2 * HZ; adap->retries = 0; adap->algo = &stm32f4_i2c_algo; adap->dev.parent = &pdev->dev; adap->dev.of_node = pdev->dev.of_node; init_completion(&i2c_dev->complete); ret = i2c_add_adapter(adap); if (ret) goto clk_free; platform_set_drvdata(pdev, i2c_dev); clk_disable(i2c_dev->clk); dev_info(i2c_dev->dev, "STM32F4 I2C driver registered\n"); return 0; clk_free: clk_disable_unprepare(i2c_dev->clk); return ret; } static int stm32f4_i2c_remove(struct platform_device *pdev) { struct stm32f4_i2c_dev *i2c_dev = platform_get_drvdata(pdev); i2c_del_adapter(&i2c_dev->adap); clk_unprepare(i2c_dev->clk); return 0; } static const struct of_device_id stm32f4_i2c_match[] = { { .compatible = "st,stm32f4-i2c", }, {}, }; MODULE_DEVICE_TABLE(of, stm32f4_i2c_match); static struct platform_driver stm32f4_i2c_driver = { .driver = { .name = "stm32f4-i2c", .of_match_table = stm32f4_i2c_match, }, .probe = stm32f4_i2c_probe, .remove = stm32f4_i2c_remove, }; module_platform_driver(stm32f4_i2c_driver); MODULE_AUTHOR("M'boumba Cedric Madianga "); MODULE_DESCRIPTION("STMicroelectronics STM32F4 I2C driver"); MODULE_LICENSE("GPL v2");