This patch adds initial support for the STM32F7 I2C controller. Signed-off-by: M'boumba Cedric Madianga <cedric.madianga@xxxxxxxxx> --- drivers/i2c/busses/Kconfig | 10 + drivers/i2c/busses/Makefile | 1 + drivers/i2c/busses/i2c-stm32f7.c | 562 +++++++++++++++++++++++++++++++++++++++ 3 files changed, 573 insertions(+) create mode 100644 drivers/i2c/busses/i2c-stm32f7.c diff --git a/drivers/i2c/busses/Kconfig b/drivers/i2c/busses/Kconfig index 8adc0f1..ab0caec 100644 --- a/drivers/i2c/busses/Kconfig +++ b/drivers/i2c/busses/Kconfig @@ -897,6 +897,16 @@ config I2C_STM32F4 This driver can also be built as module. If so, the module will be called i2c-stm32f4. +config I2C_STM32F7 + tristate "STMicroelectronics STM32F7 I2C support" + depends on ARCH_STM32 || COMPILE_TEST + help + Enable this option to add support for STM32 I2C controller embedded + in STM32F7 SoCs. + + This driver can also be built as module. If so, the module + will be called i2c-stm32f7. + config I2C_STU300 tristate "ST Microelectronics DDC I2C interface" depends on MACH_U300 diff --git a/drivers/i2c/busses/Makefile b/drivers/i2c/busses/Makefile index 30b6085..5449ece 100644 --- a/drivers/i2c/busses/Makefile +++ b/drivers/i2c/busses/Makefile @@ -86,6 +86,7 @@ obj-$(CONFIG_I2C_SIMTEC) += i2c-simtec.o obj-$(CONFIG_I2C_SIRF) += i2c-sirf.o obj-$(CONFIG_I2C_ST) += i2c-st.o obj-$(CONFIG_I2C_STM32F4) += i2c-stm32f4.o +obj-$(CONFIG_I2C_STM32F7) += i2c-stm32f7.o obj-$(CONFIG_I2C_STU300) += i2c-stu300.o obj-$(CONFIG_I2C_SUN6I_P2WI) += i2c-sun6i-p2wi.o obj-$(CONFIG_I2C_TEGRA) += i2c-tegra.o diff --git a/drivers/i2c/busses/i2c-stm32f7.c b/drivers/i2c/busses/i2c-stm32f7.c new file mode 100644 index 0000000..844a98b --- /dev/null +++ b/drivers/i2c/busses/i2c-stm32f7.c @@ -0,0 +1,562 @@ +/* + * Driver for STMicroelectronics STM32F7 I2C controller + * + * This I2C controller is described in the STM32F75xxx and STM32F74xxx Soc + * reference manual. + * Please see below a link to the documentation: + * http://www.st.com/resource/en/reference_manual/dm00124865.pdf + * + * Copyright (C) M'boumba Cedric Madianga 2017 + * Author: M'boumba Cedric Madianga <cedric.madianga@xxxxxxxxx> + * + * This driver is based on i2c-stm32f4.c + * + * License terms: GNU General Public License (GPL), version 2 + */ +#include <linux/clk.h> +#include <linux/delay.h> +#include <linux/err.h> +#include <linux/i2c.h> +#include <linux/interrupt.h> +#include <linux/io.h> +#include <linux/iopoll.h> +#include <linux/module.h> +#include <linux/of.h> +#include <linux/of_address.h> +#include <linux/of_irq.h> +#include <linux/platform_device.h> +#include <linux/reset.h> + +#include "i2c-stm32.h" + +/* STM32F7 I2C registers */ +#define STM32F7_I2C_CR1 0x00 +#define STM32F7_I2C_CR2 0x04 +#define STM32F7_I2C_TIMINGR 0x10 +#define STM32F7_I2C_ISR 0x18 +#define STM32F7_I2C_ICR 0x1C +#define STM32F7_I2C_RXDR 0x24 +#define STM32F7_I2C_TXDR 0x28 + +/* STM32F7 I2C control 1 */ +#define STM32F7_I2C_CR1_ERRIE BIT(7) +#define STM32F7_I2C_CR1_TCIE BIT(6) +#define STM32F7_I2C_CR1_STOPIE BIT(5) +#define STM32F7_I2C_CR1_NACKIE BIT(4) +#define STM32F7_I2C_CR1_ADDRIE BIT(3) +#define STM32F7_I2C_CR1_RXIE BIT(2) +#define STM32F7_I2C_CR1_TXIE BIT(1) +#define STM32F7_I2C_CR1_PE BIT(0) +#define STM32F7_I2C_ALL_IRQ_MASK (STM32F7_I2C_CR1_ERRIE \ + | STM32F7_I2C_CR1_TCIE \ + | STM32F7_I2C_CR1_STOPIE \ + | STM32F7_I2C_CR1_NACKIE \ + | STM32F7_I2C_CR1_RXIE \ + | STM32F7_I2C_CR1_TXIE) + +/* STM32F7 I2C control 2 */ +#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) +#define STM32F7_I2C_CR2_NACK BIT(15) +#define STM32F7_I2C_CR2_STOP BIT(14) +#define STM32F7_I2C_CR2_START BIT(13) +#define STM32F7_I2C_CR2_RD_WRN BIT(10) +#define STM32F7_I2C_CR2_SADD7_MASK GENMASK(7, 1) +#define STM32F7_I2C_CR2_SADD7(n) (((n) & 0x7f) << 1) + +/* STM32F7 I2C Interrupt Status */ +#define STM32F7_I2C_ISR_BUSY BIT(15) +#define STM32F7_I2C_ISR_ARLO BIT(9) +#define STM32F7_I2C_ISR_BERR BIT(8) +#define STM32F7_I2C_ISR_TCR BIT(7) +#define STM32F7_I2C_ISR_TC BIT(6) +#define STM32F7_I2C_ISR_STOPF BIT(5) +#define STM32F7_I2C_ISR_NACKF BIT(4) +#define STM32F7_I2C_ISR_RXNE BIT(2) +#define STM32F7_I2C_ISR_TXIS BIT(1) + +/* STM32F7 I2C Interrupt Clear */ +#define STM32F7_I2C_ICR_ARLOCF BIT(9) +#define STM32F7_I2C_ICR_BERRCF BIT(8) +#define STM32F7_I2C_ICR_STOPCF BIT(5) +#define STM32F7_I2C_ICR_NACKCF BIT(4) + +#define STM32F7_I2C_MAX_LEN 0xff + +/** + * struct stm32f7_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 stm32f7_i2c_msg { + u8 addr; + u32 count; + u8 *buf; + int result; + bool stop; +}; + +/** + * struct stm32f7_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, Fast or Fast+ + * @msg: Pointer to data to be written + * @msg_num: number of I2C messages to be executed + * @msg_id: message identifiant + * @f7_msg: customized i2c msg for driver usage + */ +struct stm32f7_i2c_dev { + struct i2c_adapter adap; + struct device *dev; + void __iomem *base; + struct completion complete; + struct clk *clk; + int speed; + struct i2c_msg *msg; + unsigned int msg_num; + unsigned int msg_id; + struct stm32f7_i2c_msg f7_msg; +}; + +static inline void stm32f7_i2c_set_bits(void __iomem *reg, u32 mask) +{ + writel_relaxed(readl_relaxed(reg) | mask, reg); +} + +static inline void stm32f7_i2c_clr_bits(void __iomem *reg, u32 mask) +{ + writel_relaxed(readl_relaxed(reg) & ~mask, reg); +} + +static int stm32f7_i2c_hw_config(struct stm32f7_i2c_dev *i2c_dev) +{ + struct device_node *of_node = i2c_dev->dev->of_node; + u32 timing; + int ret; + + ret = of_property_read_u32(of_node, "st,i2c-timing", &timing); + if (ret) { + dev_err(i2c_dev->dev, "Error: missing i2c timing property\n"); + return ret; + } + + /* Timing settings */ + writel_relaxed(timing, i2c_dev->base + STM32F7_I2C_TIMINGR); + + /* Enable I2C */ + writel_relaxed(STM32F7_I2C_CR1_PE, i2c_dev->base + STM32F7_I2C_CR1); + + return 0; +} + +static void stm32f7_i2c_write_tx_data(struct stm32f7_i2c_dev *i2c_dev) +{ + struct stm32f7_i2c_msg *f7_msg = &i2c_dev->f7_msg; + void __iomem *base = i2c_dev->base; + + if (f7_msg->count) { + writeb_relaxed(*f7_msg->buf++, base + STM32F7_I2C_TXDR); + f7_msg->count--; + } +} + +static void stm32f7_i2c_read_rx_data(struct stm32f7_i2c_dev *i2c_dev) +{ + struct stm32f7_i2c_msg *f7_msg = &i2c_dev->f7_msg; + void __iomem *base = i2c_dev->base; + + if (f7_msg->count) { + *f7_msg->buf++ = readb_relaxed(base + STM32F7_I2C_RXDR); + f7_msg->count--; + } +} + +static void stm32f7_i2c_reload(struct stm32f7_i2c_dev *i2c_dev) +{ + struct stm32f7_i2c_msg *f7_msg = &i2c_dev->f7_msg; + u32 cr2; + + cr2 = readl_relaxed(i2c_dev->base + STM32F7_I2C_CR2); + + cr2 &= ~STM32F7_I2C_CR2_NBYTES_MASK; + if (f7_msg->count > STM32F7_I2C_MAX_LEN) { + cr2 |= STM32F7_I2C_CR2_NBYTES(STM32F7_I2C_MAX_LEN); + } else { + cr2 &= ~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; + int ret; + + ret = readl_relaxed_poll_timeout(i2c_dev->base + STM32F7_I2C_ISR, + status, + !(status & STM32F7_I2C_ISR_BUSY), + 10, 1000); + if (ret) { + dev_dbg(i2c_dev->dev, "bus busy\n"); + ret = -EBUSY; + } + + return ret; +} + +static void stm32f7_i2c_xfer_msg(struct stm32f7_i2c_dev *i2c_dev, + struct i2c_msg *msg) +{ + struct stm32f7_i2c_msg *f7_msg = &i2c_dev->f7_msg; + void __iomem *base = i2c_dev->base; + u32 cr1, cr2; + + f7_msg->addr = msg->addr; + f7_msg->buf = msg->buf; + f7_msg->count = msg->len; + f7_msg->result = 0; + f7_msg->stop = (i2c_dev->msg_id >= i2c_dev->msg_num - 1); + + reinit_completion(&i2c_dev->complete); + + cr1 = readl_relaxed(base + STM32F7_I2C_CR1); + cr2 = readl_relaxed(base + STM32F7_I2C_CR2); + + /* Set transfer direction */ + cr2 &= ~STM32F7_I2C_CR2_RD_WRN; + if (msg->flags & I2C_M_RD) + cr2 |= STM32F7_I2C_CR2_RD_WRN; + + /* Set slave address */ + cr2 &= ~STM32F7_I2C_CR2_SADD7_MASK; + cr2 |= STM32F7_I2C_CR2_SADD7(f7_msg->addr); + + /* Set nb bytes to transfer and reload if needed */ + cr2 &= ~(STM32F7_I2C_CR2_NBYTES_MASK | STM32F7_I2C_CR2_RELOAD); + if (f7_msg->count > STM32F7_I2C_MAX_LEN) { + cr2 |= STM32F7_I2C_CR2_NBYTES(STM32F7_I2C_MAX_LEN); + cr2 |= STM32F7_I2C_CR2_RELOAD; + } else { + 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 (msg->flags & I2C_M_RD) + cr1 |= STM32F7_I2C_CR1_RXIE; + else + cr1 |= STM32F7_I2C_CR1_TXIE; + + /* Configure Start/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 void stm32f7_i2c_disable_irq(struct stm32f7_i2c_dev *i2c_dev, u32 mask) +{ + stm32f7_i2c_clr_bits(i2c_dev->base + STM32F7_I2C_CR1, mask); +} + +static irqreturn_t stm32f7_i2c_isr_event(int irq, void *data) +{ + struct stm32f7_i2c_dev *i2c_dev = data; + struct stm32f7_i2c_msg *f7_msg = &i2c_dev->f7_msg; + void __iomem *base = i2c_dev->base; + u32 status, mask; + + status = readl_relaxed(i2c_dev->base + STM32F7_I2C_ISR); + + /* Tx empty */ + if (status & STM32F7_I2C_ISR_TXIS) + stm32f7_i2c_write_tx_data(i2c_dev); + + /* RX not empty */ + if (status & STM32F7_I2C_ISR_RXNE) + stm32f7_i2c_read_rx_data(i2c_dev); + + /* NACK received */ + if (status & STM32F7_I2C_ISR_NACKF) { + dev_dbg(i2c_dev->dev, "<%s>: Receive NACK\n", __func__); + writel_relaxed(STM32F7_I2C_ICR_NACKCF, base + STM32F7_I2C_ICR); + f7_msg->result = -EBADE; + } + + /* STOP detection flag */ + if (status & STM32F7_I2C_ISR_STOPF) { + /* Disable interrupts */ + stm32f7_i2c_disable_irq(i2c_dev, STM32F7_I2C_ALL_IRQ_MASK); + + /* Clear STOP flag */ + writel_relaxed(STM32F7_I2C_ICR_STOPCF, base + STM32F7_I2C_ICR); + + complete(&i2c_dev->complete); + } + + /* Transfer complete */ + if (status & STM32F7_I2C_ISR_TC) { + if (f7_msg->stop) { + mask = STM32F7_I2C_CR2_STOP; + stm32f7_i2c_set_bits(base + STM32F7_I2C_CR2, mask); + } else { + i2c_dev->msg_id++; + i2c_dev->msg++; + stm32f7_i2c_xfer_msg(i2c_dev, i2c_dev->msg); + } + } + + /* + * 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); + + return IRQ_HANDLED; +} + +static irqreturn_t stm32f7_i2c_isr_error(int irq, void *data) +{ + struct stm32f7_i2c_dev *i2c_dev = data; + struct stm32f7_i2c_msg *f7_msg = &i2c_dev->f7_msg; + void __iomem *base = i2c_dev->base; + struct device *dev = i2c_dev->dev; + u32 status; + + status = readl_relaxed(i2c_dev->base + STM32F7_I2C_ISR); + + /* Bus error */ + if (status & STM32F7_I2C_ISR_BERR) { + dev_err(dev, "<%s>: Bus error\n", __func__); + writel_relaxed(STM32F7_I2C_ICR_BERRCF, base + STM32F7_I2C_ICR); + f7_msg->result = -EIO; + } + + /* Arbitration loss */ + if (status & STM32F7_I2C_ISR_ARLO) { + dev_err(dev, "<%s>: Arbitration loss\n", __func__); + writel_relaxed(STM32F7_I2C_ICR_ARLOCF, base + STM32F7_I2C_ICR); + f7_msg->result = -EAGAIN; + } + + stm32f7_i2c_disable_irq(i2c_dev, STM32F7_I2C_ALL_IRQ_MASK); + + complete(&i2c_dev->complete); + + return IRQ_HANDLED; +} + +static int stm32f7_i2c_xfer(struct i2c_adapter *i2c_adap, + struct i2c_msg msgs[], int num) +{ + struct stm32f7_i2c_dev *i2c_dev = i2c_get_adapdata(i2c_adap); + struct stm32f7_i2c_msg *f7_msg = &i2c_dev->f7_msg; + unsigned long timeout; + int ret; + + i2c_dev->msg = msgs; + i2c_dev->msg_num = num; + i2c_dev->msg_id = 0; + + 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; + + stm32f7_i2c_xfer_msg(i2c_dev, msgs); + + timeout = wait_for_completion_timeout(&i2c_dev->complete, + i2c_dev->adap.timeout); + ret = f7_msg->result; + + if (!timeout) { + dev_dbg(i2c_dev->dev, "Access to slave 0x%x timed out\n", + i2c_dev->msg->addr); + ret = -ETIMEDOUT; + } + +clk_free: + clk_disable(i2c_dev->clk); + + return (ret < 0) ? ret : num; +} + +static u32 stm32f7_i2c_func(struct i2c_adapter *adap) +{ + return I2C_FUNC_I2C | I2C_FUNC_SMBUS_EMUL; +} + +static struct i2c_algorithm stm32f7_i2c_algo = { + .master_xfer = stm32f7_i2c_xfer, + .functionality = stm32f7_i2c_func, +}; + +static int stm32f7_i2c_probe(struct platform_device *pdev) +{ + struct device_node *np = pdev->dev.of_node; + struct stm32f7_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(&pdev->dev, "Failed to prepare_enable clock\n"); + return ret; + } + + rst = devm_reset_control_get(&pdev->dev, NULL); + if (IS_ERR(rst)) { + dev_err(&pdev->dev, "Error: Missing controller reset\n"); + ret = PTR_ERR(rst); + 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; + else if ((!ret) && (clk_rate == 1000000)) + i2c_dev->speed = STM32_I2C_SPEED_FAST_PLUS; + + i2c_dev->dev = &pdev->dev; + + ret = devm_request_irq(&pdev->dev, irq_event, stm32f7_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, stm32f7_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 = stm32f7_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), "STM32F7 I2C(%pa)", + &res->start); + adap->owner = THIS_MODULE; + adap->timeout = 2 * HZ; + adap->retries = 0; + adap->algo = &stm32f7_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) { + dev_err(&pdev->dev, "Failed to add adapter\n"); + goto clk_free; + } + + platform_set_drvdata(pdev, i2c_dev); + + clk_disable(i2c_dev->clk); + + dev_info(i2c_dev->dev, "STM32F7 I2C-%d driver registered\n", adap->nr); + + return 0; + +clk_free: + clk_disable_unprepare(i2c_dev->clk); + + return ret; +} + +static int stm32f7_i2c_remove(struct platform_device *pdev) +{ + struct stm32f7_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 stm32f7_i2c_match[] = { + { .compatible = "st,stm32f7-i2c", }, + {}, +}; +MODULE_DEVICE_TABLE(of, stm32f7_i2c_match); + +static struct platform_driver stm32f7_i2c_driver = { + .driver = { + .name = "stm32f7-i2c", + .of_match_table = stm32f7_i2c_match, + }, + .probe = stm32f7_i2c_probe, + .remove = stm32f7_i2c_remove, +}; + +module_platform_driver(stm32f7_i2c_driver); + +MODULE_AUTHOR("M'boumba Cedric Madianga <cedric.madianga@xxxxxxxxx>"); +MODULE_DESCRIPTION("STMicroelectronics STM32F7 I2C driver"); +MODULE_LICENSE("GPL v2"); -- 1.9.1 -- To unsubscribe from this list: send the line "unsubscribe linux-i2c" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
