diff options
Diffstat (limited to 'drivers/i2c/busses/i2c-stm32f7.c')
| -rw-r--r-- | drivers/i2c/busses/i2c-stm32f7.c | 972 |
1 files changed, 972 insertions, 0 deletions
diff --git a/drivers/i2c/busses/i2c-stm32f7.c b/drivers/i2c/busses/i2c-stm32f7.c new file mode 100644 index 000000000000..47c67b0ca896 --- /dev/null +++ b/drivers/i2c/busses/i2c-stm32f7.c @@ -0,0 +1,972 @@ +/* + * 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@gmail.com> + * + * 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/of_platform.h> +#include <linux/platform_device.h> +#include <linux/reset.h> +#include <linux/slab.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_ANFOFF BIT(12) +#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) + +/* STM32F7 I2C Timing */ +#define STM32F7_I2C_TIMINGR_PRESC(n) (((n) & 0xf) << 28) +#define STM32F7_I2C_TIMINGR_SCLDEL(n) (((n) & 0xf) << 20) +#define STM32F7_I2C_TIMINGR_SDADEL(n) (((n) & 0xf) << 16) +#define STM32F7_I2C_TIMINGR_SCLH(n) (((n) & 0xff) << 8) +#define STM32F7_I2C_TIMINGR_SCLL(n) ((n) & 0xff) + +#define STM32F7_I2C_MAX_LEN 0xff + +#define STM32F7_I2C_DNF_DEFAULT 0 +#define STM32F7_I2C_DNF_MAX 16 + +#define STM32F7_I2C_ANALOG_FILTER_ENABLE 1 +#define STM32F7_I2C_ANALOG_FILTER_DELAY_MIN 50 /* ns */ +#define STM32F7_I2C_ANALOG_FILTER_DELAY_MAX 260 /* ns */ + +#define STM32F7_I2C_RISE_TIME_DEFAULT 25 /* ns */ +#define STM32F7_I2C_FALL_TIME_DEFAULT 10 /* ns */ + +#define STM32F7_PRESC_MAX BIT(4) +#define STM32F7_SCLDEL_MAX BIT(4) +#define STM32F7_SDADEL_MAX BIT(4) +#define STM32F7_SCLH_MAX BIT(8) +#define STM32F7_SCLL_MAX BIT(8) + +/** + * struct stm32f7_i2c_spec - private i2c specification timing + * @rate: I2C bus speed (Hz) + * @rate_min: 80% of I2C bus speed (Hz) + * @rate_max: 100% of I2C bus speed (Hz) + * @fall_max: Max fall time of both SDA and SCL signals (ns) + * @rise_max: Max rise time of both SDA and SCL signals (ns) + * @hddat_min: Min data hold time (ns) + * @vddat_max: Max data valid time (ns) + * @sudat_min: Min data setup time (ns) + * @l_min: Min low period of the SCL clock (ns) + * @h_min: Min high period of the SCL clock (ns) + */ +struct stm32f7_i2c_spec { + u32 rate; + u32 rate_min; + u32 rate_max; + u32 fall_max; + u32 rise_max; + u32 hddat_min; + u32 vddat_max; + u32 sudat_min; + u32 l_min; + u32 h_min; +}; + +/** + * struct stm32f7_i2c_setup - private I2C timing setup parameters + * @speed: I2C speed mode (standard, Fast Plus) + * @speed_freq: I2C speed frequency (Hz) + * @clock_src: I2C clock source frequency (Hz) + * @rise_time: Rise time (ns) + * @fall_time: Fall time (ns) + * @dnf: Digital filter coefficient (0-16) + * @analog_filter: Analog filter delay (On/Off) + */ +struct stm32f7_i2c_setup { + enum stm32_i2c_speed speed; + u32 speed_freq; + u32 clock_src; + u32 rise_time; + u32 fall_time; + u8 dnf; + bool analog_filter; +}; + +/** + * struct stm32f7_i2c_timings - private I2C output parameters + * @prec: Prescaler value + * @scldel: Data setup time + * @sdadel: Data hold time + * @sclh: SCL high period (master mode) + * @sclh: SCL low period (master mode) + */ +struct stm32f7_i2c_timings { + struct list_head node; + u8 presc; + u8 scldel; + u8 sdadel; + u8 sclh; + u8 scll; +}; + +/** + * 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 + * @setup: I2C timing input setup + * @timing: I2C computed timings + */ +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; + struct stm32f7_i2c_setup *setup; + struct stm32f7_i2c_timings timing; +}; + +/** + * All these values are coming from I2C Specification, Version 6.0, 4th of + * April 2014. + * + * Table10. Characteristics of the SDA and SCL bus lines for Standard, Fast, + * and Fast-mode Plus I2C-bus devices + */ +static struct stm32f7_i2c_spec i2c_specs[] = { + [STM32_I2C_SPEED_STANDARD] = { + .rate = 100000, + .rate_min = 80000, + .rate_max = 100000, + .fall_max = 300, + .rise_max = 1000, + .hddat_min = 0, + .vddat_max = 3450, + .sudat_min = 250, + .l_min = 4700, + .h_min = 4000, + }, + [STM32_I2C_SPEED_FAST] = { + .rate = 400000, + .rate_min = 320000, + .rate_max = 400000, + .fall_max = 300, + .rise_max = 300, + .hddat_min = 0, + .vddat_max = 900, + .sudat_min = 100, + .l_min = 1300, + .h_min = 600, + }, + [STM32_I2C_SPEED_FAST_PLUS] = { + .rate = 1000000, + .rate_min = 800000, + .rate_max = 1000000, + .fall_max = 100, + .rise_max = 120, + .hddat_min = 0, + .vddat_max = 450, + .sudat_min = 50, + .l_min = 500, + .h_min = 260, + }, +}; + +struct stm32f7_i2c_setup stm32f7_setup = { + .rise_time = STM32F7_I2C_RISE_TIME_DEFAULT, + .fall_time = STM32F7_I2C_FALL_TIME_DEFAULT, + .dnf = STM32F7_I2C_DNF_DEFAULT, + .analog_filter = STM32F7_I2C_ANALOG_FILTER_ENABLE, +}; + +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_compute_timing(struct stm32f7_i2c_dev *i2c_dev, + struct stm32f7_i2c_setup *setup, + struct stm32f7_i2c_timings *output) +{ + u32 p_prev = STM32F7_PRESC_MAX; + u32 i2cclk = DIV_ROUND_CLOSEST(NSEC_PER_SEC, + setup->clock_src); + u32 i2cbus = DIV_ROUND_CLOSEST(NSEC_PER_SEC, + setup->speed_freq); + u32 clk_error_prev = i2cbus; + u32 tsync; + u32 af_delay_min, af_delay_max; + u32 dnf_delay; + u32 clk_min, clk_max; + int sdadel_min, sdadel_max; + int scldel_min; + struct stm32f7_i2c_timings *v, *_v, *s; + struct list_head solutions; + u16 p, l, a, h; + int ret = 0; + + if (setup->speed >= STM32_I2C_SPEED_END) { + dev_err(i2c_dev->dev, "speed out of bound {%d/%d}\n", + setup->speed, STM32_I2C_SPEED_END - 1); + return -EINVAL; + } + + if ((setup->rise_time > i2c_specs[setup->speed].rise_max) || + (setup->fall_time > i2c_specs[setup->speed].fall_max)) { + dev_err(i2c_dev->dev, + "timings out of bound Rise{%d>%d}/Fall{%d>%d}\n", + setup->rise_time, i2c_specs[setup->speed].rise_max, + setup->fall_time, i2c_specs[setup->speed].fall_max); + return -EINVAL; + } + + if (setup->dnf > STM32F7_I2C_DNF_MAX) { + dev_err(i2c_dev->dev, + "DNF out of bound %d/%d\n", + setup->dnf, STM32F7_I2C_DNF_MAX); + return -EINVAL; + } + + if (setup->speed_freq > i2c_specs[setup->speed].rate) { + dev_err(i2c_dev->dev, "ERROR: Freq {%d/%d}\n", + setup->speed_freq, i2c_specs[setup->speed].rate); + return -EINVAL; + } + + /* Analog and Digital Filters */ + af_delay_min = + (setup->analog_filter ? + STM32F7_I2C_ANALOG_FILTER_DELAY_MIN : 0); + af_delay_max = + (setup->analog_filter ? + STM32F7_I2C_ANALOG_FILTER_DELAY_MAX : 0); + dnf_delay = setup->dnf * i2cclk; + + sdadel_min = setup->fall_time - i2c_specs[setup->speed].hddat_min - + af_delay_min - (setup->dnf + 3) * i2cclk; + + sdadel_max = i2c_specs[setup->speed].vddat_max - setup->rise_time - + af_delay_max - (setup->dnf + 4) * i2cclk; + + scldel_min = setup->rise_time + i2c_specs[setup->speed].sudat_min; + + if (sdadel_min < 0) + sdadel_min = 0; + if (sdadel_max < 0) + sdadel_max = 0; + + dev_dbg(i2c_dev->dev, "SDADEL(min/max): %i/%i, SCLDEL(Min): %i\n", + sdadel_min, sdadel_max, scldel_min); + + INIT_LIST_HEAD(&solutions); + /* Compute possible values for PRESC, SCLDEL and SDADEL */ + for (p = 0; p < STM32F7_PRESC_MAX; p++) { + for (l = 0; l < STM32F7_SCLDEL_MAX; l++) { + u32 scldel = (l + 1) * (p + 1) * i2cclk; + + if (scldel < scldel_min) + continue; + + for (a = 0; a < STM32F7_SDADEL_MAX; a++) { + u32 sdadel = (a * (p + 1) + 1) * i2cclk; + + if (((sdadel >= sdadel_min) && + (sdadel <= sdadel_max)) && + (p != p_prev)) { + v = kmalloc(sizeof(*v), GFP_KERNEL); + if (!v) { + ret = -ENOMEM; + goto exit; + } + + v->presc = p; + v->scldel = l; + v->sdadel = a; + p_prev = p; + + list_add_tail(&v->node, + &solutions); + } + } + } + } + + if (list_empty(&solutions)) { + dev_err(i2c_dev->dev, "no Prescaler solution\n"); + ret = -EPERM; + goto exit; + } + + tsync = af_delay_min + dnf_delay + (2 * i2cclk); + s = NULL; + clk_max = NSEC_PER_SEC / i2c_specs[setup->speed].rate_min; + clk_min = NSEC_PER_SEC / i2c_specs[setup->speed].rate_max; + + /* + * Among Prescaler possibilities discovered above figures out SCL Low + * and High Period. Provided: + * - SCL Low Period has to be higher than SCL Clock Low Period + * defined by I2C Specification. I2C Clock has to be lower than + * (SCL Low Period - Analog/Digital filters) / 4. + * - SCL High Period has to be lower than SCL Clock High Period + * defined by I2C Specification + * - I2C Clock has to be lower than SCL High Period + */ + list_for_each_entry(v, &solutions, node) { + u32 prescaler = (v->presc + 1) * i2cclk; + + for (l = 0; l < STM32F7_SCLL_MAX; l++) { + u32 tscl_l = (l + 1) * prescaler + tsync; + + if ((tscl_l < i2c_specs[setup->speed].l_min) || + (i2cclk >= + ((tscl_l - af_delay_min - dnf_delay) / 4))) { + continue; + } + + for (h = 0; h < STM32F7_SCLH_MAX; h++) { + u32 tscl_h = (h + 1) * prescaler + tsync; + u32 tscl = tscl_l + tscl_h + + setup->rise_time + setup->fall_time; + + if ((tscl >= clk_min) && (tscl <= clk_max) && + (tscl_h >= i2c_specs[setup->speed].h_min) && + (i2cclk < tscl_h)) { + int clk_error = tscl - i2cbus; + + if (clk_error < 0) + clk_error = -clk_error; + + if (clk_error < clk_error_prev) { + clk_error_prev = clk_error; + v->scll = l; + v->sclh = h; + s = v; + } + } + } + } + } + + if (!s) { + dev_err(i2c_dev->dev, "no solution at all\n"); + ret = -EPERM; + goto exit; + } + + output->presc = s->presc; + output->scldel = s->scldel; + output->sdadel = s->sdadel; + output->scll = s->scll; + output->sclh = s->sclh; + + dev_dbg(i2c_dev->dev, + "Presc: %i, scldel: %i, sdadel: %i, scll: %i, sclh: %i\n", + output->presc, + output->scldel, output->sdadel, + output->scll, output->sclh); + +exit: + /* Release list and memory */ + list_for_each_entry_safe(v, _v, &solutions, node) { + list_del(&v->node); + kfree(v); + } + + return ret; +} + +static int stm32f7_i2c_setup_timing(struct stm32f7_i2c_dev *i2c_dev, + struct stm32f7_i2c_setup *setup) +{ + int ret = 0; + + setup->speed = i2c_dev->speed; + setup->speed_freq = i2c_specs[setup->speed].rate; + setup->clock_src = clk_get_rate(i2c_dev->clk); + + if (!setup->clock_src) { + dev_err(i2c_dev->dev, "clock rate is 0\n"); + return -EINVAL; + } + + do { + ret = stm32f7_i2c_compute_timing(i2c_dev, setup, + &i2c_dev->timing); + if (ret) { + dev_err(i2c_dev->dev, + "failed to compute I2C timings.\n"); + if (i2c_dev->speed > STM32_I2C_SPEED_STANDARD) { + i2c_dev->speed--; + setup->speed = i2c_dev->speed; + setup->speed_freq = + i2c_specs[setup->speed].rate; + dev_warn(i2c_dev->dev, + "downgrade I2C Speed Freq to (%i)\n", + i2c_specs[setup->speed].rate); + } else { + break; + } + } + } while (ret); + + if (ret) { + dev_err(i2c_dev->dev, "Impossible to compute I2C timings.\n"); + return ret; + } + + dev_dbg(i2c_dev->dev, "I2C Speed(%i), Freq(%i), Clk Source(%i)\n", + setup->speed, setup->speed_freq, setup->clock_src); + dev_dbg(i2c_dev->dev, "I2C Rise(%i) and Fall(%i) Time\n", + setup->rise_time, setup->fall_time); + dev_dbg(i2c_dev->dev, "I2C Analog Filter(%s), DNF(%i)\n", + (setup->analog_filter ? "On" : "Off"), setup->dnf); + + return 0; +} + +static void stm32f7_i2c_hw_config(struct stm32f7_i2c_dev *i2c_dev) +{ + struct stm32f7_i2c_timings *t = &i2c_dev->timing; + u32 timing = 0; + + /* Timing settings */ + timing |= STM32F7_I2C_TIMINGR_PRESC(t->presc); + timing |= STM32F7_I2C_TIMINGR_SCLDEL(t->scldel); + timing |= STM32F7_I2C_TIMINGR_SDADEL(t->sdadel); + timing |= STM32F7_I2C_TIMINGR_SCLH(t->sclh); + timing |= STM32F7_I2C_TIMINGR_SCLL(t->scll); + writel_relaxed(timing, i2c_dev->base + STM32F7_I2C_TIMINGR); + + /* Enable I2C */ + if (i2c_dev->setup->analog_filter) + stm32f7_i2c_clr_bits(i2c_dev->base + STM32F7_I2C_CR1, + STM32F7_I2C_CR1_ANFOFF); + else + stm32f7_i2c_set_bits(i2c_dev->base + STM32F7_I2C_CR1, + STM32F7_I2C_CR1_ANFOFF); + stm32f7_i2c_set_bits(i2c_dev->base + STM32F7_I2C_CR1, + STM32F7_I2C_CR1_PE); +} + +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 = -ENXIO; + } + + /* 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_dbg(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 time_left; + 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); + + time_left = wait_for_completion_timeout(&i2c_dev->complete, + i2c_dev->adap.timeout); + ret = f7_msg->result; + + if (!time_left) { + 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; + const struct stm32f7_i2c_setup *setup; + struct resource *res; + u32 irq_error, irq_event, clk_rate, rise_time, fall_time; + 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; + } + + i2c_dev->speed = STM32_I2C_SPEED_STANDARD; + ret = device_property_read_u32(&pdev->dev, "clock-frequency", + &clk_rate); + if (!ret && clk_rate >= 1000000) + i2c_dev->speed = STM32_I2C_SPEED_FAST_PLUS; + else if (!ret && clk_rate >= 400000) + i2c_dev->speed = STM32_I2C_SPEED_FAST; + else if (!ret && clk_rate >= 100000) + i2c_dev->speed = STM32_I2C_SPEED_STANDARD; + + 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->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; + } + + setup = of_device_get_match_data(&pdev->dev); + i2c_dev->setup->rise_time = setup->rise_time; + i2c_dev->setup->fall_time = setup->fall_time; + i2c_dev->setup->dnf = setup->dnf; + i2c_dev->setup->analog_filter = setup->analog_filter; + + ret = device_property_read_u32(i2c_dev->dev, "i2c-scl-rising-time-ns", + &rise_time); + if (!ret) + i2c_dev->setup->rise_time = rise_time; + + ret = device_property_read_u32(i2c_dev->dev, "i2c-scl-falling-time-ns", + &fall_time); + if (!ret) + i2c_dev->setup->fall_time = fall_time; + + ret = stm32f7_i2c_setup_timing(i2c_dev, i2c_dev->setup); + if (ret) + goto clk_free; + + stm32f7_i2c_hw_config(i2c_dev); + + 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 = 3; + 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) + goto clk_free; + + platform_set_drvdata(pdev, i2c_dev); + + clk_disable(i2c_dev->clk); + + dev_info(i2c_dev->dev, "STM32F7 I2C-%d bus adapter\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", .data = &stm32f7_setup}, + {}, +}; +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@gmail.com>"); +MODULE_DESCRIPTION("STMicroelectronics STM32F7 I2C driver"); +MODULE_LICENSE("GPL v2"); |