| /* |
| * 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, |
| }, |
| }; |
| |
| static const 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 = i2c_specs[setup->speed].hddat_min + setup->fall_time - |
| 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); |
| if (!setup) { |
| dev_err(&pdev->dev, "Can't get device data\n"); |
| ret = -ENODEV; |
| goto clk_free; |
| } |
| i2c_dev->setup = *setup; |
| |
| 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"); |