[U-Boot] [PATCH 1/1] i2c: add i2c driver for stm32

From: Patrice Chotard patrice.chotard@st.com

Add i2c driver which can be used on both STM32F7 and STM32H7. This I2C block supports the following features: _ Slave and master modes _ Multimaster capability _ Standard-mode (up to 100 kHz) _ Fast-mode (up to 400 kHz) _ Fast-mode Plus (up to 1 MHz) _ 7-bit and 10-bit addressing mode _ Multiple 7-bit slave addresses (2 addresses, 1 with configurable mask) _ All 7-bit addresses acknowledge mode _ General call _ Programmable setup and hold times _ Easy to use event management _ Optional clock stretching _ Software reset

Signed-off-by: Christophe Kerello christophe.kerello@st.com Signed-off-by: Patrice Chotard patrice.chotard@st.com --- doc/device-tree-bindings/i2c/i2c-stm32.txt | 30 ++ drivers/i2c/Kconfig | 7 + drivers/i2c/Makefile | 1 + drivers/i2c/stm32f7_i2c.c | 839 +++++++++++++++++++++++++++++ 4 files changed, 877 insertions(+) create mode 100644 doc/device-tree-bindings/i2c/i2c-stm32.txt create mode 100644 drivers/i2c/stm32f7_i2c.c

diff --git a/doc/device-tree-bindings/i2c/i2c-stm32.txt b/doc/device-tree-bindings/i2c/i2c-stm32.txt new file mode 100644 index 0000000..df03743 --- /dev/null +++ b/doc/device-tree-bindings/i2c/i2c-stm32.txt @@ -0,0 +1,30 @@ +* I2C controller embedded in STMicroelectronis STM32 platforms + +Required properties : +- compatible : Must be "st,stm32f7-i2c" +- reg : Offset and length of the register set for the device +- resets: Must contain the phandle to the reset controller +- clocks: Must contain the input clock of the I2C instance +- A pinctrl state named "default" must be defined to set pins in mode of + operation for I2C transfer +- #address-cells = <1>; +- #size-cells = <0>; + +Optional properties : +- clock-frequency : Desired I2C bus clock frequency in Hz. If not specified, + the default 100 kHz frequency will be used. As only Normal, Fast and Fast+ + modes are implemented, possible values are 100000, 400000 and 1000000. + +Example : + + i2c1: i2c@40005400 { + compatible = "st,stm32f7-i2c"; + reg = <0x40005400 0x400>; + resets = <&rcc 181>; + clocks = <&clk_pclk1>; + pinctrl-names = "default"; + pinctrl-0 = <&pinctrl_i2c1>; + clock-frequency = <400000>; + #address-cells = <1>; + #size-cells = <0>; + }; diff --git a/drivers/i2c/Kconfig b/drivers/i2c/Kconfig index 8ac1cc6..5ca8b86 100644 --- a/drivers/i2c/Kconfig +++ b/drivers/i2c/Kconfig @@ -168,6 +168,13 @@ config SYS_I2C_S3C24X0 help Support for Samsung I2C controller as Samsung SoCs.

+config SYS_I2C_STM32F7 + bool "STMicroelectronics STM32F7 I2C support" + depends on (STM32F7 || STM32H7) && DM_I2C + help + Enable this option to add support for STM32 I2C controller + introduced with STM32F7/H7 SoCs. + config SYS_I2C_UNIPHIER bool "UniPhier I2C driver" depends on ARCH_UNIPHIER && DM_I2C diff --git a/drivers/i2c/Makefile b/drivers/i2c/Makefile index 4bbf0c9..9b88732 100644 --- a/drivers/i2c/Makefile +++ b/drivers/i2c/Makefile @@ -38,6 +38,7 @@ obj-$(CONFIG_SYS_I2C_S3C24X0) += s3c24x0_i2c.o exynos_hs_i2c.o obj-$(CONFIG_SYS_I2C_SANDBOX) += sandbox_i2c.o i2c-emul-uclass.o obj-$(CONFIG_SYS_I2C_SH) += sh_i2c.o obj-$(CONFIG_SYS_I2C_SOFT) += soft_i2c.o +obj-$(CONFIG_SYS_I2C_STM32F7) += stm32f7_i2c.o obj-$(CONFIG_SYS_I2C_TEGRA) += tegra_i2c.o obj-$(CONFIG_SYS_I2C_UNIPHIER) += i2c-uniphier.o obj-$(CONFIG_SYS_I2C_UNIPHIER_F) += i2c-uniphier-f.o diff --git a/drivers/i2c/stm32f7_i2c.c b/drivers/i2c/stm32f7_i2c.c new file mode 100644 index 0000000..255b38a --- /dev/null +++ b/drivers/i2c/stm32f7_i2c.c @@ -0,0 +1,839 @@ +/* + * (C) Copyright 2017 STMicroelectronics + * + * SPDX-License-Identifier: GPL-2.0+ + */ + +#include <common.h> +#include <clk.h> +#include <dm.h> +#include <i2c.h> +#include <reset.h> + +#include <dm/device.h> +#include <linux/io.h> + +/* STM32 I2C registers */ +struct stm32_i2c_regs { + u32 cr1; /* I2C control register 1 */ + u32 cr2; /* I2C control register 2 */ + u32 oar1; /* I2C own address 1 register */ + u32 oar2; /* I2C own address 2 register */ + u32 timingr; /* I2C timing register */ + u32 timeoutr; /* I2C timeout register */ + u32 isr; /* I2C interrupt and status register */ + u32 icr; /* I2C interrupt clear register */ + u32 pecr; /* I2C packet error checking register */ + u32 rxdr; /* I2C receive data register */ + u32 txdr; /* I2C transmit data register */ +}; + +#define STM32_I2C_CR1 0x00 +#define STM32_I2C_CR2 0x04 +#define STM32_I2C_TIMINGR 0x10 +#define STM32_I2C_ISR 0x18 +#define STM32_I2C_ICR 0x1C +#define STM32_I2C_RXDR 0x24 +#define STM32_I2C_TXDR 0x28 + +/* STM32 I2C control 1 */ +#define STM32_I2C_CR1_ANFOFF BIT(12) +#define STM32_I2C_CR1_ERRIE BIT(7) +#define STM32_I2C_CR1_TCIE BIT(6) +#define STM32_I2C_CR1_STOPIE BIT(5) +#define STM32_I2C_CR1_NACKIE BIT(4) +#define STM32_I2C_CR1_ADDRIE BIT(3) +#define STM32_I2C_CR1_RXIE BIT(2) +#define STM32_I2C_CR1_TXIE BIT(1) +#define STM32_I2C_CR1_PE BIT(0) + +/* STM32 I2C control 2 */ +#define STM32_I2C_CR2_AUTOEND BIT(25) +#define STM32_I2C_CR2_RELOAD BIT(24) +#define STM32_I2C_CR2_NBYTES_MASK GENMASK(23, 16) +#define STM32_I2C_CR2_NBYTES(n) ((n & 0xff) << 16) +#define STM32_I2C_CR2_NACK BIT(15) +#define STM32_I2C_CR2_STOP BIT(14) +#define STM32_I2C_CR2_START BIT(13) +#define STM32_I2C_CR2_HEAD10R BIT(12) +#define STM32_I2C_CR2_ADD10 BIT(11) +#define STM32_I2C_CR2_RD_WRN BIT(10) +#define STM32_I2C_CR2_SADD10_MASK GENMASK(9, 0) +#define STM32_I2C_CR2_SADD10(n) ((n & STM32_I2C_CR2_SADD10_MASK)) +#define STM32_I2C_CR2_SADD7_MASK GENMASK(7, 1) +#define STM32_I2C_CR2_SADD7(n) ((n & 0x7f) << 1) +#define STM32_I2C_CR2_RESET_MASK (STM32_I2C_CR2_HEAD10R \ + | STM32_I2C_CR2_NBYTES_MASK \ + | STM32_I2C_CR2_SADD7_MASK \ + | STM32_I2C_CR2_RELOAD \ + | STM32_I2C_CR2_RD_WRN) + +/* STM32 I2C Interrupt Status */ +#define STM32_I2C_ISR_BUSY BIT(15) +#define STM32_I2C_ISR_ARLO BIT(9) +#define STM32_I2C_ISR_BERR BIT(8) +#define STM32_I2C_ISR_TCR BIT(7) +#define STM32_I2C_ISR_TC BIT(6) +#define STM32_I2C_ISR_STOPF BIT(5) +#define STM32_I2C_ISR_NACKF BIT(4) +#define STM32_I2C_ISR_ADDR BIT(3) +#define STM32_I2C_ISR_RXNE BIT(2) +#define STM32_I2C_ISR_TXIS BIT(1) +#define STM32_I2C_ISR_TXE BIT(0) +#define STM32_I2C_ISR_ERRORS (STM32_I2C_ISR_BERR \ + | STM32_I2C_ISR_ARLO) + +/* STM32 I2C Interrupt Clear */ +#define STM32_I2C_ICR_ARLOCF BIT(9) +#define STM32_I2C_ICR_BERRCF BIT(8) +#define STM32_I2C_ICR_STOPCF BIT(5) +#define STM32_I2C_ICR_NACKCF BIT(4) + +/* STM32 I2C Timing */ +#define STM32_I2C_TIMINGR_PRESC(n) ((n & 0xf) << 28) +#define STM32_I2C_TIMINGR_SCLDEL(n) ((n & 0xf) << 20) +#define STM32_I2C_TIMINGR_SDADEL(n) ((n & 0xf) << 16) +#define STM32_I2C_TIMINGR_SCLH(n) ((n & 0xff) << 8) +#define STM32_I2C_TIMINGR_SCLL(n) (n & 0xff) + +#define STM32_I2C_MAX_LEN 0xff + +#define STM32_I2C_DNF_DEFAULT 0 +#define STM32_I2C_DNF_MAX 16 + +#define STM32_I2C_ANALOG_FILTER_ENABLE 1 +#define STM32_I2C_ANALOG_FILTER_DELAY_MIN 50 /* ns */ +#define STM32_I2C_ANALOG_FILTER_DELAY_MAX 260 /* ns */ + +#define STM32_I2C_RISE_TIME_DEFAULT 25 /* ns */ +#define STM32_I2C_FALL_TIME_DEFAULT 10 /* ns */ + +#define STM32_PRESC_MAX BIT(4) +#define STM32_SCLDEL_MAX BIT(4) +#define STM32_SDADEL_MAX BIT(4) +#define STM32_SCLH_MAX BIT(8) +#define STM32_SCLL_MAX BIT(8) + +#define STM32_NSEC_PER_SEC 1000000000L + +enum stm32_i2c_speed { + STM32_I2C_SPEED_STANDARD, /* 100 kHz */ + STM32_I2C_SPEED_FAST, /* 400 kHz */ + STM32_I2C_SPEED_FAST_PLUS, /* 1 MHz */ + STM32_I2C_SPEED_END, +}; + +/** + * struct stm32_i2c_spec - private i2c specification timing + * @rate: I2C bus speed (Hz) + * @rate_min: 80% of I2C bus speed (Hz) + * @rate_max: 120% 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 stm32_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 stm32_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 stm32_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 stm32_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 stm32_i2c_timings { + struct list_head node; + u8 presc; + u8 scldel; + u8 sdadel; + u8 sclh; + u8 scll; +}; + +struct stm32_i2c_dev { + struct stm32_i2c_regs *regs; + struct clk clk; + struct stm32_i2c_setup *setup; + int speed; +}; + +static struct stm32_i2c_spec i2c_specs[] = { + [STM32_I2C_SPEED_STANDARD] = { + .rate = 100000, + .rate_min = 8000, + .rate_max = 120000, + .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 = 480000, + .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 = 1200000, + .fall_max = 100, + .rise_max = 120, + .hddat_min = 0, + .vddat_max = 450, + .sudat_min = 50, + .l_min = 500, + .h_min = 260, + }, +}; + +static struct stm32_i2c_setup stm32mp_setup = { + .rise_time = STM32_I2C_RISE_TIME_DEFAULT, + .fall_time = STM32_I2C_FALL_TIME_DEFAULT, + .dnf = STM32_I2C_DNF_DEFAULT, + .analog_filter = STM32_I2C_ANALOG_FILTER_ENABLE, +}; + +DECLARE_GLOBAL_DATA_PTR; + +static int stm32mp_check_device_busy(struct stm32_i2c_dev *i2c_dev) +{ + struct stm32_i2c_regs *regs = i2c_dev->regs; + u32 status = readl(&regs->isr); + + if (status & STM32_I2C_ISR_BUSY) + return -EBUSY; + + return 0; +} + +static void stm32_i2c_message_start(struct stm32_i2c_dev *i2c_dev, + struct i2c_msg *msg, bool stop) +{ + struct stm32_i2c_regs *regs = i2c_dev->regs; + u32 cr2 = readl(&regs->cr2); + + /* Set transfer direction */ + cr2 &= ~STM32_I2C_CR2_RD_WRN; + if (msg->flags & I2C_M_RD) + cr2 |= STM32_I2C_CR2_RD_WRN; + + /* Set slave address */ + cr2 &= ~(STM32_I2C_CR2_HEAD10R | STM32_I2C_CR2_ADD10); + if (msg->flags & I2C_M_TEN) { + cr2 &= ~STM32_I2C_CR2_SADD10_MASK; + cr2 |= STM32_I2C_CR2_SADD10(msg->addr); + cr2 |= STM32_I2C_CR2_ADD10; + } else { + cr2 &= ~STM32_I2C_CR2_SADD7_MASK; + cr2 |= STM32_I2C_CR2_SADD7(msg->addr); + } + + /* Set nb bytes to transfer and reload or autoend bits */ + cr2 &= ~(STM32_I2C_CR2_NBYTES_MASK | STM32_I2C_CR2_RELOAD | + STM32_I2C_CR2_AUTOEND); + if (msg->len > STM32_I2C_MAX_LEN) { + cr2 |= STM32_I2C_CR2_NBYTES(STM32_I2C_MAX_LEN); + cr2 |= STM32_I2C_CR2_RELOAD; + } else { + cr2 |= STM32_I2C_CR2_NBYTES(msg->len); + } + + /* Write configurations register */ + writel(cr2, &regs->cr2); + + /* START/ReSTART generation */ + setbits_le32(&regs->cr2, STM32_I2C_CR2_START); +} + +static void stm32_i2c_handle_reload(struct stm32_i2c_dev *i2c_dev, + struct i2c_msg *msg, bool stop) +{ + struct stm32_i2c_regs *regs = i2c_dev->regs; + u32 cr2 = readl(&regs->cr2); + + cr2 &= ~STM32_I2C_CR2_NBYTES_MASK; + + if (msg->len > STM32_I2C_MAX_LEN) { + cr2 |= STM32_I2C_CR2_NBYTES(STM32_I2C_MAX_LEN); + } else { + cr2 &= ~STM32_I2C_CR2_RELOAD; + cr2 |= STM32_I2C_CR2_NBYTES(msg->len); + } + + writel(cr2, &regs->cr2); +} + +static int stm32_i2c_wait_flags(struct stm32_i2c_dev *i2c_dev, + u32 flags, u32 *status) +{ + struct stm32_i2c_regs *regs = i2c_dev->regs; + u32 time_start = get_timer(0); + + *status = readl(&regs->isr); + while (!(*status & flags)) { + if (get_timer(time_start) > CONFIG_SYS_HZ) { + debug("%s: i2c timeout\n", __func__); + return -ETIMEDOUT; + } + + *status = readl(&regs->isr); + } + + return 0; +} + +static int stm32_i2c_check_end_of_message(struct stm32_i2c_dev *i2c_dev) +{ + struct stm32_i2c_regs *regs = i2c_dev->regs; + u32 mask = STM32_I2C_ISR_ERRORS | STM32_I2C_ISR_NACKF | + STM32_I2C_ISR_STOPF; + u32 status; + int ret; + + ret = stm32_i2c_wait_flags(i2c_dev, mask, &status); + if (ret) + return ret; + + if (status & STM32_I2C_ISR_BERR) { + debug("%s: Bus error\n", __func__); + + /* Clear BERR flag */ + setbits_le32(&regs->icr, STM32_I2C_ICR_BERRCF); + + return -EIO; + } + + if (status & STM32_I2C_ISR_ARLO) { + debug("%s: Arbitration lost\n", __func__); + + /* Clear ARLO flag */ + setbits_le32(&regs->icr, STM32_I2C_ICR_ARLOCF); + + return -EAGAIN; + } + + if (status & STM32_I2C_ISR_NACKF) { + debug("%s: Receive NACK\n", __func__); + + /* Clear NACK flag */ + setbits_le32(&regs->icr, STM32_I2C_ICR_NACKCF); + + /* Wait until STOPF flag is set */ + mask = STM32_I2C_ISR_STOPF; + ret = stm32_i2c_wait_flags(i2c_dev, mask, &status); + if (ret) + return ret; + + ret = -EIO; + } + + if (status & STM32_I2C_ISR_STOPF) { + /* Clear STOP flag */ + setbits_le32(&regs->icr, STM32_I2C_ICR_STOPCF); + + /* Clear control register 2 */ + setbits_le32(&regs->cr2, STM32_I2C_CR2_RESET_MASK); + } + + return ret; +} + +static int stm32_i2c_message_xfer(struct stm32_i2c_dev *i2c_dev, + struct i2c_msg *msg, bool stop) +{ + struct stm32_i2c_regs *regs = i2c_dev->regs; + u32 status; + u32 mask = msg->flags & I2C_M_RD ? STM32_I2C_ISR_RXNE : + STM32_I2C_ISR_TXIS | STM32_I2C_ISR_NACKF; + int bytes_to_rw = msg->len > STM32_I2C_MAX_LEN ? + STM32_I2C_MAX_LEN : msg->len; + int ret = 0; + + /* Add errors */ + mask |= STM32_I2C_ISR_ERRORS; + + stm32_i2c_message_start(i2c_dev, msg, stop); + + while (msg->len) { + /* + * Wait until TXIS/NACKF/BERR/ARLO flags or + * RXNE/BERR/ARLO flags are set + */ + ret = stm32_i2c_wait_flags(i2c_dev, mask, &status); + if (ret) + break; + + if (status & (STM32_I2C_ISR_NACKF | STM32_I2C_ISR_ERRORS)) + break; + + if (status & STM32_I2C_ISR_RXNE) { + *msg->buf++ = readb(&regs->rxdr); + msg->len--; + bytes_to_rw--; + } + + if (status & STM32_I2C_ISR_TXIS) { + writeb(*msg->buf++, &regs->txdr); + msg->len--; + bytes_to_rw--; + } + + if (!bytes_to_rw && msg->len) { + /* Wait until TCR flag is set */ + mask = STM32_I2C_ISR_TCR; + ret = stm32_i2c_wait_flags(i2c_dev, mask, &status); + if (ret) + break; + + bytes_to_rw = msg->len > STM32_I2C_MAX_LEN ? + STM32_I2C_MAX_LEN : msg->len; + mask = msg->flags & I2C_M_RD ? STM32_I2C_ISR_RXNE : + STM32_I2C_ISR_TXIS | STM32_I2C_ISR_NACKF; + + stm32_i2c_handle_reload(i2c_dev, msg, stop); + } else if (!bytes_to_rw) { + /* Wait until TC flag is set */ + mask = STM32_I2C_ISR_TC; + ret = stm32_i2c_wait_flags(i2c_dev, mask, &status); + if (ret) + break; + + if (!stop) + /* Message sent, new message has to be sent */ + return 0; + } + } + + /* End of transfer, send stop condition */ + mask = STM32_I2C_CR2_STOP; + setbits_le32(&regs->cr2, mask); + + return stm32_i2c_check_end_of_message(i2c_dev); +} + +static int stm32_i2c_xfer(struct udevice *bus, struct i2c_msg *msg, + int nmsgs) +{ + struct stm32_i2c_dev *i2c_dev = dev_get_priv(bus); + int ret; + + ret = stm32mp_check_device_busy(i2c_dev); + if (ret) + return ret; + + for (; nmsgs > 0; nmsgs--, msg++) { + ret = stm32_i2c_message_xfer(i2c_dev, msg, nmsgs == 1); + if (ret) + return ret; + } + + return 0; +} + +static int stm32_i2c_compute_timing(struct stm32_i2c_dev *i2c_dev, + struct stm32_i2c_setup *setup, + struct stm32_i2c_timings *output) +{ + u32 p_prev = STM32_PRESC_MAX; + u32 i2cclk = DIV_ROUND_CLOSEST(STM32_NSEC_PER_SEC, + setup->clock_src); + u32 i2cbus = DIV_ROUND_CLOSEST(STM32_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 stm32_i2c_timings *v, *_v, *s; + struct list_head solutions; + u16 p, l, a, h; + int ret = 0; + + if (setup->speed >= STM32_I2C_SPEED_END) { + error("%s: speed out of bound {%d/%d}\n", __func__, + 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)) { + error("%s :timings out of bound Rise{%d>%d}/Fall{%d>%d}\n", + __func__, + setup->rise_time, i2c_specs[setup->speed].rise_max, + setup->fall_time, i2c_specs[setup->speed].fall_max); + return -EINVAL; + } + + if (setup->dnf > STM32_I2C_DNF_MAX) { + error("%s: DNF out of bound %d/%d\n", __func__, + setup->dnf, STM32_I2C_DNF_MAX); + return -EINVAL; + } + + if (setup->speed_freq > i2c_specs[setup->speed].rate) { + error("%s: Freq {%d/%d}\n", __func__, + setup->speed_freq, i2c_specs[setup->speed].rate); + return -EINVAL; + } + + /* Analog and Digital Filters */ + af_delay_min = setup->analog_filter ? + STM32_I2C_ANALOG_FILTER_DELAY_MIN : 0; + af_delay_max = setup->analog_filter ? + STM32_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; + + debug("%s: SDADEL(min/max): %i/%i, SCLDEL(Min): %i\n", __func__, + sdadel_min, sdadel_max, scldel_min); + + INIT_LIST_HEAD(&solutions); + /* Compute possible values for PRESC, SCLDEL and SDADEL */ + for (p = 0; p < STM32_PRESC_MAX; p++) { + for (l = 0; l < STM32_SCLDEL_MAX; l++) { + u32 scldel = (l + 1) * (p + 1) * i2cclk; + + if (scldel < scldel_min) + continue; + + for (a = 0; a < STM32_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)) { + error("%s: no Prescaler solution\n", __func__); + ret = -EPERM; + goto exit; + } + + tsync = af_delay_min + dnf_delay + (2 * i2cclk); + s = NULL; + clk_max = STM32_NSEC_PER_SEC / i2c_specs[setup->speed].rate_min; + clk_min = STM32_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 Low Period of tehs SCL Clock + * 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 High Period of the SCL Clock + * 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 < STM32_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 < STM32_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) { + error("%s: no solution at all\n", __func__); + ret = -EPERM; + goto exit; + } + + output->presc = s->presc; + output->scldel = s->scldel; + output->sdadel = s->sdadel; + output->scll = s->scll; + output->sclh = s->sclh; + + debug("%s: Presc: %i, scldel: %i, sdadel: %i, scll: %i, sclh: %i\n", + __func__, 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 stm32_i2c_setup_timing(struct stm32_i2c_dev *i2c_dev, + struct stm32_i2c_timings *timing) +{ + struct stm32_i2c_setup *setup = i2c_dev->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) { + error("%s: clock rate is 0\n", __func__); + return -EINVAL; + } + + do { + ret = stm32_i2c_compute_timing(i2c_dev, setup, timing); + if (ret) { + debug("%s: failed to compute I2C timings.\n", + __func__); + if (i2c_dev->speed > STM32_I2C_SPEED_STANDARD) { + i2c_dev->speed--; + setup->speed = i2c_dev->speed; + setup->speed_freq = + i2c_specs[setup->speed].rate; + debug("%s: downgrade I2C Speed Freq to (%i)\n", + __func__, i2c_specs[setup->speed].rate); + } else { + break; + } + } + } while (ret); + + if (ret) { + error("%s: impossible to compute I2C timings.\n", __func__); + return ret; + } + + debug("%s: I2C Speed(%i), Freq(%i), Clk Source(%i)\n", __func__, + setup->speed, setup->speed_freq, setup->clock_src); + debug("%s: I2C Rise(%i) and Fall(%i) Time\n", __func__, + setup->rise_time, setup->fall_time); + debug("%s: I2C Analog Filter(%s), DNF(%i)\n", __func__, + setup->analog_filter ? "On" : "Off", setup->dnf); + + return 0; +} + +static int stm32_i2c_hw_config(struct stm32_i2c_dev *i2c_dev) +{ + struct stm32_i2c_regs *regs = i2c_dev->regs; + struct stm32_i2c_timings t; + int ret; + u32 timing = 0; + + ret = stm32_i2c_setup_timing(i2c_dev, &t); + if (ret) + return ret; + + /* Disable I2C */ + clrbits_le32(&regs->cr1, STM32_I2C_CR1_PE); + + /* Timing settings */ + timing |= STM32_I2C_TIMINGR_PRESC(t.presc); + timing |= STM32_I2C_TIMINGR_SCLDEL(t.scldel); + timing |= STM32_I2C_TIMINGR_SDADEL(t.sdadel); + timing |= STM32_I2C_TIMINGR_SCLH(t.sclh); + timing |= STM32_I2C_TIMINGR_SCLL(t.scll); + writel(timing, &regs->timingr); + + /* Enable I2C */ + if (i2c_dev->setup->analog_filter) + clrbits_le32(&regs->cr1, STM32_I2C_CR1_ANFOFF); + else + setbits_le32(&regs->cr1, STM32_I2C_CR1_ANFOFF); + setbits_le32(&regs->cr1, STM32_I2C_CR1_PE); + + return 0; +} + +static int stm32_i2c_set_bus_speed(struct udevice *bus, unsigned int speed) +{ + struct stm32_i2c_dev *i2c_dev = dev_get_priv(bus); + + switch (speed) { + case 100000: + i2c_dev->speed = STM32_I2C_SPEED_STANDARD; + break; + case 400000: + i2c_dev->speed = STM32_I2C_SPEED_FAST; + break; + case 1000000: + i2c_dev->speed = STM32_I2C_SPEED_FAST_PLUS; + break; + default: + debug("%s: Speed %d not supported\n", __func__, speed); + return -EINVAL; + } + + return stm32_i2c_hw_config(i2c_dev); +} + +static int stm32_i2c_probe(struct udevice *dev) +{ + struct stm32_i2c_dev *i2c_dev = dev_get_priv(dev); + struct reset_ctl reset_ctl; + fdt_addr_t addr; + u32 rise_time, fall_time; + int ret; + + addr = dev_read_addr(dev); + if (addr == FDT_ADDR_T_NONE) + return -EINVAL; + + i2c_dev->regs = (struct stm32_i2c_regs *)addr; + + i2c_dev->setup = (struct stm32_i2c_setup *)dev_get_driver_data(dev); + if (!i2c_dev->setup) + return -EINVAL; + + rise_time = dev_read_u32_default(dev, "i2c-scl-rising-time-ns", 0); + if (rise_time) + i2c_dev->setup->rise_time = rise_time; + + fall_time = dev_read_u32_default(dev, "i2c-scl-falling-time-ns", 0); + if (fall_time) + i2c_dev->setup->fall_time = fall_time; + + ret = clk_get_by_index(dev, 0, &i2c_dev->clk); + if (ret) + return ret; + + ret = clk_enable(&i2c_dev->clk); + if (ret) + goto clk_free; + + ret = reset_get_by_index(dev, 0, &reset_ctl); + if (ret) + goto clk_disable; + + reset_assert(&reset_ctl); + udelay(2); + reset_deassert(&reset_ctl); + + return 0; + +clk_disable: + clk_disable(&i2c_dev->clk); +clk_free: + clk_free(&i2c_dev->clk); + + return ret; +} + +static const struct dm_i2c_ops stm32_i2c_ops = { + .xfer = stm32_i2c_xfer, + .set_bus_speed = stm32_i2c_set_bus_speed, +}; + +static const struct udevice_id stm32_i2c_of_match[] = { + { .compatible = "st,stm32f7-i2c", .data = (ulong)&stm32mp_setup }, + {} +}; + +U_BOOT_DRIVER(stm32f7_i2c) = { + .name = "stm32f7-i2c", + .id = UCLASS_I2C, + .of_match = stm32_i2c_of_match, + .probe = stm32_i2c_probe, + .priv_auto_alloc_size = sizeof(struct stm32_i2c_dev), + .ops = &stm32_i2c_ops, +};