[U-Boot] [PATCH 1/1] i2c: add i2c driver for stm32
patrice.chotard at st.com
patrice.chotard at st.com
Tue Jul 25 16:02:46 UTC 2017
From: Patrice Chotard <patrice.chotard at 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 at st.com>
Signed-off-by: Patrice Chotard <patrice.chotard at 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 at 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(®s->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(®s->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, ®s->cr2);
+
+ /* START/ReSTART generation */
+ setbits_le32(®s->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(®s->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, ®s->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(®s->isr);
+ while (!(*status & flags)) {
+ if (get_timer(time_start) > CONFIG_SYS_HZ) {
+ debug("%s: i2c timeout\n", __func__);
+ return -ETIMEDOUT;
+ }
+
+ *status = readl(®s->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(®s->icr, STM32_I2C_ICR_BERRCF);
+
+ return -EIO;
+ }
+
+ if (status & STM32_I2C_ISR_ARLO) {
+ debug("%s: Arbitration lost\n", __func__);
+
+ /* Clear ARLO flag */
+ setbits_le32(®s->icr, STM32_I2C_ICR_ARLOCF);
+
+ return -EAGAIN;
+ }
+
+ if (status & STM32_I2C_ISR_NACKF) {
+ debug("%s: Receive NACK\n", __func__);
+
+ /* Clear NACK flag */
+ setbits_le32(®s->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(®s->icr, STM32_I2C_ICR_STOPCF);
+
+ /* Clear control register 2 */
+ setbits_le32(®s->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(®s->rxdr);
+ msg->len--;
+ bytes_to_rw--;
+ }
+
+ if (status & STM32_I2C_ISR_TXIS) {
+ writeb(*msg->buf++, ®s->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(®s->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(®s->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, ®s->timingr);
+
+ /* Enable I2C */
+ if (i2c_dev->setup->analog_filter)
+ clrbits_le32(®s->cr1, STM32_I2C_CR1_ANFOFF);
+ else
+ setbits_le32(®s->cr1, STM32_I2C_CR1_ANFOFF);
+ setbits_le32(®s->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,
+};
--
1.9.1
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