[U-Boot] [PATCH 1/1] i2c: add i2c driver for stm32
Simon Glass
sjg at chromium.org
Sun Aug 6 05:15:36 UTC 2017
Hi Patrice,
On 25 July 2017 at 10:02, <patrice.chotard at st.com> wrote:
> 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.
Can you briefly mention what features it provides, as (it seems) you
do in the commit message?
> +
> 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
Do you really need these STM32_I2C prefixes?
> +#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 {
How about stm32_i2c_priv since it is the driver's private data.
> + 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)
It would be good to add function comments to these non-trivial functions.
> +{
> + 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 */
This function is very long. How about splitting this bit out:
> + 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
> + */
And this:
> + 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);
what happens to t? Isn't this a memory leak? Also it seems to produce
a list of timings, but this function only uses one?
> + 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:
Should you not have an enum for these speeds? The same number are
repeated above.
> + 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;
You might consider moving the above code to an ofdata_to_platdata function.
> +
> + 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 },
Will there be other setup structures later?
> + {}
> +};
> +
> +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
>
Regards,
Simon
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