[U-Boot] [PATCH v2] i2c: Add support for the Arm's Versatile Express I2C controller.
Heiko Schocher
hs at denx.de
Wed Oct 3 11:08:27 UTC 2018
Hello Liviu,
Am 28.09.2018 um 14:46 schrieb Liviu Dudau:
> The Arm Versatile Express I2C controller is a simple register-based
> controller that uses a register to control the state of the SCL and
> SDA lines. Add support for it.
>
> Signed-off-by: Liviu Dudau <liviu.dudau at foss.arm.com>
> Reviewed-by: Heiko Schocher <hs at denx.de>
> ---
> Changelog:
> - v2: Added MAINTAINERS entry and fixed checkpatch warnings.
>
> MAINTAINERS | 1 +
> drivers/i2c/Kconfig | 7 +
> drivers/i2c/Makefile | 1 +
> drivers/i2c/i2c-versatile.c | 280 ++++++++++++++++++++++++++++++++++++
> 4 files changed, 289 insertions(+)
> create mode 100644 drivers/i2c/i2c-versatile.c
After fixing some merge conflict in MAINTAINERS, applied to
u-boot-i2c.git master
Thanks!
bye,
Heiko
>
> diff --git a/MAINTAINERS b/MAINTAINERS
> index 1aa68e8135..11fc404167 100644
> --- a/MAINTAINERS
> +++ b/MAINTAINERS
> @@ -291,6 +291,7 @@ M: Liviu Dudau <liviu.dudau at foss.arm.com>
> S: Maintained
> T: git git://github.com/ARM-software/u-boot.git
> F: drivers/clk/clk_vexpress_osc.c
> +F: drivers/i2c/i2c-versatile.c
> F: drivers/misc/vexpress_config.c
> N: vexpress
>
> diff --git a/drivers/i2c/Kconfig b/drivers/i2c/Kconfig
> index ae3b501555..1ef22e6bcd 100644
> --- a/drivers/i2c/Kconfig
> +++ b/drivers/i2c/Kconfig
> @@ -416,6 +416,13 @@ config SYS_I2C_UNIPHIER_F
> Support for UniPhier FIFO-builtin I2C controller driver.
> This I2C controller is used on PH1-Pro4 or newer UniPhier SoCs.
>
> +config SYS_I2C_VERSATILE
> + bool "Arm Ltd Versatile I2C bus driver"
> + depends on DM_I2C && (TARGET_VEXPRESS_CA15_TC2 || TARGET_VEXPRESS64_JUNO)
> + help
> + Add support for the Arm Ltd Versatile Express I2C driver. The I2C host
> + controller is present in the development boards manufactured by Arm Ltd.
> +
> config SYS_I2C_MVTWSI
> bool "Marvell I2C driver"
> depends on DM_I2C
> diff --git a/drivers/i2c/Makefile b/drivers/i2c/Makefile
> index f2cbe78c53..d3637bcd8d 100644
> --- a/drivers/i2c/Makefile
> +++ b/drivers/i2c/Makefile
> @@ -36,6 +36,7 @@ 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
> +obj-$(CONFIG_SYS_I2C_VERSATILE) += i2c-versatile.o
> obj-$(CONFIG_SYS_I2C_ZYNQ) += zynq_i2c.o
> obj-$(CONFIG_TEGRA186_BPMP_I2C) += tegra186_bpmp_i2c.o
>
> diff --git a/drivers/i2c/i2c-versatile.c b/drivers/i2c/i2c-versatile.c
> new file mode 100644
> index 0000000000..f523844204
> --- /dev/null
> +++ b/drivers/i2c/i2c-versatile.c
> @@ -0,0 +1,280 @@
> +// SPDX-License-Identifier: GPL-2.0+
> +/*
> + * Copyright (c) 2018 Arm Ltd.
> + * Author: Liviu Dudau <liviu.dudau at foss.arm.com>
> + *
> + */
> +
> +#include <common.h>
> +#include <dm.h>
> +#include <errno.h>
> +#include <i2c.h>
> +#include <asm/io.h>
> +#include <clk.h>
> +#include <linux/io.h>
> +
> +#define I2C_CONTROL_REG 0x00
> +#define I2C_SET_REG 0x00
> +#define I2C_CLEAR_REG 0x04
> +
> +#define SCL BIT(0)
> +#define SDA BIT(1)
> +
> +struct versatile_i2c_priv {
> + phys_addr_t base;
> + u32 delay;
> +};
> +
> +static inline void versatile_sda_set(struct versatile_i2c_priv *priv, u8 state)
> +{
> + writel(SDA, priv->base + (state ? I2C_SET_REG : I2C_CLEAR_REG));
> + udelay(priv->delay);
> +}
> +
> +static inline int versatile_sda_get(struct versatile_i2c_priv *priv)
> +{
> + int v = !!(readl(priv->base + I2C_CONTROL_REG) & SDA);
> +
> + udelay(priv->delay);
> + return v;
> +}
> +
> +static inline void versatile_scl_set(struct versatile_i2c_priv *priv, u8 state)
> +{
> + writel(SCL, priv->base + (state ? I2C_SET_REG : I2C_CLEAR_REG));
> + udelay(priv->delay);
> +}
> +
> +static inline int versatile_scl_get(struct versatile_i2c_priv *priv)
> +{
> + int v = !!(readl(priv->base + I2C_CONTROL_REG) & SCL);
> +
> + udelay(priv->delay);
> + return v;
> +}
> +
> +/* start: SDA goes from high to low while SCL is high */
> +static void versatile_i2c_start(struct versatile_i2c_priv *priv)
> +{
> + udelay(priv->delay);
> + versatile_sda_set(priv, 1);
> + versatile_scl_set(priv, 1);
> + versatile_sda_set(priv, 0);
> +}
> +
> +/* stop: SDA goes from low to high while SCL is high */
> +static void versatile_i2c_stop(struct versatile_i2c_priv *priv)
> +{
> + versatile_scl_set(priv, 0);
> + versatile_sda_set(priv, 0);
> + versatile_scl_set(priv, 1);
> + versatile_sda_set(priv, 1);
> +}
> +
> +/* read a bit from the SDA line (data or ACK/NACK) */
> +static u8 versatile_i2c_read_bit(struct versatile_i2c_priv *priv)
> +{
> + versatile_scl_set(priv, 0);
> + versatile_sda_set(priv, 1);
> + versatile_scl_set(priv, 1);
> + udelay(priv->delay);
> + return (u8)versatile_sda_get(priv);
> +}
> +
> +/* write a bit on the SDA line */
> +static void versatile_i2c_write_bit(struct versatile_i2c_priv *priv, u8 bit)
> +{
> + versatile_scl_set(priv, 0);
> + versatile_sda_set(priv, bit);
> + versatile_scl_set(priv, 1);
> + udelay(priv->delay);
> +}
> +
> +/* send a reset sequence of 9 clocks with SDA high */
> +static void versatile_i2c_reset_bus(struct versatile_i2c_priv *priv)
> +{
> + int i;
> +
> + for (i = 0; i < 9; i++)
> + versatile_i2c_write_bit(priv, 1);
> +
> + versatile_i2c_stop(priv);
> +}
> +
> +/* write byte without start/stop sequence */
> +static int versatile_i2c_write_byte(struct versatile_i2c_priv *priv, u8 byte)
> +{
> + u8 nak, i;
> +
> + for (i = 0; i < 8; i++) {
> + versatile_i2c_write_bit(priv, byte & 0x80);
> + byte <<= 1;
> + }
> +
> + /* read ACK */
> + nak = versatile_i2c_read_bit(priv);
> + versatile_scl_set(priv, 0);
> +
> + return nak; /* not a nack is an ack */
> +}
> +
> +static int versatile_i2c_read_byte(struct versatile_i2c_priv *priv,
> + u8 *byte, u8 ack)
> +{
> + u8 i;
> +
> + *byte = 0;
> + for (i = 0; i < 8; i++) {
> + *byte <<= 1;
> + *byte |= versatile_i2c_read_bit(priv);
> + }
> + /* write the nack */
> + versatile_i2c_write_bit(priv, ack);
> +
> + return 0;
> +}
> +
> +static int versatile_i2c_send_slave_addr(struct versatile_i2c_priv *priv,
> + struct i2c_msg *msg)
> +{
> + u8 addr;
> + int ret;
> +
> + if (msg->flags & I2C_M_TEN) {
> + /* 10-bit address, send extended address code first */
> + addr = 0xf0 | ((msg->addr >> 7) & 0x06);
> + ret = versatile_i2c_write_byte(priv, addr);
> + if (ret) {
> + versatile_i2c_stop(priv);
> + return -EIO;
> + }
> +
> + /* remaining bits */
> + ret = versatile_i2c_write_byte(priv, msg->addr & 0xff);
> + if (ret) {
> + versatile_i2c_stop(priv);
> + return -EIO;
> + }
> + /* reads need to resend the addr */
> + if (msg->flags & I2C_M_RD) {
> + versatile_i2c_start(priv);
> + addr |= 1;
> + ret = versatile_i2c_write_byte(priv, addr);
> + if (ret) {
> + versatile_i2c_stop(priv);
> + return -EIO;
> + }
> + }
> + } else {
> + /* normal 7-bit address */
> + addr = msg->addr << 1;
> + if (msg->flags & I2C_M_RD)
> + addr |= 1;
> + ret = versatile_i2c_write_byte(priv, addr);
> + if (ret) {
> + versatile_i2c_stop(priv);
> + return -EIO;
> + }
> + }
> +
> + return 0;
> +}
> +
> +static int versatile_i2c_message_xfer(struct versatile_i2c_priv *priv,
> + struct i2c_msg *msg)
> +{
> + int i, ret;
> + u8 ack;
> +
> + versatile_i2c_start(priv);
> + if (versatile_i2c_send_slave_addr(priv, msg))
> + return -EIO;
> +
> + for (i = 0; i < msg->len; i++) {
> + if (msg->flags & I2C_M_RD) {
> + ack = (msg->len - i - 1) == 0 ? 1 : 0;
> + ret = versatile_i2c_read_byte(priv, &msg->buf[i], ack);
> + } else {
> + ret = versatile_i2c_write_byte(priv, msg->buf[i]);
> + }
> +
> + if (ret)
> + break;
> + }
> +
> + versatile_i2c_stop(priv);
> +
> + return ret;
> +}
> +
> +static int versatile_i2c_xfer(struct udevice *bus,
> + struct i2c_msg *msg, int nmsgs)
> +{
> + struct versatile_i2c_priv *priv = dev_get_priv(bus);
> + int ret;
> +
> + for ( ; nmsgs > 0; nmsgs--, msg++) {
> + ret = versatile_i2c_message_xfer(priv, msg);
> + if (ret)
> + return -EREMOTEIO;
> + }
> +
> + return 0;
> +}
> +
> +static int versatile_i2c_chip_probe(struct udevice *bus,
> + uint chip, uint chip_flags)
> +{
> + /* probe the presence of a slave by writing a 0-size message */
> + struct i2c_msg msg = { .addr = chip, .flags = chip_flags,
> + .len = 0, .buf = NULL };
> + struct versatile_i2c_priv *priv = dev_get_priv(bus);
> +
> + return versatile_i2c_message_xfer(priv, &msg);
> +}
> +
> +static int versatile_i2c_set_bus_speed(struct udevice *bus, unsigned int speed)
> +{
> + struct versatile_i2c_priv *priv = dev_get_priv(bus);
> +
> + priv->delay = 1000000 / (speed << 2);
> +
> + versatile_i2c_reset_bus(priv);
> +
> + return 0;
> +}
> +
> +static int versatile_i2c_probe(struct udevice *dev)
> +{
> + struct versatile_i2c_priv *priv = dev_get_priv(dev);
> +
> + priv->base = (phys_addr_t)dev_read_addr(dev);
> + priv->delay = 25; /* 25us * 4 = 100kHz */
> + /*
> + * U-Boot still doesn't assign automatically
> + * sequence numbers to devices
> + */
> + dev->req_seq = 1;
> +
> + return 0;
> +}
> +
> +static const struct dm_i2c_ops versatile_i2c_ops = {
> + .xfer = versatile_i2c_xfer,
> + .probe_chip = versatile_i2c_chip_probe,
> + .set_bus_speed = versatile_i2c_set_bus_speed,
> +};
> +
> +static const struct udevice_id versatile_i2c_of_match[] = {
> + { .compatible = "arm,versatile-i2c" },
> + { }
> +};
> +
> +U_BOOT_DRIVER(versatile_i2c) = {
> + .name = "i2c-bus-versatile",
> + .id = UCLASS_I2C,
> + .of_match = versatile_i2c_of_match,
> + .probe = versatile_i2c_probe,
> + .priv_auto_alloc_size = sizeof(struct versatile_i2c_priv),
> + .ops = &versatile_i2c_ops,
> +};
>
--
DENX Software Engineering GmbH, Managing Director: Wolfgang Denk
HRB 165235 Munich, Office: Kirchenstr.5, D-82194 Groebenzell, Germany
Phone: +49-8142-66989-52 Fax: +49-8142-66989-80 Email: hs at denx.de
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