From: Markus Gothe markus.gothe@genexis.eu

Linux DTS compatible MDIO bitbanging driver. Both clause 22 and clause 45 MDIO supported and validated.

Heavily based on the Linux drivers (more or less the same code base).

Signed-off-by: Markus Gothe markus.gothe@genexis.eu --- drivers/net/Kconfig | 6 + drivers/net/Makefile | 1 + drivers/net/mdio_gpio.c | 313 ++++++++++++++++++++++++++++++++++++++++ 3 files changed, 320 insertions(+) create mode 100644 drivers/net/mdio_gpio.c

diff --git a/drivers/net/Kconfig b/drivers/net/Kconfig index 576cd2d50ad9..5e862158c566 100644 --- a/drivers/net/Kconfig +++ b/drivers/net/Kconfig @@ -1007,6 +1007,12 @@ config FSL_ENETC This driver supports the NXP ENETC Ethernet controller found on some of the NXP SoCs.

+config MDIO_GPIO_BITBANG + bool "GPIO bitbanging MDIO driver" + depends on DM_MDIO && DM_GPIO + help + Driver for bitbanging MDIO + config MDIO_MUX_I2CREG bool "MDIO MUX accessed as a register over I2C" depends on DM_MDIO_MUX && DM_I2C diff --git a/drivers/net/Makefile b/drivers/net/Makefile index f5ab1f5dedf6..e51a917933eb 100644 --- a/drivers/net/Makefile +++ b/drivers/net/Makefile @@ -61,6 +61,7 @@ obj-$(CONFIG_LITEETH) += liteeth.o obj-$(CONFIG_MACB) += macb.o obj-$(CONFIG_MCFFEC) += mcffec.o mcfmii.o obj-$(CONFIG_MDIO_IPQ4019) += mdio-ipq4019.o +obj-$(CONFIG_MDIO_GPIO_BITBANG) += mdio_gpio.o obj-$(CONFIG_MDIO_MUX_I2CREG) += mdio_mux_i2creg.o obj-$(CONFIG_MDIO_MUX_MESON_G12A) += mdio_mux_meson_g12a.o obj-$(CONFIG_MDIO_MUX_MESON_GXL) += mdio_mux_meson_gxl.o diff --git a/drivers/net/mdio_gpio.c b/drivers/net/mdio_gpio.c new file mode 100644 index 000000000000..a2a41f95190c --- /dev/null +++ b/drivers/net/mdio_gpio.c @@ -0,0 +1,313 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * GPIO based MDIO bitbang driver. + * + * Copyright 2024 Markus Gothe markus.gothe@genexis.eu + * + * This file is based on the Linux kernel drivers drivers/net/phy/mdio-gpio.c + * and drivers/net/phy/mdio-bitbang.c which have the following copyrights: + * + * Copyright (c) 2008 CSE Semaphore Belgium. + * by Laurent Pinchart laurentp@cse-semaphore.com + * + * Copyright (C) 2008, Paulius Zaleckas paulius.zaleckas@teltonika.lt + * + * Author: Scott Wood scottwood@freescale.com + * Copyright (c) 2007 Freescale Semiconductor + * + * Copyright (c) 2003 Intracom S.A. + * by Pantelis Antoniou panto@intracom.gr + * + * 2005 (c) MontaVista Software, Inc. + * Vitaly Bordug vbordug@ru.mvista.com + */ + +#include <dm.h> +#include <log.h> +#include <miiphy.h> +#include <asm/gpio.h> +#include <linux/bitops.h> +#include <linux/delay.h> +#include <linux/mdio.h> + +#define MDIO_READ 2 +#define MDIO_WRITE 1 + +#define MDIO_C45 BIT(15) +#define MDIO_C45_ADDR (MDIO_C45 | 0) +#define MDIO_C45_READ (MDIO_C45 | 3) +#define MDIO_C45_WRITE (MDIO_C45 | 1) + +/* Minimum MDC period is 400 ns, plus some margin for error. MDIO_DELAY + * is done twice per period. + */ +#define MDIO_DELAY 250 + +/* The PHY may take up to 300 ns to produce data, plus some margin + * for error. + */ +#define MDIO_READ_DELAY 350 + +#define MDIO_GPIO_MDC 0 +#define MDIO_GPIO_MDIO 1 +#define MDIO_GPIO_MDO 2 + +struct mdio_gpio_priv { + struct gpio_desc mdc, mdio, mdo; +}; + +static void mdio_dir(struct udevice *mdio_dev, int dir) +{ + struct mdio_gpio_priv *priv = dev_get_priv(mdio_dev); + + if (dm_gpio_is_valid(&priv->mdo)) { + /* Separate output pin. Always set its value to high + * when changing direction. If direction is input, + * assume the pin serves as pull-up. If direction is + * output, the default value is high. + */ + dm_gpio_set_value(&priv->mdo, 1); + return; + } + + if (dir) + dm_gpio_set_dir_flags(&priv->mdio, GPIOD_IS_OUT | GPIOD_IS_OUT_ACTIVE); + else + dm_gpio_set_dir_flags(&priv->mdio, GPIOD_IS_IN); +} + +static int mdio_get(struct udevice *mdio_dev) +{ + struct mdio_gpio_priv *priv = dev_get_priv(mdio_dev); + + return dm_gpio_get_value(&priv->mdio); +} + +static void mdio_set(struct udevice *mdio_dev, int what) +{ + struct mdio_gpio_priv *priv = dev_get_priv(mdio_dev); + + if (dm_gpio_is_valid(&priv->mdo)) + dm_gpio_set_value(&priv->mdo, what); + else + dm_gpio_set_value(&priv->mdio, what); +} + +static void mdc_set(struct udevice *mdio_dev, int what) +{ + struct mdio_gpio_priv *priv = dev_get_priv(mdio_dev); + + dm_gpio_set_value(&priv->mdc, what); +} + +/* MDIO must already be configured as output. */ +static void mdio_gpio_send_bit(struct udevice *mdio_dev, int val) +{ + mdio_set(mdio_dev, val); + ndelay(MDIO_DELAY); + mdc_set(mdio_dev, 1); + ndelay(MDIO_DELAY); + mdc_set(mdio_dev, 0); +} + +/* MDIO must already be configured as input. */ +static int mdio_gpio_get_bit(struct udevice *mdio_dev) +{ + ndelay(MDIO_DELAY); + mdc_set(mdio_dev, 1); + ndelay(MDIO_READ_DELAY); + mdc_set(mdio_dev, 0); + + return mdio_get(mdio_dev); +} + +/* MDIO must already be configured as output. */ +static void mdio_gpio_send_num(struct udevice *mdio_dev, u16 val, int bits) +{ + int i; + + for (i = bits - 1; i >= 0; i--) + mdio_gpio_send_bit(mdio_dev, (val >> i) & 1); +} + +/* MDIO must already be configured as input. */ +static u16 mdio_gpio_get_num(struct udevice *mdio_dev, int bits) +{ + int i; + u16 ret = 0; + + for (i = bits - 1; i >= 0; i--) { + ret <<= 1; + ret |= mdio_gpio_get_bit(mdio_dev); + } + + return ret; +} + +/* Utility to send the preamble, address, and + * register (common to read and write). + */ +static void mdio_gpio_cmd(struct udevice *mdio_dev, int op, u8 phy, u8 reg) +{ + int i; + + mdio_dir(mdio_dev, 1); + + /* + * Send a 32 bit preamble ('1's) with an extra '1' bit for good + * measure. The IEEE spec says this is a PHY optional + * requirement. The AMD 79C874 requires one after power up and + * one after a MII communications error. This means that we are + * doing more preambles than we need, but it is safer and will be + * much more robust. + */ + for (i = 0; i < 32; i++) + mdio_gpio_send_bit(mdio_dev, 1); + + /* + * Send the start bit (01) and the read opcode (10) or write (01). + * Clause 45 operation uses 00 for the start and 11, 10 for + * read/write. + */ + mdio_gpio_send_bit(mdio_dev, 0); + if (op & MDIO_C45) + mdio_gpio_send_bit(mdio_dev, 0); + else + mdio_gpio_send_bit(mdio_dev, 1); + mdio_gpio_send_bit(mdio_dev, (op >> 1) & 1); + mdio_gpio_send_bit(mdio_dev, (op >> 0) & 1); + + mdio_gpio_send_num(mdio_dev, phy, 5); + mdio_gpio_send_num(mdio_dev, reg, 5); +} + +/* + * In clause 45 mode all commands are prefixed by MDIO_ADDR to specify the + * lower 16 bits of the 21 bit address. This transfer is done identically to a + * MDIO_WRITE except for a different code. To enable clause 45 mode or + * MII_ADDR_C45 into the address. Theoretically clause 45 and normal devices + * can exist on the same bus. Normal devices should ignore the MDIO_ADDR + * phase. + */ +static int mdio_gpio_cmd_addr(struct udevice *mdio_dev, int phy, u32 dev_addr, u32 reg) +{ + mdio_gpio_cmd(mdio_dev, MDIO_C45_ADDR, phy, dev_addr); + + /* send the turnaround (10) */ + mdio_gpio_send_bit(mdio_dev, 1); + mdio_gpio_send_bit(mdio_dev, 0); + + mdio_gpio_send_num(mdio_dev, reg, 16); + + mdio_dir(mdio_dev, 0); + mdio_gpio_get_bit(mdio_dev); + + return dev_addr; +} + +static int mdio_gpio_read(struct udevice *mdio_dev, int addr, int devad, int reg) +{ + int ret, i; + + if (devad != MDIO_DEVAD_NONE) { + reg = mdio_gpio_cmd_addr(mdio_dev, addr, devad, reg); + mdio_gpio_cmd(mdio_dev, MDIO_C45_READ, addr, reg); + } else { + mdio_gpio_cmd(mdio_dev, MDIO_READ, addr, reg); + } + + mdio_dir(mdio_dev, 0); + + /* check the turnaround bit: the PHY should be driving it to zero. + */ + if (mdio_gpio_get_bit(mdio_dev) != 0) { + /* PHY didn't drive TA low -- flush any bits it + * may be trying to send. + */ + for (i = 0; i < 32; i++) + mdio_gpio_get_bit(mdio_dev); + + return 0xffff; + } + + ret = mdio_gpio_get_num(mdio_dev, 16); + mdio_gpio_get_bit(mdio_dev); + + return ret; +} + +static int mdio_gpio_write(struct udevice *mdio_dev, int addr, int devad, int reg, u16 val) +{ + if (devad != MDIO_DEVAD_NONE) { + reg = mdio_gpio_cmd_addr(mdio_dev, addr, devad, reg); + mdio_gpio_cmd(mdio_dev, MDIO_C45_WRITE, addr, reg); + } else { + mdio_gpio_cmd(mdio_dev, MDIO_WRITE, addr, reg); + } + + /* send the turnaround (10) */ + mdio_gpio_send_bit(mdio_dev, 1); + mdio_gpio_send_bit(mdio_dev, 0); + + mdio_gpio_send_num(mdio_dev, val, 16); + + mdio_dir(mdio_dev, 0); + mdio_gpio_get_bit(mdio_dev); + + return 0; +} + +static const struct mdio_ops mdio_gpio_ops = { + .read = mdio_gpio_read, + .write = mdio_gpio_write, + .reset = NULL, +}; + +/* + * Name the device, we use the device tree node name. + * This can be overwritten by MDIO class code if device-name property is + * present. + */ +static int mdio_gpio_bind(struct udevice *mdio_dev) +{ + if (ofnode_valid(dev_ofnode(mdio_dev))) + device_set_name(mdio_dev, ofnode_get_name(dev_ofnode(mdio_dev))); + + return 0; +} + +static int mdio_gpio_probe(struct udevice *mdio_dev) +{ + struct mdio_gpio_priv *priv = dev_get_priv(mdio_dev); + int ret = 0; + + ret = gpio_request_by_name(mdio_dev, "gpios", MDIO_GPIO_MDC, &priv->mdc, GPIOD_IS_OUT); + if (ret) + return ret; + + ret = gpio_request_by_name(mdio_dev, "gpios", MDIO_GPIO_MDIO, &priv->mdio, GPIOD_IS_IN); + if (ret) + return ret; + + ret = gpio_request_by_name(mdio_dev, "gpios", MDIO_GPIO_MDO, &priv->mdo, GPIOD_IS_OUT); + if (ret && ret != -ENOENT) + return ret; + + return 0; +} + +static const struct udevice_id mdio_gpio_ids[] = { + { .compatible = "virtual,mdio-gpio" }, + { /* sentinel */ } +}; + +U_BOOT_DRIVER(gpio_mdio) = { + .name = "gpio_mdio", + .id = UCLASS_MDIO, + .of_match = mdio_gpio_ids, + .bind = mdio_gpio_bind, + .probe = mdio_gpio_probe, + .ops = &mdio_gpio_ops, + .plat_auto = sizeof(struct mdio_perdev_priv), + .priv_auto = sizeof(struct mdio_gpio_priv), +};