[PATCH 1/2] gpio: Add Turris Omnia MCU driver

["Pali Rohár" <pali@kernel.org>]

This driver registers GPIO controller and allows U-Boot to control GPIO
pins on MCU which is connected to Turris Omnia via i2c.

Signed-off-by: Pali Rohár <pali@kernel.org>
---
 board/CZ.NIC/turris_omnia/MAINTAINERS |   1 +
 drivers/gpio/Kconfig                  |   7 +
 drivers/gpio/Makefile                 |   1 +
 drivers/gpio/turris_omnia_mcu.c       | 314 ++++++++++++++++++++++++++
 4 files changed, 323 insertions(+)
 create mode 100644 drivers/gpio/turris_omnia_mcu.c

diff --git a/board/CZ.NIC/turris_omnia/MAINTAINERS b/board/CZ.NIC/turris_omnia/MAINTAINERS
index 8258f4fc5b23..8bff97cc2737 100644
--- a/board/CZ.NIC/turris_omnia/MAINTAINERS
+++ b/board/CZ.NIC/turris_omnia/MAINTAINERS
@@ -6,4 +6,5 @@ F:	arch/arm/dts/armada-385-turris-omnia*.dts*
 F:	board/CZ.NIC/turris_atsha_otp.*
 F:	board/CZ.NIC/turris_omnia/
 F:	configs/turris_omnia_defconfig
+F:	drivers/gpio/turris_omnia_mcu.c
 F:	include/configs/turris_omnia.h
diff --git a/drivers/gpio/Kconfig b/drivers/gpio/Kconfig
index aaa152fae73b..82a8bca27000 100644
--- a/drivers/gpio/Kconfig
+++ b/drivers/gpio/Kconfig
@@ -598,4 +598,11 @@ config SLG7XL45106_I2C_GPO
 	   8-bit gpo expander, all gpo lines are controlled by writing
 	   value into data register.
 
+config TURRIS_OMNIA_MCU
+	bool "Turris Omnia MCU GPIO driver"
+	depends on DM_GPIO
+	default y if TARGET_TURRIS_OMNIA
+	help
+	   Support for GPIOs on MCU connected to Turris Omnia via i2c.
+
 endif
diff --git a/drivers/gpio/Makefile b/drivers/gpio/Makefile
index d7552762d065..219f37e0e434 100644
--- a/drivers/gpio/Makefile
+++ b/drivers/gpio/Makefile
@@ -75,3 +75,4 @@ obj-$(CONFIG_MAX7320_GPIO)	+= max7320_gpio.o
 obj-$(CONFIG_SL28CPLD_GPIO)	+= sl28cpld-gpio.o
 obj-$(CONFIG_ZYNQMP_GPIO_MODEPIN)	+= zynqmp_gpio_modepin.o
 obj-$(CONFIG_SLG7XL45106_I2C_GPO)	+= gpio_slg7xl45106.o
+obj-$(CONFIG_$(SPL_TPL_)TURRIS_OMNIA_MCU)	+= turris_omnia_mcu.o
diff --git a/drivers/gpio/turris_omnia_mcu.c b/drivers/gpio/turris_omnia_mcu.c
new file mode 100644
index 000000000000..44a6574d5f17
--- /dev/null
+++ b/drivers/gpio/turris_omnia_mcu.c
@@ -0,0 +1,314 @@
+// SPDX-License-Identifier: GPL-2.0+
+// (C) 2022 Pali Rohár <pali@kernel.org>
+
+#include <common.h>
+#include <dm.h>
+#include <i2c.h>
+#include <asm/gpio.h>
+#include <linux/log2.h>
+
+enum commands_e {
+	CMD_GET_STATUS_WORD                 = 0x01,
+	CMD_GENERAL_CONTROL                 = 0x02,
+
+	/* available if STS_FEATURES_SUPPORTED bit set in status word */
+	CMD_GET_FEATURES                    = 0x10,
+
+	/* available if FEAT_EXT_CMDS bit is set in features */
+	CMD_GET_EXT_STATUS_DWORD            = 0x11,
+	CMD_EXT_CONTROL                     = 0x12,
+	CMD_GET_EXT_CONTROL_STATUS          = 0x13,
+};
+
+/* CMD_GET_STATUS_WORD */
+enum sts_word_e {
+	STS_MCU_TYPE_MASK                = GENMASK(1, 0),
+	STS_MCU_TYPE_STM32               = 0,
+	STS_MCU_TYPE_GD32                = 1,
+	STS_MCU_TYPE_MKL                 = 2,
+	STS_FEATURES_SUPPORTED           = BIT(2),
+	STS_USER_REGULATOR_NOT_SUPPORTED = BIT(3),
+	STS_CARD_DET                     = BIT(4),
+	STS_MSATA_IND                    = BIT(5),
+	STS_USB30_OVC                    = BIT(6),
+	STS_USB31_OVC                    = BIT(7),
+	STS_USB30_PWRON                  = BIT(8),
+	STS_USB31_PWRON                  = BIT(9),
+	STS_ENABLE_4V5                   = BIT(10),
+	STS_BUTTON_MODE                  = BIT(11),
+	STS_BUTTON_PRESSED               = BIT(12),
+	STS_BUTTON_COUNTER_MASK          = GENMASK(15, 13)
+};
+
+/* CMD_GENERAL_CONTROL */
+enum ctl_byte_e {
+	CTL_LIGHT_RST   = BIT(0),
+	CTL_HARD_RST    = BIT(1),
+	/*CTL_RESERVED    = BIT(2),*/
+	CTL_USB30_PWRON = BIT(3),
+	CTL_USB31_PWRON = BIT(4),
+	CTL_ENABLE_4V5  = BIT(5),
+	CTL_BUTTON_MODE = BIT(6),
+	CTL_BOOTLOADER  = BIT(7)
+};
+
+/* CMD_GET_FEATURES */
+enum features_e {
+	FEAT_EXT_CMDS           = BIT(1),
+};
+
+struct turris_omnia_mcu_info {
+	u16 features;
+};
+
+static int turris_omnia_mcu_get_function(struct udevice *dev, uint offset)
+{
+	struct turris_omnia_mcu_info *info = dev_get_plat(dev);
+
+	switch (offset) {
+	/* bank 0 */
+	case 0 ... 15:
+		switch (offset) {
+		case ilog2(STS_USB30_PWRON):
+		case ilog2(STS_USB31_PWRON):
+		case ilog2(STS_ENABLE_4V5):
+		case ilog2(STS_BUTTON_MODE):
+			return GPIOF_OUTPUT;
+		default:
+			return GPIOF_INPUT;
+		}
+
+	/* bank 1 - supported only when FEAT_EXT_CMDS is set */
+	case (16 + 0) ... (16 + 31):
+		if (!(info->features & FEAT_EXT_CMDS))
+			return -EINVAL;
+		return GPIOF_INPUT;
+
+	/* bank 2 - supported only when FEAT_EXT_CMDS is set */
+	case (16 + 32 + 0) ... (16 + 32 + 15):
+		if (!(info->features & FEAT_EXT_CMDS))
+			return -EINVAL;
+		return GPIOF_OUTPUT;
+
+	default:
+		return -EINVAL;
+	}
+}
+
+static int turris_omnia_mcu_get_value(struct udevice *dev, uint offset)
+{
+	struct turris_omnia_mcu_info *info = dev_get_plat(dev);
+	u8 val16[2];
+	u8 val32[4];
+	int ret;
+
+	switch (offset) {
+	/* bank 0 */
+	case 0 ... 15:
+		ret = dm_i2c_read(dev, CMD_GET_STATUS_WORD, val16, 2);
+		if (ret)
+			return ret;
+		return ((((u16)val16[1] << 8) | val16[0]) >> offset) & 0x1;
+
+	/* bank 1 - supported only when FEAT_EXT_CMDS is set */
+	case (16 + 0) ... (16 + 31):
+		if (!(info->features & FEAT_EXT_CMDS))
+			return -EINVAL;
+		ret = dm_i2c_read(dev, CMD_GET_EXT_STATUS_DWORD, val32, 4);
+		if (ret)
+			return ret;
+		return ((((u32)val32[3] << 24) | ((u32)val32[2] << 16) |
+			 ((u32)val32[1] << 8) | val32[0]) >> (offset - 16)) & 0x1;
+
+	/* bank 2 - supported only when FEAT_EXT_CMDS is set */
+	case (16 + 32 + 0) ... (16 + 32 + 15):
+		if (!(info->features & FEAT_EXT_CMDS))
+			return -EINVAL;
+		ret = dm_i2c_read(dev, CMD_GET_EXT_CONTROL_STATUS, val16, 2);
+		if (ret)
+			return ret;
+		return ((((u16)val16[1] << 8) | val16[0]) >> (offset - 16 - 32)) & 0x1;
+
+	default:
+		return -EINVAL;
+	}
+}
+
+static int turris_omnia_mcu_set_value(struct udevice *dev, uint offset, int value)
+{
+	struct turris_omnia_mcu_info *info = dev_get_plat(dev);
+	u8 val[2];
+	int ret;
+	u8 reg;
+
+	switch (offset) {
+	/* bank 0 */
+	case ilog2(STS_USB30_PWRON):
+		reg = CMD_GENERAL_CONTROL;
+		val[1] = CTL_USB30_PWRON;
+		break;
+	case ilog2(STS_USB31_PWRON):
+		reg = CMD_GENERAL_CONTROL;
+		val[1] = CTL_USB31_PWRON;
+		break;
+	case ilog2(STS_ENABLE_4V5):
+		reg = CMD_GENERAL_CONTROL;
+		val[1] = CTL_ENABLE_4V5;
+		break;
+	case ilog2(STS_BUTTON_MODE):
+		reg = CMD_GENERAL_CONTROL;
+		val[1] = CTL_BUTTON_MODE;
+		break;
+
+	/* bank 2 - supported only when FEAT_EXT_CMDS is set */
+	case (16 + 32 + 0) ... (16 + 32 + 15):
+		if (!(info->features & FEAT_EXT_CMDS))
+			return -EINVAL;
+		reg = CMD_EXT_CONTROL;
+		val[1] = BIT(offset - 16 - 32);
+		break;
+
+	default:
+		return -EINVAL;
+	}
+
+	val[0] = value ? val[1] : 0;
+
+	ret = dm_i2c_write(dev, reg, val, 2);
+	if (ret)
+		return ret;
+
+	return 0;
+}
+
+static int turris_omnia_mcu_direction_input(struct udevice *dev, uint offset)
+{
+	int ret;
+
+	ret = turris_omnia_mcu_get_function(dev, offset);
+	if (ret < 0)
+		return ret;
+	else if (ret != GPIOF_INPUT)
+		return -EOPNOTSUPP;
+
+	return 0;
+}
+
+static int turris_omnia_mcu_direction_output(struct udevice *dev, uint offset, int value)
+{
+	int ret;
+
+	ret = turris_omnia_mcu_get_function(dev, offset);
+	if (ret < 0)
+		return ret;
+	else if (ret != GPIOF_OUTPUT)
+		return -EOPNOTSUPP;
+
+	return turris_omnia_mcu_set_value(dev, offset, value);
+}
+
+static int turris_omnia_mcu_xlate(struct udevice *dev, struct gpio_desc *desc,
+				  struct ofnode_phandle_args *args)
+{
+	uint bank, gpio, flags, offset;
+	int ret;
+
+	if (args->args_count != 3)
+		return -EINVAL;
+
+	bank = args->args[0];
+	gpio = args->args[1];
+	flags = args->args[2];
+
+	switch (bank) {
+	case 0:
+		if (gpio >= 16)
+			return -EINVAL;
+		offset = gpio;
+		break;
+	case 1:
+		if (gpio >= 32)
+			return -EINVAL;
+		offset = 16 + gpio;
+		break;
+	case 2:
+		if (gpio >= 16)
+			return -EINVAL;
+		offset = 16 + 32 + gpio;
+		break;
+	default:
+		return -EINVAL;
+	}
+
+	ret = turris_omnia_mcu_get_function(dev, offset);
+	if (ret < 0)
+		return ret;
+
+	if (ret == GPIOF_OUTPUT && ((flags & GPIOD_IS_IN) || !(flags & GPIOD_IS_OUT)))
+		return -EINVAL;
+	else if (ret == GPIOF_INPUT && (!(flags & GPIOD_IS_IN) || (flags & GPIOD_IS_OUT)))
+		return -EINVAL;
+
+	desc->offset = offset;
+	desc->flags = flags;
+
+	return 0;
+}
+
+static const struct dm_gpio_ops turris_omnia_mcu_ops = {
+	.direction_input	= turris_omnia_mcu_direction_input,
+	.direction_output	= turris_omnia_mcu_direction_output,
+	.get_value		= turris_omnia_mcu_get_value,
+	.set_value		= turris_omnia_mcu_set_value,
+	.get_function		= turris_omnia_mcu_get_function,
+	.xlate			= turris_omnia_mcu_xlate,
+};
+
+static int turris_omnia_mcu_probe(struct udevice *dev)
+{
+	struct turris_omnia_mcu_info *info = dev_get_plat(dev);
+	struct gpio_dev_priv *uc_priv = dev_get_uclass_priv(dev);
+	u16 status;
+	u8 val[2];
+	int ret;
+
+	ret = dm_i2c_read(dev, CMD_GET_STATUS_WORD, val, 2);
+	if (ret) {
+		printf("Error: turris_omnia_mcu CMD_GET_STATUS_WORD failed: %d\n", ret);
+		return ret;
+	}
+
+	status = ((u16)val[1] << 8) | val[0];
+
+	if (status & STS_FEATURES_SUPPORTED) {
+		ret = dm_i2c_read(dev, CMD_GET_FEATURES, val, 2);
+		if (ret) {
+			printf("Error: turris_omnia_mcu CMD_GET_FEATURES failed: %d\n", ret);
+			return ret;
+		}
+		info->features = ((u16)val[1] << 8) | val[0];
+	}
+
+	uc_priv->bank_name = "mcu_";
+
+	if (info->features & FEAT_EXT_CMDS)
+		uc_priv->gpio_count = 16 + 32 + 16;
+	else
+		uc_priv->gpio_count = 16;
+
+	return 0;
+}
+
+static const struct udevice_id turris_omnia_mcu_ids[] = {
+	{ .compatible = "cznic,turris-omnia-mcu" },
+	{ }
+};
+
+U_BOOT_DRIVER(turris_omnia_mcu) = {
+	.name		= "turris-omnia-mcu",
+	.id		= UCLASS_GPIO,
+	.ops		= &turris_omnia_mcu_ops,
+	.probe		= turris_omnia_mcu_probe,
+	.plat_auto	= sizeof(struct turris_omnia_mcu_info),
+	.of_match	= turris_omnia_mcu_ids,
+};
-- 
2.20.1