gpio: tc9563: Add support for the embedded GPIO controller

Add a driver for the GPIO controller embedded in the Toshiba TC9563 PCIe
switch (and the Qualcomm QPS615). The device implements 37 GPIOs using two
register banks: three registers control the first 32 GPIOs and three more
control GPIOs 32-36.  GPIOs 20 and 21 are reserved while GPIOs 22-24,
27-28, 31, and 34 are input-only.

Register the driver as an auxiliary device driver. The TC9563 power
controller creates the auxiliary device and provides a regmap that gives
access to the GPIO registers, so use the gpio-regmap helpers to implement
the GPIO chip.

Signed-off-by: Alex Elder <elder@riscstar.com>
Co-developed-by: Daniel Thompson <daniel@riscstar.com>
Signed-off-by: Daniel Thompson <daniel@riscstar.com>
Co-developed-by: Lorenzo Bianconi <lorenzo.bianconi@oss.qualcomm.com>
Signed-off-by: Lorenzo Bianconi <lorenzo.bianconi@oss.qualcomm.com>
[bhelgaas: commit log per https://lore.kernel.org/arQ2mDjqHv4gmoOK@lore-desk]
[bhelgaas: squash Geert Uytterhoeven <geert+renesas@glider.be> Kconfig fix:
  https://lore.kernel.org/all/45484c37512a3102495d8b75b6e9f72a141ba42e.1792574560.git.geert+renesas@glider.be,
  Reviewed-by: Bartosz Golaszewski <bartosz.golaszewski@oss.qualcomm.com>
  Acked-by: Lorenzo Bianconi <lorenzo.bianconi@oss.qualcomm.com>]
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Reviewed-by: Linus Walleij <linusw@kernel.org>
Reviewed-by: Manivannan Sadhasivam <manivannan.sadhasivam@oss.qualcomm.com>
Acked-by: Bartosz Golaszewski <bartosz.golaszewski@oss.qualcomm.com>
Link: https://patch.msgid.link/20260909-pci-tc9563-aux-v5-2-c9b33f56c8d3@oss.qualcomm.com

4 files changed, 128 insertions, 0 deletions

diff --git a/drivers/gpio/Kconfig b/drivers/gpio/Kconfig
index a48586bb8edb..d429c730161f 100644
--- a/drivers/gpio/Kconfig
+++ b/drivers/gpio/Kconfig
@@ -1830,6 +1830,18 @@ config GPIO_LTC4283
 
 endmenu
 
+config GPIO_TC9563
+	tristate "Toshiba TC9563 GPIO support"
+	depends on PCI_PWRCTRL_TC9563 || COMPILE_TEST
+	default m if ARCH_QCOM
+	select AUXILIARY_BUS
+	select GPIO_REGMAP
+	help
+	  This enables support for the GPIO controller embedded in the Toshiba
+	  TC9563 (and Qualcomm QPS615).  This device connects to the host
+	  via PCIe port, which is the upstream port on an internal PCIe
+	  switch.
+
 menu "PCI GPIO expanders"
 	depends on PCI
 
diff --git a/drivers/gpio/Makefile b/drivers/gpio/Makefile
index dc9e6d643b5b..792faa2668c9 100644
--- a/drivers/gpio/Makefile
+++ b/drivers/gpio/Makefile
@@ -182,6 +182,7 @@ obj-$(CONFIG_GPIO_SYSCON)		+= gpio-syscon.o
 obj-$(CONFIG_GPIO_TANGIER)		+= gpio-tangier.o
 obj-$(CONFIG_GPIO_TB10X)		+= gpio-tb10x.o
 obj-$(CONFIG_GPIO_TC3589X)		+= gpio-tc3589x.o
+obj-$(CONFIG_GPIO_TC9563)		+= gpio-tc9563.o
 obj-$(CONFIG_GPIO_TEGRA186)		+= gpio-tegra186.o
 obj-$(CONFIG_GPIO_TEGRA)		+= gpio-tegra.o
 obj-$(CONFIG_GPIO_THUNDERX)		+= gpio-thunderx.o
diff --git a/drivers/gpio/gpio-tc9563.c b/drivers/gpio/gpio-tc9563.c
new file mode 100644
index 000000000000..68c20c8cba79
--- /dev/null
+++ b/drivers/gpio/gpio-tc9563.c
@@ -0,0 +1,99 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Copyright (C) 2026 by RISCstar Solutions Corporation.  All rights reserved.
+ */
+
+/*
+ * The Toshiba TC9563 implements a PCIe Gen 3 switch that connects an
+ * upstream x4 port to two downstream PCIe x2 ports. It incorporates
+ * an internal endpoint on a internal PCIe port that implements two
+ * Synopsys XGMAC Ethernet interfaces.
+ *
+ * 37 GPIOs are also implemented by an embedded GPIO controller.  Three
+ * registers control the first 32 GPIOs (other than 20 and 21, which are
+ * reserved). Three other registers control GPIOs 32 through 36. GPIOs
+ * 22-24, 27-28, 31, and 34 are treated as "input only".
+ *
+ */
+
+#include <linux/auxiliary_bus.h>
+#include <linux/gpio/driver.h>
+#include <linux/gpio/regmap.h>
+#include <linux/platform_device.h>
+#include <linux/regmap.h>
+#include <linux/soc/qcom/tc9563.h>
+
+/*
+ * There are two sets of registers, each representing (up to) 32 GPIOs with a
+ * stride of 4 bytes (IN1 is 4 bytes past IN0, EN1 is 4 bytes past EN0, etc.).
+ */
+#define TC9563_GPIO_COUNT		37
+#define TC9563_GPIO_PER_REG		32
+#define TC9563_GPIO_REG_STRIDE		4
+
+static int tc9563_gpio_init_valid_mask(struct gpio_chip *gc,
+				       unsigned long *valid_mask,
+				       unsigned int ngpios)
+{
+	/* GPIOs 20 and 21 are reserved */
+	bitmap_fill(valid_mask, ngpios);
+	bitmap_clear(valid_mask, 20, 2);
+
+	return 0;
+}
+
+static int tc9563_gpio_probe(struct auxiliary_device *adev,
+			     const struct auxiliary_device_id *id)
+{
+	struct gpio_regmap_config config = {
+		.parent = &adev->dev,
+		.ngpio = TC9563_GPIO_COUNT,
+		.reg_stride = TC9563_GPIO_REG_STRIDE,
+		.ngpio_per_reg = TC9563_GPIO_PER_REG,
+		.reg_dat_base = GPIO_REGMAP_ADDR(TC9563_GPIO_IN0_OFFSET),
+		.reg_set_base = GPIO_REGMAP_ADDR(TC9563_GPIO_OUT0_OFFSET),
+		.reg_dir_in_base = GPIO_REGMAP_ADDR(TC9563_GPIO_EN0_OFFSET),
+		.init_valid_mask = tc9563_gpio_init_valid_mask,
+	};
+	DECLARE_BITMAP(fixed_dir_mask, TC9563_GPIO_COUNT);
+	DECLARE_BITMAP(fixed_dir_out, TC9563_GPIO_COUNT);
+
+	config.regmap = dev_get_platdata(&adev->dev);
+	if (!config.regmap)
+		return -EINVAL;
+
+	/*
+	 * Only some of our GPIOs are fixed direction:
+	 * 22, 23, 24, 27, 28, 31, and 34 are input-only.
+	 */
+	bitmap_zero(fixed_dir_mask, TC9563_GPIO_COUNT);
+	bitmap_set(fixed_dir_mask, 22, 3);
+	bitmap_set(fixed_dir_mask, 27, 2);
+	set_bit(31, fixed_dir_mask);
+	set_bit(34, fixed_dir_mask);
+	config.fixed_direction_mask = fixed_dir_mask;
+
+	bitmap_zero(fixed_dir_out, TC9563_GPIO_COUNT);
+	config.fixed_direction_output = fixed_dir_out;
+
+	return PTR_ERR_OR_ZERO(devm_gpio_regmap_register(&adev->dev, &config));
+};
+
+static const struct auxiliary_device_id tc9563_gpio_ids[] = {
+	{ "pci_pwrctrl_tc9563." TC9563_GPIO_DEV_NAME },
+	{ /* sentinel */ }
+};
+MODULE_DEVICE_TABLE(auxiliary, tc9563_gpio_ids);
+
+static struct auxiliary_driver tc9563_gpio_driver = {
+	.name		= TC9563_GPIO_DEV_NAME,
+	.probe		= tc9563_gpio_probe,
+	.id_table	= tc9563_gpio_ids,
+};
+module_auxiliary_driver(tc9563_gpio_driver);
+
+MODULE_AUTHOR("Alex Elder <elder@riscstar.com>");
+MODULE_AUTHOR("Daniel Thompson <daniel@riscstar.com>");
+MODULE_AUTHOR("Lorenzo Bianconi <lorenzo.bianconi@oss.qualcomm.com>");
+MODULE_DESCRIPTION("Toshiba TC9563 GPIO Driver");
+MODULE_LICENSE("GPL");
diff --git a/include/linux/soc/qcom/tc9563.h b/include/linux/soc/qcom/tc9563.h
new file mode 100644
index 000000000000..0dfd25747b9a
--- /dev/null
+++ b/include/linux/soc/qcom/tc9563.h
@@ -0,0 +1,16 @@
+/* SPDX-License-Identifier: GPL-2.0-only */
+/*
+ * Copyright (c) 2026 Qualcomm Innovation Center, Inc. All rights reserved.
+ * Author: Lorenzo Bianconi <lorenzo.bianconi@oss.qualcomm.com>
+ */
+
+#ifndef __QCOM_TC9563_H
+#define __QCOM_TC9563_H
+
+#define TC9563_GPIO_DEV_NAME	"tc9563-gpio"
+
+#define TC9563_GPIO_IN0_OFFSET		0x801200
+#define TC9563_GPIO_EN0_OFFSET		0x801208
+#define TC9563_GPIO_OUT0_OFFSET		0x801210
+
+#endif /* __QCOM_TC9563_H */