PCI/pwrctrl: tc9563: Add GPIO auxiliary device support

The TC9563 embeds a GPIO controller used for per-port reset signals.
Create an auxiliary device for it so the gpio-tc9563 driver can register
the GPIO chip and enable DT-based GPIO lookups. Pass the tc9563 regmap to
the auxiliary device as its platform data.

The pwrctrl driver does not wait for the GPIO chip to be probed. The
per-port reset GPIO lookup, returning -EPROBE_DEFER until the chip is
registered, is added in the next patch.

Signed-off-by: Lorenzo Bianconi <lorenzo.bianconi@oss.qualcomm.com>
[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: Bartosz Golaszewski <bartosz.golaszewski@oss.qualcomm.com>
Reviewed-by: Manivannan Sadhasivam <manivannan.sadhasivam@oss.qualcomm.com>
Reviewed-by: Alex Elder <elder@riscstar.com>
Link: https://patch.msgid.link/20260909-pci-tc9563-aux-v5-3-c9b33f56c8d3@oss.qualcomm.com

2 files changed, 81 insertions, 0 deletions

diff --git a/drivers/pci/pwrctrl/Kconfig b/drivers/pci/pwrctrl/Kconfig
index 1952ab4f29b6..a2fc2a359702 100644
--- a/drivers/pci/pwrctrl/Kconfig
+++ b/drivers/pci/pwrctrl/Kconfig
@@ -29,6 +29,7 @@ config PCI_PWRCTRL_TC9563
 	select PCI_PWRCTRL
 	default m if ARCH_QCOM
 	depends on I2C
+	select AUXILIARY_BUS
 	select REGMAP_I2C
 	help
 	  Say Y here to enable the PCI Power Control driver of TC9563 PCIe
diff --git a/drivers/pci/pwrctrl/pci-pwrctrl-tc9563.c b/drivers/pci/pwrctrl/pci-pwrctrl-tc9563.c
index 59ad219c26c0..3fb862105fa5 100644
--- a/drivers/pci/pwrctrl/pci-pwrctrl-tc9563.c
+++ b/drivers/pci/pwrctrl/pci-pwrctrl-tc9563.c
@@ -4,12 +4,14 @@
  */
 
 #include <linux/array_size.h>
+#include <linux/auxiliary_bus.h>
 #include <linux/bitfield.h>
 #include <linux/bits.h>
 #include <linux/delay.h>
 #include <linux/device.h>
 #include <linux/gpio/consumer.h>
 #include <linux/i2c.h>
+#include <linux/idr.h>
 #include <linux/module.h>
 #include <linux/of.h>
 #include <linux/of_platform.h>
@@ -18,6 +20,7 @@
 #include <linux/platform_device.h>
 #include <linux/regmap.h>
 #include <linux/regulator/consumer.h>
+#include <linux/soc/qcom/tc9563.h>
 #include <linux/string.h>
 #include <linux/types.h>
 
@@ -151,6 +154,8 @@ static const struct reg_sequence dsp2_pwroff_seq[] = {
 	{TC9563_PORT_ACCESS_ENABLE, 0x8},
 };
 
+static DEFINE_IDA(tc9563_pwrctrl_ida);
+
 static int tc9563_pwrctrl_disable_port(struct tc9563_pwrctrl *tc9563,
 				       enum tc9563_pwrctrl_ports port)
 {
@@ -393,6 +398,77 @@ static int tc9563_pwrctrl_parse_device_dt(struct device_node *node,
 	return 0;
 }
 
+static void tc9563_pwrctrl_adev_release(struct device *dev)
+{
+	struct auxiliary_device *adev = to_auxiliary_dev(dev);
+
+	ida_free(&tc9563_pwrctrl_ida, adev->id);
+	of_node_put(adev->dev.of_node);
+	kfree(adev);
+}
+
+static void tc9563_pwrctrl_adev_remove(void *data)
+{
+	struct auxiliary_device *adev = data;
+
+	auxiliary_device_delete(adev);
+	auxiliary_device_uninit(adev);
+}
+
+static int tc9563_pwrctrl_adev_add(struct device *dev, const char *name,
+				   struct device_node *of_node,
+				   void *priv_data)
+{
+	struct auxiliary_device *adev;
+	int id, ret;
+
+	adev = kzalloc_obj(*adev);
+	if (!adev)
+		return -ENOMEM;
+
+	id = ida_alloc(&tc9563_pwrctrl_ida, GFP_KERNEL);
+	if (id < 0) {
+		kfree(adev);
+		return id;
+	}
+
+	adev->id = id;
+	adev->name = name;
+	adev->dev.parent = dev;
+	adev->dev.platform_data = priv_data;
+	adev->dev.release = tc9563_pwrctrl_adev_release;
+	adev->dev.of_node = of_node_get(of_node);
+	dev_set_of_node_reused(&adev->dev);
+
+	ret = auxiliary_device_init(adev);
+	if (ret) {
+		ida_free(&tc9563_pwrctrl_ida, id);
+		of_node_put(adev->dev.of_node);
+		kfree(adev);
+		return ret;
+	}
+
+	ret = auxiliary_device_add(adev);
+	if (ret) {
+		auxiliary_device_uninit(adev);
+		return ret;
+	}
+
+	return devm_add_action_or_reset(dev, tc9563_pwrctrl_adev_remove, adev);
+}
+
+static int tc9563_pwrctrl_add_gpio_adev(struct tc9563_pwrctrl *tc9563)
+{
+	struct device *dev = tc9563->pwrctrl.dev;
+
+	if (!of_property_read_bool(dev->of_node, "gpio-controller") ||
+	    !of_property_present(dev->of_node, "#gpio-cells"))
+		return 0;
+
+	return tc9563_pwrctrl_adev_add(dev, TC9563_GPIO_DEV_NAME, dev->of_node,
+				       tc9563->regmap);
+}
+
 static int tc9563_pwrctrl_power_off(struct pci_pwrctrl *pwrctrl)
 {
 	struct tc9563_pwrctrl *tc9563 = container_of(pwrctrl,
@@ -596,6 +672,10 @@ static int tc9563_pwrctrl_probe(struct platform_device *pdev)
 	tc9563->pwrctrl.power_on = tc9563_pwrctrl_power_on;
 	tc9563->pwrctrl.power_off = tc9563_pwrctrl_power_off;
 
+	ret = tc9563_pwrctrl_add_gpio_adev(tc9563);
+	if (ret)
+		goto remove_i2c;
+
 	ret = devm_pci_pwrctrl_device_set_ready(dev, &tc9563->pwrctrl);
 	if (ret)
 		goto power_off;