misc: microchip: pci1xxxx: load gpio driver for the gpio controller auxiliary device enumerated by the auxiliary bus driver.

PIO function's auxiliary bus driver enumerates separate child devices for
GPIO controller and OTP/EEPROM interface. This gpio driver implemented
based on the gpio framework is loaded for the gpio auxiliary device.

Signed-off-by: Kumaravel Thiagarajan <kumaravel.thiagarajan@microchip.com>
Link: https://lore.kernel.org/r/20220824200047.150308-3-kumaravel.thiagarajan@microchip.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

MAINTAINERS

@@ -13428,6 +13428,7 @@ L:	linux-gpio@vger.kernel.org
 S:	Supported
 F:	drivers/misc/mchp_pci1xxxx/mchp_pci1xxxx_gp.c
 F:	drivers/misc/mchp_pci1xxxx/mchp_pci1xxxx_gp.h
+F:	drivers/misc/mchp_pci1xxxx/mchp_pci1xxxx_gpio.c
 
 MICROCHIP OTPC DRIVER
 M:	Claudiu Beznea <claudiu.beznea@microchip.com>

drivers/misc/mchp_pci1xxxx/Makefile

@@ -1 +1 @@
-obj-$(CONFIG_GP_PCI1XXXX) := mchp_pci1xxxx_gp.o
+obj-$(CONFIG_GP_PCI1XXXX) := mchp_pci1xxxx_gp.o mchp_pci1xxxx_gpio.o

drivers/misc/mchp_pci1xxxx/mchp_pci1xxxx_gpio.c

@@ -0,0 +1,163 @@
+// SPDX-License-Identifier: GPL-2.0
+// Copyright (C) 2022 Microchip Technology Inc.
+// pci1xxxx gpio driver
+
+#include <linux/module.h>
+#include <linux/spinlock.h>
+#include <linux/gpio/driver.h>
+#include <linux/bio.h>
+#include <linux/spinlock.h>
+#include <linux/mutex.h>
+#include <linux/kthread.h>
+
+#include "mchp_pci1xxxx_gp.h"
+
+#define PCI1XXXX_NR_PINS		93
+#define PULLUP_OFFSET(x)		((((x) / 32) * 4) + 0x400 + 0x40)
+#define PULLDOWN_OFFSET(x)		((((x) / 32) * 4) + 0x400 + 0x50)
+#define OPENDRAIN_OFFSET(x)		((((x) / 32) * 4) + 0x400 + 0x60)
+#define DEBOUNCE_OFFSET(x)		((((x) / 32) * 4) + 0x400 + 0xE0)
+#define PIO_GLOBAL_CONFIG_OFFSET	(0x400 + 0xF0)
+#define PIO_PCI_CTRL_REG_OFFSET	(0x400 + 0xF4)
+#define INTR_MASK_OFFSET(x)		((((x) / 32) * 4) + 0x400 + 0x100)
+#define INTR_STATUS_OFFSET(x)		(((x) * 4) + 0x400 + 0xD0)
+
+struct pci1xxxx_gpio {
+	struct auxiliary_device *aux_dev;
+	void __iomem *reg_base;
+	struct gpio_chip gpio;
+	spinlock_t lock;
+	int irq_base;
+};
+
+static inline void pci1xxx_assign_bit(void __iomem *base_addr, unsigned int reg_offset,
+				      unsigned int bitpos, bool set)
+{
+	u32 data;
+
+	data = readl(base_addr + reg_offset);
+	if (set)
+		data |= BIT(bitpos);
+	else
+		data &= ~BIT(bitpos);
+	writel(data, base_addr + reg_offset);
+}
+
+static int pci1xxxx_gpio_set_config(struct gpio_chip *gpio, unsigned int offset,
+				    unsigned long config)
+{
+	struct pci1xxxx_gpio *priv = gpiochip_get_data(gpio);
+	unsigned long flags;
+	int ret = 0;
+
+	spin_lock_irqsave(&priv->lock, flags);
+	switch (pinconf_to_config_param(config)) {
+	case PIN_CONFIG_BIAS_PULL_UP:
+		pci1xxx_assign_bit(priv->reg_base, PULLUP_OFFSET(offset), (offset % 32), true);
+		break;
+	case PIN_CONFIG_BIAS_PULL_DOWN:
+		pci1xxx_assign_bit(priv->reg_base, PULLDOWN_OFFSET(offset), (offset % 32), true);
+		break;
+	case PIN_CONFIG_BIAS_DISABLE:
+		pci1xxx_assign_bit(priv->reg_base, PULLUP_OFFSET(offset), (offset % 32), false);
+		pci1xxx_assign_bit(priv->reg_base, PULLDOWN_OFFSET(offset), (offset % 32), false);
+		break;
+	case PIN_CONFIG_DRIVE_OPEN_DRAIN:
+		pci1xxx_assign_bit(priv->reg_base, OPENDRAIN_OFFSET(offset), (offset % 32), true);
+		break;
+	default:
+		ret = -EOPNOTSUPP;
+		break;
+	}
+	spin_unlock_irqrestore(&priv->lock, flags);
+
+	return ret;
+}
+
+static int pci1xxxx_gpio_setup(struct pci1xxxx_gpio *priv, int irq)
+{
+	struct gpio_chip *gchip = &priv->gpio;
+
+	gchip->label = dev_name(&priv->aux_dev->dev);
+	gchip->parent = &priv->aux_dev->dev;
+	gchip->owner = THIS_MODULE;
+	gchip->set_config = pci1xxxx_gpio_set_config;
+	gchip->dbg_show = NULL;
+	gchip->base = -1;
+	gchip->ngpio =  PCI1XXXX_NR_PINS;
+	gchip->can_sleep = false;
+
+	return 0;
+}
+
+static int pci1xxxx_gpio_probe(struct auxiliary_device *aux_dev,
+			       const struct auxiliary_device_id *id)
+
+{
+	struct auxiliary_device_wrapper *aux_dev_wrapper;
+	struct gp_aux_data_type *pdata;
+	struct pci1xxxx_gpio *priv;
+	int retval;
+
+	aux_dev_wrapper = (struct auxiliary_device_wrapper *)
+			  container_of(aux_dev, struct auxiliary_device_wrapper, aux_dev);
+
+	pdata = &aux_dev_wrapper->gp_aux_data;
+
+	if (!pdata)
+		return -EINVAL;
+
+	priv = devm_kzalloc(&aux_dev->dev, sizeof(struct pci1xxxx_gpio), GFP_KERNEL);
+	if (!priv)
+		return -ENOMEM;
+
+	priv->aux_dev = aux_dev;
+
+	if (!devm_request_mem_region(&aux_dev->dev, pdata->region_start, 0x800, aux_dev->name))
+		return -EBUSY;
+
+	priv->reg_base = devm_ioremap(&aux_dev->dev, pdata->region_start, 0x800);
+	if (!priv->reg_base)
+		return -ENOMEM;
+
+	writel(0x0264, (priv->reg_base + 0x400 + 0xF0));
+
+	retval = pci1xxxx_gpio_setup(priv, pdata->irq_num);
+
+	if (retval < 0)
+		return retval;
+
+	dev_set_drvdata(&aux_dev->dev, priv);
+
+	return devm_gpiochip_add_data(&aux_dev->dev, &priv->gpio, priv);
+}
+
+const struct auxiliary_device_id pci1xxxx_gpio_auxiliary_id_table[] = {
+	{.name = "mchp_pci1xxxx_gp.gp_gpio"},
+	{}
+};
+
+static struct auxiliary_driver pci1xxxx_gpio_driver = {
+	.driver = {
+		.name = "PCI1xxxxGPIO",
+		},
+	.probe = pci1xxxx_gpio_probe,
+	.id_table = pci1xxxx_gpio_auxiliary_id_table
+};
+
+static int __init pci1xxxx_gpio_driver_init(void)
+{
+	return auxiliary_driver_register(&pci1xxxx_gpio_driver);
+}
+
+static void __exit pci1xxxx_gpio_driver_exit(void)
+{
+	auxiliary_driver_unregister(&pci1xxxx_gpio_driver);
+}
+
+module_init(pci1xxxx_gpio_driver_init);
+module_exit(pci1xxxx_gpio_driver_exit);
+
+MODULE_DESCRIPTION("Microchip Technology Inc. PCI1xxxx GPIO controller");
+MODULE_AUTHOR("Kumaravel Thiagarajan <kumaravel.thiagarajan@microchip.com>");
+MODULE_LICENSE("GPL");