rM2: gpio: Copy rM2 BD7181x driver

Copy the rM2 zero-sugar branch
(https://github.com/reMarkable/linux/tree/zero-sugar) to the new kernel.

Signed-off-by: Alistair Francis <alistair@alistair23.me>

drivers/gpio/Kconfig

@@ -869,6 +869,12 @@ config GPIO_GW_PLD
 	  Say yes here to provide access to the Gateworks I2C PLD GPIO
 	  Expander. This is used at least on the Cambria GW2358-4.
 
+config GPIO_BD7181X
+	tristate "BD7181X GPO"
+	depends on MFD_BD7181X
+	help
+	  Say yes here to access the GPO signals of bd71815/bd71817 chip from ROHM.
+
 config GPIO_MAX7300
 	tristate "Maxim MAX7300 GPIO expander"
 	select GPIO_MAX730X

drivers/gpio/Makefile

@@ -38,6 +38,7 @@ obj-$(CONFIG_GPIO_BD70528)		+= gpio-bd70528.o
 obj-$(CONFIG_GPIO_BD9571MWV)		+= gpio-bd9571mwv.o
 obj-$(CONFIG_GPIO_BRCMSTB)		+= gpio-brcmstb.o
 obj-$(CONFIG_GPIO_BT8XX)		+= gpio-bt8xx.o
+obj-$(CONFIG_GPIO_BD7181X)		+= gpio-bd7181x.o
 obj-$(CONFIG_GPIO_CADENCE)		+= gpio-cadence.o
 obj-$(CONFIG_GPIO_CLPS711X)		+= gpio-clps711x.o
 obj-$(CONFIG_GPIO_SNPS_CREG)		+= gpio-creg-snps.o

drivers/gpio/gpio-bd7181x.c

@@ -0,0 +1,202 @@
+/*
+ * gpio-bd7181x.c
+ * @file Access to GPOs on ROHM BD7181XMWV chip
+ *
+ * Copyright 2014 Embest Technology Co. Ltd. Inc.
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307 USA
+ */
+#define DEBUG
+#include <linux/module.h>
+#include <linux/init.h>
+#include <linux/kthread.h>
+#include <linux/irq.h>
+#include <linux/gpio.h>
+#include <linux/platform_device.h>
+#include <linux/of.h>
+
+#include <linux/mfd/bd7181x.h>
+
+/** @brief bd7181x gpio chip core data */
+static struct gpio_chip bd7181xgpo_chip;
+
+/** @brief get gpo output value
+ * @param chip pointer to core data
+ * @param offset gpo number, start from 0
+ * @retval 0 success
+ * @retval negative error number
+ */
+static int bd7181xgpo_get(struct gpio_chip *chip, unsigned offset)
+{
+	struct bd7181x *bd7181x = dev_get_drvdata(chip->parent);
+	int ret = 0;
+
+	ret = bd7181x_reg_read(bd7181x, BD7181X_REG_GPO);
+	if (ret < 0)
+		return ret;
+
+	return (ret >> offset) & 1;
+}
+
+/** @brief set gpo direction as output
+ * @param chip pointer to core data
+ * @param offset gpo number, start from 0
+ * @param value output value when set direction out
+ * @retval 0 success
+ */
+static int bd7181xgpo_direction_out(struct gpio_chip *chip, unsigned offset,
+				    int value)
+{
+	/* This only drives GPOs, and can't change direction */
+	return 0;
+}
+
+/** @brief set gpo output value
+ * @param chip pointer to core data
+ * @param offset gpo number, start from 0
+ * @param value output value, not zero as high level, 0 as low level
+ * @retval 0 success
+ * @retval negative error number
+ */
+static void bd7181xgpo_set(struct gpio_chip *chip, unsigned offset, int value)
+{
+	struct bd7181x *bd7181x = dev_get_drvdata(chip->parent);
+	int ret;
+	u8 gpoctl;
+
+	ret = bd7181x_reg_read(bd7181x, BD7181X_REG_GPO);
+	if (ret < 0)
+		return;
+
+	if (value)
+		gpoctl = ret | (1 << offset);
+	else
+		gpoctl = ret & ~(1 << offset);
+
+	bd7181x_reg_write(bd7181x, BD7181X_REG_GPO, gpoctl);
+}
+
+/** @brief bd7181x gpio chip core data */
+static struct gpio_chip bd7181xgpo_chip = {
+	.label			= "bd7181x",		///< gpio chip name
+	.owner			= THIS_MODULE,
+	.get			= bd7181xgpo_get,
+	.direction_output	= bd7181xgpo_direction_out,
+	.set			= bd7181xgpo_set,
+	.can_sleep		= 1,
+};
+
+/*----------------------------------------------------------------------*/
+#ifdef CONFIG_OF
+/** @brief retrive gpo platform data from device tree
+ * @param pdev platfrom device pointer
+ * @return pointer to platform data
+ * @retval NULL error
+ */
+static struct bd7181x_gpo_plat_data *of_gpio_bd7181x(
+	struct platform_device *pdev)
+{
+	struct bd7181x_gpo_plat_data *platform_data;
+	struct device_node *np, *gpio_np;
+
+	platform_data = devm_kzalloc(&pdev->dev, sizeof(*platform_data), GFP_KERNEL);
+	if (!platform_data) {
+		return NULL;
+	}
+
+	np = of_node_get(pdev->dev.parent->of_node);
+	gpio_np = of_find_node_by_name(np, "gpo");
+	if (!gpio_np) {
+		dev_err(&pdev->dev, "gpio node not found\n");
+		return NULL;
+	}
+
+	pdev->dev.of_node = gpio_np;
+	
+	if (of_property_read_u32(gpio_np, "rohm,mode", &platform_data->mode)) {
+		platform_data->mode = -1;
+	}
+	
+	return platform_data;
+}
+#endif
+
+/** @brief probe bd7181x gpo device
+ * @param pdev platfrom device pointer
+ * @retval 0 success
+ * @retval negative error number
+ */
+static int gpo_bd7181x_probe(struct platform_device *pdev)
+{
+	struct bd7181x_gpo_plat_data *pdata = pdev->dev.platform_data;
+	struct device *mfd_dev = pdev->dev.parent;
+	struct bd7181x *bd7181x = dev_get_drvdata(mfd_dev);
+	int ret;
+
+#ifdef CONFIG_OF
+	pdata = of_gpio_bd7181x(pdev);
+#endif
+	if (pdata && pdata->gpio_base > 0)
+		bd7181xgpo_chip.base = pdata->gpio_base;
+	else
+		bd7181xgpo_chip.base = -1;
+
+	bd7181xgpo_chip.ngpio = 2;	/* bd71815/bd71817 have 2 GPO */
+
+	bd7181xgpo_chip.parent = &pdev->dev;
+
+	ret = gpiochip_add(&bd7181xgpo_chip);
+	if (ret < 0) {
+		dev_err(&pdev->dev, "Could not register gpiochip, %d\n", ret);
+		bd7181xgpo_chip.ngpio = 0;
+		return ret;
+	}
+
+	if (pdata && pdata->mode != -1UL) {
+		bd7181x_update_bits(bd7181x, BD7181X_REG_GPO, 0x70, pdata->mode);
+	}
+
+	return ret;
+}
+
+/** @brief remove bd7181x gpo device
+ * @param pdev platfrom device pointer
+ * @retval 0 success
+ * @retval negative error number
+ */
+static int gpo_bd7181x_remove(struct platform_device *pdev)
+{
+	gpiochip_remove(&bd7181xgpo_chip);
+	return 0;
+}
+
+/* Note:  this hardware lives inside an I2C-based multi-function device. */
+MODULE_ALIAS("platform:bd7181x-gpo");
+
+/** @brief bd7181x gpo driver core data */
+static struct platform_driver gpo_bd7181x_driver = {
+	.driver = {
+		.name	= "bd7181x-gpo",
+		.owner	= THIS_MODULE,
+	},
+	.probe		= gpo_bd7181x_probe,
+	.remove		= gpo_bd7181x_remove,
+};
+
+module_platform_driver(gpo_bd7181x_driver);
+
+MODULE_AUTHOR("Peter Yang <yanglsh@embest-tech.com>");
+MODULE_DESCRIPTION("GPO interface for BD71815/BD71817");
+MODULE_LICENSE("GPL");