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Subject[PATCH 4/5] gpio: Add support for LMP92001 GPIO
Date
From: Abhisit Sangjan <s.abhisit@gmail.com>

---
drivers/gpio/Kconfig | 7 ++
drivers/gpio/Makefile | 1 +
drivers/gpio/gpio-lmp92001.c | 235 +++++++++++++++++++++++++++++++++++++++++++
3 files changed, 243 insertions(+)
create mode 100644 drivers/gpio/gpio-lmp92001.c

diff --git a/drivers/gpio/Kconfig b/drivers/gpio/Kconfig
index f235eae..b9b5c97 100644
--- a/drivers/gpio/Kconfig
+++ b/drivers/gpio/Kconfig
@@ -1119,6 +1119,13 @@ config GPIO_WM8994
Say yes here to access the GPIO signals of WM8994 audio hub
CODECs from Wolfson Microelectronics.

+config GPIO_LMP92001
+ tristate "LMP92001 GPIOs"
+ depends on MFD_LMP92001
+ help
+ Say yes here to access the GPIO signals of TI LMP92001 Analog System
+ Monitor and Controller.
+
endmenu

menu "PCI GPIO expanders"
diff --git a/drivers/gpio/Makefile b/drivers/gpio/Makefile
index a9fda6c..153daea 100644
--- a/drivers/gpio/Makefile
+++ b/drivers/gpio/Makefile
@@ -148,3 +148,4 @@ obj-$(CONFIG_GPIO_ZEVIO) += gpio-zevio.o
obj-$(CONFIG_GPIO_ZYNQ) += gpio-zynq.o
obj-$(CONFIG_GPIO_ZX) += gpio-zx.o
obj-$(CONFIG_GPIO_LOONGSON1) += gpio-loongson1.o
+obj-$(CONFIG_GPIO_LMP92001) += gpio-lmp92001.o
diff --git a/drivers/gpio/gpio-lmp92001.c b/drivers/gpio/gpio-lmp92001.c
new file mode 100644
index 0000000..ac0eb4d5
--- /dev/null
+++ b/drivers/gpio/gpio-lmp92001.c
@@ -0,0 +1,235 @@
+/*
+ * gpio-lmp92001.c - Support for TI LMP92001 GPIOs
+ *
+ * Copyright 2016-2017 Celestica Ltd.
+ *
+ * Author: Abhisit Sangjan <s.abhisit@gmail.com>
+ *
+ * Inspired by wm831x driver.
+ *
+ * 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.
+ *
+ */
+
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/gpio.h>
+#include <linux/platform_device.h>
+#include <linux/seq_file.h>
+#include <linux/mfd/core.h>
+#include <linux/version.h>
+
+#include <linux/mfd/lmp92001/core.h>
+
+struct lmp92001_gpio {
+ struct lmp92001 *lmp92001;
+ struct gpio_chip gpio_chip;
+};
+
+static inline struct lmp92001_gpio *to_lmp92001_gpio(struct gpio_chip *chip)
+{
+ return container_of(chip, struct lmp92001_gpio, gpio_chip);
+}
+
+static int lmp92001_gpio_get_direction(struct gpio_chip *chip, unsigned offset)
+{
+ struct lmp92001_gpio *lmp92001_gpio = to_lmp92001_gpio(chip);
+ struct lmp92001 *lmp92001 = lmp92001_gpio->lmp92001;
+ unsigned int val;
+ int ret;
+
+ ret = regmap_read(lmp92001->regmap, LMP92001_CGPO, &val);
+ if (ret < 0)
+ return ret;
+
+ return (val >> offset) & 1;
+}
+
+static int lmp92001_gpio_direction_in(struct gpio_chip *chip, unsigned offset)
+{
+ struct lmp92001_gpio *lmp92001_gpio = to_lmp92001_gpio(chip);
+ struct lmp92001 *lmp92001 = lmp92001_gpio->lmp92001;
+
+ return regmap_update_bits(lmp92001->regmap, LMP92001_CGPO, 1 << offset,
+ 1 << offset);
+}
+
+static int lmp92001_gpio_get(struct gpio_chip *chip, unsigned offset)
+{
+ struct lmp92001_gpio *lmp92001_gpio = to_lmp92001_gpio(chip);
+ struct lmp92001 *lmp92001 = lmp92001_gpio->lmp92001;
+ unsigned int val, sgen;
+
+ /*
+ * Does the GPIO input mode?
+ * Does the GPIO was set?
+ * Reading indicated logic level.
+ * Clear indicated logic level.
+ */
+ regmap_read(lmp92001->regmap, LMP92001_CGPO, &val);
+ if ((val >> offset) & 1)
+ {
+ regmap_read(lmp92001->regmap, LMP92001_SGEN, &sgen);
+ if (sgen & 1)
+ {
+ regmap_read(lmp92001->regmap, LMP92001_SGPI, &val);
+ regmap_update_bits(lmp92001->regmap, LMP92001_CGPO,
+ 0xFF, val);
+ }
+ }
+
+ return (val >> offset) & 1;
+}
+
+static int lmp92001_gpio_direction_out(struct gpio_chip *chip, unsigned offset,
+ int value)
+{
+ struct lmp92001_gpio *lmp92001_gpio = to_lmp92001_gpio(chip);
+ struct lmp92001 *lmp92001 = lmp92001_gpio->lmp92001;
+
+ return regmap_update_bits(lmp92001->regmap, LMP92001_CGPO, 1 << offset,
+ 0 << offset);
+}
+
+static void lmp92001_gpio_set(struct gpio_chip *chip, unsigned offset,
+ int value)
+{
+ struct lmp92001_gpio *lmp92001_gpio = to_lmp92001_gpio(chip);
+ struct lmp92001 *lmp92001 = lmp92001_gpio->lmp92001;
+
+ regmap_update_bits(lmp92001->regmap, LMP92001_CGPO, 1 << offset,
+ value << offset);
+}
+
+#ifdef CONFIG_DEBUG_FS
+static void lmp92001_gpio_dbg_show(struct seq_file *s, struct gpio_chip *chip)
+{
+ struct lmp92001_gpio *lmp92001_gpio = to_lmp92001_gpio(chip);
+ struct lmp92001 *lmp92001 = lmp92001_gpio->lmp92001;
+ int i, gpio;
+ unsigned int cgpo;
+ const char *label, *dir, *logic;
+
+ for (i = 0; i < chip->ngpio; i++)
+ {
+ gpio = i + chip->base;
+
+ label = gpiochip_is_requested(chip, i);
+ if (!label)
+ continue;
+
+ regmap_read(lmp92001->regmap, LMP92001_CGPO, &cgpo);
+ if ((cgpo>>i) & 1)
+ dir = "in";
+ else
+ dir = "out";
+
+ if (lmp92001_gpio_get(chip, i))
+ logic = "hi";
+ else
+ logic = "lo";
+
+ seq_printf(s, " gpio-%-3d (%-20.20s) %-3.3s %-2.2s\n",
+ gpio, label, dir, logic);
+ }
+}
+#else
+#define lmp92001_gpio_dbg_show NULL
+#endif
+
+static struct gpio_chip lmp92001_gpio_chip = {
+ .label = "lmp92001",
+ .owner = THIS_MODULE,
+ .get_direction = lmp92001_gpio_get_direction,
+ .direction_input = lmp92001_gpio_direction_in,
+ .get = lmp92001_gpio_get,
+ .direction_output = lmp92001_gpio_direction_out,
+ .set = lmp92001_gpio_set,
+ .dbg_show = lmp92001_gpio_dbg_show,
+};
+
+static int lmp92001_gpio_probe(struct platform_device *pdev)
+{
+ struct lmp92001 *lmp92001 = dev_get_drvdata(pdev->dev.parent);
+ struct lmp92001_gpio *lmp92001_gpio;
+ struct device_node *np = pdev->dev.of_node;
+ u8 dir;
+ int ret;
+
+ lmp92001_gpio = devm_kzalloc(&pdev->dev, sizeof(*lmp92001_gpio),
+ GFP_KERNEL);
+ if (!lmp92001_gpio)
+ return -ENOMEM;
+
+ lmp92001_gpio->lmp92001 = lmp92001;
+ lmp92001_gpio->gpio_chip = lmp92001_gpio_chip;
+ lmp92001_gpio->gpio_chip.ngpio = 8;
+
+#if LINUX_VERSION_CODE <= KERNEL_VERSION(4, 1, 15)
+ lmp92001_gpio->gpio_chip.dev = &pdev->dev;
+#else
+ lmp92001_gpio->gpio_chip.parent = &pdev->dev;
+#endif
+
+ lmp92001_gpio->gpio_chip.base = -1;
+
+ ret = of_property_read_u8(np, "ti,lmp92001-gpio-dir", &dir);
+ if (!ret)
+ {
+ ret = regmap_update_bits(lmp92001->regmap, LMP92001_CGPO,
+ 0xFF, dir);
+ if (ret < 0)
+ dev_info(&pdev->dev, "could not initial direction\n");
+ }
+
+ ret = gpiochip_add(&lmp92001_gpio->gpio_chip);
+ if (ret < 0) {
+ dev_err(&pdev->dev, "could not register gpiochip, %d\n", ret);
+ return ret;
+ }
+
+ platform_set_drvdata(pdev, lmp92001_gpio);
+
+ return ret;
+}
+
+static int lmp92001_gpio_remove(struct platform_device *pdev)
+{
+ struct lmp92001_gpio *lmp92001_gpio = platform_get_drvdata(pdev);
+
+ gpiochip_remove(&lmp92001_gpio->gpio_chip);
+
+ return 0;
+}
+
+static struct platform_driver lmp92001_gpio_driver = {
+ .driver.name = "lmp92001-gpio",
+ .driver.owner = THIS_MODULE,
+ .probe = lmp92001_gpio_probe,
+ .remove = lmp92001_gpio_remove,
+};
+
+static int __init lmp92001_gpio_init(void)
+{
+ return platform_driver_register(&lmp92001_gpio_driver);
+}
+subsys_initcall(lmp92001_gpio_init);
+
+static void __exit lmp92001_gpio_exit(void)
+{
+ platform_driver_unregister(&lmp92001_gpio_driver);
+}
+module_exit(lmp92001_gpio_exit);
+
+MODULE_AUTHOR("Abhisit Sangjan <s.abhisit@gmail.com>");
+MODULE_DESCRIPTION("GPIO interface for TI LMP92001");
+MODULE_LICENSE("GPL");
+MODULE_ALIAS("platform:lmp92001-gpio");
--
2.7.4
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