Exar XR17V352/354/358 chips have 16 multi-purpose inputs/outputs which
can be controlled using gpio interface.
Add support to use these pins and select GPIO_SYSFS also so that these
pins can be used from the userspace through sysfs.
Tested-by: Rob Groner
Signed-off-by: Sudip Mukherjee
---
drivers/tty/serial/8250/8250.h | 14 ++
drivers/tty/serial/8250/8250_gpio.c | 276
drivers/tty/serial/8250/8250_pci.c | 26 +++-
drivers/tty/serial/8250/Kconfig | 8 ++
drivers/tty/serial/8250/Makefile| 1 +
5 files changed, 324 insertions(+), 1 deletion(-)
create mode 100644 drivers/tty/serial/8250/8250_gpio.c
diff --git a/drivers/tty/serial/8250/8250.h b/drivers/tty/serial/8250/8250.h
index d54dcd8..507447d 100644
--- a/drivers/tty/serial/8250/8250.h
+++ b/drivers/tty/serial/8250/8250.h
@@ -217,6 +217,20 @@ static inline int serial_index(struct uart_port *port)
return port->minor - 64;
}
+#ifdef CONFIG_GPIOLIB
+int xr17v35x_gpio_init(struct pci_dev *dev,
+ struct uart_8250_port *port);
+void xr17v35x_gpio_exit(struct uart_8250_port *port);
+#else
+static inline int xr17v35x_gpio_init(struct pci_dev *dev,
+struct uart_8250_port *port)
+{
+ return 0;
+}
+
+static void xr17v35x_gpio_exit(struct uart_8250_port *port) { }
+#endif
+
#if 0
#define DEBUG_INTR(fmt...) printk(fmt)
#else
diff --git a/drivers/tty/serial/8250/8250_gpio.c
b/drivers/tty/serial/8250/8250_gpio.c
new file mode 100644
index 000..1b14dd2
--- /dev/null
+++ b/drivers/tty/serial/8250/8250_gpio.c
@@ -0,0 +1,276 @@
+/*
+ * GPIO driver for Exar XR17V35X chip
+ *
+ * Copyright (C) 2015 Sudip Mukherjee
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ */
+
+#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
+#include
+#include
+#include
+#include
+#include
+#include
+#include "8250.h"
+
+#define EXAR_OFFSET_MPIOLVL_LO 0x90
+#define EXAR_OFFSET_MPIOSEL_LO 0x93
+#define EXAR_OFFSET_MPIOLVL_HI 0x96
+#define EXAR_OFFSET_MPIOSEL_HI 0x99
+
+static LIST_HEAD(exar_list);
+static DEFINE_MUTEX(exar_mtx); /* lock while manipulating the list */
+
+struct exar_gpio_chip {
+ struct gpio_chip gpio_chip;
+ struct mutex lock;
+ struct uart_8250_port *port;
+ struct list_head list;
+ int index;
+ void __iomem *regs;
+};
+
+#define to_exar_chip(n) container_of(n, struct exar_gpio_chip, gpio_chip)
+
+static inline unsigned int read_exar_reg(struct exar_gpio_chip *chip,
+int offset)
+{
+ if (!chip) {
+ pr_err("%s exar_gpio is NULL\n", __func__);
+ return -ENOMEM;
+ }
+ pr_debug("%s regs=%p offset=%x\n", __func__, chip->regs, offset);
+
+ return readb(chip->regs + offset);
+}
+
+static inline void write_exar_reg(struct exar_gpio_chip *chip, int offset,
+ int value)
+{
+ if (!chip) {
+ pr_err("%s exar_gpio is NULL\n", __func__);
+ return;
+ }
+ pr_debug("%s regs=%p value=%x offset=%x\n", __func__, chip->regs,
+value, offset);
+
+ writeb(value, chip->regs + offset);
+}
+
+void xr17v35x_gpio_exit(struct uart_8250_port *port)
+{
+ struct exar_gpio_chip *exar_gpio, *exar_temp1, *exar_temp2;
+
+ if (!port)
+ return;
+
+ exar_gpio = port->port.private_data;
+ if (!exar_gpio)
+ return;
+
+ mutex_lock(&exar_mtx);
+ list_for_each_entry_safe(exar_temp1, exar_temp2, &exar_list, list) {
+ if (exar_temp1->index == exar_gpio->index) {
+ list_del(&exar_temp1->list);
+ break;
+ }
+ }
+ mutex_unlock(&exar_mtx);
+
+ gpiochip_remove(&exar_gpio->gpio_chip);
+ mutex_destroy(&exar_gpio->lock);
+ iounmap(exar_gpio->regs);
+}
+EXPORT_SYMBOL(xr17v35x_gpio_exit);
+
+static void exar_set(struct gpio_chip *chip, unsigned int reg, int val,
+unsigned int offset)
+{
+ struct exar_gpio_chip *exar_gpio = to_exar_chip(chip);
+ int temp;
+
+ mutex_lock(&exar_gpio->lock);
+ temp = read_exar_reg(exar_gpio, reg);
+ temp &= ~(1 << offset);
+ temp |= val << offset;
+ write_exar_reg(exar_gpio, reg, temp);
+ mutex_unlock(&exar_gpio->lock);
+}
+
+static int exar_direction_output(struct gpio_chip *chip, unsigned int offset,
+int value)
+{
+ if (offset < 8)
+ exar_set(chip, EXAR_OFFSET_MPIOSEL_LO, 0, offset);
+ else
+ exar_set(chip, EXAR_OFFSET_MPIOSEL_HI, 0, offset - 8);
+ return 0;
+}
+
+static int exar_direction_input(struct gpio_chip *chip, unsigned int offset)
+{
+ if (offset < 8)
+ exar
