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-rw-r--r--drivers/gpio/gpio-reg.c183
1 files changed, 183 insertions, 0 deletions
diff --git a/drivers/gpio/gpio-reg.c b/drivers/gpio/gpio-reg.c
new file mode 100644
index 000000000..d35169bde
--- /dev/null
+++ b/drivers/gpio/gpio-reg.c
@@ -0,0 +1,183 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * gpio-reg: single register individually fixed-direction GPIOs
+ *
+ * Copyright (C) 2016 Russell King
+ */
+#include <linux/gpio/driver.h>
+#include <linux/gpio/gpio-reg.h>
+#include <linux/io.h>
+#include <linux/slab.h>
+#include <linux/spinlock.h>
+
+struct gpio_reg {
+ struct gpio_chip gc;
+ spinlock_t lock;
+ u32 direction;
+ u32 out;
+ void __iomem *reg;
+ struct irq_domain *irqdomain;
+ const int *irqs;
+};
+
+#define to_gpio_reg(x) container_of(x, struct gpio_reg, gc)
+
+static int gpio_reg_get_direction(struct gpio_chip *gc, unsigned offset)
+{
+ struct gpio_reg *r = to_gpio_reg(gc);
+
+ return r->direction & BIT(offset) ? GPIO_LINE_DIRECTION_IN :
+ GPIO_LINE_DIRECTION_OUT;
+}
+
+static int gpio_reg_direction_output(struct gpio_chip *gc, unsigned offset,
+ int value)
+{
+ struct gpio_reg *r = to_gpio_reg(gc);
+
+ if (r->direction & BIT(offset))
+ return -ENOTSUPP;
+
+ gc->set(gc, offset, value);
+ return 0;
+}
+
+static int gpio_reg_direction_input(struct gpio_chip *gc, unsigned offset)
+{
+ struct gpio_reg *r = to_gpio_reg(gc);
+
+ return r->direction & BIT(offset) ? 0 : -ENOTSUPP;
+}
+
+static void gpio_reg_set(struct gpio_chip *gc, unsigned offset, int value)
+{
+ struct gpio_reg *r = to_gpio_reg(gc);
+ unsigned long flags;
+ u32 val, mask = BIT(offset);
+
+ spin_lock_irqsave(&r->lock, flags);
+ val = r->out;
+ if (value)
+ val |= mask;
+ else
+ val &= ~mask;
+ r->out = val;
+ writel_relaxed(val, r->reg);
+ spin_unlock_irqrestore(&r->lock, flags);
+}
+
+static int gpio_reg_get(struct gpio_chip *gc, unsigned offset)
+{
+ struct gpio_reg *r = to_gpio_reg(gc);
+ u32 val, mask = BIT(offset);
+
+ if (r->direction & mask) {
+ /*
+ * double-read the value, some registers latch after the
+ * first read.
+ */
+ readl_relaxed(r->reg);
+ val = readl_relaxed(r->reg);
+ } else {
+ val = r->out;
+ }
+ return !!(val & mask);
+}
+
+static void gpio_reg_set_multiple(struct gpio_chip *gc, unsigned long *mask,
+ unsigned long *bits)
+{
+ struct gpio_reg *r = to_gpio_reg(gc);
+ unsigned long flags;
+
+ spin_lock_irqsave(&r->lock, flags);
+ r->out = (r->out & ~*mask) | (*bits & *mask);
+ writel_relaxed(r->out, r->reg);
+ spin_unlock_irqrestore(&r->lock, flags);
+}
+
+static int gpio_reg_to_irq(struct gpio_chip *gc, unsigned offset)
+{
+ struct gpio_reg *r = to_gpio_reg(gc);
+ int irq = r->irqs[offset];
+
+ if (irq >= 0 && r->irqdomain)
+ irq = irq_find_mapping(r->irqdomain, irq);
+
+ return irq;
+}
+
+/**
+ * gpio_reg_init - add a fixed in/out register as gpio
+ * @dev: optional struct device associated with this register
+ * @base: start gpio number, or -1 to allocate
+ * @num: number of GPIOs, maximum 32
+ * @label: GPIO chip label
+ * @direction: bitmask of fixed direction, one per GPIO signal, 1 = in
+ * @def_out: initial GPIO output value
+ * @names: array of %num strings describing each GPIO signal or %NULL
+ * @irqdom: irq domain or %NULL
+ * @irqs: array of %num ints describing the interrupt mapping for each
+ * GPIO signal, or %NULL. If @irqdom is %NULL, then this
+ * describes the Linux interrupt number, otherwise it describes
+ * the hardware interrupt number in the specified irq domain.
+ *
+ * Add a single-register GPIO device containing up to 32 GPIO signals,
+ * where each GPIO has a fixed input or output configuration. Only
+ * input GPIOs are assumed to be readable from the register, and only
+ * then after a double-read. Output values are assumed not to be
+ * readable.
+ */
+struct gpio_chip *gpio_reg_init(struct device *dev, void __iomem *reg,
+ int base, int num, const char *label, u32 direction, u32 def_out,
+ const char *const *names, struct irq_domain *irqdom, const int *irqs)
+{
+ struct gpio_reg *r;
+ int ret;
+
+ if (dev)
+ r = devm_kzalloc(dev, sizeof(*r), GFP_KERNEL);
+ else
+ r = kzalloc(sizeof(*r), GFP_KERNEL);
+
+ if (!r)
+ return ERR_PTR(-ENOMEM);
+
+ spin_lock_init(&r->lock);
+
+ r->gc.label = label;
+ r->gc.get_direction = gpio_reg_get_direction;
+ r->gc.direction_input = gpio_reg_direction_input;
+ r->gc.direction_output = gpio_reg_direction_output;
+ r->gc.set = gpio_reg_set;
+ r->gc.get = gpio_reg_get;
+ r->gc.set_multiple = gpio_reg_set_multiple;
+ if (irqs)
+ r->gc.to_irq = gpio_reg_to_irq;
+ r->gc.base = base;
+ r->gc.ngpio = num;
+ r->gc.names = names;
+ r->direction = direction;
+ r->out = def_out;
+ r->reg = reg;
+ r->irqs = irqs;
+
+ if (dev)
+ ret = devm_gpiochip_add_data(dev, &r->gc, r);
+ else
+ ret = gpiochip_add_data(&r->gc, r);
+
+ return ret ? ERR_PTR(ret) : &r->gc;
+}
+
+int gpio_reg_resume(struct gpio_chip *gc)
+{
+ struct gpio_reg *r = to_gpio_reg(gc);
+ unsigned long flags;
+
+ spin_lock_irqsave(&r->lock, flags);
+ writel_relaxed(r->out, r->reg);
+ spin_unlock_irqrestore(&r->lock, flags);
+
+ return 0;
+}