aboutsummaryrefslogtreecommitdiff
path: root/arch/arm/plat-orion/gpio.c
diff options
context:
space:
mode:
Diffstat (limited to 'arch/arm/plat-orion/gpio.c')
-rw-r--r--arch/arm/plat-orion/gpio.c415
1 files changed, 415 insertions, 0 deletions
diff --git a/arch/arm/plat-orion/gpio.c b/arch/arm/plat-orion/gpio.c
new file mode 100644
index 00000000000..967186425ca
--- /dev/null
+++ b/arch/arm/plat-orion/gpio.c
@@ -0,0 +1,415 @@
+/*
+ * arch/arm/plat-orion/gpio.c
+ *
+ * Marvell Orion SoC GPIO handling.
+ *
+ * This file is licensed under the terms of the GNU General Public
+ * License version 2. This program is licensed "as is" without any
+ * warranty of any kind, whether express or implied.
+ */
+
+#include <linux/kernel.h>
+#include <linux/init.h>
+#include <linux/irq.h>
+#include <linux/module.h>
+#include <linux/spinlock.h>
+#include <linux/bitops.h>
+#include <linux/io.h>
+#include <asm/gpio.h>
+
+static DEFINE_SPINLOCK(gpio_lock);
+static const char *gpio_label[GPIO_MAX]; /* non null for allocated GPIOs */
+static unsigned long gpio_valid[BITS_TO_LONGS(GPIO_MAX)];
+
+static inline void __set_direction(unsigned pin, int input)
+{
+ u32 u;
+
+ u = readl(GPIO_IO_CONF(pin));
+ if (input)
+ u |= 1 << (pin & 31);
+ else
+ u &= ~(1 << (pin & 31));
+ writel(u, GPIO_IO_CONF(pin));
+}
+
+static void __set_level(unsigned pin, int high)
+{
+ u32 u;
+
+ u = readl(GPIO_OUT(pin));
+ if (high)
+ u |= 1 << (pin & 31);
+ else
+ u &= ~(1 << (pin & 31));
+ writel(u, GPIO_OUT(pin));
+}
+
+
+/*
+ * GENERIC_GPIO primitives.
+ */
+int gpio_direction_input(unsigned pin)
+{
+ unsigned long flags;
+
+ if (pin >= GPIO_MAX || !test_bit(pin, gpio_valid)) {
+ pr_debug("%s: invalid GPIO %d\n", __func__, pin);
+ return -EINVAL;
+ }
+
+ spin_lock_irqsave(&gpio_lock, flags);
+
+ /*
+ * Some callers might not have used gpio_request(),
+ * so flag this pin as requested now.
+ */
+ if (gpio_label[pin] == NULL)
+ gpio_label[pin] = "?";
+
+ /*
+ * Configure GPIO direction.
+ */
+ __set_direction(pin, 1);
+
+ spin_unlock_irqrestore(&gpio_lock, flags);
+
+ return 0;
+}
+EXPORT_SYMBOL(gpio_direction_input);
+
+int gpio_direction_output(unsigned pin, int value)
+{
+ unsigned long flags;
+ u32 u;
+
+ if (pin >= GPIO_MAX || !test_bit(pin, gpio_valid)) {
+ pr_debug("%s: invalid GPIO %d\n", __func__, pin);
+ return -EINVAL;
+ }
+
+ spin_lock_irqsave(&gpio_lock, flags);
+
+ /*
+ * Some callers might not have used gpio_request(),
+ * so flag this pin as requested now.
+ */
+ if (gpio_label[pin] == NULL)
+ gpio_label[pin] = "?";
+
+ /*
+ * Disable blinking.
+ */
+ u = readl(GPIO_BLINK_EN(pin));
+ u &= ~(1 << (pin & 31));
+ writel(u, GPIO_BLINK_EN(pin));
+
+ /*
+ * Configure GPIO output value.
+ */
+ __set_level(pin, value);
+
+ /*
+ * Configure GPIO direction.
+ */
+ __set_direction(pin, 0);
+
+ spin_unlock_irqrestore(&gpio_lock, flags);
+
+ return 0;
+}
+EXPORT_SYMBOL(gpio_direction_output);
+
+int gpio_get_value(unsigned pin)
+{
+ int val;
+
+ if (readl(GPIO_IO_CONF(pin)) & (1 << (pin & 31)))
+ val = readl(GPIO_DATA_IN(pin)) ^ readl(GPIO_IN_POL(pin));
+ else
+ val = readl(GPIO_OUT(pin));
+
+ return (val >> (pin & 31)) & 1;
+}
+EXPORT_SYMBOL(gpio_get_value);
+
+void gpio_set_value(unsigned pin, int value)
+{
+ unsigned long flags;
+ u32 u;
+
+ spin_lock_irqsave(&gpio_lock, flags);
+
+ /*
+ * Disable blinking.
+ */
+ u = readl(GPIO_BLINK_EN(pin));
+ u &= ~(1 << (pin & 31));
+ writel(u, GPIO_BLINK_EN(pin));
+
+ /*
+ * Configure GPIO output value.
+ */
+ __set_level(pin, value);
+
+ spin_unlock_irqrestore(&gpio_lock, flags);
+}
+EXPORT_SYMBOL(gpio_set_value);
+
+int gpio_request(unsigned pin, const char *label)
+{
+ unsigned long flags;
+ int ret;
+
+ if (pin >= GPIO_MAX || !test_bit(pin, gpio_valid)) {
+ pr_debug("%s: invalid GPIO %d\n", __func__, pin);
+ return -EINVAL;
+ }
+
+ spin_lock_irqsave(&gpio_lock, flags);
+ if (gpio_label[pin] == NULL) {
+ gpio_label[pin] = label ? label : "?";
+ ret = 0;
+ } else {
+ pr_debug("%s: GPIO %d already used as %s\n",
+ __func__, pin, gpio_label[pin]);
+ ret = -EBUSY;
+ }
+ spin_unlock_irqrestore(&gpio_lock, flags);
+
+ return ret;
+}
+EXPORT_SYMBOL(gpio_request);
+
+void gpio_free(unsigned pin)
+{
+ if (pin >= GPIO_MAX || !test_bit(pin, gpio_valid)) {
+ pr_debug("%s: invalid GPIO %d\n", __func__, pin);
+ return;
+ }
+
+ if (gpio_label[pin] == NULL)
+ pr_warning("%s: GPIO %d already freed\n", __func__, pin);
+ else
+ gpio_label[pin] = NULL;
+}
+EXPORT_SYMBOL(gpio_free);
+
+
+/*
+ * Orion-specific GPIO API extensions.
+ */
+void __init orion_gpio_set_unused(unsigned pin)
+{
+ /*
+ * Configure as output, drive low.
+ */
+ __set_level(pin, 0);
+ __set_direction(pin, 0);
+}
+
+void __init orion_gpio_set_valid(unsigned pin, int valid)
+{
+ if (valid)
+ __set_bit(pin, gpio_valid);
+ else
+ __clear_bit(pin, gpio_valid);
+}
+
+void orion_gpio_set_blink(unsigned pin, int blink)
+{
+ unsigned long flags;
+ u32 u;
+
+ spin_lock_irqsave(&gpio_lock, flags);
+
+ /*
+ * Set output value to zero.
+ */
+ __set_level(pin, 0);
+
+ u = readl(GPIO_BLINK_EN(pin));
+ if (blink)
+ u |= 1 << (pin & 31);
+ else
+ u &= ~(1 << (pin & 31));
+ writel(u, GPIO_BLINK_EN(pin));
+
+ spin_unlock_irqrestore(&gpio_lock, flags);
+}
+EXPORT_SYMBOL(orion_gpio_set_blink);
+
+
+/*****************************************************************************
+ * Orion GPIO IRQ
+ *
+ * GPIO_IN_POL register controls whether GPIO_DATA_IN will hold the same
+ * value of the line or the opposite value.
+ *
+ * Level IRQ handlers: DATA_IN is used directly as cause register.
+ * Interrupt are masked by LEVEL_MASK registers.
+ * Edge IRQ handlers: Change in DATA_IN are latched in EDGE_CAUSE.
+ * Interrupt are masked by EDGE_MASK registers.
+ * Both-edge handlers: Similar to regular Edge handlers, but also swaps
+ * the polarity to catch the next line transaction.
+ * This is a race condition that might not perfectly
+ * work on some use cases.
+ *
+ * Every eight GPIO lines are grouped (OR'ed) before going up to main
+ * cause register.
+ *
+ * EDGE cause mask
+ * data-in /--------| |-----| |----\
+ * -----| |----- ---- to main cause reg
+ * X \----------------| |----/
+ * polarity LEVEL mask
+ *
+ ****************************************************************************/
+static void gpio_irq_edge_ack(u32 irq)
+{
+ int pin = irq_to_gpio(irq);
+
+ writel(~(1 << (pin & 31)), GPIO_EDGE_CAUSE(pin));
+}
+
+static void gpio_irq_edge_mask(u32 irq)
+{
+ int pin = irq_to_gpio(irq);
+ u32 u;
+
+ u = readl(GPIO_EDGE_MASK(pin));
+ u &= ~(1 << (pin & 31));
+ writel(u, GPIO_EDGE_MASK(pin));
+}
+
+static void gpio_irq_edge_unmask(u32 irq)
+{
+ int pin = irq_to_gpio(irq);
+ u32 u;
+
+ u = readl(GPIO_EDGE_MASK(pin));
+ u |= 1 << (pin & 31);
+ writel(u, GPIO_EDGE_MASK(pin));
+}
+
+static void gpio_irq_level_mask(u32 irq)
+{
+ int pin = irq_to_gpio(irq);
+ u32 u;
+
+ u = readl(GPIO_LEVEL_MASK(pin));
+ u &= ~(1 << (pin & 31));
+ writel(u, GPIO_LEVEL_MASK(pin));
+}
+
+static void gpio_irq_level_unmask(u32 irq)
+{
+ int pin = irq_to_gpio(irq);
+ u32 u;
+
+ u = readl(GPIO_LEVEL_MASK(pin));
+ u |= 1 << (pin & 31);
+ writel(u, GPIO_LEVEL_MASK(pin));
+}
+
+static int gpio_irq_set_type(u32 irq, u32 type)
+{
+ int pin = irq_to_gpio(irq);
+ struct irq_desc *desc;
+ u32 u;
+
+ u = readl(GPIO_IO_CONF(pin)) & (1 << (pin & 31));
+ if (!u) {
+ printk(KERN_ERR "orion gpio_irq_set_type failed "
+ "(irq %d, pin %d).\n", irq, pin);
+ return -EINVAL;
+ }
+
+ desc = irq_desc + irq;
+
+ /*
+ * Set edge/level type.
+ */
+ if (type & (IRQ_TYPE_EDGE_RISING | IRQ_TYPE_EDGE_FALLING)) {
+ desc->chip = &orion_gpio_irq_edge_chip;
+ } else if (type & (IRQ_TYPE_LEVEL_HIGH | IRQ_TYPE_LEVEL_LOW)) {
+ desc->chip = &orion_gpio_irq_level_chip;
+ } else {
+ printk(KERN_ERR "failed to set irq=%d (type=%d)\n", irq, type);
+ return -EINVAL;
+ }
+
+ /*
+ * Configure interrupt polarity.
+ */
+ if (type == IRQ_TYPE_EDGE_RISING || type == IRQ_TYPE_LEVEL_HIGH) {
+ u = readl(GPIO_IN_POL(pin));
+ u &= ~(1 << (pin & 31));
+ writel(u, GPIO_IN_POL(pin));
+ } else if (type == IRQ_TYPE_EDGE_FALLING || type == IRQ_TYPE_LEVEL_LOW) {
+ u = readl(GPIO_IN_POL(pin));
+ u |= 1 << (pin & 31);
+ writel(u, GPIO_IN_POL(pin));
+ } else if (type == IRQ_TYPE_EDGE_BOTH) {
+ u32 v;
+
+ v = readl(GPIO_IN_POL(pin)) ^ readl(GPIO_DATA_IN(pin));
+
+ /*
+ * set initial polarity based on current input level
+ */
+ u = readl(GPIO_IN_POL(pin));
+ if (v & (1 << (pin & 31)))
+ u |= 1 << (pin & 31); /* falling */
+ else
+ u &= ~(1 << (pin & 31)); /* rising */
+ writel(u, GPIO_IN_POL(pin));
+ }
+
+ desc->status = (desc->status & ~IRQ_TYPE_SENSE_MASK) | type;
+
+ return 0;
+}
+
+struct irq_chip orion_gpio_irq_edge_chip = {
+ .name = "orion_gpio_irq_edge",
+ .ack = gpio_irq_edge_ack,
+ .mask = gpio_irq_edge_mask,
+ .unmask = gpio_irq_edge_unmask,
+ .set_type = gpio_irq_set_type,
+};
+
+struct irq_chip orion_gpio_irq_level_chip = {
+ .name = "orion_gpio_irq_level",
+ .mask = gpio_irq_level_mask,
+ .mask_ack = gpio_irq_level_mask,
+ .unmask = gpio_irq_level_unmask,
+ .set_type = gpio_irq_set_type,
+};
+
+void orion_gpio_irq_handler(int pinoff)
+{
+ u32 cause;
+ int pin;
+
+ cause = readl(GPIO_DATA_IN(pinoff)) & readl(GPIO_LEVEL_MASK(pinoff));
+ cause |= readl(GPIO_EDGE_CAUSE(pinoff)) & readl(GPIO_EDGE_MASK(pinoff));
+
+ for (pin = pinoff; pin < pinoff + 8; pin++) {
+ int irq = gpio_to_irq(pin);
+ struct irq_desc *desc = irq_desc + irq;
+
+ if (!(cause & (1 << (pin & 31))))
+ continue;
+
+ if ((desc->status & IRQ_TYPE_SENSE_MASK) == IRQ_TYPE_EDGE_BOTH) {
+ /* Swap polarity (race with GPIO line) */
+ u32 polarity;
+
+ polarity = readl(GPIO_IN_POL(pin));
+ polarity ^= 1 << (pin & 31);
+ writel(polarity, GPIO_IN_POL(pin));
+ }
+ desc_handle_irq(irq, desc);
+ }
+}
generated by cgit v1.2.3-18-g5258 (git 2.32.0) at 2024-12-15 20:45:07 +0000