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Subject[PATCH v1 char-misc-next 3/5] misc: microchip: pci1xxxx: Add functions to configure gpio pins as input / output, get status, handle I/O for gpio pins.
Date
direction_input and direction_output functions configures a gpio pin as
input and output respectively. get_direction function returns if a gpio
pin is output or input. get function returns the value of a gpio pin
whereas set function assigns output value for a gpio pin.

Signed-off-by: Kumaravel Thiagarajan <kumaravel.thiagarajan@microchip.com>
---
.../misc/mchp_pci1xxxx/mchp_pci1xxxx_gpio.c | 79 +++++++++++++++++++
1 file changed, 79 insertions(+)

diff --git a/drivers/misc/mchp_pci1xxxx/mchp_pci1xxxx_gpio.c b/drivers/misc/mchp_pci1xxxx/mchp_pci1xxxx_gpio.c
index 97ed7ae1baaa..45e197fe3a3e 100644
--- a/drivers/misc/mchp_pci1xxxx/mchp_pci1xxxx_gpio.c
+++ b/drivers/misc/mchp_pci1xxxx/mchp_pci1xxxx_gpio.c
@@ -13,6 +13,10 @@
#include "mchp_pci1xxxx_gp.h"

#define PCI1XXXX_NR_PINS 93
+#define OUT_EN_OFFSET(x) ((((x) / 32) * 4) + 0x400)
+#define INP_EN_OFFSET(x) ((((x) / 32) * 4) + 0x400 + 0x10)
+#define OUT_OFFSET(x) ((((x) / 32) * 4) + 0x400 + 0x20)
+#define INP_OFFSET(x) ((((x) / 32) * 4) + 0x400 + 0x30)
#define PULLUP_OFFSET(x) ((((x) / 32) * 4) + 0x400 + 0x40)
#define PULLDOWN_OFFSET(x) ((((x) / 32) * 4) + 0x400 + 0x50)
#define OPENDRAIN_OFFSET(x) ((((x) / 32) * 4) + 0x400 + 0x60)
@@ -30,6 +34,24 @@ struct pci1xxxx_gpio {
int irq_base;
};

+static int pci1xxxx_gpio_get_direction(struct gpio_chip *gpio, unsigned int nr)
+{
+ struct pci1xxxx_gpio *priv = gpiochip_get_data(gpio);
+ u32 data;
+ int ret = -EINVAL;
+
+ data = readl(priv->reg_base + INP_EN_OFFSET(nr));
+ if (data & BIT(nr % 32)) {
+ ret = 1;
+ } else {
+ data = readl(priv->reg_base + OUT_EN_OFFSET(nr));
+ if (data & BIT(nr % 32))
+ ret = 0;
+ }
+
+ return ret;
+}
+
static inline void pci1xxx_assign_bit(void __iomem *base_addr, unsigned int reg_offset,
unsigned int bitpos, bool set)
{
@@ -43,6 +65,58 @@ static inline void pci1xxx_assign_bit(void __iomem *base_addr, unsigned int reg_
writel(data, base_addr + reg_offset);
}

+static int pci1xxxx_gpio_direction_input(struct gpio_chip *gpio, unsigned int nr)
+{
+ struct pci1xxxx_gpio *priv = gpiochip_get_data(gpio);
+ unsigned long flags;
+
+ spin_lock_irqsave(&priv->lock, flags);
+ pci1xxx_assign_bit(priv->reg_base, INP_EN_OFFSET(nr), (nr % 32), true);
+ pci1xxx_assign_bit(priv->reg_base, OUT_EN_OFFSET(nr), (nr % 32), false);
+ spin_unlock_irqrestore(&priv->lock, flags);
+
+ return 0;
+}
+
+static int pci1xxxx_gpio_get(struct gpio_chip *gpio, unsigned int nr)
+{
+ struct pci1xxxx_gpio *priv = gpiochip_get_data(gpio);
+
+ return (readl(priv->reg_base + INP_OFFSET(nr)) >> (nr % 32)) & 1;
+}
+
+static int pci1xxxx_gpio_direction_output(struct gpio_chip *gpio,
+ unsigned int nr, int val)
+{
+ struct pci1xxxx_gpio *priv = gpiochip_get_data(gpio);
+ unsigned long flags;
+ u32 data;
+
+ spin_lock_irqsave(&priv->lock, flags);
+ pci1xxx_assign_bit(priv->reg_base, INP_EN_OFFSET(nr), (nr % 32), false);
+ pci1xxx_assign_bit(priv->reg_base, OUT_EN_OFFSET(nr), (nr % 32), true);
+ data = readl(priv->reg_base + OUT_OFFSET(nr));
+ if (val)
+ data |= (1 << (nr % 32));
+ else
+ data &= ~(1 << (nr % 32));
+ writel(data, priv->reg_base + OUT_OFFSET(nr));
+ spin_unlock_irqrestore(&priv->lock, flags);
+
+ return 0;
+}
+
+static void pci1xxxx_gpio_set(struct gpio_chip *gpio,
+ unsigned int nr, int val)
+{
+ struct pci1xxxx_gpio *priv = gpiochip_get_data(gpio);
+ unsigned long flags;
+
+ spin_lock_irqsave(&priv->lock, flags);
+ pci1xxx_assign_bit(priv->reg_base, OUT_OFFSET(nr), (nr % 32), val);
+ spin_unlock_irqrestore(&priv->lock, flags);
+}
+
static int pci1xxxx_gpio_set_config(struct gpio_chip *gpio, unsigned int offset,
unsigned long config)
{
@@ -81,6 +155,11 @@ static int pci1xxxx_gpio_setup(struct pci1xxxx_gpio *priv, int irq)
gchip->label = dev_name(&priv->aux_dev->dev);
gchip->parent = &priv->aux_dev->dev;
gchip->owner = THIS_MODULE;
+ gchip->direction_input = pci1xxxx_gpio_direction_input;
+ gchip->direction_output = pci1xxxx_gpio_direction_output;
+ gchip->get_direction = pci1xxxx_gpio_get_direction;
+ gchip->get = pci1xxxx_gpio_get;
+ gchip->set = pci1xxxx_gpio_set;
gchip->set_config = pci1xxxx_gpio_set_config;
gchip->dbg_show = NULL;
gchip->base = -1;
--
2.25.1
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