Revert "gpio: lp3943: Drop pin_used and lp3943_gpio_request/lp3943_gpio_free"

This reverts commit 3fab91ea284a3b795327dda915a3c150a49e4be2.

2 files changed, 28 insertions, 0 deletions

diff --git a/drivers/gpio/gpio-lp3943.c b/drivers/gpio/gpio-lp3943.c
index fdec94b0cfb0..6dc6725403ec 100644
--- a/drivers/gpio/gpio-lp3943.c
+++ b/drivers/gpio/gpio-lp3943.c
@@ -45,6 +45,26 @@ struct lp3943_gpio {
         u16 input_mask;         /* 1 = GPIO is input direction, 0 = output */
 };
 
+static int lp3943_gpio_request(struct gpio_chip *chip, unsigned offset)
+{
+        struct lp3943_gpio *lp3943_gpio = gpiochip_get_data(chip);
+        struct lp3943 *lp3943 = lp3943_gpio->lp3943;
+
+        /* Return an error if the pin is already assigned */
+        if (test_and_set_bit(offset, &lp3943->pin_used))
+                return -EBUSY;
+
+        return 0;
+}
+
+static void lp3943_gpio_free(struct gpio_chip *chip, unsigned offset)
+{
+        struct lp3943_gpio *lp3943_gpio = gpiochip_get_data(chip);
+        struct lp3943 *lp3943 = lp3943_gpio->lp3943;
+
+        clear_bit(offset, &lp3943->pin_used);
+}
+
 static int lp3943_gpio_set_mode(struct lp3943_gpio *lp3943_gpio, u8 offset,
                                 u8 val)
 {
@@ -157,6 +177,8 @@ static int lp3943_gpio_direction_output(struct gpio_chip *chip, unsigned offset,
 static const struct gpio_chip lp3943_gpio_chip = {
         .label                  = "lp3943",
         .owner                  = THIS_MODULE,
+        .request                = lp3943_gpio_request,
+        .free                   = lp3943_gpio_free,
         .direction_input        = lp3943_gpio_direction_input,
         .get                    = lp3943_gpio_get,
         .direction_output       = lp3943_gpio_direction_output,
diff --git a/include/linux/mfd/lp3943.h b/include/linux/mfd/lp3943.h
index d3a738118b27..3490db782988 100644
--- a/include/linux/mfd/lp3943.h
+++ b/include/linux/mfd/lp3943.h
@@ -94,12 +94,18 @@ struct lp3943_reg_cfg {
  * @regmap: Used for I2C communication on accessing registers
  * @pdata: LP3943 platform specific data
  * @mux_cfg: Register configuration for pin MUX
+ * @pin_used: Bit mask for output pin used.
+ *            This bitmask is used for pin assignment management.
+ *            1 = pin used, 0 = available.
+ *            Only LSB 16 bits are used, but it is unsigned long type
+ *            for atomic bitwise operations.
  */
 struct lp3943 {
         struct device *dev;
         struct regmap *regmap;
         struct lp3943_platform_data *pdata;
         const struct lp3943_reg_cfg *mux_cfg;
+        unsigned long pin_used;
 };
 
 int lp3943_read_byte(struct lp3943 *lp3943, u8 reg, u8 *read);