gpio: 74x164: Allocate buffer with gen_74x164_chip

By moving the internal buffer to the end of struct gen_74x164_chip and
converting it from a pointer to a zero-sized array, it can be allocated
together with gen_74x164_chip, reducing the number of managed
allocations.

Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>

diff --git a/drivers/gpio/gpio-74x164.c b/drivers/gpio/gpio-74x164.c
index fb555300008f491e32bb5d82a1610172a44d880c..b0939e0ff0b9b3e254137a44c406633a41aa1838 100644 (file)
--- a/drivers/gpio/gpio-74x164.c
+++ b/drivers/gpio/gpio-74x164.c
@@ -20,10 +20,10 @@
 #define GEN_74X164_NUMBER_GPIOS        8
 
 struct gen_74x164_chip {
-       u8                      *buffer;
        struct gpio_chip        gpio_chip;
        struct mutex            lock;
        u32                     registers;
+       u8                      buffer[0];
 };
 
 static struct gen_74x164_chip *gpio_to_74x164_chip(struct gpio_chip *gc)
@@ -107,6 +107,7 @@ static int gen_74x164_direction_output(struct gpio_chip *gc,
 static int gen_74x164_probe(struct spi_device *spi)
 {
        struct gen_74x164_chip *chip;
+       u32 nregs;
        int ret;
 
        /*
@@ -118,7 +119,14 @@ static int gen_74x164_probe(struct spi_device *spi)
        if (ret < 0)
                return ret;
 
-       chip = devm_kzalloc(&spi->dev, sizeof(*chip), GFP_KERNEL);
+       if (of_property_read_u32(spi->dev.of_node, "registers-number",
+                                &nregs)) {
+               dev_err(&spi->dev,
+                       "Missing registers-number property in the DT.\n");
+               return -EINVAL;
+       }
+
+       chip = devm_kzalloc(&spi->dev, sizeof(*chip) + nregs, GFP_KERNEL);
        if (!chip)
                return -ENOMEM;
 
@@ -130,17 +138,8 @@ static int gen_74x164_probe(struct spi_device *spi)
        chip->gpio_chip.set = gen_74x164_set_value;
        chip->gpio_chip.base = -1;
 
-       if (of_property_read_u32(spi->dev.of_node, "registers-number",
-                                &chip->registers)) {
-               dev_err(&spi->dev,
-                       "Missing registers-number property in the DT.\n");
-               return -EINVAL;
-       }
-
+       chip->registers = nregs;
        chip->gpio_chip.ngpio = GEN_74X164_NUMBER_GPIOS * chip->registers;
-       chip->buffer = devm_kzalloc(&spi->dev, chip->registers, GFP_KERNEL);
-       if (!chip->buffer)
-               return -ENOMEM;
 
        chip->gpio_chip.can_sleep = true;
        chip->gpio_chip.parent = &spi->dev;