basic_mmio_gpio: remove runtime width/endianness evaluation

Remove endianness/width calculations at runtime by installing function
pointers for bit-to-mask conversion and register accessors.

Reported-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Jamie Iles <jamie@jamieiles.com>
Acked-by: Anton Vorontsov <cbouatmailru@gmail.com>
Signed-off-by: Grant Likely <grant.likely@secretlab.ca>

1 files changed, 92 insertions, 44 deletions

diff --git a/drivers/gpio/basic_mmio_gpio.c b/drivers/gpio/basic_mmio_gpio.c
index 3addea65894e..e935a24f7d29 100644
--- a/drivers/gpio/basic_mmio_gpio.c
+++ b/drivers/gpio/basic_mmio_gpio.c
@@ -63,6 +63,10 @@ o        `                     ~~~~\___/~~~~    ` controller in FPGA is ,.`
 
 struct bgpio_chip {
         struct gpio_chip gc;
+
+        unsigned long (*read_reg)(void __iomem *reg);
+        void (*write_reg)(void __iomem *reg, unsigned long data);
+
         void __iomem *reg_dat;
         void __iomem *reg_set;
         void __iomem *reg_clr;
@@ -74,7 +78,7 @@ struct bgpio_chip {
          * Some GPIO controllers work with the big-endian bits notation,
          * e.g. in a 8-bits register, GPIO7 is the least significant bit.
          */
-        int big_endian_bits;
+        unsigned long (*pin2mask)(struct bgpio_chip *bgc, unsigned int pin);
 
         /*
          * Used to lock bgpio_chip->data. Also, this is needed to keep
@@ -91,70 +95,77 @@ static struct bgpio_chip *to_bgpio_chip(struct gpio_chip *gc)
         return container_of(gc, struct bgpio_chip, gc);
 }
 
-static unsigned long bgpio_in(struct bgpio_chip *bgc)
+static void bgpio_write8(void __iomem *reg, unsigned long data)
 {
-        switch (bgc->bits) {
-        case 8:
-                return __raw_readb(bgc->reg_dat);
-        case 16:
-                return __raw_readw(bgc->reg_dat);
-        case 32:
-                return __raw_readl(bgc->reg_dat);
-#if BITS_PER_LONG >= 64
-        case 64:
-                return __raw_readq(bgc->reg_dat);
-#endif
-        }
-        return -EINVAL;
+        __raw_writeb(data, reg);
 }
 
-static void bgpio_out(struct bgpio_chip *bgc, void __iomem *reg,
-                      unsigned long data)
+static unsigned long bgpio_read8(void __iomem *reg)
 {
-        switch (bgc->bits) {
-        case 8:
-                __raw_writeb(data, reg);
-                return;
-        case 16:
-                __raw_writew(data, reg);
-                return;
-        case 32:
-                __raw_writel(data, reg);
-                return;
+        return __raw_readb(reg);
+}
+
+static void bgpio_write16(void __iomem *reg, unsigned long data)
+{
+        __raw_writew(data, reg);
+}
+
+static unsigned long bgpio_read16(void __iomem *reg)
+{
+        return __raw_readw(reg);
+}
+
+static void bgpio_write32(void __iomem *reg, unsigned long data)
+{
+        __raw_writel(data, reg);
+}
+
+static unsigned long bgpio_read32(void __iomem *reg)
+{
+        return __raw_readl(reg);
+}
+
 #if BITS_PER_LONG >= 64
-        case 64:
-                __raw_writeq(data, reg);
-                return;
-#endif
-        }
+static void bgpio_write64(void __iomem *reg, unsigned long data)
+{
+        __raw_writeq(data, reg);
 }
 
+static unsigned long bgpio_read64(void __iomem *reg)
+{
+        return __raw_readq(reg);
+}
+#endif /* BITS_PER_LONG >= 64 */
+
 static unsigned long bgpio_pin2mask(struct bgpio_chip *bgc, unsigned int pin)
 {
-        if (bgc->big_endian_bits)
-                return 1 << (bgc->bits - 1 - pin);
-        else
-                return 1 << pin;
+        return 1 << pin;
+}
+
+static unsigned long bgpio_pin2mask_be(struct bgpio_chip *bgc,
+                                       unsigned int pin)
+{
+        return 1 << (bgc->bits - 1 - pin);
 }
 
 static int bgpio_get(struct gpio_chip *gc, unsigned int gpio)
 {
         struct bgpio_chip *bgc = to_bgpio_chip(gc);
 
-        return bgpio_in(bgc) & bgpio_pin2mask(bgc, gpio);
+        return bgc->read_reg(bgc->reg_dat) & bgc->pin2mask(bgc, gpio);
 }
 
 static void bgpio_set(struct gpio_chip *gc, unsigned int gpio, int val)
 {
         struct bgpio_chip *bgc = to_bgpio_chip(gc);
-        unsigned long mask = bgpio_pin2mask(bgc, gpio);
+        unsigned long mask = bgc->pin2mask(bgc, gpio);
         unsigned long flags;
 
         if (bgc->reg_set) {
                 if (val)
-                        bgpio_out(bgc, bgc->reg_set, mask);
+                        bgc->write_reg(bgc->reg_set, mask);
                 else
-                        bgpio_out(bgc, bgc->reg_clr, mask);
+                        bgc->write_reg(bgc->reg_clr, mask);
                 return;
         }
 
@@ -165,7 +176,7 @@ static void bgpio_set(struct gpio_chip *gc, unsigned int gpio, int val)
         else
                 bgc->data &= ~mask;
 
-        bgpio_out(bgc, bgc->reg_dat, bgc->data);
+        bgc->write_reg(bgc->reg_dat, bgc->data);
 
         spin_unlock_irqrestore(&bgc->lock, flags);
 }
@@ -181,9 +192,44 @@ static int bgpio_dir_out(struct gpio_chip *gc, unsigned int gpio, int val)
         return 0;
 }
 
-static int __devinit bgpio_probe(struct platform_device *pdev)
+static int bgpio_setup_accessors(struct platform_device *pdev,
+                                 struct bgpio_chip *bgc)
 {
         const struct platform_device_id *platid = platform_get_device_id(pdev);
+
+        switch (bgc->bits) {
+        case 8:
+                bgc->read_reg   = bgpio_read8;
+                bgc->write_reg  = bgpio_write8;
+                break;
+        case 16:
+                bgc->read_reg   = bgpio_read16;
+                bgc->write_reg  = bgpio_write16;
+                break;
+        case 32:
+                bgc->read_reg   = bgpio_read32;
+                bgc->write_reg  = bgpio_write32;
+                break;
+#if BITS_PER_LONG >= 64
+        case 64:
+                bgc->read_reg   = bgpio_read64;
+                bgc->write_reg  = bgpio_write64;
+                break;
+#endif /* BITS_PER_LONG >= 64 */
+        default:
+                dev_err(&pdev->dev, "unsupported data width %u bits\n",
+                        bgc->bits);
+                return -EINVAL;
+        }
+
+        bgc->pin2mask = strcmp(platid->name, "basic-mmio-gpio-be") ?
+                bgpio_pin2mask : bgpio_pin2mask_be;
+
+        return 0;
+}
+
+static int __devinit bgpio_probe(struct platform_device *pdev)
+{
         struct device *dev = &pdev->dev;
         struct bgpio_pdata *pdata = dev_get_platdata(dev);
         struct bgpio_chip *bgc;
@@ -232,9 +278,11 @@ static int __devinit bgpio_probe(struct platform_device *pdev)
         spin_lock_init(&bgc->lock);
 
         bgc->bits = bits;
-        bgc->big_endian_bits = !strcmp(platid->name, "basic-mmio-gpio-be");
-        bgc->data = bgpio_in(bgc);
+        ret = bgpio_setup_accessors(pdev, bgc);
+        if (ret)
+                return ret;
 
+        bgc->data = bgc->read_reg(bgc->reg_dat);
         bgc->gc.ngpio = bits;
         bgc->gc.direction_input = bgpio_dir_in;
         bgc->gc.direction_output = bgpio_dir_out;