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Subject[PATCHv3 1/7] basic_mmio_gpio: remove runtime width/endianness evaluation
Date
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>
Cc: Grant Likely <grant.likely@secretlab.ca>
---
drivers/gpio/basic_mmio_gpio.c | 136 +++++++++++++++++++++++++++-------------
1 files changed, 92 insertions(+), 44 deletions(-)
diff --git a/drivers/gpio/basic_mmio_gpio.c b/drivers/gpio/basic_mmio_gpio.c
index 3addea6..e935a24 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;
--
1.7.4.2


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