i2c: nomadik: simplify IRQ masking logic

IRQ_MASK and I2C_CLEAR_ALL_INTS both mask available interrupts. IRQ_MASK
removes top options (bits 29-31). I2C_CLEAR_ALL_INTS removes reserved
options including top bits. Keep the latter.

31  29  27  25  23  21  19  17  15  13  11  09  07  05  03  01
  30  28  26  24  22  20  18  16  14  12  10  08  06  04  02  00
-- IRQ_MASK: ---------------------------------------------------
      1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1
0 0 0
-- I2C_CLEAR_ALL_INTS: -----------------------------------------
      1     1 1       1 1 1 1 1                   1 1 1 1 1 1 1
0 0 0   0 0     0 0 0           0 0 0 0 0 0 0 0 0

Notice I2C_CLEAR_ALL_INTS is more restrictive than IRQ_MASK.
Reviewed-by: Linus Walleij <linus.walleij@linaro.org>
Reviewed-by: Andi Shyti <andi.shyti@kernel.org>
Signed-off-by: Théo Lebrun <theo.lebrun@bootlin.com>
Signed-off-by: Andi Shyti <andi.shyti@kernel.org>

drivers/i2c/busses/i2c-nomadik.c

@@ -94,9 +94,6 @@
 /* some bits in ICR are reserved */
 #define I2C_CLEAR_ALL_INTS	0x131f007f
 
-/* first three msb bits are reserved */
-#define IRQ_MASK(mask)		(mask & 0x1fffffff)
-
 /* maximum threshold value */
 #define MAX_I2C_FIFO_THRESHOLD	15
 
@@ -249,8 +246,7 @@ static int flush_i2c_fifo(struct nmk_i2c_dev *priv)
  */
 static void disable_all_interrupts(struct nmk_i2c_dev *priv)
 {
-	u32 mask = IRQ_MASK(0);
-	writel(mask, priv->virtbase + I2C_IMSCR);
+	writel(0, priv->virtbase + I2C_IMSCR);
 }
 
 /**
@@ -259,9 +255,7 @@ static void disable_all_interrupts(struct nmk_i2c_dev *priv)
  */
 static void clear_all_interrupts(struct nmk_i2c_dev *priv)
 {
-	u32 mask;
-	mask = IRQ_MASK(I2C_CLEAR_ALL_INTS);
-	writel(mask, priv->virtbase + I2C_ICR);
+	writel(I2C_CLEAR_ALL_INTS, priv->virtbase + I2C_ICR);
 }
 
 /**
@@ -468,7 +462,7 @@ static int read_i2c(struct nmk_i2c_dev *priv, u16 flags)
 	else
 		irq_mask |= I2C_IT_MTDWS;
 
-	irq_mask = I2C_CLEAR_ALL_INTS & IRQ_MASK(irq_mask);
+	irq_mask &= I2C_CLEAR_ALL_INTS;
 
 	writel(readl(priv->virtbase + I2C_IMSCR) | irq_mask,
 	       priv->virtbase + I2C_IMSCR);
@@ -547,7 +541,7 @@ static int write_i2c(struct nmk_i2c_dev *priv, u16 flags)
 	else
 		irq_mask |= I2C_IT_MTDWS;
 
-	irq_mask = I2C_CLEAR_ALL_INTS & IRQ_MASK(irq_mask);
+	irq_mask &= I2C_CLEAR_ALL_INTS;
 
 	writel(readl(priv->virtbase + I2C_IMSCR) | irq_mask,
 	       priv->virtbase + I2C_IMSCR);
@@ -703,8 +697,8 @@ static int nmk_i2c_xfer(struct i2c_adapter *i2c_adap,
  */
 static int disable_interrupts(struct nmk_i2c_dev *priv, u32 irq)
 {
-	irq = IRQ_MASK(irq);
-	writel(readl(priv->virtbase + I2C_IMSCR) & ~(I2C_CLEAR_ALL_INTS & irq),
+	irq &= I2C_CLEAR_ALL_INTS;
+	writel(readl(priv->virtbase + I2C_IMSCR) & ~irq,
 	       priv->virtbase + I2C_IMSCR);
 	return 0;
 }