From dff66169ef56103337ae2677c9b46733535df78f Mon Sep 17 00:00:00 2001
From: "H. Nikolaus Schaller" <hns@goldelico.com>
Date: Thu, 17 May 2018 06:59:49 +0200
Subject: [PATCH 1589/1795] gpio: pca953x: fix address calculation for pcal6524

The register constants are so far defined in a way that they fit
for the pcal9555a when shifted by the number of banks, i.e. are
multiplied by 2 in the accessor function.

Now, the pcal6524 has 3 banks which means the relative offset
is multiplied by 4 for the standard registers.

Simply applying the bit shift to the extended registers gives
a wrong result, since the base offset is already included in
the offset.

Therefore, we have to add code to the 24 bit accessor functions
that adjusts the register number for these exended registers.

The formula finally used was developed and proposed by
Andy Shevchenko <andy.shevchenko@gmail.com>.

Suggested-by: Andy Shevchenko <andy.shevchenko@gmail.com>
Signed-off-by: H. Nikolaus Schaller <hns@goldelico.com>
Reviewed-by: Andy Shevchenko <andy.shevchenko@gmail.com>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
(cherry picked from commit d5dbf9c266ccf632cdf259146e4ec62b381db655)
Signed-off-by: Simon Horman <horms+renesas@verge.net.au>
Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
---
 drivers/gpio/gpio-pca953x.c | 8 ++++++--
 1 file changed, 6 insertions(+), 2 deletions(-)

diff --git a/drivers/gpio/gpio-pca953x.c b/drivers/gpio/gpio-pca953x.c
index 9aabe2091af0..f7301d03bb07 100644
--- a/drivers/gpio/gpio-pca953x.c
+++ b/drivers/gpio/gpio-pca953x.c
@@ -222,9 +222,11 @@ static int pca957x_write_regs_16(struct pca953x_chip *chip, int reg, u8 *val)
 static int pca953x_write_regs_24(struct pca953x_chip *chip, int reg, u8 *val)
 {
 	int bank_shift = fls((chip->gpio_chip.ngpio - 1) / BANK_SZ);
+	int addr = (reg & PCAL_GPIO_MASK) << bank_shift;
+	int pinctrl = (reg & PCAL_PINCTRL_MASK) << 1;
 
 	return i2c_smbus_write_i2c_block_data(chip->client,
-					      (reg << bank_shift) | REG_ADDR_AI,
+					      pinctrl | addr | REG_ADDR_AI,
 					      NBANK(chip), val);
 }
 
@@ -264,9 +266,11 @@ static int pca953x_read_regs_16(struct pca953x_chip *chip, int reg, u8 *val)
 static int pca953x_read_regs_24(struct pca953x_chip *chip, int reg, u8 *val)
 {
 	int bank_shift = fls((chip->gpio_chip.ngpio - 1) / BANK_SZ);
+	int addr = (reg & PCAL_GPIO_MASK) << bank_shift;
+	int pinctrl = (reg & PCAL_PINCTRL_MASK) << 1;
 
 	return i2c_smbus_read_i2c_block_data(chip->client,
-					     (reg << bank_shift) | REG_ADDR_AI,
+					     pinctrl | addr | REG_ADDR_AI,
 					     NBANK(chip), val);
 }
 
-- 
2.19.0