linux-kernel - [PATCH 3.16 009/346] gpio: pca953x: Fix NBANK calculation for PCA9536

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Message-ID: <lsq.1479082460.719079376@decadent.org.uk>
Date:   Mon, 14 Nov 2016 00:14:20 +0000
From:   Ben Hutchings <ben@...adent.org.uk>
To:     linux-kernel@...r.kernel.org, stable@...r.kernel.org
CC:     akpm@...ux-foundation.org, "Vignesh R" <vigneshr@...com>,
        "Linus Walleij" <linus.walleij@...aro.org>
Subject: [PATCH 3.16 009/346] gpio: pca953x: Fix NBANK calculation for PCA9536

3.16.39-rc1 review patch.  If anyone has any objections, please let me know.

------------------

From: Vignesh R <vigneshr@...com>

commit a246b8198f776a16d1d3a3bbfc2d437bad766b29 upstream.

NBANK() macro assumes that ngpios is a multiple of 8(BANK_SZ) and
hence results in 0 banks for PCA9536 which has just 4 gpios. This is
wrong as PCA9356 has 1 bank with 4 gpios. This results in uninitialized
PCA953X_INVERT register. Fix this by using DIV_ROUND_UP macro in
NBANK().

Signed-off-by: Vignesh R <vigneshr@...com>
Signed-off-by: Linus Walleij <linus.walleij@...aro.org>
Signed-off-by: Ben Hutchings <ben@...adent.org.uk>
---
 drivers/gpio/gpio-pca953x.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

--- a/drivers/gpio/gpio-pca953x.c
+++ b/drivers/gpio/gpio-pca953x.c
@@ -76,7 +76,7 @@ MODULE_DEVICE_TABLE(i2c, pca953x_id);
 #define MAX_BANK 5
 #define BANK_SZ 8
 
-#define NBANK(chip) (chip->gpio_chip.ngpio / BANK_SZ)
+#define NBANK(chip) DIV_ROUND_UP(chip->gpio_chip.ngpio, BANK_SZ)
 
 struct pca953x_chip {
 	unsigned gpio_start;