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authorLinus Walleij <linus.walleij@linaro.org>2017-11-07 21:18:57 +0100
committerWolfram Sang <wsa@the-dreams.de>2017-11-10 15:48:07 +0100
commitd82e99a6f9b38cb1a044b4cd979bd49fd3f67cd2 (patch)
tree7c3d4e2a7a80ce0751d8569fae43044cd6d2c277 /arch/mips
parentedd20e95bca4a5434f264d8ab40d729761479825 (diff)
ARM: sa1100: simpad: Correct I2C GPIO offsets
Arnd reported the following build bug bug: In file included from arch/arm/mach-sa1100/simpad.c:20:0: arch/arm/mach-sa1100/include/mach/SA-1100.h:1118:18: error: large integer implicitly truncated to unsigned type [-Werror=overflow] (0x00000001 << (Nb)) ^ include/linux/gpio/machine.h:56:16: note: in definition of macro 'GPIO_LOOKUP_IDX' .chip_hwnum = _chip_hwnum, ^~~~~~~~~~~ arch/arm/mach-sa1100/include/mach/SA-1100.h:1140:21: note: in expansion of macro 'GPIO_GPIO' ^~~~~~~~~ arch/arm/mach-sa1100/simpad.c:331:27: note: in expansion of macro 'GPIO_GPIO21' GPIO_LOOKUP_IDX("gpio", GPIO_GPIO21, NULL, 0, This is what happened: commit b2e63555592f81331c8da3afaa607d8cf83e8138 "i2c: gpio: Convert to use descriptors" commit 4d0ce62c0a02e41a65cfdcfe277f5be430edc371 "i2c: gpio: Augment all boardfiles to use open drain" together uncovered an old bug in the Simpad board file: as theGPIO_LOOKUP_IDX() encodes GPIO offsets on gpiochips in an u16 (see <linux/gpio/machine.h>) these GPIO "numbers" does not fit, since in arch/arm/mach-sa1100/include/mach/SA-1100.h it is defined as: #define GPIO_GPIO(Nb) (0x00000001 << (Nb)) (...) #define GPIO_GPIO21 GPIO_GPIO(21) /* GPIO [21] */ This is however provably wrong, since the i2c-gpio driver uses proper GPIO numbers, albeit earlier from the global number space, whereas this GPIO_GPIO21 is the local line offset in the GPIO register, which is used in other code but certainly not in the gpiolib GPIO driver in drivers/gpio/gpio-sa1100.c, which has code like this: static void sa1100_gpio_set(struct gpio_chip *chip, unsigned offset, int value) { int reg = value ? R_GPSR : R_GPCR; writel_relaxed(BIT(offset), sa1100_gpio_chip(chip)->membase + reg); } So far everything however compiled fine as an unsigned int was used to pass the GPIO numbers in struct i2c_gpio_platform_data. We can trace the actual error back to commit dbd406f9d0a1d33a1303eb75cbe3f9435513d339 "ARM: 7025/1: simpad: add GPIO based device definitions." This added the i2c_gpio with the wrong offsets. This commit was before the SA1100 was converted to use the gpiolib, but as can be seen from the contemporary gpio.c in mach-sa1100, it was already using: static int sa1100_gpio_get(struct gpio_chip *chip, unsigned offset) { return GPLR & GPIO_GPIO(offset); } And GPIO_GPIO() is essentially the BIT() macro. Reported-by: Arnd Bergmann <arnd@arndb.de> Signed-off-by: Linus Walleij <linus.walleij@linaro.org> Acked-by: Arnd Bergmann <arnd@arndb.de> Signed-off-by: Wolfram Sang <wsa@the-dreams.de>
Diffstat (limited to 'arch/mips')
0 files changed, 0 insertions, 0 deletions