To ease the implementation of other MPC85xx board ports, several common GPIO helpers are added to <asm/mpc85xx_gpio.h>.
Since each of these compiles to no more than 4-5 instructions it would be very inefficient to call them out of line, therefore we put them entirely in the header file.
The HWW-1U-1A board port which these were written for strongly prefers to set multiple GPIOs as a single batch operation, so the API is designed around that basis.
To assist other board ports, a small set of wrappers are used which provides a standard gpio_request() interface around the MPC85xx-specific functions. This can be enabled with CONFIG_MPC85XX_GENERIC_GPIO.
Signed-off-by: Kyle Moffett Kyle.D.Moffett@boeing.com Cc: Andy Fleming afleming@gmail.com Cc: Kumar Gala kumar.gala@freescale.com Cc: Peter Tyser ptyser@xes-inc.com
-- Changelog: v2: Moved the inline functions to a non-board-specific header v3: Added generic Linux-standard GPIO wrappers v4: Improved comments and fixed minor bugs in the wrapper functions v6: Rebased onto the 'next' branch of git://git.denx.de/u-boot-mpc85xx.git
arch/powerpc/include/asm/mpc85xx_gpio.h | 120 +++++++++++++++++++++++++++++++ 1 files changed, 120 insertions(+), 0 deletions(-) create mode 100644 arch/powerpc/include/asm/mpc85xx_gpio.h
diff --git a/arch/powerpc/include/asm/mpc85xx_gpio.h b/arch/powerpc/include/asm/mpc85xx_gpio.h new file mode 100644 index 0000000..ad54b4e --- /dev/null +++ b/arch/powerpc/include/asm/mpc85xx_gpio.h @@ -0,0 +1,120 @@ +/* + * Copyright 2010 eXMeritus, A Boeing Company + * + * This program is free software; you can redistribute it and/or + * modify it under the terms of the GNU General Public License as + * published by the Free Software Foundation; either version 2 of + * the License, or (at your option) any later version. + * + * This program is distributed in the hope that it will be useful, + * but WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + * GNU General Public License for more details. + * + * You should have received a copy of the GNU General Public License + * along with this program; if not, write to the Free Software + * Foundation, Inc., 59 Temple Place, Suite 330, Boston, + * MA 02111-1307 USA + */ + +#include <asm/immap_85xx.h> + +/* + * The following internal functions are an MPC85XX-specific GPIO API which + * allows setting and querying multiple GPIOs in a single operation. + * + * All of these look relatively large, but the arguments are almost always + * constants, so they compile down to just a few instructions and a + * memory-mapped IO operation or two. + */ +static inline void mpc85xx_gpio_set(unsigned int mask, + unsigned int dir, unsigned int val) +{ + ccsr_gpio_t *gpio = (void *)(CONFIG_SYS_MPC85xx_GPIO_ADDR + 0xc00); + + /* First mask off the unwanted parts of "dir" and "val" */ + dir &= mask; + val &= mask; + + /* Now read in the values we're supposed to preserve */ + dir |= (in_be32(&gpio->gpdir) & ~mask); + val |= (in_be32(&gpio->gpdat) & ~mask); + + /* + * Poke the new output values first, then set the direction. This + * helps to avoid transient data when switching from input to output + * and vice versa. + */ + out_be32(&gpio->gpdat, val); + out_be32(&gpio->gpdir, dir); +} + +static inline void mpc85xx_gpio_set_in(unsigned int gpios) +{ + mpc85xx_gpio_set(gpios, 0x00000000, 0x00000000); +} + +static inline void mpc85xx_gpio_set_low(unsigned int gpios) +{ + mpc85xx_gpio_set(gpios, 0xFFFFFFFF, 0x00000000); +} + +static inline void mpc85xx_gpio_set_high(unsigned int gpios) +{ + mpc85xx_gpio_set(gpios, 0xFFFFFFFF, 0xFFFFFFFF); +} + +static inline unsigned int mpc85xx_gpio_get(unsigned int mask) +{ + ccsr_gpio_t *gpio = (void *)(CONFIG_SYS_MPC85xx_GPIO_ADDR + 0xc00); + + /* Read the requested values */ + return in_be32(&gpio->gpdat) & mask; +} + +/* + * These implement the generic Linux GPIO API on top of the other functions + * in this header. + */ +#ifdef CONFIG_MPC85XX_GENERIC_GPIO +static inline int gpio_request(unsigned gpio, const char *label) +{ + /* Compatibility shim */ + return 0; +} + +static inline void gpio_free(unsigned gpio) +{ + /* Compatibility shim */ +} + +static inline int gpio_direction_input(unsigned gpio) +{ + mpc85xx_gpio_set_in(1U << gpio); + return 0; +} + +static inline int gpio_direction_output(unsigned gpio, int value) +{ + mpc85xx_gpio_set_low(1U << gpio); + return 0; +} + +static inline int gpio_get_value(unsigned gpio) +{ + return !!mpc85xx_gpio_get(1U << gpio) +} + +static inline void gpio_set_value(unsigned gpio, int value) +{ + if (value) + mpc85xx_gpio_set_high(1U << gpio); + else + mpc85xx_gpio_set_low(1U << gpio); +} + +static inline int gpio_is_valid(int gpio) +{ + return (gpio >= 0) && (gpio < 32); +} +#endif /* CONFIG_MPC85XX_GENERIC_GPIO */