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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: Peter Tyser <ptyser@xes-inc.com> Signed-off-by: Kumar Gala <galak@kernel.crashing.org>
124 lines
3.2 KiB
C
124 lines
3.2 KiB
C
/*
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* Copyright 2010 eXMeritus, A Boeing Company
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*
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* This program is free software; you can redistribute it and/or
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* modify it under the terms of the GNU General Public License as
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* published by the Free Software Foundation; either version 2 of
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* the License, or (at your option) any later version.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program; if not, write to the Free Software
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* Foundation, Inc., 59 Temple Place, Suite 330, Boston,
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* MA 02111-1307 USA
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*/
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#ifndef POWERPC_ASM_MPC85XX_GPIO_H_
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#define POWERPC_ASM_MPC85XX_GPIO_H_
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# include <asm/immap_85xx.h>
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/*
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* The following internal functions are an MPC85XX-specific GPIO API which
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* allows setting and querying multiple GPIOs in a single operation.
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*
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* All of these look relatively large, but the arguments are almost always
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* constants, so they compile down to just a few instructions and a
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* memory-mapped IO operation or two.
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*/
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static inline void mpc85xx_gpio_set(unsigned int mask,
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unsigned int dir, unsigned int val)
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{
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ccsr_gpio_t *gpio = (void *)(CONFIG_SYS_MPC85xx_GPIO_ADDR + 0xc00);
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/* First mask off the unwanted parts of "dir" and "val" */
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dir &= mask;
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val &= mask;
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/* Now read in the values we're supposed to preserve */
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dir |= (in_be32(&gpio->gpdir) & ~mask);
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val |= (in_be32(&gpio->gpdat) & ~mask);
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/*
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* Poke the new output values first, then set the direction. This
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* helps to avoid transient data when switching from input to output
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* and vice versa.
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*/
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out_be32(&gpio->gpdat, val);
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out_be32(&gpio->gpdir, dir);
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}
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static inline void mpc85xx_gpio_set_in(unsigned int gpios)
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{
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mpc85xx_gpio_set(gpios, 0x00000000, 0x00000000);
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}
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static inline void mpc85xx_gpio_set_low(unsigned int gpios)
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{
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mpc85xx_gpio_set(gpios, 0xFFFFFFFF, 0x00000000);
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}
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static inline void mpc85xx_gpio_set_high(unsigned int gpios)
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{
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mpc85xx_gpio_set(gpios, 0xFFFFFFFF, 0xFFFFFFFF);
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}
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static inline unsigned int mpc85xx_gpio_get(unsigned int mask)
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{
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ccsr_gpio_t *gpio = (void *)(CONFIG_SYS_MPC85xx_GPIO_ADDR + 0xc00);
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/* Read the requested values */
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return in_be32(&gpio->gpdat) & mask;
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}
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/*
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* These implement the generic Linux GPIO API on top of the other functions
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* in this header.
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*/
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static inline int gpio_request(unsigned gpio, const char *label)
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{
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/* Compatibility shim */
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return 0;
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}
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static inline void gpio_free(unsigned gpio)
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{
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/* Compatibility shim */
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}
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static inline int gpio_direction_input(unsigned gpio)
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{
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mpc85xx_gpio_set_in(1U << gpio);
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return 0;
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}
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static inline int gpio_direction_output(unsigned gpio, int value)
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{
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mpc85xx_gpio_set_low(1U << gpio);
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return 0;
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}
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static inline int gpio_get_value(unsigned gpio)
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{
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return !!mpc85xx_gpio_get(1U << gpio);
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}
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static inline void gpio_set_value(unsigned gpio, int value)
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{
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if (value)
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mpc85xx_gpio_set_high(1U << gpio);
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else
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mpc85xx_gpio_set_low(1U << gpio);
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}
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static inline int gpio_is_valid(int gpio)
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{
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return (gpio >= 0) && (gpio < 32);
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}
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#endif /* not POWERPC_ASM_MPC85XX_GPIO_H_ */
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