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authorKyle Moffett <Kyle.D.Moffett@boeing.com>2011-10-19 14:58:15 -0400
committerKumar Gala <galak@kernel.crashing.org>2011-10-21 00:04:28 -0500
commit710308ee185b3087e474fb9b205f47613c65dda4 (patch)
treef79c00c52451614f6ae4b31a43b274a512b22418 /arch/powerpc/include
parenta836626cc4ddae53bfa46195a39194f21ad157af (diff)
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mpc85xx: Add inline GPIO acessor functions
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>
Diffstat (limited to 'arch/powerpc/include')
-rw-r--r--arch/powerpc/include/asm/mpc85xx_gpio.h123
1 files changed, 123 insertions, 0 deletions
diff --git a/arch/powerpc/include/asm/mpc85xx_gpio.h b/arch/powerpc/include/asm/mpc85xx_gpio.h
new file mode 100644
index 0000000..5a608a5
--- /dev/null
+++ b/arch/powerpc/include/asm/mpc85xx_gpio.h
@@ -0,0 +1,123 @@
+/*
+ * 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
+ */
+
+#ifndef POWERPC_ASM_MPC85XX_GPIO_H_
+#define POWERPC_ASM_MPC85XX_GPIO_H_
+
+# 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.
+ */
+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 /* not POWERPC_ASM_MPC85XX_GPIO_H_ */