gpio: mxc: prevent glitches when switching GPIO direction by setting the data registe...

[karo-tx-uboot.git] / drivers / gpio / mxc_gpio.c

diff --git a/drivers/gpio/mxc_gpio.c b/drivers/gpio/mxc_gpio.c
index a3880641f0a8c73e64896b5b3512dc9dfbbf4297..65dc50df39442e83b24b6690458e3499acdf8ec5 100644 (file)
--- a/drivers/gpio/mxc_gpio.c
+++ b/drivers/gpio/mxc_gpio.c
@@ -5,23 +5,7 @@
  * Copyright (C) 2011
  * Stefano Babic, DENX Software Engineering, <sbabic@denx.de>
  *
- * See file CREDITS for list of people who contributed to this
- * project.
- *
- * 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
+ * SPDX-License-Identifier:    GPL-2.0+
  */
 #include <common.h>
 #include <asm/arch/imx-regs.h>
@@ -34,7 +18,7 @@ enum mxc_gpio_direction {
        MXC_GPIO_DIRECTION_OUT,
 };
 
-#define GPIO_TO_PORT(n)                (n / 32)
+#define GPIO_TO_PORT(n)                ((n) / 32)
 
 /* GPIO port description */
 static unsigned long gpio_ports[] = {
@@ -61,8 +45,10 @@ static int mxc_gpio_direction(unsigned int gpio,
        struct gpio_regs *regs;
        u32 l;
 
-       if (port >= ARRAY_SIZE(gpio_ports))
+       if (port >= ARRAY_SIZE(gpio_ports)) {
+               printf("%s: Invalid GPIO %d\n", __func__, gpio);
                return -1;
+       }
 
        gpio &= 0x1f;
 
@@ -88,8 +74,10 @@ int gpio_set_value(unsigned gpio, int value)
        struct gpio_regs *regs;
        u32 l;
 
-       if (port >= ARRAY_SIZE(gpio_ports))
+       if (port >= ARRAY_SIZE(gpio_ports)) {
+               printf("%s: Invalid GPIO %d\n", __func__, gpio);
                return -1;
+       }
 
        gpio &= 0x1f;
 
@@ -111,28 +99,42 @@ int gpio_get_value(unsigned gpio)
        struct gpio_regs *regs;
        u32 val;
 
-       if (port >= ARRAY_SIZE(gpio_ports))
+       if (port >= ARRAY_SIZE(gpio_ports)) {
+               printf("%s: Invalid GPIO %d\n", __func__, gpio);
                return -1;
+       }
 
        gpio &= 0x1f;
 
        regs = (struct gpio_regs *)gpio_ports[port];
 
-       val = (readl(&regs->gpio_psr) >> gpio) & 0x01;
-
+       if (readl(&regs->gpio_dir) & (1 << gpio)) {
+               printf("WARNING: Reading status of output GPIO_%d_%d\n",
+                       port - GPIO_TO_PORT(0), gpio);
+               val = (readl(&regs->gpio_dr) >> gpio) & 0x01;
+       } else {
+               val = (readl(&regs->gpio_psr) >> gpio) & 0x01;
+       }
        return val;
 }
 
 int gpio_request(unsigned gpio, const char *label)
 {
        unsigned int port = GPIO_TO_PORT(gpio);
-       if (port >= ARRAY_SIZE(gpio_ports))
+       if (port >= ARRAY_SIZE(gpio_ports)) {
+               printf("%s: Invalid GPIO %d\n", __func__, gpio);
                return -1;
+       }
        return 0;
 }
 
 int gpio_free(unsigned gpio)
 {
+       unsigned int port = GPIO_TO_PORT(gpio);
+       if (port >= ARRAY_SIZE(gpio_ports)) {
+               printf("%s: Invalid GPIO %d\n", __func__, gpio);
+               return -1;
+       }
        return 0;
 }
 
@@ -143,10 +145,10 @@ int gpio_direction_input(unsigned gpio)
 
 int gpio_direction_output(unsigned gpio, int value)
 {
-       int ret = mxc_gpio_direction(gpio, MXC_GPIO_DIRECTION_OUT);
+       int ret = gpio_set_value(gpio, value);
 
        if (ret < 0)
                return ret;
 
-       return gpio_set_value(gpio, value);
+       return mxc_gpio_direction(gpio, MXC_GPIO_DIRECTION_OUT);
 }