pinmux: stm32: add support for STM32F4

STM32F401 allows for upto 16 alternate functions on each pin.

Change-Id: Ib1c14fd31abaa2b05a5ab0f7bd1b4a4748f10f84
Signed-off-by: Ricardo Salveti <ricardo.salveti@linaro.org>
Signed-off-by: Amit Kucheria <amit.kucheria@linaro.org>
Signed-off-by: Kumar Gala <kumar.gala@linaro.org>

arch/arm/soc/st_stm32/stm32f4/Makefile

@@ -1,6 +1,7 @@
 obj-y += soc.o
 
 obj-$(CONFIG_GPIO) += soc_gpio.o
+obj-$(CONFIG_PINMUX) += soc_pinmux.o
 
 zephyr: $(KERNEL_HEX_NAME)
 all: $(KERNEL_HEX_NAME)

arch/arm/soc/st_stm32/stm32f4/soc_pinmux.c

@@ -0,0 +1,82 @@
+/*
+ * Copyright (c) 2016 Linaro Limited.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#include <errno.h>
+
+#include "soc.h"
+#include <device.h>
+#include <misc/util.h>
+#include <pinmux/stm32/pinmux_stm32.h>
+#include <drivers/clock_control/stm32_clock_control.h>
+
+static const stm32_pin_func_t pin_pb6_funcs[] = {
+	[STM32F4_PINMUX_FUNC_PB6_USART1_TX - 1] =
+			STM32F4X_PIN_CONFIG_AF_PUSH_UP,
+};
+
+static const stm32_pin_func_t pin_pb7_funcs[] = {
+	[STM32F4_PINMUX_FUNC_PB7_USART1_RX - 1] =
+			STM32F4X_PIN_CONFIG_AF_PUSH_UP,
+};
+
+static const stm32_pin_func_t pin_pa2_funcs[] = {
+	[STM32F4_PINMUX_FUNC_PA2_USART2_TX - 1] =
+			STM32F4X_PIN_CONFIG_AF_PUSH_UP,
+};
+
+static const stm32_pin_func_t pin_pa3_funcs[] = {
+	[STM32F4_PINMUX_FUNC_PA3_USART2_RX - 1] =
+			STM32F4X_PIN_CONFIG_AF_PUSH_UP,
+};
+
+/**
+ * @brief pin configuration
+ */
+static const struct stm32_pinmux_conf pins[] = {
+	STM32_PIN_CONF(STM32_PIN_PB6, pin_pb6_funcs),
+	STM32_PIN_CONF(STM32_PIN_PB7, pin_pb7_funcs),
+	STM32_PIN_CONF(STM32_PIN_PA2, pin_pa2_funcs),
+	STM32_PIN_CONF(STM32_PIN_PA3, pin_pa3_funcs),
+};
+
+int stm32_get_pin_config(int pin, int func)
+{
+	/* GPIO function is always available, to save space it is not
+	 * listed in alternate functions array
+	 */
+	if (func == STM32_PINMUX_FUNC_GPIO) {
+		return STM32F4X_PIN_CONFIG_BIAS_HIGH_IMPEDANCE;
+	}
+
+	/* analog function is another 'known' setting */
+	if (func == STM32_PINMUX_FUNC_ANALOG) {
+		return STM32F4X_PIN_CONFIG_ANALOG;
+	}
+
+	func -= 1;
+
+	for (int i = 0; i < ARRAY_SIZE(pins); i++) {
+		if (pins[i].pin == pin) {
+			if (func > pins[i].nfuncs) {
+				return -EINVAL;
+			}
+
+			return pins[i].funcs[func];
+		}
+	}
+
+	return -EINVAL;
+}