rpi3: Add GPIO driver

This commit adds GPIO driver for RaspberryPi3. The GPIO driver for RPi3
also provides the way to do pinmux selections.
Signed-off-by: Ying-Chun Liu (PaulLiu) <paulliu@debian.org>

drivers/rpi3/gpio/rpi3_gpio.c

+/*
+ * Copyright (c) 2019, Linaro Limited
+ * Copyright (c) 2019, Ying-Chun Liu (PaulLiu) <paul.liu@linaro.org>
+ *
+ * SPDX-License-Identifier: BSD-3-Clause
+ */
+
+#include <string.h>
+#include <assert.h>
+#include <lib/mmio.h>
+#include <drivers/delay_timer.h>
+#include <drivers/rpi3/gpio/rpi3_gpio.h>
+
+static struct rpi3_gpio_params rpi3_gpio_params;
+
+static int rpi3_gpio_get_direction(int gpio);
+static void rpi3_gpio_set_direction(int gpio, int direction);
+static int rpi3_gpio_get_value(int gpio);
+static void rpi3_gpio_set_value(int gpio, int value);
+static void rpi3_gpio_set_pull(int gpio, int pull);
+
+static const gpio_ops_t rpi3_gpio_ops = {
+	.get_direction  = rpi3_gpio_get_direction,
+	.set_direction  = rpi3_gpio_set_direction,
+	.get_value      = rpi3_gpio_get_value,
+	.set_value      = rpi3_gpio_set_value,
+	.set_pull       = rpi3_gpio_set_pull,
+};
+
+/**
+ * Get selection of GPIO pinmux settings.
+ *
+ * @param gpio The pin number of GPIO. From 0 to 53.
+ * @return The selection of pinmux. RPI3_GPIO_FUNC_INPUT: input,
+ *                                  RPI3_GPIO_FUNC_OUTPUT: output,
+ *                                  RPI3_GPIO_FUNC_ALT0: alt-0,
+ *                                  RPI3_GPIO_FUNC_ALT1: alt-1,
+ *                                  RPI3_GPIO_FUNC_ALT2: alt-2,
+ *                                  RPI3_GPIO_FUNC_ALT3: alt-3,
+ *                                  RPI3_GPIO_FUNC_ALT4: alt-4,
+ *                                  RPI3_GPIO_FUNC_ALT5: alt-5
+ */
+int rpi3_gpio_get_select(int gpio)
+{
+	int ret;
+	uintptr_t reg_base = rpi3_gpio_params.reg_base;
+	int regN = gpio / 10;
+	int shift = 3 * (gpio % 10);
+	uintptr_t reg_sel = reg_base + RPI3_GPIO_GPFSEL(regN);
+	uint32_t sel = mmio_read_32(reg_sel);
+
+	ret = (sel >> shift) & 0x07;
+
+	return ret;
+}
+
+/**
+ * Set selection of GPIO pinmux settings.
+ *
+ * @param gpio The pin number of GPIO. From 0 to 53.
+ * @param fsel The selection of pinmux. RPI3_GPIO_FUNC_INPUT: input,
+ *                                      RPI3_GPIO_FUNC_OUTPUT: output,
+ *                                      RPI3_GPIO_FUNC_ALT0: alt-0,
+ *                                      RPI3_GPIO_FUNC_ALT1: alt-1,
+ *                                      RPI3_GPIO_FUNC_ALT2: alt-2,
+ *                                      RPI3_GPIO_FUNC_ALT3: alt-3,
+ *                                      RPI3_GPIO_FUNC_ALT4: alt-4,
+ *                                      RPI3_GPIO_FUNC_ALT5: alt-5
+ */
+void rpi3_gpio_set_select(int gpio, int fsel)
+{
+	uintptr_t reg_base = rpi3_gpio_params.reg_base;
+	int regN = gpio / 10;
+	int shift = 3 * (gpio % 10);
+	uintptr_t reg_sel = reg_base + RPI3_GPIO_GPFSEL(regN);
+	uint32_t sel = mmio_read_32(reg_sel);
+	uint32_t mask = U(0x07) << shift;
+
+	sel = (sel & (~mask)) | ((fsel << shift) & mask);
+	mmio_write_32(reg_sel, sel);
+}
+
+static int rpi3_gpio_get_direction(int gpio)
+{
+	int result = rpi3_gpio_get_select(gpio);
+
+	if (result == RPI3_GPIO_FUNC_INPUT)
+		return GPIO_DIR_IN;
+	else if (result == RPI3_GPIO_FUNC_OUTPUT)
+		return GPIO_DIR_OUT;
+
+	return GPIO_DIR_IN;
+}
+
+static void rpi3_gpio_set_direction(int gpio, int direction)
+{
+	switch (direction) {
+	case GPIO_DIR_IN:
+		rpi3_gpio_set_select(gpio, RPI3_GPIO_FUNC_INPUT);
+		break;
+	case GPIO_DIR_OUT:
+		rpi3_gpio_set_select(gpio, RPI3_GPIO_FUNC_OUTPUT);
+		break;
+	}
+}
+
+static int rpi3_gpio_get_value(int gpio)
+{
+	uintptr_t reg_base = rpi3_gpio_params.reg_base;
+	int regN = gpio / 32;
+	int shift = gpio % 32;
+	uintptr_t reg_lev = reg_base + RPI3_GPIO_GPLEV(regN);
+	uint32_t value = mmio_read_32(reg_lev);
+
+	if ((value >> shift) & 0x01)
+		return GPIO_LEVEL_HIGH;
+	return GPIO_LEVEL_LOW;
+}
+
+static void rpi3_gpio_set_value(int gpio, int value)
+{
+	uintptr_t reg_base = rpi3_gpio_params.reg_base;
+	int regN = gpio / 32;
+	int shift = gpio % 32;
+	uintptr_t reg_set = reg_base + RPI3_GPIO_GPSET(regN);
+	uintptr_t reg_clr = reg_base + RPI3_GPIO_GPSET(regN);
+
+	switch (value) {
+	case GPIO_LEVEL_LOW:
+		mmio_write_32(reg_clr, U(1) << shift);
+		break;
+	case GPIO_LEVEL_HIGH:
+		mmio_write_32(reg_set, U(1) << shift);
+		break;
+	}
+}
+
+static void rpi3_gpio_set_pull(int gpio, int pull)
+{
+	uintptr_t reg_base = rpi3_gpio_params.reg_base;
+	int regN = gpio / 32;
+	int shift = gpio % 32;
+	uintptr_t reg_pud = reg_base + RPI3_GPIO_GPPUD;
+	uintptr_t reg_clk = reg_base + RPI3_GPIO_GPPUDCLK(regN);
+
+	switch (pull) {
+	case GPIO_PULL_NONE:
+		mmio_write_32(reg_pud, 0x0);
+		break;
+	case GPIO_PULL_UP:
+		mmio_write_32(reg_pud, 0x2);
+		break;
+	case GPIO_PULL_DOWN:
+		mmio_write_32(reg_pud, 0x1);
+		break;
+	}
+	mdelay(150);
+	mmio_write_32(reg_clk, U(1) << shift);
+	mdelay(150);
+	mmio_write_32(reg_clk, 0x0);
+	mmio_write_32(reg_pud, 0x0);
+}
+
+void rpi3_gpio_init(struct rpi3_gpio_params *params)
+{
+	assert(params != 0);
+	memcpy(&rpi3_gpio_params, params, sizeof(struct rpi3_gpio_params));
+	gpio_init(&rpi3_gpio_ops);
+}

include/drivers/rpi3/gpio/rpi3_gpio.h

+/*
+ * Copyright (c) 2019, Linaro Limited
+ * Copyright (c) 2019, Ying-Chun Liu (PaulLiu) <paul.liu@linaro.org>
+ *
+ * SPDX-License-Identifier: BSD-3-Clause
+ */
+
+#ifndef RPI3_GPIO_H
+#define RPI3_GPIO_H
+
+#include <stdint.h>
+#include <drivers/gpio.h>
+
+struct rpi3_gpio_params {
+	uintptr_t       reg_base;
+};
+
+void rpi3_gpio_init(struct rpi3_gpio_params *params);
+int rpi3_gpio_get_select(int gpio);
+void rpi3_gpio_set_select(int gpio, int fsel);
+
+#define RPI3_GPIO_GPFSEL(n)	((n) * U(0x04))
+#define RPI3_GPIO_GPSET(n)	(((n) * U(0x04)) + U(0x1C))
+#define RPI3_GPIO_GPCLR(n)	(((n) * U(0x04)) + U(0x28))
+#define RPI3_GPIO_GPLEV(n) 	(((n) * U(0x04)) + U(0x34))
+#define RPI3_GPIO_GPPUD		U(0x94)
+#define RPI3_GPIO_GPPUDCLK(n)	(((n) * U(0x04)) + U(0x98))
+
+#define RPI3_GPIO_FUNC_INPUT	U(0)
+#define RPI3_GPIO_FUNC_OUTPUT	U(1)
+#define RPI3_GPIO_FUNC_ALT0	U(4)
+#define RPI3_GPIO_FUNC_ALT1	U(5)
+#define RPI3_GPIO_FUNC_ALT2	U(6)
+#define RPI3_GPIO_FUNC_ALT3	U(7)
+#define RPI3_GPIO_FUNC_ALT4	U(3)
+#define RPI3_GPIO_FUNC_ALT5	U(2)
+
+#endif  /* RPI3_GPIO_H */