mediatek/mt8183: Add I2C driver code

This patch implements i2c driver for MT8183.

BUG=b:80501386
BRANCH=none
TEST=Boot correctly on kukui.

Change-Id: I0a4d78b494819f45951f78e5a618021000cf3463
Signed-off-by: Qii Wang <qii.wang@mediatek.com>
Reviewed-on: https://review.coreboot.org/c/coreboot/+/30976
Reviewed-by: Hung-Te Lin <hungte@chromium.org>
Reviewed-by: Julius Werner <jwerner@chromium.org>
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>

1 files changed, 150 insertions, 0 deletions

diff --git a/src/soc/mediatek/mt8183/i2c.c b/src/soc/mediatek/mt8183/i2c.c
new file mode 100644
index 0000000000..a70c5e175d
--- /dev/null
+++ b/src/soc/mediatek/mt8183/i2c.c
@@ -0,0 +1,150 @@
+/*
+ * This file is part of the coreboot project.
+ *
+ * Copyright 2018 MediaTek Inc.
+ *
+ * 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; version 2 of the License.
+ *
+ * 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.
+ */
+
+#include <assert.h>
+#include <device/mmio.h>
+#include <soc/pll.h>
+#include <soc/i2c.h>
+#include <soc/gpio.h>
+
+#define I2C_CLK_HZ (UNIVPLL_HZ / 20)
+
+struct mtk_i2c mtk_i2c_bus_controller[] = {
+	/* i2c0 setting */
+	{
+		.i2c_regs = (void *)(I2C_BASE + 0x2000),
+		.i2c_dma_regs = (void *)(I2C_DMA_BASE),
+	},
+
+	/* i2c1 setting */
+	{
+		.i2c_regs = (void *)(I2C_BASE + 0xc000),
+		.i2c_dma_regs = (void *)(I2C_DMA_BASE + 0x400),
+	},
+
+	/* i2c2 setting */
+	{
+		.i2c_regs = (void *)(I2C_BASE + 0x4000),
+		.i2c_dma_regs = (void *)(I2C_DMA_BASE + 0x200),
+	},
+
+	/* i2c3 setting */
+	{
+		.i2c_regs = (void *)(I2C_BASE + 0xa000),
+		.i2c_dma_regs = (void *)(I2C_DMA_BASE + 0x380),
+	},
+
+	/* i2c4 setting */
+	{
+		.i2c_regs = (void *)(I2C_BASE + 0x3000),
+		.i2c_dma_regs = (void *)(I2C_DMA_BASE + 0x80),
+	},
+
+	/* i2c5 setting */
+	{
+		.i2c_regs = (void *)(I2C_BASE + 0x11000),
+		.i2c_dma_regs = (void *)(I2C_DMA_BASE + 0x480),
+	},
+
+	/* i2c6 setting */
+	{
+		.i2c_regs = (void *)(I2C_BASE),
+		.i2c_dma_regs = (void *)(I2C_DMA_BASE + 0x580),
+	},
+};
+
+#define I2C_BUS_NUMBER ARRAY_SIZE(mtk_i2c_bus_controller)
+
+struct pad_func {
+	gpio_t gpio;
+	u8 func;
+};
+
+#define PAD_FUNC(name, func) {GPIO(name), PAD_##name##_FUNC_##func}
+
+static const struct pad_func i2c_funcs[I2C_BUS_NUMBER][2] = {
+	{
+		PAD_FUNC(SDA0, SDA0),
+		PAD_FUNC(SCL0, SCL0),
+	},
+	{
+		PAD_FUNC(SDA1, SDA1),
+		PAD_FUNC(SCL1, SCL1),
+	},
+	{
+		PAD_FUNC(SDA2, SDA2),
+		PAD_FUNC(SCL2, SCL2),
+	},
+	{
+		PAD_FUNC(SDA3, SDA3),
+		PAD_FUNC(SCL3, SCL3),
+	},
+	{
+		PAD_FUNC(SDA4, SDA4),
+		PAD_FUNC(SCL4, SCL4),
+	},
+	{
+		PAD_FUNC(SDA5, SDA5),
+		PAD_FUNC(SCL5, SCL5),
+	},
+	{
+		PAD_FUNC(SDA6, SDA6),
+		PAD_FUNC(SCL6, SCL6),
+	},
+};
+
+static void mtk_i2c_set_gpio_pinmux(uint8_t bus)
+{
+	assert(bus < I2C_BUS_NUMBER);
+
+	const struct pad_func *ptr = i2c_funcs[bus];
+	for (size_t i = 0; i < 2; i++) {
+		gpio_set_mode(ptr[i].gpio, ptr[i].func);
+		gpio_set_pull(ptr[i].gpio, GPIO_PULL_ENABLE, GPIO_PULL_UP);
+	}
+}
+
+static void mtk_i2c_speed_init(uint8_t bus)
+{
+	uint8_t step_div;
+	const uint8_t clock_div = 5;
+	const uint8_t sample_div = 1;
+	uint32_t i2c_freq;
+
+	assert(bus < ARRAY_SIZE(mtk_i2c_bus_controller));
+
+	/* Calculate i2c frequency */
+	step_div = DIV_ROUND_UP(I2C_CLK_HZ,
+				(400 * KHz * sample_div * 2) * clock_div);
+	i2c_freq = I2C_CLK_HZ / (step_div * sample_div * 2 * clock_div);
+	assert(sample_div < 8 && step_div < 64 && i2c_freq <= 400 * KHz &&
+	       i2c_freq >= 380 * KHz);
+
+	/* Init i2c bus Timing register */
+	write32(&mtk_i2c_bus_controller[bus].i2c_regs->timing,
+		(sample_div - 1) << 8 | (step_div - 1));
+	write32(&mtk_i2c_bus_controller[bus].i2c_regs->ltiming,
+		(sample_div - 1) << 6 | (step_div - 1));
+
+	/* Init i2c bus clock_div register */
+	write32(&mtk_i2c_bus_controller[bus].i2c_regs->clock_div,
+		clock_div - 1);
+}
+
+void mtk_i2c_bus_init(uint8_t bus)
+{
+	mtk_i2c_speed_init(bus);
+	mtk_i2c_set_gpio_pinmux(bus);
+}