i2c.c

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/* SPDX-License-Identifier: GPL-2.0-only */
 
#include <assert.h>
#include <console/console.h>
#include <device/mmio.h>
#include <soc/i2c.h>
#include <soc/gpio.h>
 
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),
        },
};
 
_Static_assert(ARRAY_SIZE(mtk_i2c_bus_controller) == I2C_BUS_NUMBER,
               "Wrong size of 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_soc(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_soc(bus);
        mtk_i2c_set_gpio_pinmux(bus);
}
 
void mtk_i2c_dump_more_info(struct mt_i2c_regs *regs)
{
        printk(BIOS_DEBUG, "LTIMING %x\nCLK_DIV %x\n",
               read32(&regs->ltiming),
               read32(&regs->clock_div));
}