software_i2c.c

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/* SPDX-License-Identifier: GPL-2.0-only */
 
#include <device/mmio.h>
#include <console/console.h>
#include <device/i2c_simple.h>
#include <gpio.h>
#include <soc/grf.h>
#include <soc/i2c.h>
#include <soc/pmu.h>
 
static struct {
        gpio_t scl;
        gpio_t sda;
} pins[] = {
        [0]{.scl = GPIO(0, C, 0), .sda = GPIO(0, B, 7)},
        [1]{.scl = GPIO(8, A, 5), .sda = GPIO(8, A, 4)},
        [2]{.scl = GPIO(6, B, 2), .sda = GPIO(6, B, 1)},
        [3]{.scl = GPIO(2, C, 0), .sda = GPIO(2, C, 1)},
        [4]{.scl = GPIO(7, C, 2), .sda = GPIO(7, C, 1)},
        [5]{.scl = GPIO(7, C, 4), .sda = GPIO(7, C, 3)},
};
 
static int get_scl(unsigned int bus)
{
        return gpio_get(pins[bus].scl);
}
 
static int get_sda(unsigned int bus)
{
        return gpio_get(pins[bus].sda);
}
 
static void set_scl(unsigned int bus, int high)
{
        if (high)
                gpio_input_pullup(pins[bus].scl);
        else
                gpio_output(pins[bus].scl, 0);
}
 
static void set_sda(unsigned int bus, int high)
{
        if (high)
                gpio_input_pullup(pins[bus].sda);
        else
                gpio_output(pins[bus].sda, 0);
}
 
static struct software_i2c_ops rk_ops = {
        .get_scl = get_scl,
        .get_sda = get_sda,
        .set_scl = set_scl,
        .set_sda = set_sda,
};
 
void software_i2c_attach(unsigned int bus)
{
        software_i2c[bus] = &rk_ops;
 
        /* Mux pins to GPIO function for software I2C emulation. */
        switch (bus) {
        case 0:
                clrbits32(&rk3288_pmu->iomux_i2c0scl, IOMUX_I2C0SCL);
                clrbits32(&rk3288_pmu->iomux_i2c0sda, IOMUX_I2C0SDA);
                break;
        case 1:
                write32(&rk3288_grf->iomux_i2c1, IOMUX_GPIO(IOMUX_I2C1));
                break;
        case 2:
                write32(&rk3288_grf->iomux_i2c2, IOMUX_GPIO(IOMUX_I2C2));
                break;
        case 3:
                write32(&rk3288_grf->iomux_i2c3, IOMUX_GPIO(IOMUX_I2C3));
                break;
        case 4:
                write32(&rk3288_grf->iomux_i2c4, IOMUX_GPIO(IOMUX_I2C4));
                break;
        case 5:
                write32(&rk3288_grf->iomux_i2c5scl, IOMUX_GPIO(IOMUX_I2C5SCL));
                write32(&rk3288_grf->iomux_i2c5sda, IOMUX_GPIO(IOMUX_I2C5SDA));
                break;
        default:
                die("Unknown I2C bus number!");
        }
 
        /* Initialize bus to idle state. */
        set_scl(bus, 1);
        set_sda(bus, 1);
}
 
void software_i2c_detach(unsigned int bus)
{
        software_i2c[bus] = NULL;
 
        /* Mux pins back to hardware I2C controller. */
        switch (bus) {
        case 0:
                setbits32(&rk3288_pmu->iomux_i2c0scl, IOMUX_I2C0SCL);
                setbits32(&rk3288_pmu->iomux_i2c0sda, IOMUX_I2C0SDA);
                break;
        case 1:
                write32(&rk3288_grf->iomux_i2c1, IOMUX_I2C1);
                break;
        case 2:
                write32(&rk3288_grf->iomux_i2c2, IOMUX_I2C2);
                break;
        case 3:
                write32(&rk3288_grf->iomux_i2c3, IOMUX_I2C3);
                break;
        case 4:
                write32(&rk3288_grf->iomux_i2c4, IOMUX_I2C4);
                break;
        case 5:
                write32(&rk3288_grf->iomux_i2c5scl, IOMUX_I2C5SCL);
                write32(&rk3288_grf->iomux_i2c5sda, IOMUX_I2C5SDA);
                break;
        default:
                die("Unknown I2C bus number!");
        }
}