src/soc/mediatek/mt8183/i2c.c

   1 /*
   2  * This file is part of the coreboot project.
   3  *
   4  *
   5  * This program is free software; you can redistribute it and/or modify
   6  * it under the terms of the GNU General Public License as published by
   7  * the Free Software Foundation; version 2 of the License.
   8  *
   9  * This program is distributed in the hope that it will be useful,
  10  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  11  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  12  * GNU General Public License for more details.
  13  */
  14
  15 #include <assert.h>
  16 #include <device/mmio.h>
  17 #include <soc/pll.h>
  18 #include <soc/i2c.h>
  19 #include <soc/gpio.h>
  20
  21 #define I2C_CLK_HZ (UNIVPLL_HZ / 20)
  22
  23 struct mtk_i2c mtk_i2c_bus_controller[] = {
  24         /* i2c0 setting */
  25         {
  26                 .i2c_regs = (void *)(I2C_BASE + 0x2000),
  27                 .i2c_dma_regs = (void *)(I2C_DMA_BASE),
  28         },
  29
  30         /* i2c1 setting */
  31         {
  32                 .i2c_regs = (void *)(I2C_BASE + 0xc000),
  33                 .i2c_dma_regs = (void *)(I2C_DMA_BASE + 0x400),
  34         },
  35
  36         /* i2c2 setting */
  37         {
  38                 .i2c_regs = (void *)(I2C_BASE + 0x4000),
  39                 .i2c_dma_regs = (void *)(I2C_DMA_BASE + 0x200),
  40         },
  41
  42         /* i2c3 setting */
  43         {
  44                 .i2c_regs = (void *)(I2C_BASE + 0xa000),
  45                 .i2c_dma_regs = (void *)(I2C_DMA_BASE + 0x380),
  46         },
  47
  48         /* i2c4 setting */
  49         {
  50                 .i2c_regs = (void *)(I2C_BASE + 0x3000),
  51                 .i2c_dma_regs = (void *)(I2C_DMA_BASE + 0x80),
  52         },
  53
  54         /* i2c5 setting */
  55         {
  56                 .i2c_regs = (void *)(I2C_BASE + 0x11000),
  57                 .i2c_dma_regs = (void *)(I2C_DMA_BASE + 0x480),
  58         },
  59
  60         /* i2c6 setting */
  61         {
  62                 .i2c_regs = (void *)(I2C_BASE),
  63                 .i2c_dma_regs = (void *)(I2C_DMA_BASE + 0x580),
  64         },
  65 };
  66
  67 #define I2C_BUS_NUMBER ARRAY_SIZE(mtk_i2c_bus_controller)
  68
  69 struct pad_func {
  70         gpio_t gpio;
  71         u8 func;
  72 };
  73
  74 #define PAD_FUNC(name, func) {GPIO(name), PAD_##name##_FUNC_##func}
  75
  76 static const struct pad_func i2c_funcs[I2C_BUS_NUMBER][2] = {
  77         {
  78                 PAD_FUNC(SDA0, SDA0),
  79                 PAD_FUNC(SCL0, SCL0),
  80         },
  81         {
  82                 PAD_FUNC(SDA1, SDA1),
  83                 PAD_FUNC(SCL1, SCL1),
  84         },
  85         {
  86                 PAD_FUNC(SDA2, SDA2),
  87                 PAD_FUNC(SCL2, SCL2),
  88         },
  89         {
  90                 PAD_FUNC(SDA3, SDA3),
  91                 PAD_FUNC(SCL3, SCL3),
  92         },
  93         {
  94                 PAD_FUNC(SDA4, SDA4),
  95                 PAD_FUNC(SCL4, SCL4),
  96         },
  97         {
  98                 PAD_FUNC(SDA5, SDA5),
  99                 PAD_FUNC(SCL5, SCL5),
 100         },
 101         {
 102                 PAD_FUNC(SDA6, SDA6),
 103                 PAD_FUNC(SCL6, SCL6),
 104         },
 105 };
 106
 107 static void mtk_i2c_set_gpio_pinmux(uint8_t bus)
 108 {
 109         assert(bus < I2C_BUS_NUMBER);
 110
 111         const struct pad_func *ptr = i2c_funcs[bus];
 112         for (size_t i = 0; i < 2; i++) {
 113                 gpio_set_mode(ptr[i].gpio, ptr[i].func);
 114                 gpio_set_pull(ptr[i].gpio, GPIO_PULL_ENABLE, GPIO_PULL_UP);
 115         }
 116 }
 117
 118 static void mtk_i2c_speed_init(uint8_t bus)
 119 {
 120         uint8_t step_div;
 121         const uint8_t clock_div = 5;
 122         const uint8_t sample_div = 1;
 123         uint32_t i2c_freq;
 124
 125         assert(bus < ARRAY_SIZE(mtk_i2c_bus_controller));
 126
 127         /* Calculate i2c frequency */
 128         step_div = DIV_ROUND_UP(I2C_CLK_HZ,
 129                                 (400 * KHz * sample_div * 2) * clock_div);
 130         i2c_freq = I2C_CLK_HZ / (step_div * sample_div * 2 * clock_div);
 131         assert(sample_div < 8 && step_div < 64 && i2c_freq <= 400 * KHz &&
 132                i2c_freq >= 380 * KHz);
 133
 134         /* Init i2c bus Timing register */
 135         write32(&mtk_i2c_bus_controller[bus].i2c_regs->timing,
 136                 (sample_div - 1) << 8 | (step_div - 1));
 137         write32(&mtk_i2c_bus_controller[bus].i2c_regs->ltiming,
 138                 (sample_div - 1) << 6 | (step_div - 1));
 139
 140         /* Init i2c bus clock_div register */
 141         write32(&mtk_i2c_bus_controller[bus].i2c_regs->clock_div,
 142                 clock_div - 1);
 143 }
 144
 145 void mtk_i2c_bus_init(uint8_t bus)
 146 {
 147         mtk_i2c_speed_init(bus);
 148         mtk_i2c_set_gpio_pinmux(bus);
 149 }