1 // SPDX-License-Identifier: GPL-2.0-or-later 2 /* Hisilicon Hibmc SoC drm driver 3 * 4 * Based on the bochs drm driver. 5 * 6 * Copyright (c) 2016 Huawei Limited. 7 * 8 * Author: 9 * Tian Tao <tiantao6@hisilicon.com> 10 */ 11 12 #include <linux/delay.h> 13 #include <linux/pci.h> 14 15 #include <drm/drm_atomic_helper.h> 16 #include <drm/drm_probe_helper.h> 17 18 #include "hibmc_drm_drv.h" 19 20 #define GPIO_DATA 0x0802A0 21 #define GPIO_DATA_DIRECTION 0x0802A4 22 23 #define I2C_SCL_MASK BIT(0) 24 #define I2C_SDA_MASK BIT(1) 25 26 static void hibmc_set_i2c_signal(void *data, u32 mask, int value) 27 { 28 struct hibmc_connector *hibmc_connector = data; 29 struct hibmc_drm_private *priv = to_hibmc_drm_private(hibmc_connector->base.dev); 30 u32 tmp_dir = readl(priv->mmio + GPIO_DATA_DIRECTION); 31 32 if (value) { 33 tmp_dir &= ~mask; 34 writel(tmp_dir, priv->mmio + GPIO_DATA_DIRECTION); 35 } else { 36 u32 tmp_data = readl(priv->mmio + GPIO_DATA); 37 38 tmp_data &= ~mask; 39 writel(tmp_data, priv->mmio + GPIO_DATA); 40 41 tmp_dir |= mask; 42 writel(tmp_dir, priv->mmio + GPIO_DATA_DIRECTION); 43 } 44 } 45 46 static int hibmc_get_i2c_signal(void *data, u32 mask) 47 { 48 struct hibmc_connector *hibmc_connector = data; 49 struct hibmc_drm_private *priv = to_hibmc_drm_private(hibmc_connector->base.dev); 50 u32 tmp_dir = readl(priv->mmio + GPIO_DATA_DIRECTION); 51 52 if ((tmp_dir & mask) != mask) { 53 tmp_dir &= ~mask; 54 writel(tmp_dir, priv->mmio + GPIO_DATA_DIRECTION); 55 } 56 57 return (readl(priv->mmio + GPIO_DATA) & mask) ? 1 : 0; 58 } 59 60 static void hibmc_ddc_setsda(void *data, int state) 61 { 62 hibmc_set_i2c_signal(data, I2C_SDA_MASK, state); 63 } 64 65 static void hibmc_ddc_setscl(void *data, int state) 66 { 67 hibmc_set_i2c_signal(data, I2C_SCL_MASK, state); 68 } 69 70 static int hibmc_ddc_getsda(void *data) 71 { 72 return hibmc_get_i2c_signal(data, I2C_SDA_MASK); 73 } 74 75 static int hibmc_ddc_getscl(void *data) 76 { 77 return hibmc_get_i2c_signal(data, I2C_SCL_MASK); 78 } 79 80 int hibmc_ddc_create(struct drm_device *drm_dev, 81 struct hibmc_connector *connector) 82 { 83 connector->adapter.owner = THIS_MODULE; 84 connector->adapter.class = I2C_CLASS_DDC; 85 snprintf(connector->adapter.name, I2C_NAME_SIZE, "HIS i2c bit bus"); 86 connector->adapter.dev.parent = drm_dev->dev; 87 i2c_set_adapdata(&connector->adapter, connector); 88 connector->adapter.algo_data = &connector->bit_data; 89 90 connector->bit_data.udelay = 20; 91 connector->bit_data.timeout = usecs_to_jiffies(2000); 92 connector->bit_data.data = connector; 93 connector->bit_data.setsda = hibmc_ddc_setsda; 94 connector->bit_data.setscl = hibmc_ddc_setscl; 95 connector->bit_data.getsda = hibmc_ddc_getsda; 96 connector->bit_data.getscl = hibmc_ddc_getscl; 97 98 return i2c_bit_add_bus(&connector->adapter); 99 } 100