1 // SPDX-License-Identifier: GPL-2.0 2 /* 3 * Multiplexer driver for Analog Devices ADG792A/G Triple 4:1 mux 4 * 5 * Copyright (C) 2017 Axentia Technologies AB 6 * 7 * Author: Peter Rosin <peda@axentia.se> 8 */ 9 10 #include <linux/err.h> 11 #include <linux/i2c.h> 12 #include <linux/module.h> 13 #include <linux/mux/driver.h> 14 #include <linux/property.h> 15 16 #define ADG792A_LDSW BIT(0) 17 #define ADG792A_RESETB BIT(1) 18 #define ADG792A_DISABLE(mux) (0x50 | (mux)) 19 #define ADG792A_DISABLE_ALL (0x5f) 20 #define ADG792A_MUX(mux, state) (0xc0 | (((mux) + 1) << 2) | (state)) 21 #define ADG792A_MUX_ALL(state) (0xc0 | (state)) 22 23 static int adg792a_write_cmd(struct i2c_client *i2c, u8 cmd, int reset) 24 { 25 u8 data = ADG792A_RESETB | ADG792A_LDSW; 26 27 /* ADG792A_RESETB is active low, the chip resets when it is zero. */ 28 if (reset) 29 data &= ~ADG792A_RESETB; 30 31 return i2c_smbus_write_byte_data(i2c, cmd, data); 32 } 33 34 static int adg792a_set(struct mux_control *mux, int state) 35 { 36 struct i2c_client *i2c = to_i2c_client(mux->chip->dev.parent); 37 u8 cmd; 38 39 if (mux->chip->controllers == 1) { 40 /* parallel mux controller operation */ 41 if (state == MUX_IDLE_DISCONNECT) 42 cmd = ADG792A_DISABLE_ALL; 43 else 44 cmd = ADG792A_MUX_ALL(state); 45 } else { 46 unsigned int controller = mux_control_get_index(mux); 47 48 if (state == MUX_IDLE_DISCONNECT) 49 cmd = ADG792A_DISABLE(controller); 50 else 51 cmd = ADG792A_MUX(controller, state); 52 } 53 54 return adg792a_write_cmd(i2c, cmd, 0); 55 } 56 57 static const struct mux_control_ops adg792a_ops = { 58 .set = adg792a_set, 59 }; 60 61 static int adg792a_probe(struct i2c_client *i2c) 62 { 63 struct device *dev = &i2c->dev; 64 struct mux_chip *mux_chip; 65 s32 idle_state[3]; 66 u32 cells; 67 int ret; 68 int i; 69 70 if (!i2c_check_functionality(i2c->adapter, I2C_FUNC_SMBUS_BYTE_DATA)) 71 return -ENODEV; 72 73 ret = device_property_read_u32(dev, "#mux-control-cells", &cells); 74 if (ret < 0) 75 return ret; 76 if (cells >= 2) 77 return -EINVAL; 78 79 mux_chip = devm_mux_chip_alloc(dev, cells ? 3 : 1, 0); 80 if (IS_ERR(mux_chip)) 81 return PTR_ERR(mux_chip); 82 83 mux_chip->ops = &adg792a_ops; 84 85 ret = adg792a_write_cmd(i2c, ADG792A_DISABLE_ALL, 1); 86 if (ret < 0) 87 return ret; 88 89 ret = device_property_read_u32_array(dev, "idle-state", 90 (u32 *)idle_state, 91 mux_chip->controllers); 92 if (ret < 0) { 93 idle_state[0] = MUX_IDLE_AS_IS; 94 idle_state[1] = MUX_IDLE_AS_IS; 95 idle_state[2] = MUX_IDLE_AS_IS; 96 } 97 98 for (i = 0; i < mux_chip->controllers; ++i) { 99 struct mux_control *mux = &mux_chip->mux[i]; 100 101 mux->states = 4; 102 103 switch (idle_state[i]) { 104 case MUX_IDLE_DISCONNECT: 105 case MUX_IDLE_AS_IS: 106 case 0 ... 4: 107 mux->idle_state = idle_state[i]; 108 break; 109 default: 110 dev_err(dev, "invalid idle-state %d\n", idle_state[i]); 111 return -EINVAL; 112 } 113 } 114 115 ret = devm_mux_chip_register(dev, mux_chip); 116 if (ret < 0) 117 return ret; 118 119 if (cells) 120 dev_info(dev, "3x single pole quadruple throw muxes registered\n"); 121 else 122 dev_info(dev, "triple pole quadruple throw mux registered\n"); 123 124 return 0; 125 } 126 127 static const struct i2c_device_id adg792a_id[] = { 128 { .name = "adg792a", }, 129 { .name = "adg792g", }, 130 { } 131 }; 132 MODULE_DEVICE_TABLE(i2c, adg792a_id); 133 134 static const struct of_device_id adg792a_of_match[] = { 135 { .compatible = "adi,adg792a", }, 136 { .compatible = "adi,adg792g", }, 137 { } 138 }; 139 MODULE_DEVICE_TABLE(of, adg792a_of_match); 140 141 static struct i2c_driver adg792a_driver = { 142 .driver = { 143 .name = "adg792a", 144 .of_match_table = of_match_ptr(adg792a_of_match), 145 }, 146 .probe = adg792a_probe, 147 .id_table = adg792a_id, 148 }; 149 module_i2c_driver(adg792a_driver); 150 151 MODULE_DESCRIPTION("Analog Devices ADG792A/G Triple 4:1 mux driver"); 152 MODULE_AUTHOR("Peter Rosin <peda@axentia.se>"); 153 MODULE_LICENSE("GPL v2"); 154