1 /* 2 * Multiplexer driver for Analog Devices ADG792A/G Triple 4:1 mux 3 * 4 * Copyright (C) 2017 Axentia Technologies AB 5 * 6 * Author: Peter Rosin <peda@axentia.se> 7 * 8 * This program is free software; you can redistribute it and/or modify 9 * it under the terms of the GNU General Public License version 2 as 10 * published by the Free Software Foundation. 11 */ 12 13 #include <linux/err.h> 14 #include <linux/i2c.h> 15 #include <linux/module.h> 16 #include <linux/mux/driver.h> 17 #include <linux/property.h> 18 19 #define ADG792A_LDSW BIT(0) 20 #define ADG792A_RESETB BIT(1) 21 #define ADG792A_DISABLE(mux) (0x50 | (mux)) 22 #define ADG792A_DISABLE_ALL (0x5f) 23 #define ADG792A_MUX(mux, state) (0xc0 | (((mux) + 1) << 2) | (state)) 24 #define ADG792A_MUX_ALL(state) (0xc0 | (state)) 25 26 static int adg792a_write_cmd(struct i2c_client *i2c, u8 cmd, int reset) 27 { 28 u8 data = ADG792A_RESETB | ADG792A_LDSW; 29 30 /* ADG792A_RESETB is active low, the chip resets when it is zero. */ 31 if (reset) 32 data &= ~ADG792A_RESETB; 33 34 return i2c_smbus_write_byte_data(i2c, cmd, data); 35 } 36 37 static int adg792a_set(struct mux_control *mux, int state) 38 { 39 struct i2c_client *i2c = to_i2c_client(mux->chip->dev.parent); 40 u8 cmd; 41 42 if (mux->chip->controllers == 1) { 43 /* parallel mux controller operation */ 44 if (state == MUX_IDLE_DISCONNECT) 45 cmd = ADG792A_DISABLE_ALL; 46 else 47 cmd = ADG792A_MUX_ALL(state); 48 } else { 49 unsigned int controller = mux_control_get_index(mux); 50 51 if (state == MUX_IDLE_DISCONNECT) 52 cmd = ADG792A_DISABLE(controller); 53 else 54 cmd = ADG792A_MUX(controller, state); 55 } 56 57 return adg792a_write_cmd(i2c, cmd, 0); 58 } 59 60 static const struct mux_control_ops adg792a_ops = { 61 .set = adg792a_set, 62 }; 63 64 static int adg792a_probe(struct i2c_client *i2c, 65 const struct i2c_device_id *id) 66 { 67 struct device *dev = &i2c->dev; 68 struct mux_chip *mux_chip; 69 s32 idle_state[3]; 70 u32 cells; 71 int ret; 72 int i; 73 74 if (!i2c_check_functionality(i2c->adapter, I2C_FUNC_SMBUS_BYTE_DATA)) 75 return -ENODEV; 76 77 ret = device_property_read_u32(dev, "#mux-control-cells", &cells); 78 if (ret < 0) 79 return ret; 80 if (cells >= 2) 81 return -EINVAL; 82 83 mux_chip = devm_mux_chip_alloc(dev, cells ? 3 : 1, 0); 84 if (IS_ERR(mux_chip)) 85 return PTR_ERR(mux_chip); 86 87 mux_chip->ops = &adg792a_ops; 88 89 ret = adg792a_write_cmd(i2c, ADG792A_DISABLE_ALL, 1); 90 if (ret < 0) 91 return ret; 92 93 ret = device_property_read_u32_array(dev, "idle-state", 94 (u32 *)idle_state, 95 mux_chip->controllers); 96 if (ret < 0) { 97 idle_state[0] = MUX_IDLE_AS_IS; 98 idle_state[1] = MUX_IDLE_AS_IS; 99 idle_state[2] = MUX_IDLE_AS_IS; 100 } 101 102 for (i = 0; i < mux_chip->controllers; ++i) { 103 struct mux_control *mux = &mux_chip->mux[i]; 104 105 mux->states = 4; 106 107 switch (idle_state[i]) { 108 case MUX_IDLE_DISCONNECT: 109 case MUX_IDLE_AS_IS: 110 case 0 ... 4: 111 mux->idle_state = idle_state[i]; 112 break; 113 default: 114 dev_err(dev, "invalid idle-state %d\n", idle_state[i]); 115 return -EINVAL; 116 } 117 } 118 119 ret = devm_mux_chip_register(dev, mux_chip); 120 if (ret < 0) 121 return ret; 122 123 if (cells) 124 dev_info(dev, "3x single pole quadruple throw muxes registered\n"); 125 else 126 dev_info(dev, "triple pole quadruple throw mux registered\n"); 127 128 return 0; 129 } 130 131 static const struct i2c_device_id adg792a_id[] = { 132 { .name = "adg792a", }, 133 { .name = "adg792g", }, 134 { } 135 }; 136 MODULE_DEVICE_TABLE(i2c, adg792a_id); 137 138 static const struct of_device_id adg792a_of_match[] = { 139 { .compatible = "adi,adg792a", }, 140 { .compatible = "adi,adg792g", }, 141 { } 142 }; 143 MODULE_DEVICE_TABLE(of, adg792a_of_match); 144 145 static struct i2c_driver adg792a_driver = { 146 .driver = { 147 .name = "adg792a", 148 .of_match_table = of_match_ptr(adg792a_of_match), 149 }, 150 .probe = adg792a_probe, 151 .id_table = adg792a_id, 152 }; 153 module_i2c_driver(adg792a_driver); 154 155 MODULE_DESCRIPTION("Analog Devices ADG792A/G Triple 4:1 mux driver"); 156 MODULE_AUTHOR("Peter Rosin <peda@axentia.se>"); 157 MODULE_LICENSE("GPL v2"); 158