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157 lines
3.7 KiB
157 lines
3.7 KiB
/*
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* Multiplexer driver for Analog Devices ADG792A/G Triple 4:1 mux
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*
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* Copyright (C) 2017 Axentia Technologies AB
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*
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* Author: Peter Rosin <peda@axentia.se>
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License version 2 as
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* published by the Free Software Foundation.
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*/
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#include <linux/err.h>
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#include <linux/i2c.h>
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#include <linux/module.h>
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#include <linux/mux/driver.h>
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#include <linux/property.h>
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#define ADG792A_LDSW BIT(0)
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#define ADG792A_RESETB BIT(1)
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#define ADG792A_DISABLE(mux) (0x50 | (mux))
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#define ADG792A_DISABLE_ALL (0x5f)
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#define ADG792A_MUX(mux, state) (0xc0 | (((mux) + 1) << 2) | (state))
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#define ADG792A_MUX_ALL(state) (0xc0 | (state))
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static int adg792a_write_cmd(struct i2c_client *i2c, u8 cmd, int reset)
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{
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u8 data = ADG792A_RESETB | ADG792A_LDSW;
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/* ADG792A_RESETB is active low, the chip resets when it is zero. */
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if (reset)
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data &= ~ADG792A_RESETB;
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return i2c_smbus_write_byte_data(i2c, cmd, data);
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}
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static int adg792a_set(struct mux_control *mux, int state)
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{
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struct i2c_client *i2c = to_i2c_client(mux->chip->dev.parent);
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u8 cmd;
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if (mux->chip->controllers == 1) {
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/* parallel mux controller operation */
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if (state == MUX_IDLE_DISCONNECT)
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cmd = ADG792A_DISABLE_ALL;
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else
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cmd = ADG792A_MUX_ALL(state);
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} else {
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unsigned int controller = mux_control_get_index(mux);
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if (state == MUX_IDLE_DISCONNECT)
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cmd = ADG792A_DISABLE(controller);
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else
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cmd = ADG792A_MUX(controller, state);
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}
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return adg792a_write_cmd(i2c, cmd, 0);
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}
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static const struct mux_control_ops adg792a_ops = {
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.set = adg792a_set,
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};
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static int adg792a_probe(struct i2c_client *i2c,
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const struct i2c_device_id *id)
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{
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struct device *dev = &i2c->dev;
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struct mux_chip *mux_chip;
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s32 idle_state[3];
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u32 cells;
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int ret;
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int i;
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if (!i2c_check_functionality(i2c->adapter, I2C_FUNC_SMBUS_BYTE_DATA))
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return -ENODEV;
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ret = device_property_read_u32(dev, "#mux-control-cells", &cells);
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if (ret < 0)
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return ret;
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if (cells >= 2)
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return -EINVAL;
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mux_chip = devm_mux_chip_alloc(dev, cells ? 3 : 1, 0);
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if (IS_ERR(mux_chip))
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return PTR_ERR(mux_chip);
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mux_chip->ops = &adg792a_ops;
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ret = adg792a_write_cmd(i2c, ADG792A_DISABLE_ALL, 1);
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if (ret < 0)
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return ret;
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ret = device_property_read_u32_array(dev, "idle-state",
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(u32 *)idle_state,
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mux_chip->controllers);
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if (ret < 0) {
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idle_state[0] = MUX_IDLE_AS_IS;
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idle_state[1] = MUX_IDLE_AS_IS;
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idle_state[2] = MUX_IDLE_AS_IS;
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}
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for (i = 0; i < mux_chip->controllers; ++i) {
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struct mux_control *mux = &mux_chip->mux[i];
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mux->states = 4;
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switch (idle_state[i]) {
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case MUX_IDLE_DISCONNECT:
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case MUX_IDLE_AS_IS:
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case 0 ... 4:
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mux->idle_state = idle_state[i];
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break;
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default:
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dev_err(dev, "invalid idle-state %d\n", idle_state[i]);
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return -EINVAL;
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}
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}
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ret = devm_mux_chip_register(dev, mux_chip);
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if (ret < 0)
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return ret;
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if (cells)
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dev_info(dev, "3x single pole quadruple throw muxes registered\n");
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else
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dev_info(dev, "triple pole quadruple throw mux registered\n");
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return 0;
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}
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static const struct i2c_device_id adg792a_id[] = {
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{ .name = "adg792a", },
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{ .name = "adg792g", },
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{ }
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};
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MODULE_DEVICE_TABLE(i2c, adg792a_id);
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static const struct of_device_id adg792a_of_match[] = {
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{ .compatible = "adi,adg792a", },
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{ .compatible = "adi,adg792g", },
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{ }
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};
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MODULE_DEVICE_TABLE(of, adg792a_of_match);
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static struct i2c_driver adg792a_driver = {
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.driver = {
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.name = "adg792a",
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.of_match_table = of_match_ptr(adg792a_of_match),
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},
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.probe = adg792a_probe,
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.id_table = adg792a_id,
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};
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module_i2c_driver(adg792a_driver);
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MODULE_DESCRIPTION("Analog Devices ADG792A/G Triple 4:1 mux driver");
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MODULE_AUTHOR("Peter Rosin <peda@axentia.se>");
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MODULE_LICENSE("GPL v2");
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