diff options
Diffstat (limited to 'drivers/mux/adg792a.c')
| -rw-r--r-- | drivers/mux/adg792a.c | 157 |
1 files changed, 157 insertions, 0 deletions
diff --git a/drivers/mux/adg792a.c b/drivers/mux/adg792a.c new file mode 100644 index 000000000000..12aa221ab90d --- /dev/null +++ b/drivers/mux/adg792a.c @@ -0,0 +1,157 @@ +/* + * Multiplexer driver for Analog Devices ADG792A/G Triple 4:1 mux + * + * Copyright (C) 2017 Axentia Technologies AB + * + * Author: Peter Rosin <peda@axentia.se> + * + * This program is free software; you can redistribute it and/or modify + * it under the terms of the GNU General Public License version 2 as + * published by the Free Software Foundation. + */ + +#include <linux/err.h> +#include <linux/i2c.h> +#include <linux/module.h> +#include <linux/mux/driver.h> +#include <linux/property.h> + +#define ADG792A_LDSW BIT(0) +#define ADG792A_RESETB BIT(1) +#define ADG792A_DISABLE(mux) (0x50 | (mux)) +#define ADG792A_DISABLE_ALL (0x5f) +#define ADG792A_MUX(mux, state) (0xc0 | (((mux) + 1) << 2) | (state)) +#define ADG792A_MUX_ALL(state) (0xc0 | (state)) + +static int adg792a_write_cmd(struct i2c_client *i2c, u8 cmd, int reset) +{ + u8 data = ADG792A_RESETB | ADG792A_LDSW; + + /* ADG792A_RESETB is active low, the chip resets when it is zero. */ + if (reset) + data &= ~ADG792A_RESETB; + + return i2c_smbus_write_byte_data(i2c, cmd, data); +} + +static int adg792a_set(struct mux_control *mux, int state) +{ + struct i2c_client *i2c = to_i2c_client(mux->chip->dev.parent); + u8 cmd; + + if (mux->chip->controllers == 1) { + /* parallel mux controller operation */ + if (state == MUX_IDLE_DISCONNECT) + cmd = ADG792A_DISABLE_ALL; + else + cmd = ADG792A_MUX_ALL(state); + } else { + unsigned int controller = mux_control_get_index(mux); + + if (state == MUX_IDLE_DISCONNECT) + cmd = ADG792A_DISABLE(controller); + else + cmd = ADG792A_MUX(controller, state); + } + + return adg792a_write_cmd(i2c, cmd, 0); +} + +static const struct mux_control_ops adg792a_ops = { + .set = adg792a_set, +}; + +static int adg792a_probe(struct i2c_client *i2c, + const struct i2c_device_id *id) +{ + struct device *dev = &i2c->dev; + struct mux_chip *mux_chip; + s32 idle_state[3]; + u32 cells; + int ret; + int i; + + if (!i2c_check_functionality(i2c->adapter, I2C_FUNC_SMBUS_BYTE_DATA)) + return -ENODEV; + + ret = device_property_read_u32(dev, "#mux-control-cells", &cells); + if (ret < 0) + return ret; + if (cells >= 2) + return -EINVAL; + + mux_chip = devm_mux_chip_alloc(dev, cells ? 3 : 1, 0); + if (IS_ERR(mux_chip)) + return PTR_ERR(mux_chip); + + mux_chip->ops = &adg792a_ops; + + ret = adg792a_write_cmd(i2c, ADG792A_DISABLE_ALL, 1); + if (ret < 0) + return ret; + + ret = device_property_read_u32_array(dev, "idle-state", + (u32 *)idle_state, + mux_chip->controllers); + if (ret < 0) { + idle_state[0] = MUX_IDLE_AS_IS; + idle_state[1] = MUX_IDLE_AS_IS; + idle_state[2] = MUX_IDLE_AS_IS; + } + + for (i = 0; i < mux_chip->controllers; ++i) { + struct mux_control *mux = &mux_chip->mux[i]; + + mux->states = 4; + + switch (idle_state[i]) { + case MUX_IDLE_DISCONNECT: + case MUX_IDLE_AS_IS: + case 0 ... 4: + mux->idle_state = idle_state[i]; + break; + default: + dev_err(dev, "invalid idle-state %d\n", idle_state[i]); + return -EINVAL; + } + } + + ret = devm_mux_chip_register(dev, mux_chip); + if (ret < 0) + return ret; + + if (cells) + dev_info(dev, "3x single pole quadruple throw muxes registered\n"); + else + dev_info(dev, "triple pole quadruple throw mux registered\n"); + + return 0; +} + +static const struct i2c_device_id adg792a_id[] = { + { .name = "adg792a", }, + { .name = "adg792g", }, + { } +}; +MODULE_DEVICE_TABLE(i2c, adg792a_id); + +static const struct of_device_id adg792a_of_match[] = { + { .compatible = "adi,adg792a", }, + { .compatible = "adi,adg792g", }, + { } +}; +MODULE_DEVICE_TABLE(of, adg792a_of_match); + +static struct i2c_driver adg792a_driver = { + .driver = { + .name = "adg792a", + .of_match_table = of_match_ptr(adg792a_of_match), + }, + .probe = adg792a_probe, + .id_table = adg792a_id, +}; +module_i2c_driver(adg792a_driver); + +MODULE_DESCRIPTION("Analog Devices ADG792A/G Triple 4:1 mux driver"); +MODULE_AUTHOR("Peter Rosin <peda@axentia.se>"); +MODULE_LICENSE("GPL v2"); |