From ac8498f0ce5301c51c32607af5a318a7e05f45c5 Mon Sep 17 00:00:00 2001 From: Peter Rosin Date: Sun, 14 May 2017 21:51:12 +0200 Subject: [PATCH] i2c: i2c-mux-gpmux: new driver This is a general purpose i2c mux that uses a multiplexer controlled by the multiplexer subsystem to do the muxing. The user can select if the mux is to be mux-locked and parent-locked as described in Documentation/i2c/i2c-topology. Acked-by: Jonathan Cameron Acked-by: Wolfram Sang Signed-off-by: Peter Rosin Signed-off-by: Greg Kroah-Hartman --- drivers/i2c/muxes/Kconfig | 13 +++ drivers/i2c/muxes/Makefile | 1 + drivers/i2c/muxes/i2c-mux-gpmux.c | 173 ++++++++++++++++++++++++++++++ 3 files changed, 187 insertions(+) create mode 100644 drivers/i2c/muxes/i2c-mux-gpmux.c diff --git a/drivers/i2c/muxes/Kconfig b/drivers/i2c/muxes/Kconfig index 1e160fc37ecc..2c64d0e0740f 100644 --- a/drivers/i2c/muxes/Kconfig +++ b/drivers/i2c/muxes/Kconfig @@ -30,6 +30,19 @@ config I2C_MUX_GPIO This driver can also be built as a module. If so, the module will be called i2c-mux-gpio. +config I2C_MUX_GPMUX + tristate "General Purpose I2C multiplexer" + select MULTIPLEXER + depends on OF || COMPILE_TEST + help + If you say yes to this option, support will be included for a + general purpose I2C multiplexer. This driver provides access to + I2C busses connected through a MUX, which in turn is controlled + by a MUX-controller from the MUX subsystem. + + This driver can also be built as a module. If so, the module + will be called i2c-mux-gpmux. + config I2C_MUX_LTC4306 tristate "LTC LTC4306/5 I2C multiplexer" select GPIOLIB diff --git a/drivers/i2c/muxes/Makefile b/drivers/i2c/muxes/Makefile index ff7618cd5312..4a67d3199877 100644 --- a/drivers/i2c/muxes/Makefile +++ b/drivers/i2c/muxes/Makefile @@ -6,6 +6,7 @@ obj-$(CONFIG_I2C_ARB_GPIO_CHALLENGE) += i2c-arb-gpio-challenge.o obj-$(CONFIG_I2C_DEMUX_PINCTRL) += i2c-demux-pinctrl.o obj-$(CONFIG_I2C_MUX_GPIO) += i2c-mux-gpio.o +obj-$(CONFIG_I2C_MUX_GPMUX) += i2c-mux-gpmux.o obj-$(CONFIG_I2C_MUX_LTC4306) += i2c-mux-ltc4306.o obj-$(CONFIG_I2C_MUX_MLXCPLD) += i2c-mux-mlxcpld.o obj-$(CONFIG_I2C_MUX_PCA9541) += i2c-mux-pca9541.o diff --git a/drivers/i2c/muxes/i2c-mux-gpmux.c b/drivers/i2c/muxes/i2c-mux-gpmux.c new file mode 100644 index 000000000000..92cf5f48afe6 --- /dev/null +++ b/drivers/i2c/muxes/i2c-mux-gpmux.c @@ -0,0 +1,173 @@ +/* + * General Purpose I2C multiplexer + * + * Copyright (C) 2017 Axentia Technologies AB + * + * Author: Peter Rosin + * + * 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 +#include +#include +#include +#include +#include + +struct mux { + struct mux_control *control; + + bool do_not_deselect; +}; + +static int i2c_mux_select(struct i2c_mux_core *muxc, u32 chan) +{ + struct mux *mux = i2c_mux_priv(muxc); + int ret; + + ret = mux_control_select(mux->control, chan); + mux->do_not_deselect = ret < 0; + + return ret; +} + +static int i2c_mux_deselect(struct i2c_mux_core *muxc, u32 chan) +{ + struct mux *mux = i2c_mux_priv(muxc); + + if (mux->do_not_deselect) + return 0; + + return mux_control_deselect(mux->control); +} + +static struct i2c_adapter *mux_parent_adapter(struct device *dev) +{ + struct device_node *np = dev->of_node; + struct device_node *parent_np; + struct i2c_adapter *parent; + + parent_np = of_parse_phandle(np, "i2c-parent", 0); + if (!parent_np) { + dev_err(dev, "Cannot parse i2c-parent\n"); + return ERR_PTR(-ENODEV); + } + parent = of_find_i2c_adapter_by_node(parent_np); + of_node_put(parent_np); + if (!parent) + return ERR_PTR(-EPROBE_DEFER); + + return parent; +} + +static const struct of_device_id i2c_mux_of_match[] = { + { .compatible = "i2c-mux", }, + {}, +}; +MODULE_DEVICE_TABLE(of, i2c_mux_of_match); + +static int i2c_mux_probe(struct platform_device *pdev) +{ + struct device *dev = &pdev->dev; + struct device_node *np = dev->of_node; + struct device_node *child; + struct i2c_mux_core *muxc; + struct mux *mux; + struct i2c_adapter *parent; + int children; + int ret; + + if (!np) + return -ENODEV; + + mux = devm_kzalloc(dev, sizeof(*mux), GFP_KERNEL); + if (!mux) + return -ENOMEM; + + mux->control = devm_mux_control_get(dev, NULL); + if (IS_ERR(mux->control)) { + if (PTR_ERR(mux->control) != -EPROBE_DEFER) + dev_err(dev, "failed to get control-mux\n"); + return PTR_ERR(mux->control); + } + + parent = mux_parent_adapter(dev); + if (IS_ERR(parent)) { + if (PTR_ERR(parent) != -EPROBE_DEFER) + dev_err(dev, "failed to get i2c-parent adapter\n"); + return PTR_ERR(parent); + } + + children = of_get_child_count(np); + + muxc = i2c_mux_alloc(parent, dev, children, 0, 0, + i2c_mux_select, i2c_mux_deselect); + if (!muxc) { + ret = -ENOMEM; + goto err_parent; + } + muxc->priv = mux; + + platform_set_drvdata(pdev, muxc); + + muxc->mux_locked = of_property_read_bool(np, "mux-locked"); + + for_each_child_of_node(np, child) { + u32 chan; + + ret = of_property_read_u32(child, "reg", &chan); + if (ret < 0) { + dev_err(dev, "no reg property for node '%s'\n", + child->name); + goto err_children; + } + + if (chan >= mux_control_states(mux->control)) { + dev_err(dev, "invalid reg %u\n", chan); + ret = -EINVAL; + goto err_children; + } + + ret = i2c_mux_add_adapter(muxc, 0, chan, 0); + if (ret) + goto err_children; + } + + dev_info(dev, "%d-port mux on %s adapter\n", children, parent->name); + + return 0; + +err_children: + i2c_mux_del_adapters(muxc); +err_parent: + i2c_put_adapter(parent); + + return ret; +} + +static int i2c_mux_remove(struct platform_device *pdev) +{ + struct i2c_mux_core *muxc = platform_get_drvdata(pdev); + + i2c_mux_del_adapters(muxc); + i2c_put_adapter(muxc->parent); + + return 0; +} + +static struct platform_driver i2c_mux_driver = { + .probe = i2c_mux_probe, + .remove = i2c_mux_remove, + .driver = { + .name = "i2c-mux-gpmux", + .of_match_table = i2c_mux_of_match, + }, +}; +module_platform_driver(i2c_mux_driver); + +MODULE_DESCRIPTION("General Purpose I2C multiplexer driver"); +MODULE_AUTHOR("Peter Rosin "); +MODULE_LICENSE("GPL v2");