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 <jic23@kernel.org>
Acked-by: Wolfram Sang <wsa@the-dreams.de>
Signed-off-by: Peter Rosin <peda@axentia.se>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/drivers/i2c/muxes/Kconfig b/drivers/i2c/muxes/Kconfig
index 1e160fc37ecc309ed69cf1bbe23f6c81a6a72ee7..2c64d0e0740f0db0c4427af9d6602bc8aaa0ea24 100644 (file)
--- 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 ff7618cd5312392b850566004cacbb0a135f17c4..4a67d319987742e05d6ee1387059d3c972b35874 100644 (file)
--- 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 (file)
index 0000000..92cf5f4
--- /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 <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/i2c.h>
+#include <linux/i2c-mux.h>
+#include <linux/module.h>
+#include <linux/mux/consumer.h>
+#include <linux/of_device.h>
+#include <linux/platform_device.h>
+
+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 <peda@axentia.se>");
+MODULE_LICENSE("GPL v2");