net/mdio/mdio-mux-multiplexer.c

1 // SPDX-License-Identifier: GPL-2.0+
2 /* MDIO bus multiplexer using kernel multiplexer subsystem
7 #include <linux/mdio-mux.h>
9 #include <linux/mux/consumer.h>
19  * mdio_mux_multiplexer_switch_fn - This function is called by the mdio-mux
20  *                                  layer when it thinks the mdio bus
22  * @current_child:  current value of the mux register.
23  * @desired_child: value of the 'reg' property of the target child MDIO node.
27  * The first time this function is called, current_child == -1.
28  * If current_child == desired_child, then the mux is already set to the
44 	if (s->do_deselect)  in mdio_mux_multiplexer_switch_fn()
45 		ret = mux_control_deselect(s->muxc);  in mdio_mux_multiplexer_switch_fn()
47 		dev_err(&pdev->dev, "mux_control_deselect failed in %s: %d\n",  in mdio_mux_multiplexer_switch_fn()
52 	ret =  mux_control_select(s->muxc, desired_child);  in mdio_mux_multiplexer_switch_fn()
54 		dev_dbg(&pdev->dev, "%s %d -> %d\n", __func__, current_child,  in mdio_mux_multiplexer_switch_fn()
56 		s->do_deselect = true;  in mdio_mux_multiplexer_switch_fn()
58 		s->do_deselect = false;  in mdio_mux_multiplexer_switch_fn()
66 	struct device *dev = &pdev->dev;  in mdio_mux_multiplexer_probe()
70 	s = devm_kzalloc(&pdev->dev, sizeof(*s), GFP_KERNEL);  in mdio_mux_multiplexer_probe()
72 		return -ENOMEM;  in mdio_mux_multiplexer_probe()
74 	s->muxc = devm_mux_control_get(dev, NULL);  in mdio_mux_multiplexer_probe()
75 	if (IS_ERR(s->muxc))  in mdio_mux_multiplexer_probe()
76 		return dev_err_probe(&pdev->dev, PTR_ERR(s->muxc),  in mdio_mux_multiplexer_probe()
77 				     "Failed to get mux\n");  in mdio_mux_multiplexer_probe()
81 	ret = mdio_mux_init(&pdev->dev, pdev->dev.of_node,  in mdio_mux_multiplexer_probe()
82 			    mdio_mux_multiplexer_switch_fn, &s->mux_handle,  in mdio_mux_multiplexer_probe()
92 	mdio_mux_uninit(s->mux_handle);  in mdio_mux_multiplexer_remove()
94 	if (s->do_deselect)  in mdio_mux_multiplexer_remove()
95 		mux_control_deselect(s->muxc);  in mdio_mux_multiplexer_remove()
99 	{ .compatible = "mdio-mux-multiplexer", },
106 		.name		= "mdio-mux-multiplexer",
115 MODULE_DESCRIPTION("MDIO bus multiplexer using kernel multiplexer subsystem");