1 // SPDX-License-Identifier: GPL-2.0
3 // General Purpose SPI multiplexer
10 #include <linux/spi/spi.h>
12 #define SPI_MUX_NO_CS	((unsigned int)-1)
17  * This driver supports a MUX on an SPI bus. This can be useful when you need
21  * The driver will create an additional SPI controller. Devices added under the
26  * struct spi_mux_priv - the basic spi_mux structure
27  * @spi:		pointer to the device struct attached to the parent
28  *			spi controller
36  *			downstream spi devices
39 	struct spi_device	*spi;  member
49 static int spi_mux_select(struct spi_device *spi)  in spi_mux_select()  argument
51 	struct spi_mux_priv *priv = spi_controller_get_devdata(spi->controller);  in spi_mux_select()
54 	ret = mux_control_select(priv->mux, spi_get_chipselect(spi, 0));  in spi_mux_select()
58 	if (priv->current_cs == spi_get_chipselect(spi, 0))  in spi_mux_select()
61 	dev_dbg(&priv->spi->dev, "setting up the mux for cs %d\n",  in spi_mux_select()
62 		spi_get_chipselect(spi, 0));  in spi_mux_select()
65 	priv->spi->max_speed_hz = spi->max_speed_hz;  in spi_mux_select()
66 	priv->spi->mode = spi->mode;  in spi_mux_select()
67 	priv->spi->bits_per_word = spi->bits_per_word;  in spi_mux_select()
69 	priv->current_cs = spi_get_chipselect(spi, 0);  in spi_mux_select()
71 	spi_setup(priv->spi);  in spi_mux_select()
76 static int spi_mux_setup(struct spi_device *spi)  in spi_mux_setup()  argument
78 	struct spi_mux_priv *priv = spi_controller_get_devdata(spi->controller);  in spi_mux_setup()
85 	return spi_setup(priv->spi);  in spi_mux_setup()
91 	struct spi_controller *ctlr = spi_get_drvdata(priv->spi);  in spi_mux_complete_cb()
92 	struct spi_message *m = ctlr->cur_msg;  in spi_mux_complete_cb()
94 	m->complete = priv->child_msg_complete;  in spi_mux_complete_cb()
95 	m->context = priv->child_msg_context;  in spi_mux_complete_cb()
96 	m->spi = priv->child_msg_dev;  in spi_mux_complete_cb()
98 	mux_control_deselect(priv->mux);  in spi_mux_complete_cb()
105 	struct spi_device *spi = m->spi;  in spi_mux_transfer_one_message()  local
108 	ret = spi_mux_select(spi);  in spi_mux_transfer_one_message()
116 	priv->child_msg_complete = m->complete;  in spi_mux_transfer_one_message()
117 	priv->child_msg_context = m->context;  in spi_mux_transfer_one_message()
118 	priv->child_msg_dev = m->spi;  in spi_mux_transfer_one_message()
120 	m->complete = spi_mux_complete_cb;  in spi_mux_transfer_one_message()
121 	m->context = priv;  in spi_mux_transfer_one_message()
122 	m->spi = priv->spi;  in spi_mux_transfer_one_message()
125 	return spi_async(priv->spi, m);  in spi_mux_transfer_one_message()
128 static int spi_mux_probe(struct spi_device *spi)  in spi_mux_probe()  argument
134 	ctlr = spi_alloc_host(&spi->dev, sizeof(*priv));  in spi_mux_probe()
136 		return -ENOMEM;  in spi_mux_probe()
138 	spi_set_drvdata(spi, ctlr);  in spi_mux_probe()
140 	priv->spi = spi;  in spi_mux_probe()
146 	lockdep_set_subclass(&ctlr->io_mutex, 1);  in spi_mux_probe()
147 	lockdep_set_subclass(&ctlr->add_lock, 1);  in spi_mux_probe()
149 	priv->mux = devm_mux_control_get(&spi->dev, NULL);  in spi_mux_probe()
150 	if (IS_ERR(priv->mux)) {  in spi_mux_probe()
151 		ret = dev_err_probe(&spi->dev, PTR_ERR(priv->mux),  in spi_mux_probe()
152 				    "failed to get control-mux\n");  in spi_mux_probe()
156 	priv->current_cs = SPI_MUX_NO_CS;  in spi_mux_probe()
159 	ctlr->mode_bits = spi->controller->mode_bits;  in spi_mux_probe()
160 	ctlr->flags = spi->controller->flags;  in spi_mux_probe()
161 	ctlr->bits_per_word_mask = spi->controller->bits_per_word_mask;  in spi_mux_probe()
162 	ctlr->transfer_one_message = spi_mux_transfer_one_message;  in spi_mux_probe()
163 	ctlr->setup = spi_mux_setup;  in spi_mux_probe()
164 	ctlr->num_chipselect = mux_control_states(priv->mux);  in spi_mux_probe()
165 	ctlr->bus_num = -1;  in spi_mux_probe()
166 	ctlr->dev.of_node = spi->dev.of_node;  in spi_mux_probe()
167 	ctlr->must_async = true;  in spi_mux_probe()
168 	ctlr->defer_optimize_message = true;  in spi_mux_probe()
170 	ret = devm_spi_register_controller(&spi->dev, ctlr);  in spi_mux_probe()
183 	{ "spi-mux" },
186 MODULE_DEVICE_TABLE(spi, spi_mux_id);
189 	{ .compatible = "spi-mux" },
197 		.name   = "spi-mux",
205 MODULE_DESCRIPTION("SPI multiplexer");