3 // General Purpose SPI multiplexer
10 #include <linux/spi/spi.h>
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
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()
74 static int spi_mux_setup(struct spi_device *spi)  in spi_mux_setup()  argument
76 	struct spi_mux_priv *priv = spi_controller_get_devdata(spi->controller);  in spi_mux_setup()
83 	return spi_setup(priv->spi);  in spi_mux_setup()
89 	struct spi_controller *ctlr = spi_get_drvdata(priv->spi);  in spi_mux_complete_cb()
94 	m->spi = priv->child_msg_dev;  in spi_mux_complete_cb()
103 	struct spi_device *spi = m->spi;  in spi_mux_transfer_one_message()  local
106 	ret = spi_mux_select(spi);  in spi_mux_transfer_one_message()
116 	priv->child_msg_dev = m->spi;  in spi_mux_transfer_one_message()
120 	m->spi = priv->spi;  in spi_mux_transfer_one_message()
123 	return spi_async(priv->spi, m);  in spi_mux_transfer_one_message()
126 static int spi_mux_probe(struct spi_device *spi)  in spi_mux_probe()  argument
132 	ctlr = spi_alloc_master(&spi->dev, sizeof(*priv));  in spi_mux_probe()
136 	spi_set_drvdata(spi, ctlr);  in spi_mux_probe()
138 	priv->spi = spi;  in spi_mux_probe()
147 	priv->mux = devm_mux_control_get(&spi->dev, NULL);  in spi_mux_probe()
149 		ret = dev_err_probe(&spi->dev, PTR_ERR(priv->mux),  in spi_mux_probe()
157 	ctlr->mode_bits = spi->controller->mode_bits;  in spi_mux_probe()
158 	ctlr->flags = spi->controller->flags;  in spi_mux_probe()
159 	ctlr->bits_per_word_mask = spi->controller->bits_per_word_mask;  in spi_mux_probe()
164 	ctlr->dev.of_node = spi->dev.of_node;  in spi_mux_probe()
167 	ret = devm_spi_register_controller(&spi->dev, ctlr);  in spi_mux_probe()
180 	{ "spi-mux" },
183 MODULE_DEVICE_TABLE(spi, spi_mux_id);
186 	{ .compatible = "spi-mux" },
194 		.name   = "spi-mux",
202 MODULE_DESCRIPTION("SPI multiplexer");