^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1) // SPDX-License-Identifier: GPL-2.0
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2) //
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 3) // General Purpose SPI multiplexer
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 4)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 5) #include <linux/err.h>
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 6) #include <linux/kernel.h>
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 7) #include <linux/module.h>
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 8) #include <linux/mux/consumer.h>
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 9) #include <linux/slab.h>
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 10) #include <linux/spi/spi.h>
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 11)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 12) #define SPI_MUX_NO_CS ((unsigned int)-1)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 13)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 14) /**
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 15) * DOC: Driver description
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 16) *
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 17) * This driver supports a MUX on an SPI bus. This can be useful when you need
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 18) * more chip selects than the hardware peripherals support, or than are
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 19) * available in a particular board setup.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 20) *
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 21) * The driver will create an additional SPI controller. Devices added under the
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 22) * mux will be handled as 'chip selects' on this controller.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 23) */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 24)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 25) /**
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 26) * struct spi_mux_priv - the basic spi_mux structure
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 27) * @spi: pointer to the device struct attached to the parent
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 28) * spi controller
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 29) * @current_cs: The current chip select set in the mux
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 30) * @child_msg_complete: The mux replaces the complete callback in the child's
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 31) * message to its own callback; this field is used by the
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 32) * driver to store the child's callback during a transfer
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 33) * @child_msg_context: Used to store the child's context to the callback
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 34) * @child_msg_dev: Used to store the spi_device pointer to the child
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 35) * @mux: mux_control structure used to provide chip selects for
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 36) * downstream spi devices
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 37) */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 38) struct spi_mux_priv {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 39) struct spi_device *spi;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 40) unsigned int current_cs;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 41)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 42) void (*child_msg_complete)(void *context);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 43) void *child_msg_context;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 44) struct spi_device *child_msg_dev;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 45) struct mux_control *mux;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 46) };
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 47)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 48) /* should not get called when the parent controller is doing a transfer */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 49) static int spi_mux_select(struct spi_device *spi)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 50) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 51) struct spi_mux_priv *priv = spi_controller_get_devdata(spi->controller);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 52) int ret;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 53)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 54) ret = mux_control_select(priv->mux, spi->chip_select);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 55) if (ret)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 56) return ret;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 57)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 58) if (priv->current_cs == spi->chip_select)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 59) return 0;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 60)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 61) dev_dbg(&priv->spi->dev, "setting up the mux for cs %d\n",
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 62) spi->chip_select);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 63)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 64) /* copy the child device's settings except for the cs */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 65) priv->spi->max_speed_hz = spi->max_speed_hz;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 66) priv->spi->mode = spi->mode;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 67) priv->spi->bits_per_word = spi->bits_per_word;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 68)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 69) priv->current_cs = spi->chip_select;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 70)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 71) return 0;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 72) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 73)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 74) static int spi_mux_setup(struct spi_device *spi)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 75) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 76) struct spi_mux_priv *priv = spi_controller_get_devdata(spi->controller);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 77)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 78) /*
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 79) * can be called multiple times, won't do a valid setup now but we will
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 80) * change the settings when we do a transfer (necessary because we
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 81) * can't predict from which device it will be anyway)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 82) */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 83) return spi_setup(priv->spi);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 84) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 85)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 86) static void spi_mux_complete_cb(void *context)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 87) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 88) struct spi_mux_priv *priv = (struct spi_mux_priv *)context;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 89) struct spi_controller *ctlr = spi_get_drvdata(priv->spi);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 90) struct spi_message *m = ctlr->cur_msg;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 91)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 92) m->complete = priv->child_msg_complete;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 93) m->context = priv->child_msg_context;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 94) m->spi = priv->child_msg_dev;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 95) spi_finalize_current_message(ctlr);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 96) mux_control_deselect(priv->mux);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 97) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 98)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 99) static int spi_mux_transfer_one_message(struct spi_controller *ctlr,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 100) struct spi_message *m)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 101) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 102) struct spi_mux_priv *priv = spi_controller_get_devdata(ctlr);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 103) struct spi_device *spi = m->spi;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 104) int ret;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 105)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 106) ret = spi_mux_select(spi);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 107) if (ret)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 108) return ret;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 109)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 110) /*
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 111) * Replace the complete callback, context and spi_device with our own
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 112) * pointers. Save originals
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 113) */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 114) priv->child_msg_complete = m->complete;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 115) priv->child_msg_context = m->context;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 116) priv->child_msg_dev = m->spi;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 117)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 118) m->complete = spi_mux_complete_cb;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 119) m->context = priv;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 120) m->spi = priv->spi;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 121)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 122) /* do the transfer */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 123) return spi_async(priv->spi, m);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 124) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 125)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 126) static int spi_mux_probe(struct spi_device *spi)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 127) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 128) struct spi_controller *ctlr;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 129) struct spi_mux_priv *priv;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 130) int ret;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 131)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 132) ctlr = spi_alloc_master(&spi->dev, sizeof(*priv));
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 133) if (!ctlr)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 134) return -ENOMEM;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 135)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 136) spi_set_drvdata(spi, ctlr);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 137) priv = spi_controller_get_devdata(ctlr);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 138) priv->spi = spi;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 139)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 140) priv->mux = devm_mux_control_get(&spi->dev, NULL);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 141) if (IS_ERR(priv->mux)) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 142) ret = dev_err_probe(&spi->dev, PTR_ERR(priv->mux),
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 143) "failed to get control-mux\n");
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 144) goto err_put_ctlr;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 145) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 146)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 147) priv->current_cs = SPI_MUX_NO_CS;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 148)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 149) /* supported modes are the same as our parent's */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 150) ctlr->mode_bits = spi->controller->mode_bits;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 151) ctlr->flags = spi->controller->flags;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 152) ctlr->transfer_one_message = spi_mux_transfer_one_message;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 153) ctlr->setup = spi_mux_setup;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 154) ctlr->num_chipselect = mux_control_states(priv->mux);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 155) ctlr->bus_num = -1;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 156) ctlr->dev.of_node = spi->dev.of_node;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 157)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 158) ret = devm_spi_register_controller(&spi->dev, ctlr);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 159) if (ret)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 160) goto err_put_ctlr;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 161)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 162) return 0;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 163)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 164) err_put_ctlr:
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 165) spi_controller_put(ctlr);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 166)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 167) return ret;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 168) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 169)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 170) static const struct spi_device_id spi_mux_id[] = {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 171) { "spi-mux" },
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 172) { }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 173) };
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 174) MODULE_DEVICE_TABLE(spi, spi_mux_id);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 175)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 176) static const struct of_device_id spi_mux_of_match[] = {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 177) { .compatible = "spi-mux" },
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 178) { }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 179) };
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 180) MODULE_DEVICE_TABLE(of, spi_mux_of_match);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 181)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 182) static struct spi_driver spi_mux_driver = {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 183) .probe = spi_mux_probe,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 184) .driver = {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 185) .name = "spi-mux",
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 186) .of_match_table = spi_mux_of_match,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 187) },
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 188) .id_table = spi_mux_id,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 189) };
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 190)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 191) module_spi_driver(spi_mux_driver);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 192)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 193) MODULE_DESCRIPTION("SPI multiplexer");
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 194) MODULE_LICENSE("GPL");
Orange Pi5 kernel
Deprecated Linux kernel 5.10.110 for OrangePi 5/5B/5+ boards
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