diff --git a/drivers/spi/spi.c b/drivers/spi/spi.c index 9a7def7c3237..13f447a67d67 100644 --- a/drivers/spi/spi.c +++ b/drivers/spi/spi.c @@ -19,6 +19,7 @@ #include #include #include +#include #include #include #include @@ -578,7 +579,10 @@ int spi_add_device(struct spi_device *spi) goto done; } - if (ctlr->cs_gpios) + /* Descriptors take precedence */ + if (ctlr->cs_gpiods) + spi->cs_gpiod = ctlr->cs_gpiods[spi->chip_select]; + else if (ctlr->cs_gpios) spi->cs_gpio = ctlr->cs_gpios[spi->chip_select]; /* Drivers may modify this initial i/o setup, but will @@ -772,10 +776,20 @@ static void spi_set_cs(struct spi_device *spi, bool enable) if (spi->mode & SPI_CS_HIGH) enable = !enable; - if (gpio_is_valid(spi->cs_gpio)) { - /* Honour the SPI_NO_CS flag */ - if (!(spi->mode & SPI_NO_CS)) - gpio_set_value(spi->cs_gpio, !enable); + if (spi->cs_gpiod || gpio_is_valid(spi->cs_gpio)) { + /* + * Honour the SPI_NO_CS flag and invert the enable line, as + * active low is default for SPI. Execution paths that handle + * polarity inversion in gpiolib (such as device tree) will + * enforce active high using the SPI_CS_HIGH resulting in a + * double inversion through the code above. + */ + if (!(spi->mode & SPI_NO_CS)) { + if (spi->cs_gpiod) + gpiod_set_value(spi->cs_gpiod, !enable); + else + gpio_set_value(spi->cs_gpio, !enable); + } /* Some SPI masters need both GPIO CS & slave_select */ if ((spi->controller->flags & SPI_MASTER_GPIO_SS) && spi->controller->set_cs) @@ -1615,13 +1629,21 @@ static int of_spi_parse_dt(struct spi_controller *ctlr, struct spi_device *spi, spi->mode |= SPI_CPHA; if (of_property_read_bool(nc, "spi-cpol")) spi->mode |= SPI_CPOL; - if (of_property_read_bool(nc, "spi-cs-high")) - spi->mode |= SPI_CS_HIGH; if (of_property_read_bool(nc, "spi-3wire")) spi->mode |= SPI_3WIRE; if (of_property_read_bool(nc, "spi-lsb-first")) spi->mode |= SPI_LSB_FIRST; + /* + * For descriptors associated with the device, polarity inversion is + * handled in the gpiolib, so all chip selects are "active high" in + * the logical sense, the gpiolib will invert the line if need be. + */ + if (ctlr->use_gpio_descriptors) + spi->mode |= SPI_CS_HIGH; + else if (of_property_read_bool(nc, "spi-cs-high")) + spi->mode |= SPI_CS_HIGH; + /* Device DUAL/QUAD mode */ if (!of_property_read_u32(nc, "spi-tx-bus-width", &value)) { switch (value) { @@ -2137,6 +2159,60 @@ static int of_spi_register_master(struct spi_controller *ctlr) } #endif +/** + * spi_get_gpio_descs() - grab chip select GPIOs for the master + * @ctlr: The SPI master to grab GPIO descriptors for + */ +static int spi_get_gpio_descs(struct spi_controller *ctlr) +{ + int nb, i; + struct gpio_desc **cs; + struct device *dev = &ctlr->dev; + + nb = gpiod_count(dev, "cs"); + ctlr->num_chipselect = max_t(int, nb, ctlr->num_chipselect); + + /* No GPIOs at all is fine, else return the error */ + if (nb == 0 || nb == -ENOENT) + return 0; + else if (nb < 0) + return nb; + + cs = devm_kcalloc(dev, ctlr->num_chipselect, sizeof(*cs), + GFP_KERNEL); + if (!cs) + return -ENOMEM; + ctlr->cs_gpiods = cs; + + for (i = 0; i < nb; i++) { + /* + * Most chipselects are active low, the inverted + * semantics are handled by special quirks in gpiolib, + * so initializing them GPIOD_OUT_LOW here means + * "unasserted", in most cases this will drive the physical + * line high. + */ + cs[i] = devm_gpiod_get_index_optional(dev, "cs", i, + GPIOD_OUT_LOW); + + if (cs[i]) { + /* + * If we find a CS GPIO, name it after the device and + * chip select line. + */ + char *gpioname; + + gpioname = devm_kasprintf(dev, GFP_KERNEL, "%s CS%d", + dev_name(dev), i); + if (!gpioname) + return -ENOMEM; + gpiod_set_consumer_name(cs[i], gpioname); + } + } + + return 0; +} + static int spi_controller_check_ops(struct spi_controller *ctlr) { /* @@ -2199,9 +2275,16 @@ int spi_register_controller(struct spi_controller *ctlr) return status; if (!spi_controller_is_slave(ctlr)) { - status = of_spi_register_master(ctlr); - if (status) - return status; + if (ctlr->use_gpio_descriptors) { + status = spi_get_gpio_descs(ctlr); + if (status) + return status; + } else { + /* Legacy code path for GPIOs from DT */ + status = of_spi_register_master(ctlr); + if (status) + return status; + } } /* even if it's just one always-selected device, there must @@ -2915,6 +2998,7 @@ static int __spi_validate(struct spi_device *spi, struct spi_message *message) * cs_change is set for each transfer. */ if ((spi->mode & SPI_CS_WORD) && (!(ctlr->mode_bits & SPI_CS_WORD) || + spi->cs_gpiod || gpio_is_valid(spi->cs_gpio))) { size_t maxsize; int ret; diff --git a/include/linux/spi/spi.h b/include/linux/spi/spi.h index 314d922ca607..916bba47d156 100644 --- a/include/linux/spi/spi.h +++ b/include/linux/spi/spi.h @@ -12,6 +12,7 @@ #include #include #include +#include struct dma_chan; struct property_entry; @@ -116,7 +117,10 @@ void spi_statistics_add_transfer_stats(struct spi_statistics *stats, * @modalias: Name of the driver to use with this device, or an alias * for that name. This appears in the sysfs "modalias" attribute * for driver coldplugging, and in uevents used for hotplugging - * @cs_gpio: gpio number of the chipselect line (optional, -ENOENT when + * @cs_gpio: LEGACY: gpio number of the chipselect line (optional, -ENOENT when + * not using a GPIO line) use cs_gpiod in new drivers by opting in on + * the spi_master. + * @cs_gpiod: gpio descriptor of the chipselect line (optional, NULL when * not using a GPIO line) * * @statistics: statistics for the spi_device @@ -163,7 +167,8 @@ struct spi_device { void *controller_data; char modalias[SPI_NAME_SIZE]; const char *driver_override; - int cs_gpio; /* chip select gpio */ + int cs_gpio; /* LEGACY: chip select gpio */ + struct gpio_desc *cs_gpiod; /* chip select gpio desc */ /* the statistics */ struct spi_statistics statistics; @@ -376,9 +381,17 @@ static inline void spi_unregister_driver(struct spi_driver *sdrv) * controller has native support for memory like operations. * @unprepare_message: undo any work done by prepare_message(). * @slave_abort: abort the ongoing transfer request on an SPI slave controller - * @cs_gpios: Array of GPIOs to use as chip select lines; one per CS - * number. Any individual value may be -ENOENT for CS lines that + * @cs_gpios: LEGACY: array of GPIO descs to use as chip select lines; one per + * CS number. Any individual value may be -ENOENT for CS lines that + * are not GPIOs (driven by the SPI controller itself). Use the cs_gpiods + * in new drivers. + * @cs_gpiods: Array of GPIO descs to use as chip select lines; one per CS + * number. Any individual value may be NULL for CS lines that * are not GPIOs (driven by the SPI controller itself). + * @use_gpio_descriptors: Turns on the code in the SPI core to parse and grab + * GPIO descriptors rather than using global GPIO numbers grabbed by the + * driver. This will fill in @cs_gpiods and @cs_gpios should not be used, + * and SPI devices will have the cs_gpiod assigned rather than cs_gpio. * @statistics: statistics for the spi_controller * @dma_tx: DMA transmit channel * @dma_rx: DMA receive channel @@ -557,6 +570,8 @@ struct spi_controller { /* gpio chip select */ int *cs_gpios; + struct gpio_desc **cs_gpiods; + bool use_gpio_descriptors; /* statistics */ struct spi_statistics statistics;