diff options
Diffstat (limited to 'drivers/spi/spi-gpio.c')
| -rw-r--r-- | drivers/spi/spi-gpio.c | 206 |
1 files changed, 84 insertions, 122 deletions
diff --git a/drivers/spi/spi-gpio.c b/drivers/spi/spi-gpio.c index 9c8c7948044e..c8dadb532c40 100644 --- a/drivers/spi/spi-gpio.c +++ b/drivers/spi/spi-gpio.c @@ -1,24 +1,23 @@ // SPDX-License-Identifier: GPL-2.0-or-later /* - * SPI master driver using generic bitbanged GPIO + * SPI host driver using generic bitbanged GPIO * * Copyright (C) 2006,2008 David Brownell * Copyright (C) 2017 Linus Walleij */ +#include <linux/gpio/consumer.h> #include <linux/kernel.h> +#include <linux/mod_devicetable.h> #include <linux/module.h> #include <linux/platform_device.h> -#include <linux/gpio/consumer.h> -#include <linux/of.h> -#include <linux/of_device.h> +#include <linux/property.h> #include <linux/spi/spi.h> #include <linux/spi/spi_bitbang.h> #include <linux/spi/spi_gpio.h> - /* - * This bitbanging SPI master driver should help make systems usable + * This bitbanging SPI host driver should help make systems usable * when a native hardware SPI engine is not available, perhaps because * its driver isn't yet working or because the I/O pins it requires * are used for other purposes. @@ -27,7 +26,7 @@ * * spi->controller_state ... reserved for bitbang framework code * - * spi->master->dev.driver_data ... points to spi_gpio->bitbang + * spi->controller->dev.driver_data ... points to spi_gpio->bitbang */ struct spi_gpio { @@ -40,45 +39,17 @@ struct spi_gpio { /*----------------------------------------------------------------------*/ -/* - * Because the overhead of going through four GPIO procedure calls - * per transferred bit can make performance a problem, this code - * is set up so that you can use it in either of two ways: - * - * - The slow generic way: set up platform_data to hold the GPIO - * numbers used for MISO/MOSI/SCK, and issue procedure calls for - * each of them. This driver can handle several such busses. - * - * - The quicker inlined way: only helps with platform GPIO code - * that inlines operations for constant GPIOs. This can give - * you tight (fast!) inner loops, but each such bus needs a - * new driver. You'll define a new C file, with Makefile and - * Kconfig support; the C code can be a total of six lines: - * - * #define DRIVER_NAME "myboard_spi2" - * #define SPI_MISO_GPIO 119 - * #define SPI_MOSI_GPIO 120 - * #define SPI_SCK_GPIO 121 - * #define SPI_N_CHIPSEL 4 - * #include "spi-gpio.c" - */ - -#ifndef DRIVER_NAME #define DRIVER_NAME "spi_gpio" -#define GENERIC_BITBANG /* vs tight inlines */ - -#endif - /*----------------------------------------------------------------------*/ static inline struct spi_gpio *__pure spi_to_spi_gpio(const struct spi_device *spi) { - const struct spi_bitbang *bang; + struct spi_bitbang *bang; struct spi_gpio *spi_gpio; - bang = spi_master_get_devdata(spi->master); + bang = spi_controller_get_devdata(spi->controller); spi_gpio = container_of(bang, struct spi_gpio, bitbang); return spi_gpio; } @@ -133,7 +104,7 @@ static inline int getmiso(const struct spi_device *spi) */ static u32 spi_gpio_txrx_word_mode0(struct spi_device *spi, - unsigned nsecs, u32 word, u8 bits, unsigned flags) + unsigned int nsecs, u32 word, u8 bits, unsigned int flags) { if (unlikely(spi->mode & SPI_LSB_FIRST)) return bitbang_txrx_le_cpha0(spi, nsecs, 0, flags, word, bits); @@ -142,7 +113,7 @@ static u32 spi_gpio_txrx_word_mode0(struct spi_device *spi, } static u32 spi_gpio_txrx_word_mode1(struct spi_device *spi, - unsigned nsecs, u32 word, u8 bits, unsigned flags) + unsigned int nsecs, u32 word, u8 bits, unsigned int flags) { if (unlikely(spi->mode & SPI_LSB_FIRST)) return bitbang_txrx_le_cpha1(spi, nsecs, 0, flags, word, bits); @@ -151,7 +122,7 @@ static u32 spi_gpio_txrx_word_mode1(struct spi_device *spi, } static u32 spi_gpio_txrx_word_mode2(struct spi_device *spi, - unsigned nsecs, u32 word, u8 bits, unsigned flags) + unsigned int nsecs, u32 word, u8 bits, unsigned int flags) { if (unlikely(spi->mode & SPI_LSB_FIRST)) return bitbang_txrx_le_cpha0(spi, nsecs, 1, flags, word, bits); @@ -160,7 +131,7 @@ static u32 spi_gpio_txrx_word_mode2(struct spi_device *spi, } static u32 spi_gpio_txrx_word_mode3(struct spi_device *spi, - unsigned nsecs, u32 word, u8 bits, unsigned flags) + unsigned int nsecs, u32 word, u8 bits, unsigned int flags) { if (unlikely(spi->mode & SPI_LSB_FIRST)) return bitbang_txrx_le_cpha1(spi, nsecs, 1, flags, word, bits); @@ -170,7 +141,7 @@ static u32 spi_gpio_txrx_word_mode3(struct spi_device *spi, /* * These functions do not call setmosi or getmiso if respective flag - * (SPI_MASTER_NO_RX or SPI_MASTER_NO_TX) is set, so they are safe to + * (SPI_CONTROLLER_NO_RX or SPI_CONTROLLER_NO_TX) is set, so they are safe to * call when such pin is not present or defined in the controller. * A separate set of callbacks is defined to get highest possible * speed in the generic case (when both MISO and MOSI lines are @@ -179,9 +150,9 @@ static u32 spi_gpio_txrx_word_mode3(struct spi_device *spi, */ static u32 spi_gpio_spec_txrx_word_mode0(struct spi_device *spi, - unsigned nsecs, u32 word, u8 bits, unsigned flags) + unsigned int nsecs, u32 word, u8 bits, unsigned int flags) { - flags = spi->master->flags; + flags = spi->controller->flags; if (unlikely(spi->mode & SPI_LSB_FIRST)) return bitbang_txrx_le_cpha0(spi, nsecs, 0, flags, word, bits); else @@ -189,9 +160,9 @@ static u32 spi_gpio_spec_txrx_word_mode0(struct spi_device *spi, } static u32 spi_gpio_spec_txrx_word_mode1(struct spi_device *spi, - unsigned nsecs, u32 word, u8 bits, unsigned flags) + unsigned int nsecs, u32 word, u8 bits, unsigned int flags) { - flags = spi->master->flags; + flags = spi->controller->flags; if (unlikely(spi->mode & SPI_LSB_FIRST)) return bitbang_txrx_le_cpha1(spi, nsecs, 0, flags, word, bits); else @@ -199,9 +170,9 @@ static u32 spi_gpio_spec_txrx_word_mode1(struct spi_device *spi, } static u32 spi_gpio_spec_txrx_word_mode2(struct spi_device *spi, - unsigned nsecs, u32 word, u8 bits, unsigned flags) + unsigned int nsecs, u32 word, u8 bits, unsigned int flags) { - flags = spi->master->flags; + flags = spi->controller->flags; if (unlikely(spi->mode & SPI_LSB_FIRST)) return bitbang_txrx_le_cpha0(spi, nsecs, 1, flags, word, bits); else @@ -209,9 +180,9 @@ static u32 spi_gpio_spec_txrx_word_mode2(struct spi_device *spi, } static u32 spi_gpio_spec_txrx_word_mode3(struct spi_device *spi, - unsigned nsecs, u32 word, u8 bits, unsigned flags) + unsigned int nsecs, u32 word, u8 bits, unsigned int flags) { - flags = spi->master->flags; + flags = spi->controller->flags; if (unlikely(spi->mode & SPI_LSB_FIRST)) return bitbang_txrx_le_cpha1(spi, nsecs, 1, flags, word, bits); else @@ -230,34 +201,41 @@ static void spi_gpio_chipselect(struct spi_device *spi, int is_active) /* Drive chip select line, if we have one */ if (spi_gpio->cs_gpios) { - struct gpio_desc *cs = spi_gpio->cs_gpios[spi->chip_select]; + struct gpio_desc *cs = spi_gpio->cs_gpios[spi_get_chipselect(spi, 0)]; /* SPI chip selects are normally active-low */ gpiod_set_value_cansleep(cs, (spi->mode & SPI_CS_HIGH) ? is_active : !is_active); } } +static void spi_gpio_set_mosi_idle(struct spi_device *spi) +{ + struct spi_gpio *spi_gpio = spi_to_spi_gpio(spi); + + gpiod_set_value_cansleep(spi_gpio->mosi, + !!(spi->mode & SPI_MOSI_IDLE_HIGH)); +} + static int spi_gpio_setup(struct spi_device *spi) { struct gpio_desc *cs; - int status = 0; struct spi_gpio *spi_gpio = spi_to_spi_gpio(spi); + int ret; /* * The CS GPIOs have already been * initialized from the descriptor lookup. */ if (spi_gpio->cs_gpios) { - cs = spi_gpio->cs_gpios[spi->chip_select]; - if (!spi->controller_state && cs) - status = gpiod_direction_output(cs, - !(spi->mode & SPI_CS_HIGH)); + cs = spi_gpio->cs_gpios[spi_get_chipselect(spi, 0)]; + if (!spi->controller_state && cs) { + ret = gpiod_direction_output(cs, !(spi->mode & SPI_CS_HIGH)); + if (ret) + return ret; + } } - if (!status) - status = spi_bitbang_setup(spi); - - return status; + return spi_bitbang_setup(spi); } static int spi_gpio_set_direction(struct spi_device *spi, bool output) @@ -311,7 +289,7 @@ static void spi_gpio_cleanup(struct spi_device *spi) * On platforms which can do so, configure MISO with a weak pullup unless * there's an external pullup on that signal. That saves power by avoiding * floating signals. (A weak pulldown would save power too, but many - * drivers expect to see all-ones data as the no slave "response".) + * drivers expect to see all-ones data as the no target "response".) */ static int spi_gpio_request(struct device *dev, struct spi_gpio *spi_gpio) { @@ -327,54 +305,29 @@ static int spi_gpio_request(struct device *dev, struct spi_gpio *spi_gpio) return PTR_ERR_OR_ZERO(spi_gpio->sck); } -#ifdef CONFIG_OF -static const struct of_device_id spi_gpio_dt_ids[] = { - { .compatible = "spi-gpio" }, - {} -}; -MODULE_DEVICE_TABLE(of, spi_gpio_dt_ids); - -static int spi_gpio_probe_dt(struct platform_device *pdev, - struct spi_master *master) -{ - master->dev.of_node = pdev->dev.of_node; - master->use_gpio_descriptors = true; - - return 0; -} -#else -static inline int spi_gpio_probe_dt(struct platform_device *pdev, - struct spi_master *master) -{ - return 0; -} -#endif - static int spi_gpio_probe_pdata(struct platform_device *pdev, - struct spi_master *master) + struct spi_controller *host) { struct device *dev = &pdev->dev; struct spi_gpio_platform_data *pdata = dev_get_platdata(dev); - struct spi_gpio *spi_gpio = spi_master_get_devdata(master); + struct spi_gpio *spi_gpio = spi_controller_get_devdata(host); int i; -#ifdef GENERIC_BITBANG - if (!pdata || !pdata->num_chipselect) + if (!pdata) return -ENODEV; -#endif - /* - * The master needs to think there is a chipselect even if not - * connected - */ - master->num_chipselect = pdata->num_chipselect ?: 1; - spi_gpio->cs_gpios = devm_kcalloc(dev, master->num_chipselect, + /* It's just one always-selected device, fine to continue */ + if (!pdata->num_chipselect) + return 0; + + host->num_chipselect = pdata->num_chipselect; + spi_gpio->cs_gpios = devm_kcalloc(dev, host->num_chipselect, sizeof(*spi_gpio->cs_gpios), GFP_KERNEL); if (!spi_gpio->cs_gpios) return -ENOMEM; - for (i = 0; i < master->num_chipselect; i++) { + for (i = 0; i < host->num_chipselect; i++) { spi_gpio->cs_gpios[i] = devm_gpiod_get_index(dev, "cs", i, GPIOD_OUT_HIGH); if (IS_ERR(spi_gpio->cs_gpios[i])) @@ -387,58 +340,62 @@ static int spi_gpio_probe_pdata(struct platform_device *pdev, static int spi_gpio_probe(struct platform_device *pdev) { int status; - struct spi_master *master; + struct spi_controller *host; struct spi_gpio *spi_gpio; struct device *dev = &pdev->dev; + struct fwnode_handle *fwnode = dev_fwnode(dev); struct spi_bitbang *bb; - master = devm_spi_alloc_master(dev, sizeof(*spi_gpio)); - if (!master) + host = devm_spi_alloc_host(dev, sizeof(*spi_gpio)); + if (!host) return -ENOMEM; - if (pdev->dev.of_node) - status = spi_gpio_probe_dt(pdev, master); - else - status = spi_gpio_probe_pdata(pdev, master); - - if (status) - return status; + if (fwnode) { + device_set_node(&host->dev, fwnode); + host->use_gpio_descriptors = true; + } else { + status = spi_gpio_probe_pdata(pdev, host); + if (status) + return status; + } - spi_gpio = spi_master_get_devdata(master); + spi_gpio = spi_controller_get_devdata(host); status = spi_gpio_request(dev, spi_gpio); if (status) return status; - master->bits_per_word_mask = SPI_BPW_RANGE_MASK(1, 32); - master->mode_bits = SPI_3WIRE | SPI_3WIRE_HIZ | SPI_CPHA | SPI_CPOL | - SPI_CS_HIGH | SPI_LSB_FIRST; + host->bits_per_word_mask = SPI_BPW_RANGE_MASK(1, 32); + host->mode_bits = SPI_3WIRE | SPI_3WIRE_HIZ | SPI_CPHA | SPI_CPOL | + SPI_CS_HIGH | SPI_LSB_FIRST | SPI_MOSI_IDLE_LOW | + SPI_MOSI_IDLE_HIGH; if (!spi_gpio->mosi) { /* HW configuration without MOSI pin * - * No setting SPI_MASTER_NO_RX here - if there is only + * No setting SPI_CONTROLLER_NO_RX here - if there is only * a MOSI pin connected the host can still do RX by * changing the direction of the line. */ - master->flags = SPI_MASTER_NO_TX; + host->flags = SPI_CONTROLLER_NO_TX; } - master->bus_num = pdev->id; - master->setup = spi_gpio_setup; - master->cleanup = spi_gpio_cleanup; + host->bus_num = pdev->id; + host->setup = spi_gpio_setup; + host->cleanup = spi_gpio_cleanup; bb = &spi_gpio->bitbang; - bb->master = master; + bb->ctlr = host; /* * There is some additional business, apart from driving the CS GPIO * line, that we need to do on selection. This makes the local * callback for chipselect always get called. */ - master->flags |= SPI_MASTER_GPIO_SS; + host->flags |= SPI_CONTROLLER_GPIO_SS; bb->chipselect = spi_gpio_chipselect; bb->set_line_direction = spi_gpio_set_direction; + bb->set_mosi_idle = spi_gpio_set_mosi_idle; - if (master->flags & SPI_MASTER_NO_TX) { + if (host->flags & SPI_CONTROLLER_NO_TX) { bb->txrx_word[SPI_MODE_0] = spi_gpio_spec_txrx_word_mode0; bb->txrx_word[SPI_MODE_1] = spi_gpio_spec_txrx_word_mode1; bb->txrx_word[SPI_MODE_2] = spi_gpio_spec_txrx_word_mode2; @@ -455,20 +412,25 @@ static int spi_gpio_probe(struct platform_device *pdev) if (status) return status; - return devm_spi_register_master(&pdev->dev, master); + return devm_spi_register_controller(&pdev->dev, host); } -MODULE_ALIAS("platform:" DRIVER_NAME); +static const struct of_device_id spi_gpio_dt_ids[] = { + { .compatible = "spi-gpio" }, + {} +}; +MODULE_DEVICE_TABLE(of, spi_gpio_dt_ids); static struct platform_driver spi_gpio_driver = { .driver = { .name = DRIVER_NAME, - .of_match_table = of_match_ptr(spi_gpio_dt_ids), + .of_match_table = spi_gpio_dt_ids, }, .probe = spi_gpio_probe, }; module_platform_driver(spi_gpio_driver); -MODULE_DESCRIPTION("SPI master driver using generic bitbanged GPIO "); +MODULE_DESCRIPTION("SPI host driver using generic bitbanged GPIO "); MODULE_AUTHOR("David Brownell"); MODULE_LICENSE("GPL"); +MODULE_ALIAS("platform:" DRIVER_NAME); |