diff options
Diffstat (limited to 'drivers/spi')
| -rw-r--r-- | drivers/spi/Kconfig | 26 | ||||
| -rw-r--r-- | drivers/spi/Makefile | 4 | ||||
| -rw-r--r-- | drivers/spi/spi-slave-system-control.c | 154 | ||||
| -rw-r--r-- | drivers/spi/spi-slave-time.c | 129 | ||||
| -rw-r--r-- | drivers/spi/spi.c | 181 |
5 files changed, 468 insertions, 26 deletions
diff --git a/drivers/spi/Kconfig b/drivers/spi/Kconfig index 1761c9004fc1..e6d9e329a380 100644 --- a/drivers/spi/Kconfig +++ b/drivers/spi/Kconfig @@ -784,6 +784,30 @@ config SPI_TLE62X0 endif # SPI_MASTER -# (slave support would go here) +# +# SLAVE side ... listening to other SPI masters +# + +config SPI_SLAVE + bool "SPI slave protocol handlers" + help + If your system has a slave-capable SPI controller, you can enable + slave protocol handlers. + +if SPI_SLAVE + +config SPI_SLAVE_TIME + tristate "SPI slave handler reporting boot up time" + help + SPI slave handler responding with the time of reception of the last + SPI message. + +config SPI_SLAVE_SYSTEM_CONTROL + tristate "SPI slave handler controlling system state" + help + SPI slave handler to allow remote control of system reboot, power + off, halt, and suspend. + +endif # SPI_SLAVE endif # SPI diff --git a/drivers/spi/Makefile b/drivers/spi/Makefile index b375a7a89216..1d7923e8c63b 100644 --- a/drivers/spi/Makefile +++ b/drivers/spi/Makefile @@ -105,3 +105,7 @@ obj-$(CONFIG_SPI_XILINX) += spi-xilinx.o obj-$(CONFIG_SPI_XLP) += spi-xlp.o obj-$(CONFIG_SPI_XTENSA_XTFPGA) += spi-xtensa-xtfpga.o obj-$(CONFIG_SPI_ZYNQMP_GQSPI) += spi-zynqmp-gqspi.o + +# SPI slave protocol handlers +obj-$(CONFIG_SPI_SLAVE_TIME) += spi-slave-time.o +obj-$(CONFIG_SPI_SLAVE_SYSTEM_CONTROL) += spi-slave-system-control.o diff --git a/drivers/spi/spi-slave-system-control.c b/drivers/spi/spi-slave-system-control.c new file mode 100644 index 000000000000..c0257e937995 --- /dev/null +++ b/drivers/spi/spi-slave-system-control.c @@ -0,0 +1,154 @@ +/* + * SPI slave handler controlling system state + * + * This SPI slave handler allows remote control of system reboot, power off, + * halt, and suspend. + * + * Copyright (C) 2016-2017 Glider bvba + * + * This file is subject to the terms and conditions of the GNU General Public + * License. See the file "COPYING" in the main directory of this archive + * for more details. + * + * Usage (assuming /dev/spidev2.0 corresponds to the SPI master on the remote + * system): + * + * # reboot='\x7c\x50' + * # poweroff='\x71\x3f' + * # halt='\x38\x76' + * # suspend='\x1b\x1b' + * # spidev_test -D /dev/spidev2.0 -p $suspend # or $reboot, $poweroff, $halt + */ + +#include <linux/completion.h> +#include <linux/module.h> +#include <linux/reboot.h> +#include <linux/suspend.h> +#include <linux/spi/spi.h> + +/* + * The numbers are chosen to display something human-readable on two 7-segment + * displays connected to two 74HC595 shift registers + */ +#define CMD_REBOOT 0x7c50 /* rb */ +#define CMD_POWEROFF 0x713f /* OF */ +#define CMD_HALT 0x3876 /* HL */ +#define CMD_SUSPEND 0x1b1b /* ZZ */ + +struct spi_slave_system_control_priv { + struct spi_device *spi; + struct completion finished; + struct spi_transfer xfer; + struct spi_message msg; + __be16 cmd; +}; + +static +int spi_slave_system_control_submit(struct spi_slave_system_control_priv *priv); + +static void spi_slave_system_control_complete(void *arg) +{ + struct spi_slave_system_control_priv *priv = arg; + u16 cmd; + int ret; + + if (priv->msg.status) + goto terminate; + + cmd = be16_to_cpu(priv->cmd); + switch (cmd) { + case CMD_REBOOT: + dev_info(&priv->spi->dev, "Rebooting system...\n"); + kernel_restart(NULL); + + case CMD_POWEROFF: + dev_info(&priv->spi->dev, "Powering off system...\n"); + kernel_power_off(); + break; + + case CMD_HALT: + dev_info(&priv->spi->dev, "Halting system...\n"); + kernel_halt(); + break; + + case CMD_SUSPEND: + dev_info(&priv->spi->dev, "Suspending system...\n"); + pm_suspend(PM_SUSPEND_MEM); + break; + + default: + dev_warn(&priv->spi->dev, "Unknown command 0x%x\n", cmd); + break; + } + + ret = spi_slave_system_control_submit(priv); + if (ret) + goto terminate; + + return; + +terminate: + dev_info(&priv->spi->dev, "Terminating\n"); + complete(&priv->finished); +} + +static +int spi_slave_system_control_submit(struct spi_slave_system_control_priv *priv) +{ + int ret; + + spi_message_init_with_transfers(&priv->msg, &priv->xfer, 1); + + priv->msg.complete = spi_slave_system_control_complete; + priv->msg.context = priv; + + ret = spi_async(priv->spi, &priv->msg); + if (ret) + dev_err(&priv->spi->dev, "spi_async() failed %d\n", ret); + + return ret; +} + +static int spi_slave_system_control_probe(struct spi_device *spi) +{ + struct spi_slave_system_control_priv *priv; + int ret; + + priv = devm_kzalloc(&spi->dev, sizeof(*priv), GFP_KERNEL); + if (!priv) + return -ENOMEM; + + priv->spi = spi; + init_completion(&priv->finished); + priv->xfer.rx_buf = &priv->cmd; + priv->xfer.len = sizeof(priv->cmd); + + ret = spi_slave_system_control_submit(priv); + if (ret) + return ret; + + spi_set_drvdata(spi, priv); + return 0; +} + +static int spi_slave_system_control_remove(struct spi_device *spi) +{ + struct spi_slave_system_control_priv *priv = spi_get_drvdata(spi); + + spi_slave_abort(spi); + wait_for_completion(&priv->finished); + return 0; +} + +static struct spi_driver spi_slave_system_control_driver = { + .driver = { + .name = "spi-slave-system-control", + }, + .probe = spi_slave_system_control_probe, + .remove = spi_slave_system_control_remove, +}; +module_spi_driver(spi_slave_system_control_driver); + +MODULE_AUTHOR("Geert Uytterhoeven <geert+renesas@glider.be>"); +MODULE_DESCRIPTION("SPI slave handler controlling system state"); +MODULE_LICENSE("GPL v2"); diff --git a/drivers/spi/spi-slave-time.c b/drivers/spi/spi-slave-time.c new file mode 100644 index 000000000000..f2e07a392d68 --- /dev/null +++ b/drivers/spi/spi-slave-time.c @@ -0,0 +1,129 @@ +/* + * SPI slave handler reporting uptime at reception of previous SPI message + * + * This SPI slave handler sends the time of reception of the last SPI message + * as two 32-bit unsigned integers in binary format and in network byte order, + * representing the number of seconds and fractional seconds (in microseconds) + * since boot up. + * + * Copyright (C) 2016-2017 Glider bvba + * + * This file is subject to the terms and conditions of the GNU General Public + * License. See the file "COPYING" in the main directory of this archive + * for more details. + * + * Usage (assuming /dev/spidev2.0 corresponds to the SPI master on the remote + * system): + * + * # spidev_test -D /dev/spidev2.0 -p dummy-8B + * spi mode: 0x0 + * bits per word: 8 + * max speed: 500000 Hz (500 KHz) + * RX | 00 00 04 6D 00 09 5B BB ... + * ^^^^^ ^^^^^^^^ + * seconds microseconds + */ + +#include <linux/completion.h> +#include <linux/module.h> +#include <linux/sched/clock.h> +#include <linux/spi/spi.h> + + +struct spi_slave_time_priv { + struct spi_device *spi; + struct completion finished; + struct spi_transfer xfer; + struct spi_message msg; + __be32 buf[2]; +}; + +static int spi_slave_time_submit(struct spi_slave_time_priv *priv); + +static void spi_slave_time_complete(void *arg) +{ + struct spi_slave_time_priv *priv = arg; + int ret; + + ret = priv->msg.status; + if (ret) + goto terminate; + + ret = spi_slave_time_submit(priv); + if (ret) + goto terminate; + + return; + +terminate: + dev_info(&priv->spi->dev, "Terminating\n"); + complete(&priv->finished); +} + +static int spi_slave_time_submit(struct spi_slave_time_priv *priv) +{ + u32 rem_us; + int ret; + u64 ts; + + ts = local_clock(); + rem_us = do_div(ts, 1000000000) / 1000; + + priv->buf[0] = cpu_to_be32(ts); + priv->buf[1] = cpu_to_be32(rem_us); + + spi_message_init_with_transfers(&priv->msg, &priv->xfer, 1); + + priv->msg.complete = spi_slave_time_complete; + priv->msg.context = priv; + + ret = spi_async(priv->spi, &priv->msg); + if (ret) + dev_err(&priv->spi->dev, "spi_async() failed %d\n", ret); + + return ret; +} + +static int spi_slave_time_probe(struct spi_device *spi) +{ + struct spi_slave_time_priv *priv; + int ret; + + priv = devm_kzalloc(&spi->dev, sizeof(*priv), GFP_KERNEL); + if (!priv) + return -ENOMEM; + + priv->spi = spi; + init_completion(&priv->finished); + priv->xfer.tx_buf = priv->buf; + priv->xfer.len = sizeof(priv->buf); + + ret = spi_slave_time_submit(priv); + if (ret) + return ret; + + spi_set_drvdata(spi, priv); + return 0; +} + +static int spi_slave_time_remove(struct spi_device *spi) +{ + struct spi_slave_time_priv *priv = spi_get_drvdata(spi); + + spi_slave_abort(spi); + wait_for_completion(&priv->finished); + return 0; +} + +static struct spi_driver spi_slave_time_driver = { + .driver = { + .name = "spi-slave-time", + }, + .probe = spi_slave_time_probe, + .remove = spi_slave_time_remove, +}; +module_spi_driver(spi_slave_time_driver); + +MODULE_AUTHOR("Geert Uytterhoeven <geert+renesas@glider.be>"); +MODULE_DESCRIPTION("SPI slave reporting uptime at previous SPI message"); +MODULE_LICENSE("GPL v2"); diff --git a/drivers/spi/spi.c b/drivers/spi/spi.c index bd7a546f5d9b..c3f6b524b3ce 100644 --- a/drivers/spi/spi.c +++ b/drivers/spi/spi.c @@ -1535,15 +1535,6 @@ static int of_spi_parse_dt(struct spi_master *master, struct spi_device *spi, u32 value; int rc; - /* Device address */ - rc = of_property_read_u32(nc, "reg", &value); - if (rc) { - dev_err(&master->dev, "%s has no valid 'reg' property (%d)\n", - nc->full_name, rc); - return rc; - } - spi->chip_select = value; - /* Mode (clock phase/polarity/etc.) */ if (of_find_property(nc, "spi-cpha", NULL)) spi->mode |= SPI_CPHA; @@ -1593,6 +1584,24 @@ static int of_spi_parse_dt(struct spi_master *master, struct spi_device *spi, } } + if (spi_controller_is_slave(master)) { + if (strcmp(nc->name, "slave")) { + dev_err(&master->dev, "%s is not called 'slave'\n", + nc->full_name); + return -EINVAL; + } + return 0; + } + + /* Device address */ + rc = of_property_read_u32(nc, "reg", &value); + if (rc) { + dev_err(&master->dev, "%s has no valid 'reg' property (%d)\n", + nc->full_name, rc); + return rc; + } + spi->chip_select = value; + /* Device speed */ rc = of_property_read_u32(nc, "spi-max-frequency", &value); if (rc) { @@ -1658,8 +1667,8 @@ err_out: * of_register_spi_devices() - Register child devices onto the SPI bus * @master: Pointer to spi_master device * - * Registers an spi_device for each child node of master node which has a 'reg' - * property. + * Registers an spi_device for each child node of controller node which + * represents a valid SPI slave. */ static void of_register_spi_devices(struct spi_master *master) { @@ -1828,28 +1837,129 @@ static struct class spi_master_class = { .dev_groups = spi_master_groups, }; +#ifdef CONFIG_SPI_SLAVE +/** + * spi_slave_abort - abort the ongoing transfer request on an SPI slave + * controller + * @spi: device used for the current transfer + */ +int spi_slave_abort(struct spi_device *spi) +{ + struct spi_master *master = spi->master; + + if (spi_controller_is_slave(master) && master->slave_abort) + return master->slave_abort(master); + + return -ENOTSUPP; +} +EXPORT_SYMBOL_GPL(spi_slave_abort); + +static int match_true(struct device *dev, void *data) +{ + return 1; +} + +static ssize_t spi_slave_show(struct device *dev, + struct device_attribute *attr, char *buf) +{ + struct spi_master *ctlr = container_of(dev, struct spi_master, dev); + struct device *child; + + child = device_find_child(&ctlr->dev, NULL, match_true); + return sprintf(buf, "%s\n", + child ? to_spi_device(child)->modalias : NULL); +} + +static ssize_t spi_slave_store(struct device *dev, + struct device_attribute *attr, const char *buf, + size_t count) +{ + struct spi_master *ctlr = container_of(dev, struct spi_master, dev); + struct spi_device *spi; + struct device *child; + char name[32]; + int rc; + + rc = sscanf(buf, "%31s", name); + if (rc != 1 || !name[0]) + return -EINVAL; + + child = device_find_child(&ctlr->dev, NULL, match_true); + if (child) { + /* Remove registered slave */ + device_unregister(child); + put_device(child); + } + + if (strcmp(name, "(null)")) { + /* Register new slave */ + spi = spi_alloc_device(ctlr); + if (!spi) + return -ENOMEM; + + strlcpy(spi->modalias, name, sizeof(spi->modalias)); + + rc = spi_add_device(spi); + if (rc) { + spi_dev_put(spi); + return rc; + } + } + + return count; +} + +static DEVICE_ATTR(slave, 0644, spi_slave_show, spi_slave_store); + +static struct attribute *spi_slave_attrs[] = { + &dev_attr_slave.attr, + NULL, +}; + +static const struct attribute_group spi_slave_group = { + .attrs = spi_slave_attrs, +}; + +static const struct attribute_group *spi_slave_groups[] = { + &spi_master_statistics_group, + &spi_slave_group, + NULL, +}; + +static struct class spi_slave_class = { + .name = "spi_slave", + .owner = THIS_MODULE, + .dev_release = spi_master_release, + .dev_groups = spi_slave_groups, +}; +#else +extern struct class spi_slave_class; /* dummy */ +#endif /** - * spi_alloc_master - allocate SPI master controller + * __spi_alloc_controller - allocate an SPI master or slave controller * @dev: the controller, possibly using the platform_bus * @size: how much zeroed driver-private data to allocate; the pointer to this * memory is in the driver_data field of the returned device, * accessible with spi_master_get_devdata(). + * @slave: flag indicating whether to allocate an SPI master (false) or SPI + * slave (true) controller * Context: can sleep * - * This call is used only by SPI master controller drivers, which are the + * This call is used only by SPI controller drivers, which are the * only ones directly touching chip registers. It's how they allocate * an spi_master structure, prior to calling spi_register_master(). * * This must be called from context that can sleep. * - * The caller is responsible for assigning the bus number and initializing - * the master's methods before calling spi_register_master(); and (after errors + * The caller is responsible for assigning the bus number and initializing the + * controller's methods before calling spi_register_master(); and (after errors * adding the device) calling spi_master_put() to prevent a memory leak. * - * Return: the SPI master structure on success, else NULL. + * Return: the SPI controller structure on success, else NULL. */ -struct spi_master *spi_alloc_master(struct device *dev, unsigned size) +struct spi_master *__spi_alloc_controller(struct device *dev, + unsigned int size, bool slave) { struct spi_master *master; @@ -1863,14 +1973,18 @@ struct spi_master *spi_alloc_master(struct device *dev, unsigned size) device_initialize(&master->dev); master->bus_num = -1; master->num_chipselect = 1; - master->dev.class = &spi_master_class; + master->slave = slave; + if (IS_ENABLED(CONFIG_SPI_SLAVE) && slave) + master->dev.class = &spi_slave_class; + else + master->dev.class = &spi_master_class; master->dev.parent = dev; pm_suspend_ignore_children(&master->dev, true); spi_master_set_devdata(master, &master[1]); return master; } -EXPORT_SYMBOL_GPL(spi_alloc_master); +EXPORT_SYMBOL_GPL(__spi_alloc_controller); #ifdef CONFIG_OF static int of_spi_register_master(struct spi_master *master) @@ -1946,9 +2060,11 @@ int spi_register_master(struct spi_master *master) if (!dev) return -ENODEV; - status = of_spi_register_master(master); - if (status) - return status; + if (!spi_controller_is_slave(master)) { + status = of_spi_register_master(master); + if (status) + return status; + } /* even if it's just one always-selected device, there must * be at least one chipselect @@ -1985,8 +2101,9 @@ int spi_register_master(struct spi_master *master) status = device_add(&master->dev); if (status < 0) goto done; - dev_dbg(dev, "registered master %s%s\n", dev_name(&master->dev), - dynamic ? " (dynamic)" : ""); + dev_dbg(dev, "registered %s %s%s\n", + spi_controller_is_slave(master) ? "slave" : "master", + dev_name(&master->dev), dynamic ? " (dynamic)" : ""); /* If we're using a queued driver, start the queue */ if (master->transfer) @@ -2021,7 +2138,7 @@ static void devm_spi_unregister(struct device *dev, void *res) } /** - * dev_spi_register_master - register managed SPI master controller + * devm_spi_register_master - register managed SPI master controller * @dev: device managing SPI master * @master: initialized master, originally from spi_alloc_master() * Context: can sleep @@ -3159,6 +3276,9 @@ static struct spi_master *of_find_spi_master_by_node(struct device_node *node) dev = class_find_device(&spi_master_class, NULL, node, __spi_of_master_match); + if (!dev && IS_ENABLED(CONFIG_SPI_SLAVE)) + dev = class_find_device(&spi_slave_class, NULL, node, + __spi_of_master_match); if (!dev) return NULL; @@ -3240,6 +3360,9 @@ static struct spi_master *acpi_spi_find_master_by_adev(struct acpi_device *adev) dev = class_find_device(&spi_master_class, NULL, adev, spi_acpi_master_match); + if (!dev && IS_ENABLED(CONFIG_SPI_SLAVE)) + dev = class_find_device(&spi_slave_class, NULL, adev, + spi_acpi_master_match); if (!dev) return NULL; @@ -3312,6 +3435,12 @@ static int __init spi_init(void) if (status < 0) goto err2; + if (IS_ENABLED(CONFIG_SPI_SLAVE)) { + status = class_register(&spi_slave_class); + if (status < 0) + goto err3; + } + if (IS_ENABLED(CONFIG_OF_DYNAMIC)) WARN_ON(of_reconfig_notifier_register(&spi_of_notifier)); if (IS_ENABLED(CONFIG_ACPI)) @@ -3319,6 +3448,8 @@ static int __init spi_init(void) return 0; +err3: + class_unregister(&spi_master_class); err2: bus_unregister(&spi_bus_type); err1: |