>From d429aaa794f8d578501c13fed3eae28e50049b1f Mon Sep 17 00:00:00 2001 From: Ken Mills <[email protected]> Date: Wed, 16 Dec 2009 17:44:54 -0800 Subject: [PATCH] Add support for slave controllers plus sysfs entries for power management
Signed-off-by: Ken Mills <[email protected]> --- drivers/spi/Kconfig | 12 ++ drivers/spi/spi.c | 402 +++++++++++++++++++++++++++++++++++++++++++++-- include/linux/spi/spi.h | 83 ++++++++++- 3 files changed, 482 insertions(+), 15 deletions(-) diff --git a/drivers/spi/Kconfig b/drivers/spi/Kconfig index 4b6f7cb..d1124b3 100644 --- a/drivers/spi/Kconfig +++ b/drivers/spi/Kconfig @@ -278,6 +278,18 @@ config SPI_TLE62X0 endif # SPI_MASTER + config SPI_SLAVE + bool "SPI Slave support" + help + This will enable SPI slave controller support. In this mode, clock + and frame are provided by the SPI master controller. + +if SPI_SLAVE + +comment "SPI SLAVE Controller Drivers" + # (slave support would go here) +endif # SPI_SLAVE + endif # SPI diff --git a/drivers/spi/spi.c b/drivers/spi/spi.c index b76f246..9a2a5c9 100644 --- a/drivers/spi/spi.c +++ b/drivers/spi/spi.c @@ -36,10 +36,21 @@ static void spidev_release(struct device *dev) struct spi_device *spi = to_spi_device(dev); /* spi masters may cleanup for released devices */ - if (spi->master->cleanup) - spi->master->cleanup(spi); + if (spi->master) { + if (spi->master->cleanup) + spi->master->cleanup(spi); - spi_master_put(spi->master); + spi_master_put(spi->master); + } + +#ifdef CONFIG_SPI_SLAVE + if (spi->slave) { + if (spi->slave->cleanup) + spi->slave->cleanup(spi); + + spi_slave_put(spi->slave); + } +#endif kfree(dev); } @@ -129,6 +140,73 @@ static int spi_resume(struct device *dev) } return value; } +static const char power_group[] = "power"; +static const char on_string[] = "on"; +static const char suspend_string[] = "suspend"; + +static ssize_t +show_level(struct device *s_dev, struct device_attribute *attr, char *buf) +{ + struct spi_device *dev = to_spi_device(s_dev); + const char *p; + + if (dev->state == SPI_STATE_ON) + p = on_string; /* ON or Active */ + else + p = suspend_string; /* Suspended */ + + return sprintf(buf, "%s\n", p); +} + +static ssize_t +set_level(struct device *s_dev, struct device_attribute *attr, + const char *buf, size_t count) +{ + struct spi_device *dev = to_spi_device(s_dev); + int len = count; + char *cp; + int rc = 0; + + cp = memchr(buf, '\n', count); + if (cp) + len = cp - buf; + + if (len == sizeof on_string - 1 && + strncmp(buf, on_string, len) == 0) { + + spi_resume(s_dev); /* Turn ON SPI Device */ + dev->state = SPI_STATE_ON; /* Save new State */ + + } else if (len == sizeof suspend_string - 1 && + strncmp(buf, suspend_string, len) == 0) { + + spi_suspend(s_dev, PMSG_SUSPEND); /*Suspend SPI Device*/ + dev->state = SPI_STATE_SUSPENDED; /* Save new State */ + + } else + rc = -EINVAL; + + return (rc < 0 ? rc : count); +} + +static DEVICE_ATTR(level, S_IRUGO | S_IWUSR, show_level, set_level); + +static int add_power_attributes(struct device *dev) +{ + int rc = 0; + + rc = sysfs_add_file_to_group(&dev->kobj, + &dev_attr_level.attr, + power_group); + return rc; +} + +static void remove_power_attributes(struct device *dev) +{ + sysfs_remove_file_from_group(&dev->kobj, + &dev_attr_level.attr, + power_group); +} #else #define spi_suspend NULL @@ -150,13 +228,21 @@ static int spi_drv_probe(struct device *dev) { const struct spi_driver *sdrv = to_spi_driver(dev->driver); +#ifdef CONFIG_PM + struct spi_device *sdev = to_spi_device(dev); + if (add_power_attributes(dev)) + remove_power_attributes(dev); + sdev->state = SPI_STATE_ON; /* By default set ON*/ +#endif return sdrv->probe(to_spi_device(dev)); } static int spi_drv_remove(struct device *dev) { const struct spi_driver *sdrv = to_spi_driver(dev->driver); - +#ifdef CONFIG_PM + remove_power_attributes(dev); +#endif return sdrv->remove(to_spi_device(dev)); } @@ -181,6 +267,11 @@ int spi_register_driver(struct spi_driver *sdrv) sdrv->driver.remove = spi_drv_remove; if (sdrv->shutdown) sdrv->driver.shutdown = spi_drv_shutdown; + if (sdrv->suspend) + sdrv->driver.suspend = spi_suspend; + if (sdrv->resume) + sdrv->driver.resume = spi_resume; + return driver_register(&sdrv->driver); } EXPORT_SYMBOL_GPL(spi_register_driver); @@ -235,6 +326,7 @@ struct spi_device *spi_alloc_device(struct spi_master *master) } spi->master = master; + spi->slave = NULL; spi->dev.parent = dev; spi->dev.bus = &spi_bus_type; spi->dev.release = spidev_release; @@ -255,21 +347,31 @@ EXPORT_SYMBOL_GPL(spi_alloc_device); int spi_add_device(struct spi_device *spi) { static DEFINE_MUTEX(spi_add_lock); - struct device *dev = spi->master->dev.parent; + struct device *dev = NULL; int status; - /* Chipselects are numbered 0..max; validate. */ - if (spi->chip_select >= spi->master->num_chipselect) { - dev_err(dev, "cs%d >= max %d\n", - spi->chip_select, - spi->master->num_chipselect); - return -EINVAL; - } - + if (spi->master) { + dev = spi->master->dev.parent; + /* Chipselects are numbered 0..max; validate. */ + if (spi->chip_select >= spi->master->num_chipselect) { + dev_err(dev, "cs%d >= max %d\n", + spi->chip_select, + spi->master->num_chipselect); + return -EINVAL; + } /* Set the bus ID string */ dev_set_name(&spi->dev, "%s.%u", dev_name(&spi->master->dev), spi->chip_select); + } +#ifdef CONFIG_SPI_SLAVE + if (spi->slave) { + dev = spi->slave->dev.parent; + /* Set the bus ID string */ + dev_set_name(&spi->dev, "%s.%u", dev_name(&spi->slave->dev), + spi->chip_select); + } +#endif /* We need to make sure there's no other device with this * chipselect **BEFORE** we call setup(), else we'll trash @@ -604,6 +706,262 @@ struct spi_master *spi_busnum_to_master(u16 bus_num) } EXPORT_SYMBOL_GPL(spi_busnum_to_master); +#ifdef CONFIG_SPI_SLAVE +/** +* spi_slave_new_device - instantiate one new SPI device +* @slave: Controller to which device is connected +* @chip: Describes the SPI device +* Context: can sleep +* +* On typical mainboards, this is purely internal; and it's not needed +* after board init creates the hard-wired devices. Some development +* platforms may not be able to use spi_register_board_info though, and +* this is exported so that for example a USB or parport based adapter +* driver could add devices (which it would learn about out-of-band). +* +* Returns the new device, or NULL. +*/ +struct spi_device *spi_slave_new_device(struct spi_slave *slave, + struct spi_board_info *chip) +{ + struct spi_device *proxy_slave; + int status; + + proxy_slave = spi_alloc_slave_device(slave); + + if (!proxy_slave) + return NULL; + + WARN_ON(strlen(chip->modalias) >= sizeof(proxy_slave->modalias)); + + proxy_slave->chip_select = chip->chip_select; + proxy_slave->max_speed_hz = chip->max_speed_hz; + proxy_slave->mode = chip->mode; + proxy_slave->irq = chip->irq; + strlcpy(proxy_slave->modalias, chip->modalias, + sizeof(proxy_slave->modalias)); + proxy_slave->dev.platform_data = (void *) chip->platform_data; + proxy_slave->controller_data = chip->controller_data; + proxy_slave->controller_state = NULL; + + status = spi_add_device(proxy_slave); + if (status < 0) { + spi_dev_put(proxy_slave); + return NULL; + } + + return proxy_slave; +} +EXPORT_SYMBOL_GPL(spi_slave_new_device); + + +static void spi_slave_scan_boardinfo(struct spi_slave *slave) +{ + struct boardinfo *bi; + + mutex_lock(&board_lock); + list_for_each_entry(bi, &board_list, list) { + struct spi_board_info *chip = bi->board_info; + unsigned n; + + for (n = bi->n_board_info; n > 0; n--, chip++) { + if (chip->bus_num != slave->bus_num) + continue; + /* NOTE: this relies on spi_new_device to + * issue diagnostics when given bogus inputs + */ + (void) spi_slave_new_device(slave, chip); + + } + } + mutex_unlock(&board_lock); +} + +static void spi_slave_release(struct device *dev) +{ + struct spi_slave *slave; + + slave = container_of(dev, struct spi_slave, dev); + kfree(slave); +} + +static struct class spi_slave_class = { + .name = "spi_slave", + .owner = THIS_MODULE, + .dev_release = spi_slave_release, +}; + + + + + +/** +* spi_alloc_slave - allocate SPI 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_slave_get_devdata(). +* Context: can sleep +* +* This call is used only by SPI master 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_slave(). +* +* This must be called from context that can sleep. It returns the SPI +* master structure on success, else NULL. +* +* The caller is responsible for assigning the bus number and initializing +* the master's methods before calling spi_register_slave(); and (after errors +* adding the device) calling spi_slave_put() to prevent a memory leak. +*/ +struct spi_slave *spi_alloc_slave(struct device *dev, unsigned size) +{ + struct spi_slave *slave; + + if (!dev) + return NULL; + + slave = kzalloc(size + sizeof *slave, GFP_KERNEL); + if (!slave) + return NULL; + + device_initialize(&slave->dev); + slave->dev.class = &spi_slave_class; + slave->dev.parent = get_device(dev); + spi_slave_set_devdata(slave, &slave[1]); + + return slave; +} +EXPORT_SYMBOL_GPL(spi_alloc_slave); + + +/* +* spi_alloc_slave_device - Allocate a new SPI device +* @slave: Controller to which device is connected +* Context: can sleep +* +* Allows a driver to allocate and initialize a spi_device without +* registering it immediately. This allows a driver to directly +* fill the spi_device with device parameters before calling +* spi_add_slave_device() on it. +* +* Caller is responsible to call spi_add_slave_device() on the returned +* spi_device structure to add it to the SPI slave. If the caller +* needs to discard the spi_device without adding it, then it should +* call spi_dev_slave_put() on it. +* Returns a pointer to the new device, or NULL. +*/ +struct spi_device *spi_alloc_slave_device(struct spi_slave *slave) +{ + struct spi_device *spi_s; + struct device *dev = slave->dev.parent; + + if (!spi_slave_get(slave)) + return NULL; + + spi_s = kzalloc(sizeof *spi_s, GFP_KERNEL); + if (!spi_s) { + dev_err(dev, "cannot alloc spi_slave_device\n"); + spi_slave_put(slave); + return NULL; + } + + spi_s->slave = slave; + spi_s->master = NULL; + spi_s->dev.parent = dev; + spi_s->dev.bus = &spi_bus_type; + spi_s->dev.release = spidev_release; + device_initialize(&spi_s->dev); + return spi_s; +} +EXPORT_SYMBOL_GPL(spi_alloc_slave_device); + + +/** +* spi_register_slave - register SPI slave controller +* @master: initialized master, originally from spi_alloc_slave() +* Context: can sleep +* +* SPI slave controllers connect to their drivers using some non-SPI bus, +* such as the platform bus. The final stage of probe() in that code +* includes calling spi_register_slave() to hook up to this SPI bus glue. +* +* SPI controllers use board specific (often SOC specific) bus numbers, +* and board-specific addressing for SPI devices combines those numbers +* with chip select numbers. Since SPI does not directly support dynamic +* device identification, boards need configuration tables telling which +* chip is at which address. +* +* This must be called from context that can sleep. It returns zero on +* success, else a negative error code (dropping the slave's refcount). +* After a successful return, the caller is responsible for calling +* spi_unregister_slave(). +*/ +int spi_register_slave(struct spi_slave *slave) +{ + static atomic_t dyn_bus_id = ATOMIC_INIT((1<<15) - 1); + struct device *dev = slave->dev.parent; + int status = -ENODEV; + int dynamic = 0; + + if (!dev) + return -ENODEV; + + /* even if it's just one always-selected device, there must + * be at least one chipselect + */ + if (slave->num_chipselect == 0) + return -EINVAL; + + /* convention: dynamically assigned bus IDs count down from the max */ + if (slave->bus_num < 0) { + /* FIXME switch to an IDR based scheme, something like + * I2C now uses, so we can't run out of "dynamic" IDs + */ + slave->bus_num = atomic_dec_return(&dyn_bus_id); + dynamic = 1; + } + + /* register the device, then userspace will see it. + * registration fails if the bus ID is in use. + */ + dev_set_name(&slave->dev, "spi%u", slave->bus_num); + status = device_add(&slave->dev); + if (status < 0) + goto done; + + dev_dbg(dev, "registered slave %s%s\n", dev_name(&slave->dev), + dynamic ? " (dynamic)" : ""); + + /* populate children from any spi device tables */ + spi_slave_scan_boardinfo(slave); + status = 0; +done: + return status; +} +EXPORT_SYMBOL_GPL(spi_register_slave); + +/** +* spi_unregister_slave - unregister SPI slave controller +* @master: the slave being unregistered +* Context: can sleep +* +* This call is used only by SPI slave controller drivers, which are the +* only ones directly touching chip registers. +* +* This must be called from context that can sleep. +*/ +void spi_unregister_slave(struct spi_slave *slave) +{ + int dummy; + + dummy = device_for_each_child(slave->dev.parent, &slave->dev, + __unregister); + device_unregister(&slave->dev); +} +EXPORT_SYMBOL_GPL(spi_unregister_slave); + +#endif /*-------------------------------------------------------------------------*/ @@ -634,6 +992,11 @@ int spi_setup(struct spi_device *spi) unsigned bad_bits; int status; +#ifdef CONFIG_SPI_SLAVE + if (spi->slave) + return spi->slave->setup(spi); +#endif + /* help drivers fail *cleanly* when they need options * that aren't supported with their current master */ @@ -695,7 +1058,15 @@ EXPORT_SYMBOL_GPL(spi_setup); int spi_async(struct spi_device *spi, struct spi_message *message) { struct spi_master *master = spi->master; +#ifdef CONFIG_SPI_SLAVE + struct spi_slave *slave = spi->slave; + if (slave) { + message->spi = spi; + message->status = -EINPROGRESS; + return slave->transfer(spi, message); + } +#endif /* Half-duplex links include original MicroWire, and ones with * only one data pin like SPI_3WIRE (switches direction) or where * either MOSI or MISO is missing. They can also be caused by @@ -871,6 +1242,11 @@ static int __init spi_init(void) status = class_register(&spi_master_class); if (status < 0) goto err2; +#ifdef CONFIG_SPI_SLAVE + status = class_register(&spi_slave_class); + if (status < 0) + goto err2; +#endif return 0; err2: diff --git a/include/linux/spi/spi.h b/include/linux/spi/spi.h index 97b60b3..98781a7 100644 --- a/include/linux/spi/spi.h +++ b/include/linux/spi/spi.h @@ -23,15 +23,26 @@ #include <linux/mod_devicetable.h> /* - * INTERFACES between SPI master-side drivers and SPI infrastructure. - * (There's no SPI slave support for Linux yet...) + * INTERFACES between SPI Master/Slave side drivers and + * SPI infrastructure. + * SPI Slave Support added : It uses few new APIs and + * a new spi_slave struct */ extern struct bus_type spi_bus_type; +/* SPI Device State for power managment */ +enum spi_device_state { + + SPI_STATE_SUSPENDED = 0, + SPI_STATE_ON + +}; + /** * struct spi_device - Master side proxy for an SPI slave device * @dev: Driver model representation of the device. * @master: SPI controller used with the device. + * @slave: SPI Slave Controller used with the device * @max_speed_hz: Maximum clock rate to be used with this chip * (on this board); may be changed by the device's driver. * The spi_transfer.speed_hz can override this for each transfer. @@ -68,6 +79,8 @@ extern struct bus_type spi_bus_type; struct spi_device { struct device dev; struct spi_master *master; + struct spi_slave *slave; + enum spi_device_state state; u32 max_speed_hz; u8 chip_select; u8 mode; @@ -295,16 +308,56 @@ struct spi_master { void (*cleanup)(struct spi_device *spi); }; +/** + * struct spi_slave - interface to SPI Slave Controller + * @dev: device interface to this driver + * @bus_num: board-specific (and often SOC-specific) identifier for a + * given SPI controller. + * @num_chipselect: chipselects are used to distinguish individual + * SPI slaves, and are numbered from zero to num_chipselects. + * each slave has a chipselect signal, but it's common that not + * every chipselect is connected to a slave. + * @setup: updates the device mode and clocking records used by a + * device's SPI controller; protocol code may call this. This + * must fail if an unrecognized or unsupported mode is requested. + * It's always safe to call this unless transfers are pending on + * the device whose settings are being modified. + * @transfer: adds a message to the controller's transfer queue. + * @cleanup: frees controller-specific state + */ +struct spi_slave { + struct device dev; + s16 bus_num; + u16 num_chipselect; + + int (*setup)(struct spi_device *spi); + + int (*transfer)(struct spi_device *spi, + struct spi_message *mesg); + + void (*cleanup)(struct spi_device *spi); +}; + static inline void *spi_master_get_devdata(struct spi_master *master) { return dev_get_drvdata(&master->dev); } +static inline void *spi_slave_get_devdata(struct spi_slave *slave) +{ + return dev_get_drvdata(&slave->dev); +} + static inline void spi_master_set_devdata(struct spi_master *master, void *data) { dev_set_drvdata(&master->dev, data); } +static inline void spi_slave_set_devdata(struct spi_slave *slave, void *data) +{ + dev_set_drvdata(&slave->dev, data); +} + static inline struct spi_master *spi_master_get(struct spi_master *master) { if (!master || !get_device(&master->dev)) @@ -312,12 +365,24 @@ static inline struct spi_master *spi_master_get(struct spi_master *master) return master; } +static inline struct spi_slave *spi_slave_get(struct spi_slave *slave) +{ + if (!slave || !get_device(&slave->dev)) + return NULL; + return slave; +} + static inline void spi_master_put(struct spi_master *master) { if (master) put_device(&master->dev); } +static inline void spi_slave_put(struct spi_slave *slave) +{ + if (slave) + put_device(&slave->dev); +} /* the spi driver core manages memory for the spi_master classdev */ extern struct spi_master * @@ -328,6 +393,11 @@ extern void spi_unregister_master(struct spi_master *master); extern struct spi_master *spi_busnum_to_master(u16 busnum); +extern struct spi_slave * +spi_alloc_slave(struct device *host, unsigned size); + +extern int spi_register_slave(struct spi_slave *slave); +extern void spi_unregister_slave(struct spi_slave *slave); /*---------------------------------------------------------------------------*/ /* @@ -759,12 +829,21 @@ spi_register_board_info(struct spi_board_info const *info, unsigned n) extern struct spi_device * spi_alloc_device(struct spi_master *master); +extern struct spi_device * +spi_alloc_slave_device(struct spi_slave *slave); + extern int spi_add_device(struct spi_device *spi); +extern int +spi_add_slave_device(struct spi_device *spi); + extern struct spi_device * spi_new_device(struct spi_master *, struct spi_board_info *); +extern struct spi_device * +spi_slave_new_device(struct spi_slave *, struct spi_board_info *); + static inline void spi_unregister_device(struct spi_device *spi) { -- 1.5.4.3 ------------------------------------------------------------------------------ This SF.Net email is sponsored by the Verizon Developer Community Take advantage of Verizon's best-in-class app development support A streamlined, 14 day to market process makes app distribution fast and easy Join now and get one step closer to millions of Verizon customers http://p.sf.net/sfu/verizon-dev2dev _______________________________________________ spi-devel-general mailing list [email protected] https://lists.sourceforge.net/lists/listinfo/spi-devel-general
