diff options
Diffstat (limited to 'drivers/w1/slaves/w1_ds2438.c')
| -rw-r--r-- | drivers/w1/slaves/w1_ds2438.c | 204 |
1 files changed, 204 insertions, 0 deletions
diff --git a/drivers/w1/slaves/w1_ds2438.c b/drivers/w1/slaves/w1_ds2438.c new file mode 100644 index 000000000000..4212117d9424 --- /dev/null +++ b/drivers/w1/slaves/w1_ds2438.c @@ -0,0 +1,204 @@ +/* + * Copyright 2008-2010 Freescale Semiconductor, Inc. All Rights Reserved. + */ +/* + * The code contained herein is licensed under the GNU General Public + * License. You may obtain a copy of the GNU General Public License + * Version 2 or later at the following locations: + * + * http://www.opensource.org/licenses/gpl-license.html + * http://www.gnu.org/copyleft/gpl.html + */ + +#include <linux/types.h> +#include <linux/kernel.h> +#include <linux/types.h> +#include <linux/module.h> +#include <linux/device.h> +#include <linux/platform_device.h> +#include <linux/mutex.h> +#include <linux/slab.h> +#include <linux/err.h> +#include <linux/idr.h> + +#include "../w1.h" +#include "../w1_int.h" +#include "../w1_family.h" +#include "w1_ds2438.h" + +/* W1 slave DS2438 famliy operations */ +int w1_ds2438_read_page(struct device *dev, u8 page, u8 *buf) +{ + struct w1_slave *slave = container_of(dev, struct w1_slave, dev); + if ((page >= DS2438_PAGE_NUM) || (buf == NULL)) + return -EINVAL; + + mutex_lock(&slave->master->mutex); + if (!w1_reset_select_slave(slave)) { + w1_write_8(slave->master, W1_READ_SCRATCHPAD); + w1_write_8(slave->master, page); + w1_read_block(slave->master, buf, DS2438_PAGE_SIZE); + } + mutex_unlock(&slave->master->mutex); + return 0; +} +EXPORT_SYMBOL(w1_ds2438_read_page); + +int w1_ds2438_write_page(struct device *dev, u8 page, u8 *buf) +{ + struct w1_slave *slave = container_of(dev, struct w1_slave, dev); + if ((page >= DS2438_PAGE_NUM) || (buf == NULL)) + return -EINVAL; + + mutex_lock(&slave->master->mutex); + if (!w1_reset_select_slave(slave)) { + w1_write_8(slave->master, DS2438_WRITE_SCRATCHPAD); + w1_write_8(slave->master, page); + w1_write_block(slave->master, buf, DS2438_PAGE_SIZE); + } + mutex_unlock(&slave->master->mutex); + return 0; +} +EXPORT_SYMBOL(w1_ds2438_write_page); + +int w1_ds2438_command(struct device *dev, u8 command, u8 data) +{ + struct w1_slave *slave = container_of(dev, struct w1_slave, dev); + + mutex_lock(&slave->master->mutex); + if (!w1_reset_select_slave(slave)) { + w1_write_8(slave->master, command); + switch (command) { + case DS2438_COPY_SCRATCHPAD: + case DS2438_RECALL_MEMORY: + w1_write_8(slave->master, data); + } + } + mutex_unlock(&slave->master->mutex); + return 0; +} +EXPORT_SYMBOL(w1_ds2438_command); + +int w1_ds2438_drain_sram(struct device *dev, u8 page) +{ + return w1_ds2438_command(dev, DS2438_COPY_SCRATCHPAD, page); +} +EXPORT_SYMBOL(w1_ds2438_drain_sram); + +int w1_ds2438_load_sram(struct device *dev, u8 page) +{ + return w1_ds2438_command(dev, DS2438_RECALL_MEMORY, page); +} +EXPORT_SYMBOL(w1_ds2438_load_sram); + +static DEFINE_IDR(bat_idr); +static DEFINE_MUTEX(bat_idr_lock); + +static int new_bat_id(void) +{ + int ret; + + while (1) { + int id; + + ret = idr_pre_get(&bat_idr, GFP_KERNEL); + if (ret == 0) + return -ENOMEM; + + mutex_lock(&bat_idr_lock); + ret = idr_get_new(&bat_idr, NULL, &id); + mutex_unlock(&bat_idr_lock); + + if (ret == 0) { + ret = id & MAX_ID_MASK; + break; + } else if (ret == -EAGAIN) { + continue; + } else { + break; + } + } + + return ret; +} + +static void release_bat_id(int id) +{ + mutex_lock(&bat_idr_lock); + idr_remove(&bat_idr, id); + mutex_unlock(&bat_idr_lock); +} + +static int ds2438_add_slave(struct w1_slave *slave) +{ + int ret; + int id; + struct platform_device *pdev; + + id = new_bat_id(); + if (id < 0) { + ret = id; + goto noid; + } + + pdev = platform_device_alloc(DS2438_DEV_NAME, id); + if (!pdev) { + ret = -ENOMEM; + goto pdev_alloc_failed; + } + pdev->dev.parent = &slave->dev; + + ret = platform_device_add(pdev); + if (ret) + goto pdev_add_failed; + + dev_set_drvdata(&slave->dev, pdev); + goto success; + +pdev_add_failed: + platform_device_unregister(pdev); +pdev_alloc_failed: + release_bat_id(id); +noid: +success: + return ret; +} + +static void ds2438_remove_slave(struct w1_slave *slave) +{ + struct platform_device *pdev = dev_get_drvdata(&slave->dev); + int id = pdev->id; + + platform_device_unregister(pdev); + release_bat_id(id); +} + +static struct w1_family_ops w1_ds2438_fops = { + .add_slave = ds2438_add_slave, + .remove_slave = ds2438_remove_slave, +}; + +static struct w1_family w1_family_ds2438 = { + .fid = W1_FAMILY_DS2438, + .fops = &w1_ds2438_fops, +}; + +static int __init w1_ds2438_init(void) +{ + pr_info("1-wire driver for the DS2438 smart battery monitor\n"); + idr_init(&bat_idr); + return w1_register_family(&w1_family_ds2438); +} + +static void __exit w1_ds2438_fini(void) +{ + w1_unregister_family(&w1_family_ds2438); + idr_destroy(&bat_idr); +} + +module_init(w1_ds2438_init); +module_exit(w1_ds2438_fini); + +MODULE_LICENSE("GPL"); +MODULE_AUTHOR("Freescale Semiconductors Inc"); +MODULE_DESCRIPTION("1-wire DS2438 family, smart battery monitor."); |