/* * 1-Wire implementation for the ds2781 chip * * Author: Renata Sayakhova * * Based on w1-ds2780 driver * * This program is free software; you can redistribute it and/or modify * it under the terms of the GNU General Public License version 2 as * published by the Free Software Foundation. * */ #include #include #include #include #include #include #include "../w1.h" #include "../w1_int.h" #include "../w1_family.h" #include "w1_ds2781.h" static int w1_ds2781_do_io(struct device *dev, char *buf, int addr, size_t count, int io) { struct w1_slave *sl = container_of(dev, struct w1_slave, dev); if (addr > DS2781_DATA_SIZE || addr < 0) return 0; count = min_t(int, count, DS2781_DATA_SIZE - addr); if (w1_reset_select_slave(sl) == 0) { if (io) { w1_write_8(sl->master, W1_DS2781_WRITE_DATA); w1_write_8(sl->master, addr); w1_write_block(sl->master, buf, count); } else { w1_write_8(sl->master, W1_DS2781_READ_DATA); w1_write_8(sl->master, addr); count = w1_read_block(sl->master, buf, count); } } return count; } int w1_ds2781_io(struct device *dev, char *buf, int addr, size_t count, int io) { struct w1_slave *sl = container_of(dev, struct w1_slave, dev); int ret; if (!dev) return -ENODEV; mutex_lock(&sl->master->bus_mutex); ret = w1_ds2781_do_io(dev, buf, addr, count, io); mutex_unlock(&sl->master->bus_mutex); return ret; } EXPORT_SYMBOL(w1_ds2781_io); int w1_ds2781_eeprom_cmd(struct device *dev, int addr, int cmd) { struct w1_slave *sl = container_of(dev, struct w1_slave, dev); if (!dev) return -EINVAL; mutex_lock(&sl->master->bus_mutex); if (w1_reset_select_slave(sl) == 0) { w1_write_8(sl->master, cmd); w1_write_8(sl->master, addr); } mutex_unlock(&sl->master->bus_mutex); return 0; } EXPORT_SYMBOL(w1_ds2781_eeprom_cmd); static ssize_t w1_slave_read(struct file *filp, struct kobject *kobj, struct bin_attribute *bin_attr, char *buf, loff_t off, size_t count) { struct device *dev = container_of(kobj, struct device, kobj); return w1_ds2781_io(dev, buf, off, count, 0); } static BIN_ATTR_RO(w1_slave, DS2781_DATA_SIZE); static struct bin_attribute *w1_ds2781_bin_attrs[] = { &bin_attr_w1_slave, NULL, }; static const struct attribute_group w1_ds2781_group = { .bin_attrs = w1_ds2781_bin_attrs, }; static const struct attribute_group *w1_ds2781_groups[] = { &w1_ds2781_group, NULL, }; static int w1_ds2781_add_slave(struct w1_slave *sl) { int ret; struct platform_device *pdev; pdev = platform_device_alloc("ds2781-battery", PLATFORM_DEVID_AUTO); if (!pdev) return -ENOMEM; pdev->dev.parent = &sl->dev; ret = platform_device_add(pdev); if (ret) goto pdev_add_failed; dev_set_drvdata(&sl->dev, pdev); return 0; pdev_add_failed: platform_device_put(pdev); return ret; } static void w1_ds2781_remove_slave(struct w1_slave *sl) { struct platform_device *pdev = dev_get_drvdata(&sl->dev); platform_device_unregister(pdev); } static struct w1_family_ops w1_ds2781_fops = { .add_slave = w1_ds2781_add_slave, .remove_slave = w1_ds2781_remove_slave, .groups = w1_ds2781_groups, }; static struct w1_family w1_ds2781_family = { .fid = W1_FAMILY_DS2781, .fops = &w1_ds2781_fops, }; module_w1_family(w1_ds2781_family); MODULE_LICENSE("GPL"); MODULE_AUTHOR("Renata Sayakhova "); MODULE_DESCRIPTION("1-wire Driver for Maxim/Dallas DS2781 Stand-Alone Fuel Gauge IC"); MODULE_ALIAS("w1-family-" __stringify(W1_FAMILY_DS2781)); This reverts commit c7070619f3408d9a0dffbed9149e6f00479cf43b. This has been shown to regress on some ARM systems: by forcing on DMA API usage for ARM systems, we have inadvertently kicked open a hornets' nest in terms of cache-coherency. Namely that unless the virtio device is explicitly described as capable of coherent DMA by firmware, the DMA APIs on ARM and other DT-based platforms will assume it is non-coherent. This turns out to cause a big problem for the likes of QEMU and kvmtool, which generate virtio-mmio devices in their guest DTs but neglect to add the often-overlooked "dma-coherent" property; as a result, we end up with the guest making non-cacheable accesses to the vring, the host doing so cacheably, both talking past each other and things going horribly wrong. We are working on a safer work-around. Fixes: c7070619f340 ("vring: Force use of DMA API for ARM-based systems with legacy devices") Reported-by: Robin Murphy <robin.murphy@arm.com> Cc: <stable@vger.kernel.org> Signed-off-by: Will Deacon <will.deacon@arm.com> Signed-off-by: Michael S. Tsirkin <mst@redhat.com> Acked-by: Marc Zyngier <marc.zyngier@arm.com> 2017-01-29Linux 4.10-rc6Linus Torvalds1-2/+2 2017-01-29drm/i915: Check for NULL i915_vma in intel_unpin_fb_obj()Linus Torvalds