From bde68e60b18208978c50c6fb9bdf29826d2887f3 Mon Sep 17 00:00:00 2001 From: MyungJoo Ham Date: Fri, 20 Apr 2012 14:16:26 +0900 Subject: Extcon: support mutually exclusive relation between cables. There could be cables that t recannot be attaches simulatenously. Extcon device drivers may express such information via mutually_exclusive in struct extcon_dev. For example, for an extcon device with 16 cables (bits 0 to 15 are available), if mutually_exclusive = { 0x7, 0xC0, 0x81, 0 }, then, the following attachments are prohibitted. {0, 1} {0, 2} {1, 2} {6, 7} {0, 7} and every attachment set that are superset of one of the above. For the detail, please refer to linux/include/linux/extcon.h. The concept is suggested by NeilBrown Signed-off-by: MyungJoo Ham Signed-off-by: Kyungmin Park -- Changes from V5: - Updated sysfs format Signed-off-by: Greg Kroah-Hartman --- drivers/extcon/extcon_class.c | 123 +++++++++++++++++++++++++++++++++++++++--- 1 file changed, 115 insertions(+), 8 deletions(-) (limited to 'drivers/extcon') diff --git a/drivers/extcon/extcon_class.c b/drivers/extcon/extcon_class.c index 403933bc3e9..3bc4b8af46c 100644 --- a/drivers/extcon/extcon_class.c +++ b/drivers/extcon/extcon_class.c @@ -72,6 +72,39 @@ static struct class_compat *switch_class; static LIST_HEAD(extcon_dev_list); static DEFINE_MUTEX(extcon_dev_list_lock); +/** + * check_mutually_exclusive - Check if new_state violates mutually_exclusive + * condition. + * @edev: the extcon device + * @new_state: new cable attach status for @edev + * + * Returns 0 if nothing violates. Returns the index + 1 for the first + * violated condition. + */ +static int check_mutually_exclusive(struct extcon_dev *edev, u32 new_state) +{ + int i = 0; + + if (!edev->mutually_exclusive) + return 0; + + for (i = 0; edev->mutually_exclusive[i]; i++) { + int count = 0, j; + u32 correspondants = new_state & edev->mutually_exclusive[i]; + u32 exp = 1; + + for (j = 0; j < 32; j++) { + if (exp & correspondants) + count++; + if (count > 1) + return i + 1; + exp <<= 1; + } + } + + return 0; +} + static ssize_t state_show(struct device *dev, struct device_attribute *attr, char *buf) { @@ -100,7 +133,7 @@ static ssize_t state_show(struct device *dev, struct device_attribute *attr, return count; } -void extcon_set_state(struct extcon_dev *edev, u32 state); +int extcon_set_state(struct extcon_dev *edev, u32 state); static ssize_t state_store(struct device *dev, struct device_attribute *attr, const char *buf, size_t count) { @@ -112,7 +145,7 @@ static ssize_t state_store(struct device *dev, struct device_attribute *attr, if (ret == 0) ret = -EINVAL; else - extcon_set_state(edev, state); + ret = extcon_set_state(edev, state); if (ret < 0) return ret; @@ -191,7 +224,7 @@ static ssize_t cable_state_store(struct device *dev, * Note that the notifier provides which bits are changed in the state * variable with the val parameter (second) to the callback. */ -void extcon_update_state(struct extcon_dev *edev, u32 mask, u32 state) +int extcon_update_state(struct extcon_dev *edev, u32 mask, u32 state) { char name_buf[120]; char state_buf[120]; @@ -206,6 +239,12 @@ void extcon_update_state(struct extcon_dev *edev, u32 mask, u32 state) if (edev->state != ((edev->state & ~mask) | (state & mask))) { u32 old_state = edev->state; + if (check_mutually_exclusive(edev, (edev->state & ~mask) | + (state & mask))) { + spin_unlock_irqrestore(&edev->lock, flags); + return -EPERM; + } + edev->state &= ~mask; edev->state |= state & mask; @@ -247,6 +286,8 @@ void extcon_update_state(struct extcon_dev *edev, u32 mask, u32 state) /* No changes */ spin_unlock_irqrestore(&edev->lock, flags); } + + return 0; } EXPORT_SYMBOL_GPL(extcon_update_state); @@ -258,9 +299,9 @@ EXPORT_SYMBOL_GPL(extcon_update_state); * Note that notifier provides which bits are changed in the state * variable with the val parameter (second) to the callback. */ -void extcon_set_state(struct extcon_dev *edev, u32 state) +int extcon_set_state(struct extcon_dev *edev, u32 state) { - extcon_update_state(edev, 0xffffffff, state); + return extcon_update_state(edev, 0xffffffff, state); } EXPORT_SYMBOL_GPL(extcon_set_state); @@ -334,8 +375,7 @@ int extcon_set_cable_state_(struct extcon_dev *edev, return -EINVAL; state = cable_state ? (1 << index) : 0; - extcon_update_state(edev, 1 << index, state); - return 0; + return extcon_update_state(edev, 1 << index, state); } EXPORT_SYMBOL_GPL(extcon_set_cable_state_); @@ -511,6 +551,14 @@ static void extcon_cleanup(struct extcon_dev *edev, bool skip) if (!skip && get_device(edev->dev)) { int index; + if (edev->mutually_exclusive && edev->max_supported) { + for (index = 0; edev->mutually_exclusive[index]; + index++) + kfree(edev->d_attrs_muex[index].attr.name); + kfree(edev->d_attrs_muex); + kfree(edev->attrs_muex); + } + for (index = 0; index < edev->max_supported; index++) kfree(edev->cables[index].attr_g.name); @@ -533,6 +581,7 @@ static void extcon_dev_release(struct device *dev) extcon_cleanup(edev, true); } +static const char *muex_name = "mutually_exclusive"; static void dummy_sysfs_dev_release(struct device *dev) { } @@ -625,10 +674,58 @@ int extcon_dev_register(struct extcon_dev *edev, struct device *dev) } } + if (edev->max_supported && edev->mutually_exclusive) { + char buf[80]; + char *name; + + /* Count the size of mutually_exclusive array */ + for (index = 0; edev->mutually_exclusive[index]; index++) + ; + + edev->attrs_muex = kzalloc(sizeof(struct attribute *) * + (index + 1), GFP_KERNEL); + if (!edev->attrs_muex) { + ret = -ENOMEM; + goto err_muex; + } + + edev->d_attrs_muex = kzalloc(sizeof(struct device_attribute) * + index, GFP_KERNEL); + if (!edev->d_attrs_muex) { + ret = -ENOMEM; + kfree(edev->attrs_muex); + goto err_muex; + } + + for (index = 0; edev->mutually_exclusive[index]; index++) { + sprintf(buf, "0x%x", edev->mutually_exclusive[index]); + name = kzalloc(sizeof(char) * (strlen(buf) + 1), + GFP_KERNEL); + if (!name) { + for (index--; index >= 0; index--) { + kfree(edev->d_attrs_muex[index].attr. + name); + } + kfree(edev->d_attrs_muex); + kfree(edev->attrs_muex); + ret = -ENOMEM; + goto err_muex; + } + strcpy(name, buf); + edev->d_attrs_muex[index].attr.name = name; + edev->d_attrs_muex[index].attr.mode = 0000; + edev->attrs_muex[index] = &edev->d_attrs_muex[index] + .attr; + } + edev->attr_g_muex.name = muex_name; + edev->attr_g_muex.attrs = edev->attrs_muex; + + } + if (edev->max_supported) { edev->extcon_dev_type.groups = kzalloc(sizeof(struct attribute_group *) * - (edev->max_supported + 1), GFP_KERNEL); + (edev->max_supported + 2), GFP_KERNEL); if (!edev->extcon_dev_type.groups) { ret = -ENOMEM; goto err_alloc_groups; @@ -640,6 +737,9 @@ int extcon_dev_register(struct extcon_dev *edev, struct device *dev) for (index = 0; index < edev->max_supported; index++) edev->extcon_dev_type.groups[index] = &edev->cables[index].attr_g; + if (edev->mutually_exclusive) + edev->extcon_dev_type.groups[index] = + &edev->attr_g_muex; edev->dev->type = &edev->extcon_dev_type; } @@ -672,6 +772,13 @@ err_dev: if (edev->max_supported) kfree(edev->extcon_dev_type.groups); err_alloc_groups: + if (edev->max_supported && edev->mutually_exclusive) { + for (index = 0; edev->mutually_exclusive[index]; index++) + kfree(edev->d_attrs_muex[index].attr.name); + kfree(edev->d_attrs_muex); + kfree(edev->attrs_muex); + } +err_muex: for (index = 0; index < edev->max_supported; index++) kfree(edev->cables[index].attr_g.name); err_alloc_cables: -- cgit v1.2.3