X-Git-Url: http://pilppa.org/gitweb/gitweb.cgi?a=blobdiff_plain;f=drivers%2Fof%2Fbase.c;h=7c79e94a35eac932a165367a11439a8af1d35cc0;hb=1b6bcdbe7eaacde19b5d633b33c8d056e4818de0;hp=9bd7c4a31253a5d7349d5b2fd3cb383e826d9680;hpb=904e0ab54b7591b9cb01cfc0dbbedcc8bc0d949b;p=linux-2.6-omap-h63xx.git diff --git a/drivers/of/base.c b/drivers/of/base.c index 9bd7c4a3125..7c79e94a35e 100644 --- a/drivers/of/base.c +++ b/drivers/of/base.c @@ -65,6 +65,9 @@ struct property *of_find_property(const struct device_node *np, { struct property *pp; + if (!np) + return NULL; + read_lock(&devtree_lock); for (pp = np->properties; pp != 0; pp = pp->next) { if (of_prop_cmp(pp->name, name) == 0) { @@ -382,3 +385,185 @@ struct device_node *of_find_matching_node(struct device_node *from, return np; } EXPORT_SYMBOL(of_find_matching_node); + +/** + * of_modalias_table: Table of explicit compatible ==> modalias mappings + * + * This table allows particulare compatible property values to be mapped + * to modalias strings. This is useful for busses which do not directly + * understand the OF device tree but are populated based on data contained + * within the device tree. SPI and I2C are the two current users of this + * table. + * + * In most cases, devices do not need to be listed in this table because + * the modalias value can be derived directly from the compatible table. + * However, if for any reason a value cannot be derived, then this table + * provides a method to override the implicit derivation. + * + * At the moment, a single table is used for all bus types because it is + * assumed that the data size is small and that the compatible values + * should already be distinct enough to differentiate between SPI, I2C + * and other devices. + */ +struct of_modalias_table { + char *of_device; + char *modalias; +}; +static struct of_modalias_table of_modalias_table[] = { + { "fsl,mcu-mpc8349emitx", "mcu-mpc8349emitx" }, +}; + +/** + * of_modalias_node - Lookup appropriate modalias for a device node + * @node: pointer to a device tree node + * @modalias: Pointer to buffer that modalias value will be copied into + * @len: Length of modalias value + * + * Based on the value of the compatible property, this routine will determine + * an appropriate modalias value for a particular device tree node. Two + * separate methods are attempted to derive a modalias value. + * + * First method is to lookup the compatible value in of_modalias_table. + * Second is to strip off the manufacturer prefix from the first + * compatible entry and use the remainder as modalias + * + * This routine returns 0 on success + */ +int of_modalias_node(struct device_node *node, char *modalias, int len) +{ + int i, cplen; + const char *compatible; + const char *p; + + /* 1. search for exception list entry */ + for (i = 0; i < ARRAY_SIZE(of_modalias_table); i++) { + compatible = of_modalias_table[i].of_device; + if (!of_device_is_compatible(node, compatible)) + continue; + strlcpy(modalias, of_modalias_table[i].modalias, len); + return 0; + } + + compatible = of_get_property(node, "compatible", &cplen); + if (!compatible) + return -ENODEV; + + /* 2. take first compatible entry and strip manufacturer */ + p = strchr(compatible, ','); + if (!p) + return -ENODEV; + p++; + strlcpy(modalias, p, len); + return 0; +} +EXPORT_SYMBOL_GPL(of_modalias_node); + +/** + * of_parse_phandles_with_args - Find a node pointed by phandle in a list + * @np: pointer to a device tree node containing a list + * @list_name: property name that contains a list + * @cells_name: property name that specifies phandles' arguments count + * @index: index of a phandle to parse out + * @out_node: pointer to device_node struct pointer (will be filled) + * @out_args: pointer to arguments pointer (will be filled) + * + * This function is useful to parse lists of phandles and their arguments. + * Returns 0 on success and fills out_node and out_args, on error returns + * appropriate errno value. + * + * Example: + * + * phandle1: node1 { + * #list-cells = <2>; + * } + * + * phandle2: node2 { + * #list-cells = <1>; + * } + * + * node3 { + * list = <&phandle1 1 2 &phandle2 3>; + * } + * + * To get a device_node of the `node2' node you may call this: + * of_parse_phandles_with_args(node3, "list", "#list-cells", 2, &node2, &args); + */ +int of_parse_phandles_with_args(struct device_node *np, const char *list_name, + const char *cells_name, int index, + struct device_node **out_node, + const void **out_args) +{ + int ret = -EINVAL; + const u32 *list; + const u32 *list_end; + int size; + int cur_index = 0; + struct device_node *node = NULL; + const void *args; + + list = of_get_property(np, list_name, &size); + if (!list) { + ret = -ENOENT; + goto err0; + } + list_end = list + size / sizeof(*list); + + while (list < list_end) { + const u32 *cells; + const phandle *phandle; + + phandle = list; + args = list + 1; + + /* one cell hole in the list = <>; */ + if (!*phandle) { + list++; + goto next; + } + + node = of_find_node_by_phandle(*phandle); + if (!node) { + pr_debug("%s: could not find phandle\n", + np->full_name); + goto err0; + } + + cells = of_get_property(node, cells_name, &size); + if (!cells || size != sizeof(*cells)) { + pr_debug("%s: could not get %s for %s\n", + np->full_name, cells_name, node->full_name); + goto err1; + } + + /* Next phandle is at offset of one phandle cell + #cells */ + list += 1 + *cells; + if (list > list_end) { + pr_debug("%s: insufficient arguments length\n", + np->full_name); + goto err1; + } +next: + if (cur_index == index) + break; + + of_node_put(node); + node = NULL; + cur_index++; + } + + if (!node) { + ret = -ENOENT; + goto err0; + } + + *out_node = node; + *out_args = args; + + return 0; +err1: + of_node_put(node); +err0: + pr_debug("%s failed with status %d\n", __func__, ret); + return ret; +} +EXPORT_SYMBOL(of_parse_phandles_with_args);