[U-Boot] [PATCH v3] gpio: add gpio-hog support
Heiko Schocher
hs at denx.de
Tue Jun 4 16:04:38 UTC 2019
Hello Patrick,
Am 04.06.2019 um 13:49 schrieb Patrick DELAUNAY:
> Hi Heiko,
>
>>
>> add gpio-hog support. GPIO hogging is a mechanism providing automatic GPIO
>> request and configuration as part of the gpio-controller's driver probe function.
>>
>> for more infos see:
>> doc/device-tree-bindings/gpio/gpio.txt
>>
>> Signed-off-by: Heiko Schocher <hs at denx.de>
>
> It seens the hog function can be called several times, for gpio bank probed in pre-reloc phasis:
>
> - before recocation : gpio_post_probe() => gpio_hog() .... gpio_hogs_probed = 0
> - after relocation :
> gpio_post_probe() => gpio_hog()... gpio_hogs_probed = 0
> gpio_hog_probe_all() => gpio_post_probe() => gpio_hog()... gpio_hogs_probed = 1
>
> I don't known if it is expected behavior:
> hog configuration 2 times in Uboot = before and after relocation
No, not expected.
>> ---
>> clean travis build, see result:
>> https://travis-ci.org/hsdenx/u-boot-test/builds/538734780
>>
>> Changes in v3:
>> - probe now all gpio devices with gpio-hogs
>> from board_r before board_late_init() call
>> or if someone wants to access gpio-hog
>> based gpios with gpio_hog_lookup_name()
>> This is needed, because we cannot be sure,
>> if a gpio device which contains gpio-hogs
>> is probed.
>> - add line-name property as Michal recommended
>> - renamed gpio_priv_one into gpio_priv_one_hog
>> and protected through CONFIG_DM_GPIO_HOG
>>
>> Changes in v2:
>> - move gpio_hog() call from post_probe() to post_bind()
>> call. Check if current gpio device has gpio-hog
>> definitions, if so, probe it.
>>
>> common/board_r.c | 6 +
>> doc/device-tree-bindings/gpio/gpio.txt | 55 +++++++
>> drivers/gpio/Kconfig | 10 ++
>> drivers/gpio/gpio-uclass.c | 217 ++++++++++++++++++++++---
>> include/asm-generic/gpio.h | 32 ++++
>> 5 files changed, 301 insertions(+), 19 deletions(-)
[...]
>> diff --git a/drivers/gpio/gpio-uclass.c b/drivers/gpio/gpio-uclass.c index
>> da5e9ba6e5..4ecff115f1 100644
>> --- a/drivers/gpio/gpio-uclass.c
>> +++ b/drivers/gpio/gpio-uclass.c
>> @@ -5,6 +5,7 @@
>>
>> #include <common.h>
>> #include <dm.h>
>> +#include <dm/device-internal.h>
>> #include <dt-bindings/gpio/gpio.h>
>> #include <errno.h>
>> #include <fdtdec.h>
>> @@ -15,6 +16,18 @@
>>
>> DECLARE_GLOBAL_DATA_PTR;
>>
>> +#if defined(CONFIG_DM_GPIO_HOG)
>> +struct gpio_priv_one_hog {
>> + struct list_head list;
>> + char *name;
>> + struct gpio_desc gpiod;
>> +};
>> +
>> +static struct list_head hogs;
>> +static int list_init;
>> +static int gpio_hogs_probed;
>> +#endif
>> +
>> /**
>> * gpio_to_device() - Convert global GPIO number to device, number
>> *
>> @@ -141,6 +154,147 @@ static int gpio_find_and_xlate(struct gpio_desc *desc,
>> return gpio_xlate_offs_flags(desc->dev, desc, args); }
>>
>> +#if defined(CONFIG_DM_GPIO_HOG)
>> +int gpio_hog_probe_all(void)
>> +{
>> + struct udevice *dev;
>> + ofnode node;
>> + int ret;
>> +
>> + /*
>> + * We need to probe all gpio-hog devices
>> + * at some point, as we cannot be sure,
>> + * that all gpio devices, which contain a
>> + * gpio-hog definition are probed.
>> + *
>> + */
>> + if (gpio_hogs_probed)
>> + return 0;
>> +
>> + for (uclass_first_device(UCLASS_GPIO, &dev);
>> + dev;
>> + uclass_next_device(&dev)) {
>
> uclass_next_device automatically call probe for the class (in uclass_get_device_tail)
> in this context, I think that uclass_find_next_device is better
The idea was to only probe gpio devices with gpio-hog subnodes...
>> + dev_for_each_subnode(node, dev) {
>> + if (ofnode_read_bool(node, "gpio-hog")) {
>> + ret = device_probe(dev);
>> + if (ret)
>> + return ret;
>> + break;
>> + }
>> + }
>> + }
>> + gpio_hogs_probed = 1;
>> +
>> + return 0;
>> +}
>> +
>> +struct gpio_desc *gpio_hog_lookup_name(const char *name) {
>> + struct list_head *entry;
>> + struct gpio_priv_one_hog *cur;
>> +
>> + /* be sure, all gpio devices with gpio-hogs are probed */
>> + gpio_hog_probe_all();
>> + list_for_each(entry, &hogs) {
>> + cur = list_entry(entry, struct gpio_priv_one_hog, list);
>> + if (strcmp(cur->name, name) == 0)
>> + return &cur->gpiod;
>> + }
>> +
>> + return NULL;
>> +}
>> +
>> +static int gpio_hog(struct udevice *dev) {
>> + ofnode node;
>> + int found = 0;
>> + int ret;
>> + struct gpio_dev_priv *uc_priv = NULL;
>> +
>> + if (!list_init) {
>> + INIT_LIST_HEAD(&hogs);
>> + list_init = 1;
>> + }
>> + dev_for_each_subnode(node, dev) {
>> + if (ofnode_read_bool(node, "gpio-hog")) {
>> + found = 1;
>> + break;
>> + }
>> + }
>
> This check is really needed, as it is already done in the main loop ?
> I think you can remove this first 'found' loop.
Yes if we only setup the gpio-hogs from main loop.
>> +
>> + if (!found)
>> + return 0;
>> +
>> + uc_priv = dev_get_uclass_priv(dev);
>> + if (!uc_priv) {
>> + printf("%s: missing private data.\n", __func__);
>> + return 0;
>> + }
>
> It is prossible to have uc_priv = 0 ?
> by construction, is is not allowed in driver mode, so this test can be remove I think.
Yes, just panic check. I remove this.
>> +
>> + /* scan for gpio-hog subnodes */
>> + dev_for_each_subnode(node, dev) {
>> + u32 val[2];
>> + int value = 0;
>> + int gpiod_flags;
>> + struct gpio_priv_one_hog *new;
>> + const char *nodename;
>> +
>> + if (!ofnode_read_bool(node, "gpio-hog"))
>> + continue;
>> +
>> + if (ofnode_read_bool(node, "input")) {
>> + gpiod_flags = GPIOD_IS_IN;
>> + } else if (ofnode_read_bool(node, "output-high")) {
>> + value = 1;
>> + gpiod_flags = GPIOD_IS_OUT;
>> + } else if (ofnode_read_bool(node, "output-low")) {
>> + gpiod_flags = GPIOD_IS_OUT;
>> + } else {
>> + printf("%s: missing gpio-hog state.\n", __func__);
>> + return -EINVAL;
>> + }
>> +
>> + ret = ofnode_read_u32_array(node, "gpios", val, 2);
>> + if (ret) {
>> + printf("%s: wrong gpios property, 2 values needed, ret:
>> %d\n", __func__, ret);
>> + return ret;
>> + }
>> +
>> + new = calloc(1, sizeof(struct gpio_priv_one_hog));
>> + nodename = ofnode_read_string(node, "line-name");
>> + if (!nodename)
>> + nodename = ofnode_get_name(node);
>> + ret = gpio_dev_request_index(dev, nodename, "gpio-hog",
>> + val[0], gpiod_flags, val[1],
>> + &new->gpiod);
>> + if (ret < 0) {
>> + debug("%s: node %s could not get gpio.\n", __func__,
>> + ofnode_get_name(node));
>> + free(new);
>> + return ret;
>> + }
>> +
>> + new->name = uc_priv->name[new->gpiod.offset];
>> + list_add_tail(&new->list, &hogs);
>> + dm_gpio_set_dir(&new->gpiod);
>> + if (gpiod_flags == GPIOD_IS_OUT)
>> + dm_gpio_set_value(&new->gpiod, value);
>> + }
>> +
>> + return 0;
>> +}
>> +#else
>> +static int gpio_hog(struct udevice *dev) {
>> + return 0;
>> +}
>> +
>> +struct gpio_desc *gpio_hog_lookup_name(const char *name) {
>> + return NULL;
>> +}
>> +#endif
>> +
>> int dm_gpio_request(struct gpio_desc *desc, const char *label) {
>> struct udevice *dev = desc->dev;
>> @@ -149,8 +303,9 @@ int dm_gpio_request(struct gpio_desc *desc, const char
>> *label)
>> int ret;
>>
>> uc_priv = dev_get_uclass_priv(dev);
>> - if (uc_priv->name[desc->offset])
>> - return -EBUSY;
>> + if (uc_priv)
>> + if (uc_priv->name[desc->offset])
>> + return -EBUSY;
>> str = strdup(label);
>> if (!str)
>> return -ENOMEM;
>> @@ -640,22 +795,25 @@ int dm_gpio_get_values_as_int(const struct gpio_desc
>> *desc_list, int count)
>> return vector;
>> }
>>
>> -static int gpio_request_tail(int ret, ofnode node,
>> +static int gpio_request_tail(int ret, const char *nodename,
>> struct ofnode_phandle_args *args,
>> const char *list_name, int index,
>> - struct gpio_desc *desc, int flags, bool add_index)
>> + struct gpio_desc *desc, int flags,
>> + bool add_index, struct udevice *dev)
>> {
>> - desc->dev = NULL;
>> + desc->dev = dev;
>> desc->offset = 0;
>> desc->flags = 0;
>> if (ret)
>> goto err;
>>
>> - ret = uclass_get_device_by_ofnode(UCLASS_GPIO, args->node,
>> - &desc->dev);
>> - if (ret) {
>> - debug("%s: uclass_get_device_by_ofnode failed\n", __func__);
>> - goto err;
>> + if (!desc->dev) {
>> + ret = uclass_get_device_by_ofnode(UCLASS_GPIO, args->node,
>> + &desc->dev);
>> + if (ret) {
>> + debug("%s: uclass_get_device_by_ofnode failed\n",
>> __func__);
>> + goto err;
>> + }
>> }
>> ret = gpio_find_and_xlate(desc, args);
>> if (ret) {
>> @@ -663,8 +821,7 @@ static int gpio_request_tail(int ret, ofnode node,
>> goto err;
>> }
>> ret = dm_gpio_requestf(desc, add_index ? "%s.%s%d" : "%s.%s",
>> - ofnode_get_name(node),
>> - list_name, index);
>> + nodename, list_name, index);
>> if (ret) {
>> debug("%s: dm_gpio_requestf failed\n", __func__);
>> goto err;
>> @@ -678,7 +835,7 @@ static int gpio_request_tail(int ret, ofnode node,
>> return 0;
>> err:
>> debug("%s: Node '%s', property '%s', failed to request GPIO index %d:
>> %d\n",
>> - __func__, ofnode_get_name(node), list_name, index, ret);
>> + __func__, nodename, list_name, index, ret);
>> return ret;
>> }
>>
>> @@ -692,8 +849,8 @@ static int _gpio_request_by_name_nodev(ofnode node,
>> const char *list_name,
>> ret = ofnode_parse_phandle_with_args(node, list_name, "#gpio-cells", 0,
>> index, &args);
>>
>> - return gpio_request_tail(ret, node, &args, list_name, index, desc,
>> - flags, add_index);
>> + return gpio_request_tail(ret, ofnode_get_name(node), &args, list_name,
>> + index, desc, flags, add_index, NULL);
>> }
>>
>> int gpio_request_by_name_nodev(ofnode node, const char *list_name, int index,
>> @@ -707,13 +864,14 @@ int gpio_request_by_name(struct udevice *dev, const
>> char *list_name, int index,
>> struct gpio_desc *desc, int flags)
>> {
>> struct ofnode_phandle_args args;
>> + ofnode node;
>> int ret;
>>
>> ret = dev_read_phandle_with_args(dev, list_name, "#gpio-cells", 0,
>> index, &args);
>> -
>> - return gpio_request_tail(ret, dev_ofnode(dev), &args, list_name,
>> - index, desc, flags, index > 0);
>> + node = dev_ofnode(dev);
>> + return gpio_request_tail(ret, ofnode_get_name(node), &args, list_name,
>> + index, desc, flags, index > 0, NULL);
>> }
>>
>> int gpio_request_list_by_name_nodev(ofnode node, const char *list_name, @@ -
>> 832,12 +990,17 @@ int gpio_get_number(const struct gpio_desc *desc) static int
>> gpio_post_probe(struct udevice *dev) {
>> struct gpio_dev_priv *uc_priv = dev_get_uclass_priv(dev);
>> + int ret;
>>
>> uc_priv->name = calloc(uc_priv->gpio_count, sizeof(char *));
>> if (!uc_priv->name)
>> return -ENOMEM;
>>
>> - return gpio_renumber(NULL);
>> + ret = gpio_renumber(NULL);
>> + if (ret)
>> + return ret;
>> +
>
> It is strange for me to have many device tree parsing in probe function....
>
> For me
> => hog detection + DT parsing in gpio_post_bind() .... info saved in platdata
> => gpio configuration for hog (request and set_dir) => probe function
Yes, this approach is much more cleaner.
>> + return gpio_hog(dev);
>> }
>
>
> One other solution to do it is to manage a hog with uclass (using the new UCLASS_NOP or misc for example)
> http://patchwork.ozlabs.org/patch/1098913/
Ah, thanks for this hint, wasn;t aware of it.
> Ps: we can also create a new UCLASS_GPIOHOG
Heh, I had a version (never posted) with such an approach. Thought this
is to much overhead ... I try first with UCLASS_NOP.
> And we to bind this class during GPIO binding; the parsing of DT is done only one time
> and manage privdata and platdata as expected by driver model....
Yes, cleaner.
> For example something like (not tested)
[...]
Thanks for your input! I try to rework this soon.
bye,
Heiko
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