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Date: Mon, 27 Oct 2014 17:20:51 +0100
From: Linus Walleij <linus.walleij@...aro.org>
To: John Crispin <blogic@...nwrt.org>
Cc: Ralf Baechle <ralf@...ux-mips.org>,
"linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
Linux MIPS <linux-mips@...ux-mips.org>
Subject: Re: [PATCH 2/4] pinctrl: ralink: add a pinctrl driver for the rt2880
family of SoCs
On Thu, Oct 9, 2014 at 4:55 AM, John Crispin <blogic@...nwrt.org> wrote:
> These Socs have 1-3 banks of 8-32 gpios. Rather then setting the muxing of each
> pin individually, these socs have mux groups that when set will effect 1-N pins.
> Pin groups have a 2, 4 or 8 different muxes.
>
> Signed-off-by: John Crispin <blogic@...nwrt.org>
Overall this looks nice, some minor things....
> +struct rt2880_priv {
> + struct device *dev;
> +
> + struct pinctrl_pin_desc *pads;
> + struct pinctrl_desc *desc;
> +
> + struct rt2880_pmx_func **func;
> + int func_count;
> +
> + struct rt2880_pmx_group *groups;
> + const char **group_names;
> + int group_count;
> +
> + uint8_t *gpio;
Just use u8
> + int max_pins;
> +};
Some of this would need some kerneldoc, don't you think?
> +static void rt2880_pinctrl_dt_free_map(struct pinctrl_dev *pctrldev,
> + struct pinctrl_map *map, unsigned num_maps)
> +{
> + int i;
> +
> + for (i = 0; i < num_maps; i++)
> + if (map[i].type == PIN_MAP_TYPE_CONFIGS_PIN ||
> + map[i].type == PIN_MAP_TYPE_CONFIGS_GROUP)
> + kfree(map[i].data.configs.configs);
> + kfree(map);
> +}
Can you use pinctrl_utils_dt_free_map()
from
#include "pinctrl-utils.h"
for this?
> +static void rt2880_pinctrl_pin_dbg_show(struct pinctrl_dev *pctrldev,
> + struct seq_file *s,
> + unsigned offset)
> +{
> + seq_puts(s, "ralink pio");
> +}
Hmmm rather terse debug info don't you think... ;)
> +static void rt2880_pinctrl_dt_subnode_to_map(struct pinctrl_dev *pctrldev,
> + struct device_node *np,
> + struct pinctrl_map **map)
> +{
> + const char *function;
> + int func = of_property_read_string(np, "ralink,function", &function);
> + int grps = of_property_count_strings(np, "ralink,group");
There are now standard bindings for "function" and "group" so please
if you can, just use "function" and "group".
See:
Documentation/devicetree/bindings/pinctrl/pinctrl-bindings.txt
"Generic pin multiplexing node content"
I also wanted to provide a generic parsing function for it actually,
since so many drivers look alike.
> +static int rt2880_pinctrl_dt_node_to_map(struct pinctrl_dev *pctrldev,
> + struct device_node *np_config,
> + struct pinctrl_map **map,
> + unsigned *num_maps)
> +{
> + int max_maps = 0;
> + struct pinctrl_map *tmp;
> + struct device_node *np;
> +
> + for_each_child_of_node(np_config, np) {
> + int ret = of_property_count_strings(np, "ralink,group");
> +
> + if (ret >= 0)
> + max_maps += ret;
> + }
> +
> + if (!max_maps)
> + return max_maps;
> +
> + *map = kzalloc(max_maps * sizeof(struct pinctrl_map),
> + GFP_KERNEL);
Can you use pinctrl_utils_reserve_map() here?
> +static int rt2880_pmx_group_enable(struct pinctrl_dev *pctrldev,
> + unsigned func,
> + unsigned group)
We don't have an "enable" callback anymore.
Rename this rt2880_pmx_set_mux().
> +static const struct pinmux_ops rt2880_pmx_group_ops = {
> + .get_functions_count = rt2880_pmx_func_count,
> + .get_function_name = rt2880_pmx_func_name,
> + .get_function_groups = rt2880_pmx_group_get_groups,
> + .enable = rt2880_pmx_group_enable,
.set_mux rather than .enable
And make sure you test this on say v3.18-rc2.
> +static struct rt2880_pmx_func gpio_func = {
> + .name = "gpio",
> +};
Hmmmmmm
> +static int rt2880_pinmux_index(struct rt2880_priv *p)
> +{
> + struct rt2880_pmx_func **f;
> + struct rt2880_pmx_group *mux = p->groups;
> + int i, j, c = 0;
> +
> + /* count the mux functions */
> + while (mux->name) {
> + p->group_count++;
> + mux++;
> + }
> +
> + /* allocate the group names array needed by the gpio function */
> + p->group_names = devm_kzalloc(p->dev,
> + sizeof(char *) * p->group_count, GFP_KERNEL);
> + if (!p->group_names)
> + return -1;
> +
> + for (i = 0; i < p->group_count; i++) {
> + p->group_names[i] = p->groups[i].name;
> + p->func_count += p->groups[i].func_count;
> + }
> +
> + /* we have a dummy function[0] for gpio */
> + p->func_count++;
> +
> + /* allocate our function and group mapping index buffers */
> + f = p->func = devm_kzalloc(p->dev,
> + sizeof(struct rt2880_pmx_func) * p->func_count, GFP_KERNEL);
> + gpio_func.groups = devm_kzalloc(p->dev, sizeof(int) * p->group_count,
> + GFP_KERNEL);
> + if (!f || !gpio_func.groups)
> + return -1;
Can you explain what this code is doing a bit more.
Are you avoiding to use gpio ranges by instead providing that
"gpio" function on each and every pin?
> +static int rt2880_pinmux_probe(struct platform_device *pdev)
> +{
> + struct rt2880_priv *p;
> + struct pinctrl_dev *dev;
> + struct device_node *np;
> +
> + if (!rt2880_pinmux_data)
> + return -ENOSYS;
> +
> + /* setup the private data */
> + p = devm_kzalloc(&pdev->dev, sizeof(struct rt2880_priv), GFP_KERNEL);
> + if (!p)
> + return -ENOMEM;
> +
> + p->dev = &pdev->dev;
> + p->desc = &rt2880_pctrl_desc;
> + p->groups = rt2880_pinmux_data;
> + platform_set_drvdata(pdev, p);
> +
> + /* init the device */
> + if (rt2880_pinmux_index(p)) {
> + dev_err(&pdev->dev, "failed to load index\n");
> + return -EINVAL;
> + }
> + if (rt2880_pinmux_pins(p)) {
> + dev_err(&pdev->dev, "failed to load pins\n");
> + return -EINVAL;
> + }
What is this "loading" that is happening here?
> + dev = pinctrl_register(p->desc, &pdev->dev, p);
> + if (IS_ERR(dev))
> + return PTR_ERR(dev);
> +
> + /* finalize by adding gpio ranges for enables gpio controllers */
> + for_each_compatible_node(np, NULL, "ralink,rt2880-gpio") {
> + const __be32 *ngpio, *gpiobase;
> + struct pinctrl_gpio_range *range;
> + char *name;
> +
> + if (!of_device_is_available(np))
> + continue;
> +
> + ngpio = of_get_property(np, "ralink,num-gpios", NULL);
> + gpiobase = of_get_property(np, "ralink,gpio-base", NULL);
NO GPIO BASE in the device tree.
We have NACKed this so many times that I don't know it anymore.
The gpiobase is a linux-internal thing and not OS neutral at all.
So it has nothing to do in the device tree.
(If it was allowed it would atleast be linux,gpio-base)
Several other ways to handle this is available, the best being...
(see below)
> + if (!ngpio || !gpiobase) {
> + dev_err(&pdev->dev, "failed to load chip info\n");
> + return -EINVAL;
> + }
> +
> + range = devm_kzalloc(p->dev,
> + sizeof(struct pinctrl_gpio_range) + 4, GFP_KERNEL);
> + range->name = name = (char *) &range[1];
> + sprintf(name, "pio");
> + range->npins = __be32_to_cpu(*ngpio);
> + range->base = __be32_to_cpu(*gpiobase);
> + range->pin_base = range->base;
> + pinctrl_add_gpio_range(dev, range);
...to NOT do this but instead use
gpiochip_add_pin_range() or gpiochip_add_pingroup_range()
from the gpiochip side.
The gpiochip has the ability to add ranges completely dynamically
as it can get a relative offset from the pin control subsystem.
It doesn't work the other way around unfortunately.
So I'd suggest you look at ways to modify your GPIO driver
to do this.
> +core_initcall_sync(rt2880_pinmux_init);
Do you really need it this early?
Yours,
Linus Walleij
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