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Message-ID: <CACRpkdbTwqTijFcYSwmb-pzRwc8NqA4NAAC3KsBn+NRA1hne3w@mail.gmail.com>
Date: Wed, 17 Apr 2013 16:48:55 +0200
From: Linus Walleij <linus.walleij@...aro.org>
To: Christian Ruppert <christian.ruppert@...lis.com>
Cc: "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
Grant Likely <grant.likely@...retlab.ca>,
Rob Herring <rob.herring@...xeda.com>,
Rob Landley <rob@...dley.net>,
Sascha Leuenberger <sascha.leuenberger@...lis.com>,
Pierrick Hascoet <pierrick.hascoet@...lis.com>,
"devicetree-discuss@...ts.ozlabs.org"
<devicetree-discuss@...ts.ozlabs.org>,
"linux-doc@...r.kernel.org" <linux-doc@...r.kernel.org>,
Stephen Warren <swarren@...dotorg.org>
Subject: Re: [PATCH 1/2] pinmux: Add TB10x pinmux driver
On Wed, Apr 10, 2013 at 5:45 PM, Christian Ruppert
<christian.ruppert@...lis.com> wrote:
> The pinmux driver of the Abilis Systems TB10x platform based on ARC700 CPUs.
> Used to control the pinmux and is a prerequisite for the GPIO driver.
>
> Signed-off-by: Christian Ruppert <christian.ruppert@...lis.com>
> Signed-off-by: Pierrick Hascoet <pierrick.hascoet@...lis.com>
Please include Stephen Warren on cc for checking DT bindings for these
things, I feel a bit uncertain about such things time to time.
(...)
> +++ b/Documentation/devicetree/bindings/pinctrl/abilis,tb10x-iomux.txt
(...)
> +In case a driver requires a port to be mapped, the corresponding node should
> +be compatible with "abilis,simple-pinctrl" and define a pinctrl state named
> +"abilis,simple-default" pointing to the port's respective node inside the pin
> +controller.
Oh um.... I don't understand this.
> + Drivers managing pin controller states internally can be
> +configured normally as described in the pinctrl-bindings.txt.
I don't understand this either.
Do you mean this is opposed to using hogs or something?
Have your familiarized yourself with commit
ab78029ecc347debbd737f06688d788bd9d60c1d
"drivers/pinctrl: grab default handles from device core"
?
> +The pinmux driver is connected to the TB10x GPIO driver in a way that a GPIO
> +node managing a GPIO port can point to the respective pinmux subnode using
> +the gpio-pins property
NAK - this sounds like you're reinventing the GPIO ranges.
See:
Documentation/devicetree/bindings/gpio/gpio.txt, section
2.1) gpio-controller and pinctrl subsystem
> +Example
> +-------
> +
> +iomux: iomux@...0601c {
> + #address-cells = <1>;
> + #size-cells = <1>;
> + compatible = "abilis,tb10x-iomux";
> + reg = <0xFF10601c 0x4>;
> + pctl_gpio_a: pctl-gpio-a {
> + pingrp = "gpioa_pins";
> + };
> + pctl_uart0: pctl-uart0 {
> + pingrp = "uart0_pins";
> + };
> +};
> +uart@...00000 {
> + compatible = "snps,dw-apb-uart",
> + "abilis,simple-pinctrl";
Why do you need this compatible property,
abilis,simple-pinctrl? And what is simple about it?
> + reg = <0xFF100000 0x100>;
> + clock-frequency = <166666666>;
> + interrupts = <25 1>;
> + reg-shift = <2>;
> + reg-io-width = <4>;
> + pinctrl-names = "abilis,simple-default"; /* <<<<<<<< */
> + pinctrl-0 = <&pctl_uart0>; /* <<<<<<<< */
I suggest you just put the name of the states into pinctrl-names
pinctrl-names = "default";
> +gpioa: gpio@...40000 {
> + compatible = "abilis,tb10x-gpio";
> + reg = <0xFF140000 0x1000>;
> + gpio-controller;
> + #gpio-cells = <1>;
> + gpio-count = <3>;
> + gpio-base = <0>;
> + gpio-pins = <&pctl_gpio_a>; /* <<<<<<<< */
And why doesn't this need a name?
(...)
> diff --git a/drivers/pinctrl/pinctrl-tb10x.c b/drivers/pinctrl/pinctrl-tb10x.c
> +#include <linux/stringify.h>
> +#include <linux/pinctrl/pinctrl.h>
> +#include <linux/pinctrl/pinmux.h>
> +#include <linux/pinctrl/machine.h>
> +#include <linux/platform_device.h>
> +#include <linux/module.h>
> +#include <linux/mutex.h>
> +#include <linux/err.h>
> +#include <linux/io.h>
> +#include <linux/of.h>
> +#include <linux/slab.h>
> +#include <linux/pinctrl/pinctrl-tb10x.h>
No, put that into <linux/platform_data/pinctrl-tb10x.h>
> +static const struct pinctrl_pin_desc tb10x_pins[] = {
> + /* Port 1 */
> + PINCTRL_PIN(0 + 0, "MICLK_S0"),
> + PINCTRL_PIN(0 + 1, "MISTRT_S0"),
> + PINCTRL_PIN(0 + 2, "MIVAL_S0"),
> + PINCTRL_PIN(0 + 3, "MDI_S0"),
> + PINCTRL_PIN(0 + 4, "GPIOA0"),
> + PINCTRL_PIN(0 + 5, "GPIOA1"),
> + PINCTRL_PIN(0 + 6, "GPIOA2"),
> + PINCTRL_PIN(0 + 7, "MDI_S1"),
> + PINCTRL_PIN(0 + 8, "MIVAL_S1"),
> + PINCTRL_PIN(0 + 9, "MISTRT_S1"),
> + PINCTRL_PIN(0 + 10, "MICLK_S1"),
If you're using an offset like that in every such macro,
use a #define for the offset, like
#define TB10X_PORT0 0
#define TB10X_PORT1 16
Then
PINCTRL_PIN(TB10X_PORT0 + 0, "MICLK_S0"),
start to mean something when reading it.
(...)
> +/* Port 1 */
> +static const unsigned mis0_pins[] = { 0, 1, 2, 3};
> +static const unsigned gpioa_pins[] = { 4, 5, 6};
> +static const unsigned mis1_pins[] = { 7, 8, 9, 10};
> +static const unsigned mip1_pins[] = { 0, 1, 2, 3, 4, 5,
> + 6, 7, 8, 9, 10};
Likewise you should use the same #defines here I guess.
static const unsigned mis0_pins[] = { TB10X_PORT0 + 0, TB10X_PORT0 + 1,
TB10X_PORT0 +
2, TB10X_PORT0 + 3};
An alternative is to just drop the offset everywhere above, but it needs
to be consistent. Do it one way: either offsets everywhere or just
plain numbers everywhere, not a mixture like now.
(...)
> +struct tb10x_pinctrl_state {
Usually I just call such structs "tb10x", it's quite clear
from the code that it stores the state.
> + struct pinctrl_dev *pctl;
> + void *iobase;
Just "base" is more common.
> + const struct tb10x_pinfuncgrp *pingroups;
> + unsigned int pinfuncgrpcnt;
> + struct tb10x_of_pinfunc *pinfuncs;
> + unsigned int pinfuncnt;
> + struct mutex mutex;
> + struct {
> + unsigned int mode;
> + unsigned int count;
> + } ports[TB10X_PORTS];
Why is this struct anonymous? Can't you just declare it outside this struct?
> + DECLARE_BITMAP(gpios, MAX_PIN + 1);
> +};
This struct needs kerneldoc added to it so we understand each member.
> +struct tb10x_pinfuncgrp *tb10x_prepare_gpio_range(struct device_node *dn,
> + struct pinctrl_gpio_range *gr)
> +{
> + const char *name;
> + int ret;
> + struct tb10x_pinfuncgrp *pfg;
> +
> + ret = of_property_read_string(dn, "pingrp", &name);
> + if (ret)
> + return ERR_PTR(ret);
> +
> + pfg = tb10x_get_pinfuncgrp(name);
> +
> + if (!IS_ERR(pfg)) {
> + if (!pfg->isgpio)
> + return ERR_PTR(-EINVAL);
> +
> + if (!pfg->pctl)
> + return ERR_PTR(-EPROBE_DEFER);
> +
> + gr->pin_base = pfg->pins[0];
> + gr->npins = pfg->pincnt;
> + }
> +
> + return pfg;
> +}
> +EXPORT_SYMBOL(tb10x_prepare_gpio_range);
No thanks, use the ranges we have already defined and implemented
in drivers/gpio/gpiolib-of.c, function of_gpiochip_add_pin_range
And you need none of the funky special way to register ranges.
> +static inline void tb10x_pinctrl_set_config(struct tb10x_pinctrl_state *state,
> + unsigned int port, unsigned int mode)
> +{
> + u32 pcfg;
> +
> + if (state->ports[port].count)
> + return;
> +
> + state->ports[port].mode = mode;
> +
> + pcfg = ioread32(state->iobase) & ~(0x3 << (2 * port));
> + iowrite32(pcfg | ((mode & 0x3) << (2 * port)), state->iobase);
> +}
What is 0x3 above? 2*port? Please use #define for the
magic constant 3 and explain with a comment why you do *=2.
(...)
> +static int tb10x_gpio_request_enable(struct pinctrl_dev *pctl,
> + struct pinctrl_gpio_range *range,
> + unsigned pin)
> +{
> + struct tb10x_pinctrl_state *state = pinctrl_dev_get_drvdata(pctl);
> + int muxport = -1;
> + int muxmode = -1;
> + int i;
> +
> + mutex_lock(&state->mutex);
> +
> + for (i = 0; i < ARRAY_SIZE(tb10x_pingroups); i++) {
> + struct tb10x_pinfuncgrp *pfg = &tb10x_pingroups[i];
> + unsigned int port = pfg->port;
> + unsigned int mode = pfg->mode;
> + int j;
> +
> + if (port < 0)
> + continue;
> +
> + if (pfg->isgpio) {
> + muxport = port;
> + muxmode = mode;
> + continue;
> + }
> +
> + for (j = 0; j < pfg->pincnt; j++) {
> + if (pin == pfg->pins[j]) {
> + if (state->ports[port].count
> + && (state->ports[port].mode == mode)) {
> + mutex_unlock(&state->mutex);
> + return -EBUSY;
> + }
> + break;
> + }
> + }
> + }
This looks complicated.
I suggest trying to use:
struct pinctrl_gpio_range *range =
pinctrl_find_gpio_range_from_pin(pctldev, pin);
Then use the range to figure out which GPIO to hit.
(...)
> +static void tb10x_pctl_disable(struct pinctrl_dev *pctl,
> + unsigned func_selector, unsigned group_selector)
> +{
> + struct tb10x_pinctrl_state *state = pinctrl_dev_get_drvdata(pctl);
> + const struct tb10x_pinfuncgrp *grp = &state->pingroups[group_selector];
> +
> + if (grp->port < 0)
> + return;
> +
> + mutex_lock(&state->mutex);
> +
> + state->ports[grp->port].count--;
> +
> + mutex_unlock(&state->mutex);
> +}
Keeping refcounts like that looks complicated.
> +static int tb10x_pinctrl_probe(struct platform_device *pdev)
> +{
> + int ret = -EINVAL;
> + struct resource *mem = platform_get_resource(pdev, IORESOURCE_MEM, 0);
> + struct device_node *of_node = pdev->dev.of_node;
> + struct device_node *child;
> + struct tb10x_pinctrl_state *state;
> + int i;
> +
> + if (!of_node) {
> + dev_err(&pdev->dev, "No device tree node found.\n");
> + return -EINVAL;
> + }
> +
> + if (!mem) {
> + dev_err(&pdev->dev, "No memory resource defined.\n");
> + return -EINVAL;
> + }
> +
> + state = kzalloc(sizeof(struct tb10x_pinctrl_state) +
Use devm_kzalloc().
> + of_get_child_count(of_node)
> + * sizeof(struct tb10x_of_pinfunc),
> + GFP_KERNEL);
> + if (!state)
> + return -ENOMEM;
> +
> + platform_set_drvdata(pdev, state);
> + state->pinfuncs = (struct tb10x_of_pinfunc *)(state + 1);
> + mutex_init(&state->mutex);
> +
> + if (!request_mem_region(mem->start, resource_size(mem), pdev->name)) {
Use devm_ioremap_resource().
> + dev_err(&pdev->dev, "Request register region failed.\n");
> + ret = -EBUSY;
> + goto request_mem_fail;
> + }
> +
> + state->iobase = ioremap(mem->start, resource_size(mem));
> + if (!state->iobase) {
> + dev_err(&pdev->dev, "Request register region failed.\n");
> + ret = -EBUSY;
> + goto ioremap_fail;
> + }
And that will take care of this too.
> + state->pingroups = tb10x_pingroups;
> + state->pinfuncgrpcnt = ARRAY_SIZE(tb10x_pingroups);
Basically I don't like this because it looks like your driver is trying
to duplicate the job of the core: to keep track of groups and their
counts using the callback methods.
> + state->pctl = pinctrl_register(&tb10x_pindesc, &pdev->dev, state);
> + if (IS_ERR(state->pctl)) {
> + dev_err(&pdev->dev, "could not register TB10x pin driver\n");
> + ret = PTR_ERR(state->pctl);
> + goto pinctrl_reg_fail;
> + }
> +
> + return 0;
> +
> +pinctrl_reg_fail:
> + iounmap(state->iobase);
> +ioremap_fail:
> + release_region(mem->start, resource_size(mem));
> +request_mem_fail:
> + mutex_destroy(&state->mutex);
> + kfree(state);
> + return ret;
With devm_* allocators all of this goes away and you can
just return -ERRCODE; wherever there is a problem.
> +}
> +
> +static int tb10x_pinctrl_remove(struct platform_device *pdev)
> +{
> + struct resource *mem = platform_get_resource(pdev, IORESOURCE_MEM, 0);
> + struct tb10x_pinctrl_state *state = platform_get_drvdata(pdev);
> + int i;
> +
> + pinctrl_unregister(state->pctl);
> +
> + for (i = 0; i < ARRAY_SIZE(tb10x_pingroups); i++)
> + if (tb10x_pingroups[i].pctl == state)
> + tb10x_pingroups[i].pctl = NULL;
I don't understand what this cleanup is doing.
> +
> + iounmap(state->iobase);
> +
> + release_region(mem->start, resource_size(mem));
> +
> + mutex_destroy(&state->mutex);
> +
> + kfree(state);
The above goes away with devm_* allocators.
> +static const struct of_device_id tb10x_pinctrl_dt_ids[] = {
> + { .compatible = TB10X_IOMUX_COMPATIBLE },
Can you just inline the compat string here instead of using a #define?
Yours,
Linus Walleij
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