linux/drivers/gpio/gpio-stp-xway.c
Linus Torvalds 2ec98f5678 Bulk GPIO changes for the v5.3 kernel cycle:
Core:
 
 - When a gpio_chip request GPIOs from itself, it can now fully
   control the line characteristics, both machine and consumer
   flags. This makes a lot of sense, but took some time before I
   figured out that this is how it has to work.
 
 - Several smallish documentation fixes.
 
 New drivers:
 
 - The PCA953x driver now supports the TI TCA9539.
 
 - The DaVinci driver now supports the K3 AM654 SoCs.
 
 Driver improvements:
 
 - Major overhaul and hardening of the OMAP driver by Russell
   King.
 
 - Starting to move some drivers to the new API passing irq_chip
   along with the gpio_chip when adding the gpio_chip instead
   of adding it separately.
 
 Unrelated:
 
 - Delete the FMC subsystem.
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Merge tag 'gpio-v5.3-1' of git://git.kernel.org/pub/scm/linux/kernel/git/linusw/linux-gpio

Pull GPIO updates from Linus Walleij:
 "This is the big slew of GPIO changes for the v5.3 kernel cycle. This
  is mostly incremental work this time.

  Three important things:

   - The FMC subsystem is deleted through my tree. This happens through
     GPIO as its demise was discussed in relation to a patch decoupling
     its GPIO implementation from the standard way of handling GPIO. As
     it turns out, that is not the only subsystem it reimplements and
     the authors think it is better do scratch it and start over using
     the proper kernel subsystems than try to polish the rust shiny. See
     the commit (ACKed by the maintainers) for details.

   - Arnd made a small devres patch that was ACKed by Greg and goes into
     the device core.

   - SPDX header change colissions may happen, because at times I've
     seen that quite a lot changed during the -rc:s in regards to SPDX.
     (It is good stuff, tglx has me convinced, and it is worth the
     occasional pain.)

  Apart from this is is nothing controversial or problematic.

  Summary:

  Core:

   - When a gpio_chip request GPIOs from itself, it can now fully
     control the line characteristics, both machine and consumer flags.
     This makes a lot of sense, but took some time before I figured out
     that this is how it has to work.

   - Several smallish documentation fixes.

  New drivers:

   - The PCA953x driver now supports the TI TCA9539.

   - The DaVinci driver now supports the K3 AM654 SoCs.

  Driver improvements:

   - Major overhaul and hardening of the OMAP driver by Russell King.

   - Starting to move some drivers to the new API passing irq_chip along
     with the gpio_chip when adding the gpio_chip instead of adding it
     separately.

  Unrelated:

   - Delete the FMC subsystem"

* tag 'gpio-v5.3-1' of git://git.kernel.org/pub/scm/linux/kernel/git/linusw/linux-gpio: (87 commits)
  Revert "gpio: tegra: Clean-up debugfs initialisation"
  gpiolib: Use spinlock_t instead of struct spinlock
  gpio: stp-xway: allow compile-testing
  gpio: stp-xway: get rid of the #include <lantiq_soc.h> dependency
  gpio: stp-xway: improve module clock error handling
  gpio: stp-xway: simplify error handling in xway_stp_probe()
  gpiolib: Clarify use of non-sleeping functions
  gpiolib: Fix references to gpiod_[gs]et_*value_cansleep() variants
  gpiolib: Document new gpio_chip.init_valid_mask field
  Documentation: gpio: Fix reference to gpiod_get_array()
  gpio: pl061: drop duplicate printing of device name
  gpio: altera: Pass irqchip when adding gpiochip
  gpio: siox: Use devm_ managed gpiochip
  gpio: siox: Add struct device *dev helper variable
  gpio: siox: Pass irqchip when adding gpiochip
  drivers: gpio: amd-fch: make resource struct const
  devres: allow const resource arguments
  gpio: ath79: Pass irqchip when adding gpiochip
  gpio: tegra: Clean-up debugfs initialisation
  gpio: siox: Switch to IRQ_TYPE_NONE
  ...
2019-07-09 09:07:00 -07:00

299 lines
8.2 KiB
C

// SPDX-License-Identifier: GPL-2.0-only
/*
*
* Copyright (C) 2012 John Crispin <john@phrozen.org>
*/
#include <linux/slab.h>
#include <linux/init.h>
#include <linux/module.h>
#include <linux/types.h>
#include <linux/of_platform.h>
#include <linux/mutex.h>
#include <linux/gpio/driver.h>
#include <linux/io.h>
#include <linux/clk.h>
#include <linux/err.h>
/*
* The Serial To Parallel (STP) is found on MIPS based Lantiq socs. It is a
* peripheral controller used to drive external shift register cascades. At most
* 3 groups of 8 bits can be driven. The hardware is able to allow the DSL modem
* to drive the 2 LSBs of the cascade automatically.
*/
/* control register 0 */
#define XWAY_STP_CON0 0x00
/* control register 1 */
#define XWAY_STP_CON1 0x04
/* data register 0 */
#define XWAY_STP_CPU0 0x08
/* data register 1 */
#define XWAY_STP_CPU1 0x0C
/* access register */
#define XWAY_STP_AR 0x10
/* software or hardware update select bit */
#define XWAY_STP_CON_SWU BIT(31)
/* automatic update rates */
#define XWAY_STP_2HZ 0
#define XWAY_STP_4HZ BIT(23)
#define XWAY_STP_8HZ BIT(24)
#define XWAY_STP_10HZ (BIT(24) | BIT(23))
#define XWAY_STP_SPEED_MASK (0xf << 23)
/* clock source for automatic update */
#define XWAY_STP_UPD_FPI BIT(31)
#define XWAY_STP_UPD_MASK (BIT(31) | BIT(30))
/* let the adsl core drive the 2 LSBs */
#define XWAY_STP_ADSL_SHIFT 24
#define XWAY_STP_ADSL_MASK 0x3
/* 2 groups of 3 bits can be driven by the phys */
#define XWAY_STP_PHY_MASK 0x7
#define XWAY_STP_PHY1_SHIFT 27
#define XWAY_STP_PHY2_SHIFT 15
/* STP has 3 groups of 8 bits */
#define XWAY_STP_GROUP0 BIT(0)
#define XWAY_STP_GROUP1 BIT(1)
#define XWAY_STP_GROUP2 BIT(2)
#define XWAY_STP_GROUP_MASK (0x7)
/* Edge configuration bits */
#define XWAY_STP_FALLING BIT(26)
#define XWAY_STP_EDGE_MASK BIT(26)
#define xway_stp_r32(m, reg) __raw_readl(m + reg)
#define xway_stp_w32(m, val, reg) __raw_writel(val, m + reg)
#define xway_stp_w32_mask(m, clear, set, reg) \
xway_stp_w32(m, (xway_stp_r32(m, reg) & ~(clear)) | (set), reg)
struct xway_stp {
struct gpio_chip gc;
void __iomem *virt;
u32 edge; /* rising or falling edge triggered shift register */
u32 shadow; /* shadow the shift registers state */
u8 groups; /* we can drive 1-3 groups of 8bit each */
u8 dsl; /* the 2 LSBs can be driven by the dsl core */
u8 phy1; /* 3 bits can be driven by phy1 */
u8 phy2; /* 3 bits can be driven by phy2 */
u8 reserved; /* mask out the hw driven bits in gpio_request */
};
/**
* xway_stp_get() - gpio_chip->get - get gpios.
* @gc: Pointer to gpio_chip device structure.
* @gpio: GPIO signal number.
*
* Gets the shadow value.
*/
static int xway_stp_get(struct gpio_chip *gc, unsigned int gpio)
{
struct xway_stp *chip = gpiochip_get_data(gc);
return (xway_stp_r32(chip->virt, XWAY_STP_CPU0) & BIT(gpio));
}
/**
* xway_stp_set() - gpio_chip->set - set gpios.
* @gc: Pointer to gpio_chip device structure.
* @gpio: GPIO signal number.
* @val: Value to be written to specified signal.
*
* Set the shadow value and call ltq_ebu_apply.
*/
static void xway_stp_set(struct gpio_chip *gc, unsigned gpio, int val)
{
struct xway_stp *chip = gpiochip_get_data(gc);
if (val)
chip->shadow |= BIT(gpio);
else
chip->shadow &= ~BIT(gpio);
xway_stp_w32(chip->virt, chip->shadow, XWAY_STP_CPU0);
xway_stp_w32_mask(chip->virt, 0, XWAY_STP_CON_SWU, XWAY_STP_CON0);
}
/**
* xway_stp_dir_out() - gpio_chip->dir_out - set gpio direction.
* @gc: Pointer to gpio_chip device structure.
* @gpio: GPIO signal number.
* @val: Value to be written to specified signal.
*
* Same as xway_stp_set, always returns 0.
*/
static int xway_stp_dir_out(struct gpio_chip *gc, unsigned gpio, int val)
{
xway_stp_set(gc, gpio, val);
return 0;
}
/**
* xway_stp_request() - gpio_chip->request
* @gc: Pointer to gpio_chip device structure.
* @gpio: GPIO signal number.
*
* We mask out the HW driven pins
*/
static int xway_stp_request(struct gpio_chip *gc, unsigned gpio)
{
struct xway_stp *chip = gpiochip_get_data(gc);
if ((gpio < 8) && (chip->reserved & BIT(gpio))) {
dev_err(gc->parent, "GPIO %d is driven by hardware\n", gpio);
return -ENODEV;
}
return 0;
}
/**
* xway_stp_hw_init() - Configure the STP unit and enable the clock gate
* @chip: Pointer to the xway_stp chip structure
*/
static void xway_stp_hw_init(struct xway_stp *chip)
{
/* sane defaults */
xway_stp_w32(chip->virt, 0, XWAY_STP_AR);
xway_stp_w32(chip->virt, 0, XWAY_STP_CPU0);
xway_stp_w32(chip->virt, 0, XWAY_STP_CPU1);
xway_stp_w32(chip->virt, XWAY_STP_CON_SWU, XWAY_STP_CON0);
xway_stp_w32(chip->virt, 0, XWAY_STP_CON1);
/* apply edge trigger settings for the shift register */
xway_stp_w32_mask(chip->virt, XWAY_STP_EDGE_MASK,
chip->edge, XWAY_STP_CON0);
/* apply led group settings */
xway_stp_w32_mask(chip->virt, XWAY_STP_GROUP_MASK,
chip->groups, XWAY_STP_CON1);
/* tell the hardware which pins are controlled by the dsl modem */
xway_stp_w32_mask(chip->virt,
XWAY_STP_ADSL_MASK << XWAY_STP_ADSL_SHIFT,
chip->dsl << XWAY_STP_ADSL_SHIFT,
XWAY_STP_CON0);
/* tell the hardware which pins are controlled by the phys */
xway_stp_w32_mask(chip->virt,
XWAY_STP_PHY_MASK << XWAY_STP_PHY1_SHIFT,
chip->phy1 << XWAY_STP_PHY1_SHIFT,
XWAY_STP_CON0);
xway_stp_w32_mask(chip->virt,
XWAY_STP_PHY_MASK << XWAY_STP_PHY2_SHIFT,
chip->phy2 << XWAY_STP_PHY2_SHIFT,
XWAY_STP_CON1);
/* mask out the hw driven bits in gpio_request */
chip->reserved = (chip->phy2 << 5) | (chip->phy1 << 2) | chip->dsl;
/*
* if we have pins that are driven by hw, we need to tell the stp what
* clock to use as a timer.
*/
if (chip->reserved)
xway_stp_w32_mask(chip->virt, XWAY_STP_UPD_MASK,
XWAY_STP_UPD_FPI, XWAY_STP_CON1);
}
static int xway_stp_probe(struct platform_device *pdev)
{
u32 shadow, groups, dsl, phy;
struct xway_stp *chip;
struct clk *clk;
int ret = 0;
chip = devm_kzalloc(&pdev->dev, sizeof(*chip), GFP_KERNEL);
if (!chip)
return -ENOMEM;
chip->virt = devm_platform_ioremap_resource(pdev, 0);
if (IS_ERR(chip->virt))
return PTR_ERR(chip->virt);
chip->gc.parent = &pdev->dev;
chip->gc.label = "stp-xway";
chip->gc.direction_output = xway_stp_dir_out;
chip->gc.get = xway_stp_get;
chip->gc.set = xway_stp_set;
chip->gc.request = xway_stp_request;
chip->gc.base = -1;
chip->gc.owner = THIS_MODULE;
/* store the shadow value if one was passed by the devicetree */
if (!of_property_read_u32(pdev->dev.of_node, "lantiq,shadow", &shadow))
chip->shadow = shadow;
/* find out which gpio groups should be enabled */
if (!of_property_read_u32(pdev->dev.of_node, "lantiq,groups", &groups))
chip->groups = groups & XWAY_STP_GROUP_MASK;
else
chip->groups = XWAY_STP_GROUP0;
chip->gc.ngpio = fls(chip->groups) * 8;
/* find out which gpios are controlled by the dsl core */
if (!of_property_read_u32(pdev->dev.of_node, "lantiq,dsl", &dsl))
chip->dsl = dsl & XWAY_STP_ADSL_MASK;
/* find out which gpios are controlled by the phys */
if (of_machine_is_compatible("lantiq,ar9") ||
of_machine_is_compatible("lantiq,gr9") ||
of_machine_is_compatible("lantiq,vr9")) {
if (!of_property_read_u32(pdev->dev.of_node, "lantiq,phy1", &phy))
chip->phy1 = phy & XWAY_STP_PHY_MASK;
if (!of_property_read_u32(pdev->dev.of_node, "lantiq,phy2", &phy))
chip->phy2 = phy & XWAY_STP_PHY_MASK;
}
/* check which edge trigger we should use, default to a falling edge */
if (!of_find_property(pdev->dev.of_node, "lantiq,rising", NULL))
chip->edge = XWAY_STP_FALLING;
clk = devm_clk_get(&pdev->dev, NULL);
if (IS_ERR(clk)) {
dev_err(&pdev->dev, "Failed to get clock\n");
return PTR_ERR(clk);
}
ret = clk_prepare_enable(clk);
if (ret)
return ret;
xway_stp_hw_init(chip);
ret = devm_gpiochip_add_data(&pdev->dev, &chip->gc, chip);
if (ret) {
clk_disable_unprepare(clk);
return ret;
}
dev_info(&pdev->dev, "Init done\n");
return 0;
}
static const struct of_device_id xway_stp_match[] = {
{ .compatible = "lantiq,gpio-stp-xway" },
{},
};
MODULE_DEVICE_TABLE(of, xway_stp_match);
static struct platform_driver xway_stp_driver = {
.probe = xway_stp_probe,
.driver = {
.name = "gpio-stp-xway",
.of_match_table = xway_stp_match,
},
};
static int __init xway_stp_init(void)
{
return platform_driver_register(&xway_stp_driver);
}
subsys_initcall(xway_stp_init);