/*
* This program is free software; you can redistribute it and/or modify it
* under the terms of the GNU General Public License version 2 as published
* by the Free Software Foundation.
*
* Copyright (C) 2012 John Crispin <blogic@openwrt.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.h>
#include <linux/io.h>
#include <linux/of_gpio.h>
#include <linux/clk.h>
#include <linux/err.h>
#include <lantiq_soc.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 0x3
#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) \
ltq_w32((ltq_r32(m + reg) & ~(clear)) | (set), \
m + 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_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 =
container_of(gc, struct xway_stp, 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 =
container_of(gc, struct xway_stp, gc);
if ((gpio < 8) && (chip->reserved & BIT(gpio))) {
dev_err(gc->dev, "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
* @virt: pointer to the remapped register range
*/
static int 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);
return 0;
}
static int xway_stp_probe(struct platform_device *pdev)
{
struct resource *res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
const __be32 *shadow, *groups, *dsl, *phy;
struct xway_stp *chip;
struct clk *clk;
int ret = 0;
if (!res) {
dev_err(&pdev->dev, "failed to request STP resource\n");
return -ENOENT;
}
chip = devm_kzalloc(&pdev->dev, sizeof(*chip), GFP_KERNEL);
if (!chip)
return -ENOMEM;
chip->virt = devm_ioremap_resource(&pdev->dev, res);
if (IS_ERR(chip->virt))
return PTR_ERR(chip->virt);
chip->gc.dev = &pdev->dev;
chip->gc.label = "stp-xway";
chip->gc.direction_output = xway_stp_dir_out;
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 */
shadow = of_get_property(pdev->dev.of_node, "lantiq,shadow", NULL);
if (shadow)
chip->shadow = be32_to_cpu(*shadow);
/* find out which gpio groups should be enabled */
groups = of_get_property(pdev->dev.of_node, "lantiq,groups", NULL);
if (groups)
chip->groups = be32_to_cpu(*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 */
dsl = of_get_property(pdev->dev.of_node, "lantiq,dsl", NULL);
if (dsl)
chip->dsl = be32_to_cpu(*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")) {
phy = of_get_property(pdev->dev.of_node, "lantiq,phy1", NULL);
if (phy)
chip->phy1 = be32_to_cpu(*phy) & XWAY_STP_PHY_MASK;
phy = of_get_property(pdev->dev.of_node, "lantiq,phy2", NULL);
if (phy)
chip->phy2 = be32_to_cpu(*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 = clk_get(&pdev->dev, NULL);
if (IS_ERR(clk)) {
dev_err(&pdev->dev, "Failed to get clock\n");
return PTR_ERR(clk);
}
clk_enable(clk);
ret = xway_stp_hw_init(chip);
if (!ret)
ret = gpiochip_add(&chip->gc);
if (!ret)
dev_info(&pdev->dev, "Init done\n");
return ret;
}
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",
.owner = THIS_MODULE,
.of_match_table = xway_stp_match,
},
};
int __init xway_stp_init(void)
{
return platform_driver_register(&xway_stp_driver);
}
subsys_initcall(xway_stp_init);