diff options
Diffstat (limited to 'drivers/gpio/gpio-stp-xway.c')
| -rw-r--r-- | drivers/gpio/gpio-stp-xway.c | 340 |
1 files changed, 340 insertions, 0 deletions
diff --git a/drivers/gpio/gpio-stp-xway.c b/drivers/gpio/gpio-stp-xway.c new file mode 100644 index 000000000..0ce154342 --- /dev/null +++ b/drivers/gpio/gpio-stp-xway.c @@ -0,0 +1,340 @@ +// 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 (BIT(23) | BIT(24) | BIT(25) | BIT(26) | BIT(27)) + +#define XWAY_STP_FPIS_VALUE BIT(21) +#define XWAY_STP_FPIS_MASK (BIT(20) | BIT(21)) + +/* 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 3 +#define XWAY_STP_PHY3_SHIFT 6 +#define XWAY_STP_PHY4_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 phy3; /* 3 bits can be driven by phy3 */ + u8 phy4; /* 3 bits can be driven by phy4 */ + 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); + if (!chip->reserved) + 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); + + if (of_machine_is_compatible("lantiq,grx390") + || of_machine_is_compatible("lantiq,ar10")) { + xway_stp_w32_mask(chip->virt, + XWAY_STP_PHY_MASK << XWAY_STP_PHY3_SHIFT, + chip->phy3 << XWAY_STP_PHY3_SHIFT, + XWAY_STP_CON1); + } + + if (of_machine_is_compatible("lantiq,grx390")) { + xway_stp_w32_mask(chip->virt, + XWAY_STP_PHY_MASK << XWAY_STP_PHY4_SHIFT, + chip->phy4 << XWAY_STP_PHY4_SHIFT, + XWAY_STP_CON1); + } + + /* mask out the hw driven bits in gpio_request */ + chip->reserved = (chip->phy4 << 11) | (chip->phy3 << 8) | (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); + xway_stp_w32_mask(chip->virt, XWAY_STP_SPEED_MASK, + XWAY_STP_10HZ, XWAY_STP_CON1); + xway_stp_w32_mask(chip->virt, XWAY_STP_FPIS_MASK, + XWAY_STP_FPIS_VALUE, 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") || + of_machine_is_compatible("lantiq,ar10") || + of_machine_is_compatible("lantiq,grx390")) { + 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; + } + + if (of_machine_is_compatible("lantiq,ar10") || + of_machine_is_compatible("lantiq,grx390")) { + if (!of_property_read_u32(pdev->dev.of_node, "lantiq,phy3", &phy)) + chip->phy3 = phy & XWAY_STP_PHY_MASK; + } + + if (of_machine_is_compatible("lantiq,grx390")) { + if (!of_property_read_u32(pdev->dev.of_node, "lantiq,phy4", &phy)) + chip->phy4 = 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); |