/* * 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 */ u16 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 __devinit 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_request_and_ioremap(&pdev->dev, res); if (!chip->virt) { dev_err(&pdev->dev, "failed to remap STP memory\n"); return -ENOMEM; } 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);