Fixed MTP to work with TWRP

drivers/gpio/gpio-stp-xway.c

@@ -0,0 +1,300 @@
+/*
+ *  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,
+	},
+};
+
+static int __init xway_stp_init(void)
+{
+	return platform_driver_register(&xway_stp_driver);
+}
+
+subsys_initcall(xway_stp_init);