1 files changed, 151 insertions, 72 deletions

diff --git a/drivers/i2c/busses/i2c-gpio.c b/drivers/i2c/busses/i2c-gpio.c
index c008d209f0b8..f4355b17bfbf 100644
--- a/drivers/i2c/busses/i2c-gpio.c
+++ b/drivers/i2c/busses/i2c-gpio.c
@@ -1,23 +1,22 @@
+// SPDX-License-Identifier: GPL-2.0-only
 /*
  * Bitbanging I2C bus driver using the GPIO API
  *
  * Copyright (C) 2007 Atmel Corporation
- *
- * 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.
  */
+#include <linux/completion.h>
 #include <linux/debugfs.h>
 #include <linux/delay.h>
-#include <linux/i2c.h>
+#include <linux/gpio/consumer.h>
 #include <linux/i2c-algo-bit.h>
-#include <linux/platform_data/i2c-gpio.h>
+#include <linux/i2c.h>
 #include <linux/init.h>
+#include <linux/interrupt.h>
 #include <linux/module.h>
-#include <linux/slab.h>
+#include <linux/platform_data/i2c-gpio.h>
 #include <linux/platform_device.h>
-#include <linux/gpio/consumer.h>
-#include <linux/of.h>
+#include <linux/property.h>
+#include <linux/slab.h>
 
 struct i2c_gpio_private_data {
 	struct gpio_desc *sda;
@@ -26,7 +25,9 @@ struct i2c_gpio_private_data {
 	struct i2c_algo_bit_data bit_data;
 	struct i2c_gpio_platform_data pdata;
 #ifdef CONFIG_I2C_GPIO_FAULT_INJECTOR
-	struct dentry *debug_dir;
+	/* these must be protected by bus lock */
+	struct completion scl_irq_completion;
+	u64 scl_irq_data;
 #endif
 };
 
@@ -70,7 +71,6 @@ static int i2c_gpio_getscl(void *data)
 }
 
 #ifdef CONFIG_I2C_GPIO_FAULT_INJECTOR
-static struct dentry *i2c_gpio_debug_dir;
 
 #define setsda(bd, val)	((bd)->setsda((bd)->data, val))
 #define setscl(bd, val)	((bd)->setscl((bd)->data, val))
@@ -162,60 +162,142 @@ static int fops_incomplete_write_byte_set(void *data, u64 addr)
 }
 DEFINE_DEBUGFS_ATTRIBUTE(fops_incomplete_write_byte, NULL, fops_incomplete_write_byte_set, "%llu\n");
 
-static void i2c_gpio_fault_injector_init(struct platform_device *pdev)
+static int i2c_gpio_fi_act_on_scl_irq(struct i2c_gpio_private_data *priv,
+				       irqreturn_t handler(int, void*))
 {
-	struct i2c_gpio_private_data *priv = platform_get_drvdata(pdev);
+	int ret, irq = gpiod_to_irq(priv->scl);
+
+	if (irq < 0)
+		return irq;
+
+	i2c_lock_bus(&priv->adap, I2C_LOCK_ROOT_ADAPTER);
+
+	ret = gpiod_direction_input(priv->scl);
+	if (ret)
+		goto unlock;
+
+	reinit_completion(&priv->scl_irq_completion);
 
+	ret = request_irq(irq, handler, IRQF_TRIGGER_FALLING,
+			  "i2c_gpio_fault_injector_scl_irq", priv);
+	if (ret)
+		goto output;
+
+	wait_for_completion_interruptible(&priv->scl_irq_completion);
+
+	free_irq(irq, priv);
+ output:
+	ret = gpiod_direction_output(priv->scl, 1) ?: ret;
+ unlock:
+	i2c_unlock_bus(&priv->adap, I2C_LOCK_ROOT_ADAPTER);
+
+	return ret;
+}
+
+static irqreturn_t lose_arbitration_irq(int irq, void *dev_id)
+{
+	struct i2c_gpio_private_data *priv = dev_id;
+
+	setsda(&priv->bit_data, 0);
+	udelay(priv->scl_irq_data);
+	setsda(&priv->bit_data, 1);
+
+	complete(&priv->scl_irq_completion);
+
+	return IRQ_HANDLED;
+}
+
+static int fops_lose_arbitration_set(void *data, u64 duration)
+{
+	struct i2c_gpio_private_data *priv = data;
+
+	if (duration > 100 * 1000)
+		return -EINVAL;
+
+	priv->scl_irq_data = duration;
 	/*
-	 * If there will be a debugfs-dir per i2c adapter somewhen, put the
-	 * 'fault-injector' dir there. Until then, we have a global dir with
-	 * all adapters as subdirs.
+	 * Interrupt on falling SCL. This ensures that the controller under test
+	 * has really started the transfer. Interrupt on falling SDA did only
+	 * exercise 'bus busy' detection on some HW but not 'arbitration lost'.
+	 * Note that the interrupt latency may cause the first bits to be
+	 * transmitted correctly.
 	 */
-	if (!i2c_gpio_debug_dir) {
-		i2c_gpio_debug_dir = debugfs_create_dir("i2c-fault-injector", NULL);
-		if (!i2c_gpio_debug_dir)
-			return;
-	}
+	return i2c_gpio_fi_act_on_scl_irq(priv, lose_arbitration_irq);
+}
+DEFINE_DEBUGFS_ATTRIBUTE(fops_lose_arbitration, NULL, fops_lose_arbitration_set, "%llu\n");
 
-	priv->debug_dir = debugfs_create_dir(pdev->name, i2c_gpio_debug_dir);
-	if (!priv->debug_dir)
-		return;
+static irqreturn_t inject_panic_irq(int irq, void *dev_id)
+{
+	struct i2c_gpio_private_data *priv = dev_id;
 
-	debugfs_create_file_unsafe("scl", 0600, priv->debug_dir, priv, &fops_scl);
-	debugfs_create_file_unsafe("sda", 0600, priv->debug_dir, priv, &fops_sda);
-	debugfs_create_file_unsafe("incomplete_address_phase", 0200, priv->debug_dir,
-				   priv, &fops_incomplete_addr_phase);
-	debugfs_create_file_unsafe("incomplete_write_byte", 0200, priv->debug_dir,
-				   priv, &fops_incomplete_write_byte);
+	udelay(priv->scl_irq_data);
+	panic("I2C fault injector induced panic");
+
+	return IRQ_HANDLED;
+}
+
+static int fops_inject_panic_set(void *data, u64 duration)
+{
+	struct i2c_gpio_private_data *priv = data;
+
+	if (duration > 100 * 1000)
+		return -EINVAL;
+
+	priv->scl_irq_data = duration;
+	/*
+	 * Interrupt on falling SCL. This ensures that the controller under test
+	 * has really started the transfer.
+	 */
+	return i2c_gpio_fi_act_on_scl_irq(priv, inject_panic_irq);
 }
+DEFINE_DEBUGFS_ATTRIBUTE(fops_inject_panic, NULL, fops_inject_panic_set, "%llu\n");
 
-static void i2c_gpio_fault_injector_exit(struct platform_device *pdev)
+static void i2c_gpio_fault_injector_init(struct platform_device *pdev)
 {
 	struct i2c_gpio_private_data *priv = platform_get_drvdata(pdev);
 
-	debugfs_remove_recursive(priv->debug_dir);
+	init_completion(&priv->scl_irq_completion);
+
+	debugfs_create_file_unsafe("incomplete_address_phase", 0200, priv->adap.debugfs,
+				   priv, &fops_incomplete_addr_phase);
+	debugfs_create_file_unsafe("incomplete_write_byte", 0200, priv->adap.debugfs,
+				   priv, &fops_incomplete_write_byte);
+	if (priv->bit_data.getscl) {
+		debugfs_create_file_unsafe("inject_panic", 0200, priv->adap.debugfs,
+					   priv, &fops_inject_panic);
+		debugfs_create_file_unsafe("lose_arbitration", 0200, priv->adap.debugfs,
+					   priv, &fops_lose_arbitration);
+	}
+	debugfs_create_file_unsafe("scl", 0600, priv->adap.debugfs, priv, &fops_scl);
+	debugfs_create_file_unsafe("sda", 0600, priv->adap.debugfs, priv, &fops_sda);
 }
 #else
 static inline void i2c_gpio_fault_injector_init(struct platform_device *pdev) {}
-static inline void i2c_gpio_fault_injector_exit(struct platform_device *pdev) {}
 #endif /* CONFIG_I2C_GPIO_FAULT_INJECTOR*/
 
-static void of_i2c_gpio_get_props(struct device_node *np,
-				  struct i2c_gpio_platform_data *pdata)
+/* Get i2c-gpio properties from DT or ACPI table */
+static void i2c_gpio_get_properties(struct device *dev,
+				    struct i2c_gpio_platform_data *pdata)
 {
 	u32 reg;
 
-	of_property_read_u32(np, "i2c-gpio,delay-us", &pdata->udelay);
+	device_property_read_u32(dev, "i2c-gpio,delay-us", &pdata->udelay);
 
-	if (!of_property_read_u32(np, "i2c-gpio,timeout-ms", &reg))
+	if (!device_property_read_u32(dev, "i2c-gpio,timeout-ms", &reg))
 		pdata->timeout = msecs_to_jiffies(reg);
 
 	pdata->sda_is_open_drain =
-		of_property_read_bool(np, "i2c-gpio,sda-open-drain");
+		device_property_read_bool(dev, "i2c-gpio,sda-open-drain");
 	pdata->scl_is_open_drain =
-		of_property_read_bool(np, "i2c-gpio,scl-open-drain");
+		device_property_read_bool(dev, "i2c-gpio,scl-open-drain");
 	pdata->scl_is_output_only =
-		of_property_read_bool(np, "i2c-gpio,scl-output-only");
+		device_property_read_bool(dev, "i2c-gpio,scl-output-only");
+	pdata->sda_is_output_only =
+		device_property_read_bool(dev, "i2c-gpio,sda-output-only");
+	pdata->sda_has_no_pullup =
+		device_property_read_bool(dev, "i2c-gpio,sda-has-no-pullup");
+	pdata->scl_has_no_pullup =
+		device_property_read_bool(dev, "i2c-gpio,scl-has-no-pullup");
 }
 
 static struct gpio_desc *i2c_gpio_get_desc(struct device *dev,
@@ -248,7 +330,7 @@ static struct gpio_desc *i2c_gpio_get_desc(struct device *dev,
 	if (ret == -ENOENT)
 		retdesc = ERR_PTR(-EPROBE_DEFER);
 
-	if (ret != -EPROBE_DEFER)
+	if (PTR_ERR(retdesc) != -EPROBE_DEFER)
 		dev_err(dev, "error trying to get descriptor: %d\n", ret);
 
 	return retdesc;
@@ -261,7 +343,7 @@ static int i2c_gpio_probe(struct platform_device *pdev)
 	struct i2c_algo_bit_data *bit_data;
 	struct i2c_adapter *adap;
 	struct device *dev = &pdev->dev;
-	struct device_node *np = dev->of_node;
+	struct fwnode_handle *fwnode = dev_fwnode(dev);
 	enum gpiod_flags gflags;
 	int ret;
 
@@ -273,8 +355,8 @@ static int i2c_gpio_probe(struct platform_device *pdev)
 	bit_data = &priv->bit_data;
 	pdata = &priv->pdata;
 
-	if (np) {
-		of_i2c_gpio_get_props(np, pdata);
+	if (fwnode) {
+		i2c_gpio_get_properties(dev, pdata);
 	} else {
 		/*
 		 * If all platform data settings are zero it is OK
@@ -286,13 +368,13 @@ static int i2c_gpio_probe(struct platform_device *pdev)
 
 	/*
 	 * First get the GPIO pins; if it fails, we'll defer the probe.
-	 * If the SDA line is marked from platform data or device tree as
-	 * "open drain" it means something outside of our control is making
-	 * this line being handled as open drain, and we should just handle
-	 * it as any other output. Else we enforce open drain as this is
-	 * required for an I2C bus.
+	 * If the SCL/SDA lines are marked "open drain" by platform data or
+	 * device tree then this means that something outside of our control is
+	 * marking these lines to be handled as open drain, and we should just
+	 * handle them as we handle any other output. Else we enforce open
+	 * drain as this is required for an I2C bus.
 	 */
-	if (pdata->sda_is_open_drain)
+	if (pdata->sda_is_open_drain || pdata->sda_has_no_pullup)
 		gflags = GPIOD_OUT_HIGH;
 	else
 		gflags = GPIOD_OUT_HIGH_OPEN_DRAIN;
@@ -300,14 +382,7 @@ static int i2c_gpio_probe(struct platform_device *pdev)
 	if (IS_ERR(priv->sda))
 		return PTR_ERR(priv->sda);
 
-	/*
-	 * If the SCL line is marked from platform data or device tree as
-	 * "open drain" it means something outside of our control is making
-	 * this line being handled as open drain, and we should just handle
-	 * it as any other output. Else we enforce open drain as this is
-	 * required for an I2C bus.
-	 */
-	if (pdata->scl_is_open_drain)
+	if (pdata->scl_is_open_drain || pdata->scl_has_no_pullup)
 		gflags = GPIOD_OUT_HIGH;
 	else
 		gflags = GPIOD_OUT_HIGH_OPEN_DRAIN;
@@ -317,13 +392,16 @@ static int i2c_gpio_probe(struct platform_device *pdev)
 
 	if (gpiod_cansleep(priv->sda) || gpiod_cansleep(priv->scl))
 		dev_warn(dev, "Slow GPIO pins might wreak havoc into I2C/SMBus bus timing");
+	else
+		bit_data->can_do_atomic = true;
 
 	bit_data->setsda = i2c_gpio_setsda_val;
 	bit_data->setscl = i2c_gpio_setscl_val;
 
 	if (!pdata->scl_is_output_only)
 		bit_data->getscl = i2c_gpio_getscl;
-	bit_data->getsda = i2c_gpio_getsda;
+	if (!pdata->sda_is_output_only)
+		bit_data->getsda = i2c_gpio_getsda;
 
 	if (pdata->udelay)
 		bit_data->udelay = pdata->udelay;
@@ -340,15 +418,15 @@ static int i2c_gpio_probe(struct platform_device *pdev)
 	bit_data->data = priv;
 
 	adap->owner = THIS_MODULE;
-	if (np)
-		strlcpy(adap->name, dev_name(dev), sizeof(adap->name));
+	if (fwnode)
+		strscpy(adap->name, dev_name(dev), sizeof(adap->name));
 	else
 		snprintf(adap->name, sizeof(adap->name), "i2c-gpio%d", pdev->id);
 
 	adap->algo_data = bit_data;
-	adap->class = I2C_CLASS_HWMON | I2C_CLASS_SPD;
+	adap->class = I2C_CLASS_HWMON;
 	adap->dev.parent = dev;
-	adap->dev.of_node = np;
+	device_set_node(&adap->dev, fwnode);
 
 	adap->nr = pdev->id;
 	ret = i2c_bit_add_numbered_bus(adap);
@@ -372,34 +450,35 @@ static int i2c_gpio_probe(struct platform_device *pdev)
 	return 0;
 }
 
-static int i2c_gpio_remove(struct platform_device *pdev)
+static void i2c_gpio_remove(struct platform_device *pdev)
 {
 	struct i2c_gpio_private_data *priv;
 	struct i2c_adapter *adap;
 
-	i2c_gpio_fault_injector_exit(pdev);
-
 	priv = platform_get_drvdata(pdev);
 	adap = &priv->adap;
 
 	i2c_del_adapter(adap);
-
-	return 0;
 }
 
-#if defined(CONFIG_OF)
 static const struct of_device_id i2c_gpio_dt_ids[] = {
 	{ .compatible = "i2c-gpio", },
 	{ /* sentinel */ }
 };
 
 MODULE_DEVICE_TABLE(of, i2c_gpio_dt_ids);
-#endif
+
+static const struct acpi_device_id i2c_gpio_acpi_match[] = {
+	{ "LOON0005" }, /* LoongArch */
+	{ }
+};
+MODULE_DEVICE_TABLE(acpi, i2c_gpio_acpi_match);
 
 static struct platform_driver i2c_gpio_driver = {
 	.driver		= {
 		.name	= "i2c-gpio",
-		.of_match_table	= of_match_ptr(i2c_gpio_dt_ids),
+		.of_match_table	= i2c_gpio_dt_ids,
+		.acpi_match_table = i2c_gpio_acpi_match,
 	},
 	.probe		= i2c_gpio_probe,
 	.remove		= i2c_gpio_remove,
@@ -425,5 +504,5 @@ module_exit(i2c_gpio_exit);
 
 MODULE_AUTHOR("Haavard Skinnemoen (Atmel)");
 MODULE_DESCRIPTION("Platform-independent bitbanging I2C driver");
-MODULE_LICENSE("GPL");
+MODULE_LICENSE("GPL v2");
 MODULE_ALIAS("platform:i2c-gpio");