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path: root/drivers/i2c/busses/i2c-gpio.c
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Diffstat (limited to 'drivers/i2c/busses/i2c-gpio.c')
-rw-r--r--drivers/i2c/busses/i2c-gpio.c122
1 files changed, 118 insertions, 4 deletions
diff --git a/drivers/i2c/busses/i2c-gpio.c b/drivers/i2c/busses/i2c-gpio.c
index d80ea6ce91bb..58abb3eced58 100644
--- a/drivers/i2c/busses/i2c-gpio.c
+++ b/drivers/i2c/busses/i2c-gpio.c
@@ -7,6 +7,8 @@
* it under the terms of the GNU General Public License version 2 as
* published by the Free Software Foundation.
*/
+#include <linux/debugfs.h>
+#include <linux/delay.h>
#include <linux/i2c.h>
#include <linux/i2c-algo-bit.h>
#include <linux/i2c-gpio.h>
@@ -23,6 +25,9 @@ struct i2c_gpio_private_data {
struct i2c_adapter adap;
struct i2c_algo_bit_data bit_data;
struct i2c_gpio_platform_data pdata;
+#ifdef CONFIG_I2C_GPIO_FAULT_INJECTOR
+ struct dentry *debug_dir;
+#endif
};
/*
@@ -34,7 +39,7 @@ static void i2c_gpio_setsda_val(void *data, int state)
{
struct i2c_gpio_private_data *priv = data;
- gpiod_set_value(priv->sda, state);
+ gpiod_set_value_cansleep(priv->sda, state);
}
/*
@@ -47,23 +52,125 @@ static void i2c_gpio_setscl_val(void *data, int state)
{
struct i2c_gpio_private_data *priv = data;
- gpiod_set_value(priv->scl, state);
+ gpiod_set_value_cansleep(priv->scl, state);
}
static int i2c_gpio_getsda(void *data)
{
struct i2c_gpio_private_data *priv = data;
- return gpiod_get_value(priv->sda);
+ return gpiod_get_value_cansleep(priv->sda);
}
static int i2c_gpio_getscl(void *data)
{
struct i2c_gpio_private_data *priv = data;
- return gpiod_get_value(priv->scl);
+ return gpiod_get_value_cansleep(priv->scl);
+}
+
+#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))
+#define getsda(bd) ((bd)->getsda((bd)->data))
+#define getscl(bd) ((bd)->getscl((bd)->data))
+
+#define WIRE_ATTRIBUTE(wire) \
+static int fops_##wire##_get(void *data, u64 *val) \
+{ \
+ struct i2c_gpio_private_data *priv = data; \
+ \
+ i2c_lock_adapter(&priv->adap); \
+ *val = get##wire(&priv->bit_data); \
+ i2c_unlock_adapter(&priv->adap); \
+ return 0; \
+} \
+static int fops_##wire##_set(void *data, u64 val) \
+{ \
+ struct i2c_gpio_private_data *priv = data; \
+ \
+ i2c_lock_adapter(&priv->adap); \
+ set##wire(&priv->bit_data, val); \
+ i2c_unlock_adapter(&priv->adap); \
+ return 0; \
+} \
+DEFINE_DEBUGFS_ATTRIBUTE(fops_##wire, fops_##wire##_get, fops_##wire##_set, "%llu\n")
+
+WIRE_ATTRIBUTE(scl);
+WIRE_ATTRIBUTE(sda);
+
+static int fops_incomplete_transfer_set(void *data, u64 addr)
+{
+ struct i2c_gpio_private_data *priv = data;
+ struct i2c_algo_bit_data *bit_data = &priv->bit_data;
+ int i, pattern;
+
+ if (addr > 0x7f)
+ return -EINVAL;
+
+ /* ADDR (7 bit) + RD (1 bit) + SDA hi (1 bit) */
+ pattern = (addr << 2) | 3;
+
+ i2c_lock_adapter(&priv->adap);
+
+ /* START condition */
+ setsda(bit_data, 0);
+ udelay(bit_data->udelay);
+
+ /* Send ADDR+RD, request ACK, don't send STOP */
+ for (i = 8; i >= 0; i--) {
+ setscl(bit_data, 0);
+ udelay(bit_data->udelay / 2);
+ setsda(bit_data, (pattern >> i) & 1);
+ udelay((bit_data->udelay + 1) / 2);
+ setscl(bit_data, 1);
+ udelay(bit_data->udelay);
+ }
+
+ i2c_unlock_adapter(&priv->adap);
+
+ return 0;
+}
+DEFINE_DEBUGFS_ATTRIBUTE(fops_incomplete_transfer, NULL, fops_incomplete_transfer_set, "%llu\n");
+
+static void i2c_gpio_fault_injector_init(struct platform_device *pdev)
+{
+ struct i2c_gpio_private_data *priv = platform_get_drvdata(pdev);
+
+ /*
+ * 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.
+ */
+ if (!i2c_gpio_debug_dir) {
+ i2c_gpio_debug_dir = debugfs_create_dir("i2c-fault-injector", NULL);
+ if (!i2c_gpio_debug_dir)
+ return;
+ }
+
+ priv->debug_dir = debugfs_create_dir(pdev->name, i2c_gpio_debug_dir);
+ if (!priv->debug_dir)
+ return;
+
+ 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_transfer", 0200, priv->debug_dir,
+ priv, &fops_incomplete_transfer);
}
+static void i2c_gpio_fault_injector_exit(struct platform_device *pdev)
+{
+ struct i2c_gpio_private_data *priv = platform_get_drvdata(pdev);
+
+ debugfs_remove_recursive(priv->debug_dir);
+}
+#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)
{
@@ -179,6 +286,9 @@ static int i2c_gpio_probe(struct platform_device *pdev)
if (IS_ERR(priv->scl))
return PTR_ERR(priv->scl);
+ if (gpiod_cansleep(priv->sda) || gpiod_cansleep(priv->scl))
+ dev_warn(dev, "Slow GPIO pins might wreak havoc into I2C/SMBus bus timing");
+
bit_data->setsda = i2c_gpio_setsda_val;
bit_data->setscl = i2c_gpio_setscl_val;
@@ -228,6 +338,8 @@ static int i2c_gpio_probe(struct platform_device *pdev)
pdata->scl_is_output_only
? ", no clock stretching" : "");
+ i2c_gpio_fault_injector_init(pdev);
+
return 0;
}
@@ -236,6 +348,8 @@ static int 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;