Hi Wolfram/Paul,
I have tried to fix my patches as per review comments from you.
Following is diff of the new changes i have made, I am sending a
new complete version separately:
commit 62cf40359c63ac028b3e8a6395f9440f6a3b0162
Author: Viresh Kumar <viresh.kumar@xxxxxxxxxx>
Date: Mon Dec 3 08:12:55 2012 +0530
fixup! i2c/adapter: Add bus recovery infrastructure
---
drivers/i2c/i2c-core.c | 42 +++++++++++++++++++++++++++---------------
include/linux/i2c.h | 19 +++++++++++--------
2 files changed, 38 insertions(+), 23 deletions(-)
diff --git a/drivers/i2c/i2c-core.c b/drivers/i2c/i2c-core.c
index d100276..9b6a1a6 100644
--- a/drivers/i2c/i2c-core.c
+++ b/drivers/i2c/i2c-core.c
@@ -109,15 +109,22 @@ static int i2c_device_uevent(struct device *dev,
struct kobj_uevent_env *env)
/* i2c bus recovery routines */
#define RECOVERY_CLK_CNT 9
#define DEFAULT_CLK_RATE 100 /* KHz */
+/* 10^6/KHz for delay in ns */
+unsigned long clk_delay = DIV_ROUND_UP(1000000, DEFAULT_CLK_RATE * 2);
-static void set_scl_gpio_value(struct i2c_adapter *adap, int val)
+static int get_sda_gpio_value(struct i2c_adapter *adap)
{
- gpio_set_value(adap->bus_recovery_info->scl_gpio, val);
+ return gpio_get_value(adap->bus_recovery_info->sda_gpio);
}
-static int get_sda_gpio_value(struct i2c_adapter *adap)
+static int get_scl_gpio_value(struct i2c_adapter *adap)
{
- return gpio_get_value(adap->bus_recovery_info->sda_gpio);
+ return gpio_get_value(adap->bus_recovery_info->scl_gpio);
+}
+
+static void set_scl_gpio_value(struct i2c_adapter *adap, int val)
+{
+ gpio_set_value(adap->bus_recovery_info->scl_gpio, val);
}
static int i2c_get_gpios_for_recovery(struct i2c_adapter *adap)
@@ -158,28 +165,37 @@ static void i2c_put_gpios_for_recovery(struct
i2c_adapter *adap)
static int i2c_generic_recovery(struct i2c_adapter *adap)
{
struct i2c_bus_recovery_info *bri = adap->bus_recovery_info;
- unsigned long delay = 1000000; /* 10^6/KHz for delay in ns */
int i, val = 0;
if (bri->prepare_recovery)
bri->prepare_recovery(bri);
+ /* SCL shouldn't be low here */
+ if (!bri->get_scl(adap)) {
+ dev_err(&adap->dev, "SCL is stuck Low, exiting recovery.\n");
+ goto unprepare;
+ }
+
/*
* By this time SCL is high, as we need to give 9 falling-rising edges
*/
-
- delay = DIV_ROUND_UP(delay, bri->clock_rate_khz * 2);
-
for (i = 0; i < RECOVERY_CLK_CNT * 2; i++, val = !val) {
bri->set_scl(adap, val);
- ndelay(delay);
+ ndelay(clk_delay);
/* break if sda got high, check only when scl line is high */
if (!bri->skip_sda_polling && val)
- if (unlikely(bri->get_sda(adap)))
+ /* Check SCL again to see fault condition */
+ if (!bri->get_scl(adap)) {
+ dev_err(&adap->dev, "SCL is stuck Low
during recovery, exiting recovery.\n");
+ goto unprepare;
+ }
+
+ if (bri->get_sda(adap))
break;
}
+unprepare:
if (bri->unprepare_recovery)
bri->unprepare_recovery(bri);
@@ -1008,13 +1024,9 @@ static int i2c_register_adapter(struct i2c_adapter *adap)
goto exit_recovery;
}
- if (!bri->clock_rate_khz) {
- dev_warn(&adap->dev, "default clk rate used: 100KHz\n");
- bri->clock_rate_khz = DEFAULT_CLK_RATE;
- }
-
/* GPIO recovery */
if (bri->recover_bus == i2c_generic_gpio_recovery) {
+ bri->get_scl = get_scl_gpio_value;
bri->set_scl = set_scl_gpio_value;
if (!bri->skip_sda_polling)
diff --git a/include/linux/i2c.h b/include/linux/i2c.h
index 63acd9d..165282f 100644
--- a/include/linux/i2c.h
+++ b/include/linux/i2c.h
@@ -373,14 +373,17 @@ struct i2c_algorithm {
* @recover_bus: Recover routine. Either pass driver's recover_bus()
routine, or
* i2c_generic_scl_recovery() or i2c_generic_gpio_recovery().
* @skip_sda_polling: if true, bus recovery will not poll sda line to check if
- * it became high or not. Only required if recover_bus == NULL.
- * @clock_rate_khz: clock rate of dummy clock in khz. Required for
both gpio and
- * scl type recovery.
- * @set_scl: This sets/clears scl line. For GPIO recovery set_scl_gpio_value()
- * is used here otherwise controller specific routine must be passed.
+ * it became high or not. Platforms/controllers which don't have
+ * configuration registers to control sda line must set this. Only required
+ * if recover_bus == NULL.
* @get_sda: This gets current value of sda line. For GPIO recovery
* get_sda_gpio_value() is used here otherwise controller specific routine
* must be passed.
+ * @get_scl: This gets current value of scl line. For GPIO recovery
+ * get_scl_gpio_value() is used here otherwise controller specific routine
+ * must be passed.
+ * @set_scl: This sets/clears scl line. For GPIO recovery set_scl_gpio_value()
+ * is used here otherwise controller specific routine must be passed.
* @prepare_recovery: This will be called before starting recovery.
Platform may
* configure padmux here for sda/scl line or something else they want.
* @unprepare_recovery: This will be called after completing recovery. Platform
@@ -391,15 +394,15 @@ struct i2c_algorithm {
struct i2c_bus_recovery_info {
int (*recover_bus)(struct i2c_adapter *);
bool skip_sda_polling;
- u32 clock_rate_khz;
/*
* Fn pointers for recovery, will point either to:
- * - set_scl_gpio_value and get_sda_gpio_value for gpio recovery
+ * - set_scl_gpio_value and get_[scl]sda_gpio_value for gpio recovery
* - Controller specific routines, otherwise
*/
- void (*set_scl)(struct i2c_adapter *, int val);
int (*get_sda)(struct i2c_adapter *);
+ int (*get_scl)(struct i2c_adapter *);
+ void (*set_scl)(struct i2c_adapter *, int val);
void (*prepare_recovery)(struct i2c_bus_recovery_info *bri);
void (*unprepare_recovery)(struct i2c_bus_recovery_info *bri);
--
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