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i2c-omap: add bus recovery support 

This is based on commit 9dcb0e7b999db6c420c70fd32497a979a044fcdf from
the kernel with some additional fixes.

Signed-off-by: Jan Luebbe <jluebbe@debian.org>
This commit is contained in:
Jan Luebbe 2015-07-08 15:17:41 +02:00
parent 96617c5ef3
commit af26985016
1 changed files with 81 additions and 3 deletions
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84
drivers/i2c/busses/i2c-omap.c
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@ -107,16 +107,20 @@
#define OMAP_I2C_SCLH_HSSCLH 8
/* I2C System Test Register (OMAP_I2C_SYSTEST): */
#ifdef DEBUG
#define OMAP_I2C_SYSTEST_ST_EN (1 << 15) /* System test enable */
#define OMAP_I2C_SYSTEST_FREE (1 << 14) /* Free running mode */
#define OMAP_I2C_SYSTEST_TMODE_MASK (3 << 12) /* Test mode select */
#define OMAP_I2C_SYSTEST_TMODE_SHIFT (12) /* Test mode select */
/* Functional mode */
#define OMAP_I2C_SYSTEST_SCL_I_FUNC (1 << 8) /* SCL line input value */
#define OMAP_I2C_SYSTEST_SCL_O_FUNC (1 << 7) /* SCL line output value */
#define OMAP_I2C_SYSTEST_SDA_I_FUNC (1 << 6) /* SDA line input value */
#define OMAP_I2C_SYSTEST_SDA_O_FUNC (1 << 5) /* SDA line output value */
/* SDA/SCL IO mode */
#define OMAP_I2C_SYSTEST_SCL_I (1 << 3) /* SCL line sense in */
#define OMAP_I2C_SYSTEST_SCL_O (1 << 2) /* SCL line drive out */
#define OMAP_I2C_SYSTEST_SDA_I (1 << 1) /* SDA line sense in */
#define OMAP_I2C_SYSTEST_SDA_O (1 << 0) /* SDA line drive out */
#endif
/* OCP_SYSSTATUS bit definitions */
#define SYSS_RESETDONE_MASK (1 << 0)
@ -492,7 +496,7 @@ static int omap_i2c_wait_for_bb(struct i2c_adapter *adapter)
while (omap_i2c_read_reg(i2c_omap, OMAP_I2C_STAT_REG) & OMAP_I2C_STAT_BB) {
if (is_timeout(start, MSECOND)) {
dev_warn(&adapter->dev, "timeout waiting for bus ready\n");
return -ETIMEDOUT;
return i2c_recover_bus(adapter);
}
}
@ -990,6 +994,79 @@ out:
#define OMAP_I2C_SCHEME_0 0
#define OMAP_I2C_SCHEME_1 1
static int omap_i2c_get_scl(struct i2c_adapter *adapter)
{
struct omap_i2c_struct *i2c_omap = to_omap_i2c_struct(adapter);
u32 reg;
reg = omap_i2c_read_reg(i2c_omap, OMAP_I2C_SYSTEST_REG);
return reg & OMAP_I2C_SYSTEST_SCL_I_FUNC;
}
static int omap_i2c_get_sda(struct i2c_adapter *adapter)
{
struct omap_i2c_struct *i2c_omap = to_omap_i2c_struct(adapter);
u32 reg;
reg = omap_i2c_read_reg(i2c_omap, OMAP_I2C_SYSTEST_REG);
return reg & OMAP_I2C_SYSTEST_SDA_I_FUNC;
}
static void omap_i2c_set_scl(struct i2c_adapter *adapter, int val)
{
struct omap_i2c_struct *i2c_omap = to_omap_i2c_struct(adapter);
u32 reg;
reg = omap_i2c_read_reg(i2c_omap, OMAP_I2C_SYSTEST_REG);
if (val)
reg |= OMAP_I2C_SYSTEST_SCL_O;
else
reg &= ~OMAP_I2C_SYSTEST_SCL_O;
omap_i2c_write_reg(i2c_omap, OMAP_I2C_SYSTEST_REG, reg);
}
static void omap_i2c_prepare_recovery(struct i2c_adapter *adapter)
{
struct omap_i2c_struct *i2c_omap = to_omap_i2c_struct(adapter);
u32 reg;
reg = omap_i2c_read_reg(i2c_omap, OMAP_I2C_SYSTEST_REG);
/* enable test mode */
reg |= OMAP_I2C_SYSTEST_ST_EN;
/* select SDA/SCL IO mode */
reg |= 3 << OMAP_I2C_SYSTEST_TMODE_SHIFT;
/* set SCL to high-impedance state (reset value is 0) */
reg |= OMAP_I2C_SYSTEST_SCL_O;
/* set SDA to high-impedance state (reset value is 0) */
reg |= OMAP_I2C_SYSTEST_SDA_O;
omap_i2c_write_reg(i2c_omap, OMAP_I2C_SYSTEST_REG, reg);
}
static void omap_i2c_unprepare_recovery(struct i2c_adapter *adapter)
{
struct omap_i2c_struct *i2c_omap = to_omap_i2c_struct(adapter);
u32 reg;
reg = omap_i2c_read_reg(i2c_omap, OMAP_I2C_SYSTEST_REG);
/* restore reset values */
reg &= ~OMAP_I2C_SYSTEST_ST_EN;
reg &= ~OMAP_I2C_SYSTEST_TMODE_MASK;
reg &= ~OMAP_I2C_SYSTEST_SCL_O;
reg &= ~OMAP_I2C_SYSTEST_SDA_O;
omap_i2c_write_reg(i2c_omap, OMAP_I2C_SYSTEST_REG, reg);
}
static struct i2c_bus_recovery_info omap_i2c_bus_recovery_info = {
.get_scl = omap_i2c_get_scl,
.get_sda = omap_i2c_get_sda,
.set_scl = omap_i2c_set_scl,
.prepare_recovery = omap_i2c_prepare_recovery,
.unprepare_recovery = omap_i2c_unprepare_recovery,
.recover_bus = i2c_generic_scl_recovery,
};
static int __init
i2c_omap_probe(struct device_d *pdev)
{
@ -1101,6 +1178,7 @@ i2c_omap_probe(struct device_d *pdev)
i2c_omap->adapter.nr = pdev->id;
i2c_omap->adapter.dev.parent = pdev;
i2c_omap->adapter.dev.device_node = pdev->device_node;
i2c_omap->adapter.bus_recovery_info = &omap_i2c_bus_recovery_info;
/* i2c device drivers may be active on return from add_adapter() */
r = i2c_add_numbered_adapter(&i2c_omap->adapter);