From af2698501635166f9d5ceefaf4793236b4d6da8a Mon Sep 17 00:00:00 2001 From: Jan Luebbe Date: Wed, 8 Jul 2015 15:17:41 +0200 Subject: [PATCH] i2c-omap: add bus recovery support This is based on commit 9dcb0e7b999db6c420c70fd32497a979a044fcdf from the kernel with some additional fixes. Signed-off-by: Jan Luebbe --- drivers/i2c/busses/i2c-omap.c | 84 +++++++++++++++++++++++++++++++++-- 1 file changed, 81 insertions(+), 3 deletions(-) diff --git a/drivers/i2c/busses/i2c-omap.c b/drivers/i2c/busses/i2c-omap.c index 58d2ec985..48c55daed 100644 --- a/drivers/i2c/busses/i2c-omap.c +++ b/drivers/i2c/busses/i2c-omap.c @@ -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);