This adopts i2c-s3c2410 driver for new enhancement of i2c API that exposes preparation and unpreparation stages of i2c transfer.
Signed-off-by: Paul Osmialowski <p.osmialo...@samsung.com> --- drivers/i2c/busses/i2c-s3c2410.c | 69 ++++++++++++++++++++++++++++++++++++---- 1 file changed, 63 insertions(+), 6 deletions(-) diff --git a/drivers/i2c/busses/i2c-s3c2410.c b/drivers/i2c/busses/i2c-s3c2410.c index bff20a5..4af8a9c 100644 --- a/drivers/i2c/busses/i2c-s3c2410.c +++ b/drivers/i2c/busses/i2c-s3c2410.c @@ -130,6 +130,8 @@ struct s3c24xx_i2c { #endif struct regmap *sysreg; unsigned int sys_i2c_cfg; + + int xfer_prepared; }; static struct platform_device_id s3c24xx_driver_ids[] = { @@ -771,6 +773,58 @@ static int s3c24xx_i2c_doxfer(struct s3c24xx_i2c *i2c, return ret; } +/* s3c24xx_i2c_prepare_xfer + * + * prepare for transferring message across the i2c bus (may sleep) + * + * returns 0 on success + */ + +static int s3c24xx_i2c_prepare_xfer(struct i2c_adapter *adap) +{ + struct s3c24xx_i2c *i2c = (struct s3c24xx_i2c *)adap->algo_data; + + if (i2c->xfer_prepared == 0) { + int ret; + + pm_runtime_get_sync(&adap->dev); + + ret = clk_prepare_enable(i2c->clk); + if (ret) { + pm_runtime_put(&adap->dev); + return ret; + } + + } + + i2c->xfer_prepared++; + + return 0; +} + +/* s3c24xx_i2c_unprepare_xfer + * + * unprepare after transferring message across the i2c bus (may sleep) + */ + +static void s3c24xx_i2c_unprepare_xfer(struct i2c_adapter *adap) +{ + struct s3c24xx_i2c *i2c = (struct s3c24xx_i2c *)adap->algo_data; + + if (i2c->xfer_prepared == 1) { + clk_disable_unprepare(i2c->clk); + pm_runtime_put(&adap->dev); + } + + i2c->xfer_prepared--; + + if (unlikely(i2c->xfer_prepared < 0)) { + pr_err("%s: i2c->xfer_prepared = %d < 0\n", + __func__, i2c->xfer_prepared); + i2c->xfer_prepared = 0; + } +} + /* s3c24xx_i2c_xfer * * first port of call from the i2c bus code when an message needs @@ -784,16 +838,16 @@ static int s3c24xx_i2c_xfer(struct i2c_adapter *adap, int retry; int ret; - pm_runtime_get_sync(&adap->dev); - clk_prepare_enable(i2c->clk); + ret = s3c24xx_i2c_prepare_xfer(adap); + if (ret) + return ret; for (retry = 0; retry < adap->retries; retry++) { ret = s3c24xx_i2c_doxfer(i2c, msgs, num); if (ret != -EAGAIN) { - clk_disable_unprepare(i2c->clk); - pm_runtime_put(&adap->dev); + s3c24xx_i2c_unprepare_xfer(adap); return ret; } @@ -802,8 +856,8 @@ static int s3c24xx_i2c_xfer(struct i2c_adapter *adap, udelay(100); } - clk_disable_unprepare(i2c->clk); - pm_runtime_put(&adap->dev); + s3c24xx_i2c_unprepare_xfer(adap); + return -EREMOTEIO; } @@ -818,6 +872,8 @@ static u32 s3c24xx_i2c_func(struct i2c_adapter *adap) static const struct i2c_algorithm s3c24xx_i2c_algorithm = { .master_xfer = s3c24xx_i2c_xfer, + .master_prepare_xfer = s3c24xx_i2c_prepare_xfer, + .master_unprepare_xfer = s3c24xx_i2c_unprepare_xfer, .functionality = s3c24xx_i2c_func, }; @@ -1152,6 +1208,7 @@ static int s3c24xx_i2c_probe(struct platform_device *pdev) i2c->adap.retries = 2; i2c->adap.class = I2C_CLASS_DEPRECATED; i2c->tx_setup = 50; + i2c->xfer_prepared = 0; init_waitqueue_head(&i2c->wait); -- 1.9.1 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/