[PATCH v2 1/2] fb_ddc: Allow I2C adapters without SCL read capability

Ondrej Zary
2015-09-24T22:14:28Z

i2c-algo-bit allows I2C adapters without SCL read capability to work
but fb_ddc_read fails to work on them.

Fix fb_ddc_read to work with I2C adapters not capable of reading SCL.

Signed-off-by: Ondrej Zary <linux@rainbow-software.org>
---
drivers/video/fbdev/core/fb_ddc.c | 28 ++++++++++++++++++----------
1 file changed, 18 insertions(+), 10 deletions(-)

diff --git a/drivers/video/fbdev/core/fb_ddc.c b/drivers/video/fbdev/core/fb_ddc.c
index 94322cc..8bf5f2f 100644
--- a/drivers/video/fbdev/core/fb_ddc.c
+++ b/drivers/video/fbdev/core/fb_ddc.c
@@ -67,13 +67,17 @@ unsigned char *fb_ddc_read(struct i2c_adapter *adapter)
msleep(13);

algo_data->setscl(algo_data->data, 1);
- for (j = 0; j < 5; j++) {
- msleep(10);
- if (algo_data->getscl(algo_data->data))
- break;
+ if (algo_data->getscl) {
+ for (j = 0; j < 5; j++) {
+ msleep(10);
+ if (algo_data->getscl(algo_data->data))
+ break;
+ }
+ if (j == 5)
+ continue;
+ } else {
+ udelay(algo_data->udelay);
}
- if (j == 5)
- continue;

algo_data->setsda(algo_data->data, 0);
msleep(15);
@@ -89,10 +93,14 @@ unsigned char *fb_ddc_read(struct i2c_adapter *adapter)
msleep(15);

algo_data->setscl(algo_data->data, 1);
- for (j = 0; j < 10; j++) {
- msleep(10);
- if (algo_data->getscl(algo_data->data))
- break;
+ if (algo_data->getscl) {
+ for (j = 0; j < 10; j++) {
+ msleep(10);
+ if (algo_data->getscl(algo_data->data))
+ break;
+ }
+ } else {
+ udelay(algo_data->udelay);
}

algo_data->setsda(algo_data->data, 1);
--
Ondrej Zary