fb_ddc: Allow I2C adapters without SCL read capability

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>
Signed-off-by: Tomi Valkeinen <tomi.valkeinen@ti.com>

1 files changed, 18 insertions, 10 deletions

diff --git a/drivers/video/fbdev/core/fb_ddc.c b/drivers/video/fbdev/core/fb_ddc.c
index 94322ccfedde..8bf5f2f54be7 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);