linux-kernel - [PATCH 3/4] fb_ddc: Allow I2C adapters without SCL read capability

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Message-Id: <1423342417-26069-3-git-send-email-linux@rainbow-software.org>
Date:	Sat,  7 Feb 2015 21:53:36 +0100
From:	Ondrej Zary <linux@...nbow-software.org>
To:	Krzysztof Helt <krzysztof.h1@...pl>
Cc:	linux-fbdev@...r.kernel.org,
	Kernel development list <linux-kernel@...r.kernel.org>
Subject: [PATCH 3/4] 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@...nbow-software.org>
---
 drivers/video/fbdev/core/fb_ddc.c |    8 +++++---
 1 file changed, 5 insertions(+), 3 deletions(-)

diff --git a/drivers/video/fbdev/core/fb_ddc.c b/drivers/video/fbdev/core/fb_ddc.c
index 94322cc..22c694a 100644
--- a/drivers/video/fbdev/core/fb_ddc.c
+++ b/drivers/video/fbdev/core/fb_ddc.c
@@ -69,10 +69,11 @@ unsigned char *fb_ddc_read(struct i2c_adapter *adapter)
 		algo_data->setscl(algo_data->data, 1);
 		for (j = 0; j < 5; j++) {
 			msleep(10);
-			if (algo_data->getscl(algo_data->data))
+			if (algo_data->getscl &&
+			    algo_data->getscl(algo_data->data))
 				break;
 		}
-		if (j == 5)
+		if (algo_data->getscl && j == 5)
 			continue;
 
 		algo_data->setsda(algo_data->data, 0);
@@ -91,7 +92,8 @@ unsigned char *fb_ddc_read(struct i2c_adapter *adapter)
 		algo_data->setscl(algo_data->data, 1);
 		for (j = 0; j < 10; j++) {
 			msleep(10);
-			if (algo_data->getscl(algo_data->data))
+			if (algo_data->getscl &&
+			    algo_data->getscl(algo_data->data))
 				break;
 		}
 
-- 
Ondrej Zary

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