linux-kernel - [PATCH v2] drm/bridge: it6505: Add i2c api power on check

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Date:   Wed, 13 Jul 2022 11:15:47 +0800
From:   allen <allen.chen@....com.tw>
To:     unlisted-recipients:; (no To-header on input)
CC:     Allen Chen <allen.chen@....com.tw>,
        Jau-Chih Tseng <Jau-Chih.Tseng@....com.tw>,
        Kenneth Hung <Kenneth.Hung@....com.tw>,
        Hermes Wu <Hermes.Wu@....com.tw>,
        Pin-yen Lin <treapking@...gle.com>,
        Pin-Yen Lin <treapking@...omium.org>,
        Robert Foss <robert.foss@...aro.org>,
        Andrzej Hajda <andrzej.hajda@...el.com>,
        Neil Armstrong <narmstrong@...libre.com>,
        Laurent Pinchart <Laurent.pinchart@...asonboard.com>,
        Jonas Karlman <jonas@...boo.se>,
        Jernej Skrabec <jernej.skrabec@...il.com>,
        David Airlie <airlied@...ux.ie>,
        Daniel Vetter <daniel@...ll.ch>,
        "open list:DRM DRIVERS" <dri-devel@...ts.freedesktop.org>,
        open list <linux-kernel@...r.kernel.org>
Subject: [PATCH v2] drm/bridge: it6505: Add i2c api power on check

From: allen chen <allen.chen@....com.tw>

Use i2c bus to read/write when it6505 power off will occur i2c error.
Add this check will prevent i2c error when it6505 power off.

Signed-off-by: Pin-Yen Lin <treapking@...omium.org>
Signed-off-by: Allen Chen <allen.chen@....com.tw>
Reviewed-by: Robert Foss <robert.foss@...aro.org>
---
 drivers/gpu/drm/bridge/ite-it6505.c | 12 ++++++++++--
 1 file changed, 10 insertions(+), 2 deletions(-)

diff --git a/drivers/gpu/drm/bridge/ite-it6505.c b/drivers/gpu/drm/bridge/ite-it6505.c
index aa5e0aa1af85..cfd2c3275dc5 100644
--- a/drivers/gpu/drm/bridge/ite-it6505.c
+++ b/drivers/gpu/drm/bridge/ite-it6505.c
@@ -518,6 +518,9 @@ static int it6505_read(struct it6505 *it6505, unsigned int reg_addr)
 	int err;
 	struct device *dev = &it6505->client->dev;
 
+	if (!it6505->powered)
+		return -ENODEV;
+
 	err = regmap_read(it6505->regmap, reg_addr, &value);
 	if (err < 0) {
 		dev_err(dev, "read failed reg[0x%x] err: %d", reg_addr, err);
@@ -533,6 +536,9 @@ static int it6505_write(struct it6505 *it6505, unsigned int reg_addr,
 	int err;
 	struct device *dev = &it6505->client->dev;
 
+	if (!it6505->powered)
+		return -ENODEV;
+
 	err = regmap_write(it6505->regmap, reg_addr, reg_val);
 
 	if (err < 0) {
@@ -550,6 +556,9 @@ static int it6505_set_bits(struct it6505 *it6505, unsigned int reg,
 	int err;
 	struct device *dev = &it6505->client->dev;
 
+	if (!it6505->powered)
+		return -ENODEV;
+
 	err = regmap_update_bits(it6505->regmap, reg, mask, value);
 	if (err < 0) {
 		dev_err(dev, "write reg[0x%x] = 0x%x mask = 0x%x failed err %d",
@@ -2553,13 +2562,12 @@ static int it6505_poweron(struct it6505 *it6505)
 		usleep_range(10000, 20000);
 	}
 
+	it6505->powered = true;
 	it6505_reset_logic(it6505);
 	it6505_int_mask_enable(it6505);
 	it6505_init(it6505);
 	it6505_lane_off(it6505);
 
-	it6505->powered = true;
-
 	return 0;
 }
 
-- 
2.25.1