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99 lines
3.1 KiB
Diff
99 lines
3.1 KiB
Diff
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From bce8f86dec02feb9865a6c72e450a1256b33ae2f Mon Sep 17 00:00:00 2001
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From: Dave Stevenson <dave.stevenson@raspberrypi.org>
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Date: Tue, 28 Nov 2017 10:07:29 +0000
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Subject: [PATCH 328/454] media: tc358743: Check I2C succeeded during probe.
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The probe for the TC358743 reads the CHIPID register from
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the device and compares it to the expected value of 0.
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If the I2C request fails then that also returns 0, so
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the driver loads thinking that the device is there.
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Generally I2C communications are reliable so there is
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limited need to check the return value on every transfer,
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therefore only amend the one read during probe to check
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for I2C errors.
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Signed-off-by: Dave Stevenson <dave.stevenson@raspberrypi.org>
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---
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drivers/media/i2c/tc358743.c | 27 +++++++++++++++++++++++----
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1 file changed, 23 insertions(+), 4 deletions(-)
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--- a/drivers/media/i2c/tc358743.c
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+++ b/drivers/media/i2c/tc358743.c
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@@ -119,7 +119,7 @@ static inline struct tc358743_state *to_
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/* --------------- I2C --------------- */
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-static void i2c_rd(struct v4l2_subdev *sd, u16 reg, u8 *values, u32 n)
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+static int i2c_rd(struct v4l2_subdev *sd, u16 reg, u8 *values, u32 n)
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{
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struct tc358743_state *state = to_state(sd);
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struct i2c_client *client = state->i2c_client;
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@@ -145,6 +145,7 @@ static void i2c_rd(struct v4l2_subdev *s
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v4l2_err(sd, "%s: reading register 0x%x from 0x%x failed\n",
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__func__, reg, client->addr);
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}
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+ return err != ARRAY_SIZE(msgs);
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}
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static void i2c_wr(struct v4l2_subdev *sd, u16 reg, u8 *values, u32 n)
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@@ -201,15 +202,24 @@ static void i2c_wr(struct v4l2_subdev *s
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}
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}
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-static noinline u32 i2c_rdreg(struct v4l2_subdev *sd, u16 reg, u32 n)
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+static noinline u32 i2c_rdreg_err(struct v4l2_subdev *sd, u16 reg, u32 n,
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+ int *err)
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{
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+ int error;
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__le32 val = 0;
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- i2c_rd(sd, reg, (u8 __force *)&val, n);
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+ error = i2c_rd(sd, reg, (u8 __force *)&val, n);
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+ if (err)
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+ *err = error;
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return le32_to_cpu(val);
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}
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+static inline u32 i2c_rdreg(struct v4l2_subdev *sd, u16 reg, u32 n)
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+{
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+ return i2c_rdreg_err(sd, reg, n, NULL);
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+}
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+
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static noinline void i2c_wrreg(struct v4l2_subdev *sd, u16 reg, u32 val, u32 n)
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{
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__le32 raw = cpu_to_le32(val);
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@@ -238,6 +248,13 @@ static u16 i2c_rd16(struct v4l2_subdev *
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return i2c_rdreg(sd, reg, 2);
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}
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+static int i2c_rd16_err(struct v4l2_subdev *sd, u16 reg, u16 *value)
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+{
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+ int err;
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+ *value = i2c_rdreg_err(sd, reg, 2, &err);
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+ return err;
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+}
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+
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static void i2c_wr16(struct v4l2_subdev *sd, u16 reg, u16 val)
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{
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i2c_wrreg(sd, reg, val, 2);
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@@ -1887,6 +1904,7 @@ static int tc358743_probe(struct i2c_cli
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struct tc358743_state *state;
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struct tc358743_platform_data *pdata = client->dev.platform_data;
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struct v4l2_subdev *sd;
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+ u16 chipid;
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int err;
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if (!i2c_check_functionality(client->adapter, I2C_FUNC_SMBUS_BYTE_DATA))
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@@ -1919,7 +1937,8 @@ static int tc358743_probe(struct i2c_cli
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sd->flags |= V4L2_SUBDEV_FL_HAS_DEVNODE | V4L2_SUBDEV_FL_HAS_EVENTS;
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/* i2c access */
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- if ((i2c_rd16(sd, CHIPID) & MASK_CHIPID) != 0) {
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+ if (i2c_rd16_err(sd, CHIPID, &chipid) ||
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+ (chipid & MASK_CHIPID) != 0) {
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v4l2_info(sd, "not a TC358743 on address 0x%x\n",
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client->addr << 1);
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return -ENODEV;
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