media: ov08x40: Fix burst write sequence

commit d0fef6de4f1b957e35a05a5ba4aab2a2576d6686 upstream.

It is necessary to account for I2C quirks in the burst mode path of this
driver. Not all I2C controllers can accept arbitrarily long writes and this
is represented in the quirks field of the adapter structure.

Prior to this patch the following error message is seen on a Qualcomm
X1E80100 CRD.

[   38.773524] i2c i2c-2: adapter quirk: msg too long (addr 0x0036, size 290, write)
[   38.781454] ov08x40 2-0036: Failed regs transferred: -95
[   38.787076] ov08x40 2-0036: ov08x40_start_streaming failed to set regs

Fix the error by breaking up the write sequence into the advertised maximum
write size of the quirks field if the quirks field is populated.

Fixes: 8f667d202384 ("media: ov08x40: Reduce start streaming time")
Cc: stable@vger.kernel.org # v6.9+
Tested-by: Bryan O'Donoghue <bryan.odonoghue@linaro.org> # x1e80100-crd
Signed-off-by: Bryan O'Donoghue <bryan.odonoghue@linaro.org>
Signed-off-by: Sakari Ailus <sakari.ailus@linux.intel.com>
Signed-off-by: Hans Verkuil <hverkuil@xs4all.nl>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/drivers/media/i2c/ov08x40.c b/drivers/media/i2c/ov08x40.c
index 7ead3c720e0e11af8f9ab28000ce5dbbe6dfb773..67b86dabc67eb1df7cd81a7c69428780405b83be 100644 (file)
--- a/drivers/media/i2c/ov08x40.c
+++ b/drivers/media/i2c/ov08x40.c
@@ -1339,15 +1339,13 @@ static int ov08x40_read_reg(struct ov08x40 *ov08x,
        return 0;
 }
 
-static int ov08x40_burst_fill_regs(struct ov08x40 *ov08x, u16 first_reg,
-                                  u16 last_reg,  u8 val)
+static int __ov08x40_burst_fill_regs(struct i2c_client *client, u16 first_reg,
+                                    u16 last_reg, size_t num_regs, u8 val)
 {
-       struct i2c_client *client = v4l2_get_subdevdata(&ov08x->sd);
        struct i2c_msg msgs;
-       size_t i, num_regs;
+       size_t i;
        int ret;
 
-       num_regs = last_reg - first_reg + 1;
        msgs.addr = client->addr;
        msgs.flags = 0;
        msgs.len = 2 + num_regs;
@@ -1373,6 +1371,31 @@ static int ov08x40_burst_fill_regs(struct ov08x40 *ov08x, u16 first_reg,
        return 0;
 }
 
+static int ov08x40_burst_fill_regs(struct ov08x40 *ov08x, u16 first_reg,
+                                  u16 last_reg,  u8 val)
+{
+       struct i2c_client *client = v4l2_get_subdevdata(&ov08x->sd);
+       size_t num_regs, num_write_regs;
+       int ret;
+
+       num_regs = last_reg - first_reg + 1;
+       num_write_regs = num_regs;
+
+       if (client->adapter->quirks && client->adapter->quirks->max_write_len)
+               num_write_regs = client->adapter->quirks->max_write_len - 2;
+
+       while (first_reg < last_reg) {
+               ret = __ov08x40_burst_fill_regs(client, first_reg, last_reg,
+                                               num_write_regs, val);
+               if (ret)
+                       return ret;
+
+               first_reg += num_write_regs;
+       }
+
+       return 0;
+}
+
 /* Write registers up to 4 at a time */
 static int ov08x40_write_reg(struct ov08x40 *ov08x,
                             u16 reg, u32 len, u32 __val)