[PATCH] i2c: tegra: apply size limit quirk

[Wolfram Sang <wsa-z923LK4zBo2bacvFa/9K2g@public.gmane.org>]

payload_size is a 12 bit field in the HW register, so add a limit for
this size. That way we gracefully reject the message beforehand instead
of generating an OOPS while transferring. Verified using some older
Tegra2 documentation and a more recent Jetson TK1 board.

Signed-off-by: Wolfram Sang <wsa-z923LK4zBo2bacvFa/9K2g@public.gmane.org>
---
 drivers/i2c/busses/i2c-tegra.c | 7 +++++++
 1 file changed, 7 insertions(+)

diff --git a/drivers/i2c/busses/i2c-tegra.c b/drivers/i2c/busses/i2c-tegra.c
index 0a1b6eacef0fba..78a36681469674 100644
--- a/drivers/i2c/busses/i2c-tegra.c
+++ b/drivers/i2c/busses/i2c-tegra.c
@@ -669,6 +669,12 @@ static const struct i2c_algorithm tegra_i2c_algo = {
 	.functionality	= tegra_i2c_func,
 };
 
+/* payload size is only 12 bit */
+static struct i2c_adapter_quirks tegra_i2c_quirks = {
+	.max_read_len = 4096,
+	.max_write_len = 4096,
+};
+
 static const struct tegra_i2c_hw_feature tegra20_i2c_hw = {
 	.has_continue_xfer_support = false,
 	.has_per_pkt_xfer_complete_irq = false,
@@ -739,6 +745,7 @@ static int tegra_i2c_probe(struct platform_device *pdev)
 	i2c_dev->base = base;
 	i2c_dev->div_clk = div_clk;
 	i2c_dev->adapter.algo = &tegra_i2c_algo;
+	i2c_dev->adapter.quirks = &tegra_i2c_quirks;
 	i2c_dev->irq = irq;
 	i2c_dev->cont_id = pdev->id;
 	i2c_dev->dev = &pdev->dev;
-- 
2.1.4