ACPI always sets txfifo and rxfifo to 32. This configuration will
cause problem if the IP core supports a fifo size of less than 32.
The driver should read the fifo size from the IP and select the
smaller one of the two.
Signed-off-by: Tin Huynh <tnhuynh@xxxxxxx>
---
drivers/i2c/busses/i2c-designware-platdrv.c | 26 ++++++++++++++++++++------
1 files changed, 20 insertions(+), 6 deletions(-)
Change from V2:
-Add a helper function to set fifo size.
Change from V1:
-Revert the default 32 for fifo, read parameter from IP core
and pick the smaller one of the two.
-Correct the title to describe new approach.
diff --git a/drivers/i2c/busses/i2c-designware-platdrv.c b/drivers/i2c/busses/i2c-designware-platdrv.c
index 0b42a12..665f491 100644
--- a/drivers/i2c/busses/i2c-designware-platdrv.c
+++ b/drivers/i2c/busses/i2c-designware-platdrv.c
@@ -150,6 +150,24 @@ static int i2c_dw_plat_prepare_clk(struct dw_i2c_dev *i_dev, bool prepare)
return 0;
}
+static void dw_i2c_set_fifo_size(struct dw_i2c_dev *dev)
+{
+ u32 param1, tx_fifo_depth, rx_fifo_depth;
+
+ param1 = i2c_dw_read_comp_param(dev);
+ tx_fifo_depth = ((param1 >> 16) & 0xff) + 1;
+ rx_fifo_depth = ((param1 >> 8) & 0xff) + 1;
+ if (!dev->tx_fifo_depth) {
+ dev->tx_fifo_depth = tx_fifo_depth;
+ dev->rx_fifo_depth = rx_fifo_depth;
+ } else if (tx_fifo_depth) {
+ dev->tx_fifo_depth = min_t(u32, dev->tx_fifo_depth,
+ tx_fifo_depth);
+ dev->rx_fifo_depth = min_t(u32, dev->rx_fifo_depth,
+ rx_fifo_depth);
+ }
+}
+
static int dw_i2c_plat_probe(struct platform_device *pdev)
{
struct dw_i2c_platform_data *pdata = dev_get_platdata(&pdev->dev);
@@ -246,13 +264,9 @@ static int dw_i2c_plat_probe(struct platform_device *pdev)
1000000);
}
- if (!dev->tx_fifo_depth) {
- u32 param1 = i2c_dw_read_comp_param(dev);
-
- dev->tx_fifo_depth = ((param1 >> 16) & 0xff) + 1;
- dev->rx_fifo_depth = ((param1 >> 8) & 0xff) + 1;
+ if (!dev->tx_fifo_depth)
dev->adapter.nr = pdev->id;
- }
+ dw_i2c_set_fifo_size(dev);
adap = &dev->adapter;
adap->owner = THIS_MODULE;
--
1.7.1
--
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