[PATCH 2/2] i2c: i2c-cdns.c: Update driver to read fifo-depth from device tree

Pei Yue Ho
2023-01-04T13:10:44Z

Enable driver to fetch the optional parameter (fifo-depth)
from device tree. If the parameter is not found in the device
tree, it will use the default value declared in the driver.

Signed-off-by: Pei Yue Ho <peiyue.ho@starfivetech.com>
Reviewed-by: Wei Liang Lim <weiliang.lim@starfivetech.com>
Reviewed-by: Eng Lee Teh <englee.teh@starfivetech.com>
---
drivers/i2c/i2c-cdns.c | 26 ++++++++++++++++----------
1 file changed, 16 insertions(+), 10 deletions(-)

diff --git a/drivers/i2c/i2c-cdns.c b/drivers/i2c/i2c-cdns.c
index 0da9f6f35a..65a0c76a2a 100644
--- a/drivers/i2c/i2c-cdns.c
+++ b/drivers/i2c/i2c-cdns.c
@@ -78,7 +78,7 @@ struct cdns_i2c_regs {
CDNS_I2C_INTERRUPT_RXUNF | \
CDNS_I2C_INTERRUPT_ARBLOST)

-#define CDNS_I2C_FIFO_DEPTH 16
+#define CDNS_I2C_FIFO_DEPTH_DEFAULT 16
#define CDNS_I2C_TRANSFER_SIZE_MAX 255 /* Controller transfer limit */
#define CDNS_I2C_TRANSFER_SIZE (CDNS_I2C_TRANSFER_SIZE_MAX - 3)

@@ -135,6 +135,7 @@ struct i2c_cdns_bus {

int hold_flag;
u32 quirks;
+ u32 fifo_depth;
};

struct cdns_i2c_platform_data {
@@ -277,7 +278,7 @@ static int cdns_i2c_write_data(struct i2c_cdns_bus *i2c_bus, u32 addr, u8 *data,
writel(addr, &regs->address);
start = 0;
}
- if (len && readl(&regs->transfer_size) == CDNS_I2C_FIFO_DEPTH) {
+ if (len && readl(&regs->transfer_size) == i2c_bus->fifo_depth) {
ret = cdns_i2c_wait(regs, CDNS_I2C_INTERRUPT_COMP |
CDNS_I2C_INTERRUPT_ARBLOST);
if (ret & CDNS_I2C_INTERRUPT_ARBLOST)
@@ -310,9 +311,10 @@ static int cdns_i2c_write_data(struct i2c_cdns_bus *i2c_bus, u32 addr, u8 *data,
return 0;
}

-static inline bool cdns_is_hold_quirk(int hold_quirk, int curr_recv_count)
+static inline bool cdns_is_hold_quirk(struct i2c_cdns_bus *i2c_bus, int hold_quirk,
+ int curr_recv_count)
{
- return hold_quirk && (curr_recv_count == CDNS_I2C_FIFO_DEPTH + 1);
+ return hold_quirk && (curr_recv_count == i2c_bus->fifo_depth + 1);
}

static int cdns_i2c_read_data(struct i2c_cdns_bus *i2c_bus, u32 addr, u8 *data,
@@ -327,7 +329,7 @@ static int cdns_i2c_read_data(struct i2c_cdns_bus *i2c_bus, u32 addr, u8 *data,
curr_recv_count = recv_count;

/* Check for the message size against the FIFO depth */
- if (recv_count > CDNS_I2C_FIFO_DEPTH)
+ if (recv_count > i2c_bus->fifo_depth)
setbits_le32(&regs->control, CDNS_I2C_CONTROL_HOLD);

setbits_le32(&regs->control, CDNS_I2C_CONTROL_CLR_FIFO |
@@ -349,7 +351,7 @@ static int cdns_i2c_read_data(struct i2c_cdns_bus *i2c_bus, u32 addr, u8 *data,

while (recv_count && !is_arbitration_lost(regs)) {
while (readl(&regs->status) & CDNS_I2C_STATUS_RXDV) {
- if (recv_count < CDNS_I2C_FIFO_DEPTH &&
+ if (recv_count < i2c_bus->fifo_depth &&
!i2c_bus->hold_flag) {
clrbits_le32(&regs->control,
CDNS_I2C_CONTROL_HOLD);
@@ -365,20 +367,20 @@ static int cdns_i2c_read_data(struct i2c_cdns_bus *i2c_bus, u32 addr, u8 *data,
if (cdns_is_hold_quirk(hold_quirk, curr_recv_count)) {
/* wait while fifo is full */
while (readl(&regs->transfer_size) !=
- (curr_recv_count - CDNS_I2C_FIFO_DEPTH))
+ (curr_recv_count - i2c_bus->fifo_depth))
;
/*
* Check number of bytes to be received against maximum
* transfer size and update register accordingly.
*/
- if ((recv_count - CDNS_I2C_FIFO_DEPTH) >
+ if ((recv_count - i2c_bus->fifo_depth) >
CDNS_I2C_TRANSFER_SIZE) {
writel(CDNS_I2C_TRANSFER_SIZE,
&regs->transfer_size);
curr_recv_count = CDNS_I2C_TRANSFER_SIZE +
- CDNS_I2C_FIFO_DEPTH;
+ i2c_bus->fifo_depth;
} else {
- writel(recv_count - CDNS_I2C_FIFO_DEPTH,
+ writel(recv_count - i2c_bus->fifo_depth,
&regs->transfer_size);
curr_recv_count = recv_count;
}
@@ -496,6 +498,10 @@ static int cdns_i2c_of_to_plat(struct udevice *dev)
return ret;
}

+ /* Update FIFO depth based on device tree entry */
+ i2c_bus->fifo_depth = dev_read_u32_default(dev, "fifo-depth",
+ CDNS_I2C_FIFO_DEPTH_DEFAULT);
+
return 0;
}

--
2.25.1