[PATCH v8 1/3] i2c: tegra: use readx_poll_timeout after config_load reg programmed

From: Shardar Shariff Md
Date: Fri May 27 2016 - 09:37:29 EST


After CONFIG_LOAD register programing instead of explicitly waiting for
timeout, use readx_poll_timeout() to check for register value to get
updated or wait till timeout.

Signed-off-by: Shardar Shariff Md <smohammed@xxxxxxxxxx>

---
Changes in v4:
- Split timeout calculation to separate patch

Changes in v5:
- Move disabling of clock to separate patch

Changes in v8:
- 1st change of [PATCH v7] series is merged, v8 is rebased on top of
merged change, here patch series is changed accordingly.
- Updated the commit message as per review to properly reflect change.
- calculate the register offset seperately to make code more readable.
---
drivers/i2c/busses/i2c-tegra.c | 23 ++++++++++++++---------
1 file changed, 14 insertions(+), 9 deletions(-)

diff --git a/drivers/i2c/busses/i2c-tegra.c b/drivers/i2c/busses/i2c-tegra.c
index 445398c3..7cbeb4e 100644
--- a/drivers/i2c/busses/i2c-tegra.c
+++ b/drivers/i2c/busses/i2c-tegra.c
@@ -28,6 +28,7 @@
#include <linux/of_device.h>
#include <linux/module.h>
#include <linux/reset.h>
+#include <linux/iopoll.h>

#include <asm/unaligned.h>

@@ -110,6 +111,8 @@
#define I2C_CLKEN_OVERRIDE 0x090
#define I2C_MST_CORE_CLKEN_OVR (1 << 0)

+#define I2C_CONFIG_LOAD_TIMEOUT 1000000
+
/*
* msg_end_type: The bus control which need to be send at end of transfer.
* @MSG_END_STOP: Send stop pulse at end of transfer.
@@ -428,7 +431,6 @@ static int tegra_i2c_init(struct tegra_i2c_dev *i2c_dev)
u32 val;
int err = 0;
u32 clk_divisor;
- unsigned long timeout = jiffies + HZ;

err = tegra_i2c_clock_enable(i2c_dev);
if (err < 0) {
@@ -478,15 +480,18 @@ static int tegra_i2c_init(struct tegra_i2c_dev *i2c_dev)
i2c_writel(i2c_dev, I2C_MST_CORE_CLKEN_OVR, I2C_CLKEN_OVERRIDE);

if (i2c_dev->hw->has_config_load_reg) {
+ u32 val;
+ unsigned long reg_offset;
+
+ reg_offset = tegra_i2c_reg_addr(i2c_dev, I2C_CONFIG_LOAD);
i2c_writel(i2c_dev, I2C_MSTR_CONFIG_LOAD, I2C_CONFIG_LOAD);
- while (i2c_readl(i2c_dev, I2C_CONFIG_LOAD) != 0) {
- if (time_after(jiffies, timeout)) {
- dev_warn(i2c_dev->dev,
- "timeout waiting for config load\n");
- err = -ETIMEDOUT;
- goto err;
- }
- msleep(1);
+ err = readx_poll_timeout(readl, i2c_dev->base + reg_offset,
+ val, val == 0, 1000,
+ I2C_CONFIG_LOAD_TIMEOUT);
+ if (err) {
+ dev_warn(i2c_dev->dev,
+ "timeout waiting for config load\n");
+ goto err;
}
}

--
1.8.1.5