Re: [PATCH V5] drivers: i2c: tegra: fix warning/check/error

From: Dmitry Osipenko
Date: Fri Jun 07 2019 - 02:10:57 EST

07.06.2019 8:25, Bitan Biswas ÐÐÑÐÑ:
> Fix checkpatch.pl warning(s)/error(s)/check(s) in i2c-tegra.c
>
> Ignore checkpatch WARNING for 80 character line limit at
> places where renaming fields compromises readability.
>
> Delay of approximately 1msec in flush i2c FIFO polling loop
> achieved by usleep_range call as msleep can take 20msecs.
>
> Remove redundant BUG_ON calls or replace with WARN_ON_ONCE
> as needed. Replace BUG() with error handling code.
> Define I2C_ERR_UNEXPECTED_STATUS for error handling.
>
> Signed-off-by: Bitan Biswas <bbiswas@xxxxxxxxxx>
> ---
> drivers/i2c/busses/i2c-tegra.c | 61 ++++++++++++++++++++++--------------------
> 1 file changed, 32 insertions(+), 29 deletions(-)
>
> diff --git a/drivers/i2c/busses/i2c-tegra.c b/drivers/i2c/busses/i2c-tegra.c
> index 1dbba39..161eb28 100644
> --- a/drivers/i2c/busses/i2c-tegra.c
> +++ b/drivers/i2c/busses/i2c-tegra.c
> @@ -67,17 +67,18 @@
>
> #define DVC_CTRL_REG1 0x000
> #define DVC_CTRL_REG1_INTR_EN BIT(10)
> -#define DVC_CTRL_REG2 0x004
> -#define DVC_CTRL_REG3 0x008
> +#define DVC_CTRL_REG2 BIT(2)
> +#define DVC_CTRL_REG3 BIT(3)

This is incorrect change, register address should be kept as a hex value
because it is not a bitmask.

I'd also recommend to just remove the DVC_CTRL_REG2 since it's not used
anywhere in the code. You may also check all of other #defines and
remove everything unused.

You can also check all of variables for a need to be initialized, like
for example "ret" doesn't need to be init'ed in tegra_i2c_xfer() and
some other places. That will be a good clean up as well.

> #define DVC_CTRL_REG3_SW_PROG BIT(26)
> #define DVC_CTRL_REG3_I2C_DONE_INTR_EN BIT(30)
> #define DVC_STATUS 0x00c
> #define DVC_STATUS_I2C_DONE_INTR BIT(30)
>
> -#define I2C_ERR_NONE 0x00
> -#define I2C_ERR_NO_ACK 0x01
> -#define I2C_ERR_ARBITRATION_LOST 0x02
> -#define I2C_ERR_UNKNOWN_INTERRUPT 0x04
> +#define I2C_ERR_NONE 0x0
> +#define I2C_ERR_NO_ACK BIT(0)
> +#define I2C_ERR_ARBITRATION_LOST BIT(1)
> +#define I2C_ERR_UNKNOWN_INTERRUPT BIT(2)
> +#define I2C_ERR_UNEXPECTED_STATUS BIT(3)
>
> #define PACKET_HEADER0_HEADER_SIZE_SHIFT 28
> #define PACKET_HEADER0_PACKET_ID_SHIFT 16
> @@ -280,6 +281,7 @@ struct tegra_i2c_dev {
> u32 bus_clk_rate;
> u16 clk_divisor_non_hs_mode;
> bool is_multimaster_mode;
> + /* xfer_lock: lock to serialize transfer submission and processing */
> spinlock_t xfer_lock;
> struct dma_chan *tx_dma_chan;
> struct dma_chan *rx_dma_chan;
> @@ -306,7 +308,7 @@ static u32 dvc_readl(struct tegra_i2c_dev *i2c_dev, unsigned long reg)
> * to the I2C block inside the DVC block
> */
> static unsigned long tegra_i2c_reg_addr(struct tegra_i2c_dev *i2c_dev,
> - unsigned long reg)
> + unsigned long reg)
> {
> if (i2c_dev->is_dvc)
> reg += (reg >= I2C_TX_FIFO) ? 0x10 : 0x40;
> @@ -314,7 +316,7 @@ static unsigned long tegra_i2c_reg_addr(struct tegra_i2c_dev *i2c_dev,
> }
>
> static void i2c_writel(struct tegra_i2c_dev *i2c_dev, u32 val,
> - unsigned long reg)
> + unsigned long reg)
> {
> writel(val, i2c_dev->base + tegra_i2c_reg_addr(i2c_dev, reg));
>
> @@ -329,13 +331,13 @@ static u32 i2c_readl(struct tegra_i2c_dev *i2c_dev, unsigned long reg)
> }
>
> static void i2c_writesl(struct tegra_i2c_dev *i2c_dev, void *data,
> - unsigned long reg, int len)
> + unsigned long reg, int len)
> {
> writesl(i2c_dev->base + tegra_i2c_reg_addr(i2c_dev, reg), data, len);
> }
>
> static void i2c_readsl(struct tegra_i2c_dev *i2c_dev, void *data,
> - unsigned long reg, int len)
> + unsigned long reg, int len)
> {
> readsl(i2c_dev->base + tegra_i2c_reg_addr(i2c_dev, reg), data, len);
> }
> @@ -486,7 +488,7 @@ static int tegra_i2c_flush_fifos(struct tegra_i2c_dev *i2c_dev)
> dev_warn(i2c_dev->dev, "timeout waiting for fifo flush\n");
> return -ETIMEDOUT;
> }
> - msleep(1);
> + usleep_range(1000, 2000);
> }
> return 0;
> }
> @@ -525,7 +527,6 @@ static int tegra_i2c_empty_rx_fifo(struct tegra_i2c_dev *i2c_dev)
> * prevent overwriting past the end of buf
> */
> if (rx_fifo_avail > 0 && buf_remaining > 0) {
> - BUG_ON(buf_remaining > 3);
> val = i2c_readl(i2c_dev, I2C_RX_FIFO);
> val = cpu_to_le32(val);
> memcpy(buf, &val, buf_remaining);
> @@ -533,7 +534,6 @@ static int tegra_i2c_empty_rx_fifo(struct tegra_i2c_dev *i2c_dev)
> rx_fifo_avail--;
> }
>
> - BUG_ON(rx_fifo_avail > 0 && buf_remaining > 0);
> i2c_dev->msg_buf_remaining = buf_remaining;
> i2c_dev->msg_buf = buf;
>
> @@ -591,7 +591,6 @@ static int tegra_i2c_fill_tx_fifo(struct tegra_i2c_dev *i2c_dev)
> * boundary and fault.
> */
> if (tx_fifo_avail > 0 && buf_remaining > 0) {
> - BUG_ON(buf_remaining > 3);
> memcpy(&val, buf, buf_remaining);
> val = le32_to_cpu(val);
>
> @@ -680,10 +679,11 @@ static int tegra_i2c_wait_for_config_load(struct tegra_i2c_dev *i2c_dev)
> i2c_writel(i2c_dev, I2C_MSTR_CONFIG_LOAD, I2C_CONFIG_LOAD);
> if (in_interrupt())
> err = readl_poll_timeout_atomic(addr, val, val == 0,
> - 1000, I2C_CONFIG_LOAD_TIMEOUT);
> + 1000,
> + I2C_CONFIG_LOAD_TIMEOUT);
> else
> - err = readl_poll_timeout(addr, val, val == 0,
> - 1000, I2C_CONFIG_LOAD_TIMEOUT);
> + err = readl_poll_timeout(addr, val, val == 0, 1000,
> + I2C_CONFIG_LOAD_TIMEOUT);
>
> if (err) {
> dev_warn(i2c_dev->dev,
> @@ -856,10 +856,13 @@ static irqreturn_t tegra_i2c_isr(int irq, void *dev_id)
>
> if (!i2c_dev->is_curr_dma_xfer) {
> if (i2c_dev->msg_read && (status & I2C_INT_RX_FIFO_DATA_REQ)) {
> - if (i2c_dev->msg_buf_remaining)
> + if (i2c_dev->msg_buf_remaining) {
> tegra_i2c_empty_rx_fifo(i2c_dev);
> - else
> - BUG();
> + } else {
> + dev_err(i2c_dev->dev, "unexpected rx data request\n");
> + i2c_dev->msg_err |= I2C_ERR_UNEXPECTED_STATUS;
> + goto err;
> + }
> }
>
> if (!i2c_dev->msg_read && (status & I2C_INT_TX_FIFO_DATA_REQ)) {
> @@ -885,7 +888,7 @@ static irqreturn_t tegra_i2c_isr(int irq, void *dev_id)
> if (status & I2C_INT_PACKET_XFER_COMPLETE) {
> if (i2c_dev->is_curr_dma_xfer)
> i2c_dev->msg_buf_remaining = 0;
> - BUG_ON(i2c_dev->msg_buf_remaining);
> + WARN_ON_ONCE(i2c_dev->msg_buf_remaining);
> complete(&i2c_dev->msg_complete);
> }
> goto done;
> @@ -1024,7 +1027,7 @@ static int tegra_i2c_issue_bus_clear(struct i2c_adapter *adap)
> }
>
> static int tegra_i2c_xfer_msg(struct tegra_i2c_dev *i2c_dev,
> - struct i2c_msg *msg, enum msg_end_type end_state)
> + struct i2c_msg *msg, enum msg_end_type end_state)

Probably won't hurt to carry the "enum msg_end_type end_state" to a new
line.

> {
> u32 packet_header;
> u32 int_mask;
> @@ -1161,9 +1164,8 @@ static int tegra_i2c_xfer_msg(struct tegra_i2c_dev *i2c_dev,
> if (err)
> return err;
>
> - time_left = wait_for_completion_timeout(
> - &i2c_dev->dma_complete,
> - msecs_to_jiffies(xfer_time));
> + time_left = wait_for_completion_timeout(&i2c_dev->dma_complete,
> + msecs_to_jiffies(xfer_time));
> if (time_left == 0) {
> dev_err(i2c_dev->dev, "DMA transfer timeout\n");
> dmaengine_terminate_sync(i2c_dev->msg_read ?
> @@ -1225,7 +1227,7 @@ static int tegra_i2c_xfer_msg(struct tegra_i2c_dev *i2c_dev,
> }
>
> static int tegra_i2c_xfer(struct i2c_adapter *adap, struct i2c_msg msgs[],
> - int num)
> + int num)
> {
> struct tegra_i2c_dev *i2c_dev = i2c_get_adapdata(adap);
> int i;
> @@ -1273,12 +1275,12 @@ static void tegra_i2c_parse_dt(struct tegra_i2c_dev *i2c_dev)
> int ret;
>
> ret = of_property_read_u32(np, "clock-frequency",
> - &i2c_dev->bus_clk_rate);
> + &i2c_dev->bus_clk_rate);
> if (ret)
> i2c_dev->bus_clk_rate = 100000; /* default clock rate */
>
> i2c_dev->is_multimaster_mode = of_property_read_bool(np,
> - "multi-master");
> + "multi-master");

You can avoid the line-split with something like this:

ret = of_property_read_bool(np, "multi-master");
i2c_dev->is_multimaster_mode = ret;

--
Dmitry