[PATCH v4 1/2] i2c: lpi2c: use readl_poll_timeout() for register polling
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From: Francesco Dolcini <francesco@dolcini.it>
Date: 2025-05-23 08:29:41
Also in:
imx, linux-i2c, lkml
Subsystem:
freescale imx lpi2c driver, i2c subsystem, i2c subsystem host drivers, the rest · Maintainers:
Dong Aisheng, Andi Shyti, Linus Torvalds
Revision v4 of 2 in this series; 1 review trailer.
Revisions (2)
- v4 current
- v5 [diff vs current]
From: Emanuele Ghidoli <redacted> Replace polling loops with the readl_poll_timeout() helper macro. Signed-off-by: Emanuele Ghidoli <redacted> Signed-off-by: Francesco Dolcini <redacted> Reviewed-by: Carlos Song <redacted> --- v3 -> v4 - Split the patch into two parts: one for the readl_poll_timeout() and one for the atomic implementation. - Change the readl_poll_timeout() delay to 0 us to do not change the behavior of the driver. - Use err variable consistently. v2 -> v3 - Closes: https://lore.kernel.org/oe-kbuild-all/202505130735.zh3WuTNu-lkp@intel.com/ (local). Using the return value of lpi2c_imx_read_msr_poll_timeout() to check for errors. v1 -> v2 - Rename READL_POLL_TIMEOUT to lpi2c_imx_read_msr_poll_timeout - Remove addr and timeout_us parameters from lpi2c_imx_read_msr_poll_timeout since they are used always with the same value - add r-b tag from Carlos Song --- drivers/i2c/busses/i2c-imx-lpi2c.c | 94 ++++++++++++++---------------- 1 file changed, 45 insertions(+), 49 deletions(-)
diff --git a/drivers/i2c/busses/i2c-imx-lpi2c.c b/drivers/i2c/busses/i2c-imx-lpi2c.c
index 342d47e67586..91b0f4c2b924 100644
--- a/drivers/i2c/busses/i2c-imx-lpi2c.c
+++ b/drivers/i2c/busses/i2c-imx-lpi2c.c@@ -16,6 +16,7 @@ #include <linux/init.h> #include <linux/interrupt.h> #include <linux/io.h> +#include <linux/iopoll.h> #include <linux/kernel.h> #include <linux/module.h> #include <linux/of.h>
@@ -187,6 +188,10 @@ struct lpi2c_imx_struct { struct i2c_client *target; }; +#define lpi2c_imx_read_msr_poll_timeout(val, cond) \ + readl_poll_timeout(lpi2c_imx->base + LPI2C_MSR, val, cond, \ + 0, 500000) + static void lpi2c_imx_intctrl(struct lpi2c_imx_struct *lpi2c_imx, unsigned int enable) {
@@ -195,33 +200,34 @@ static void lpi2c_imx_intctrl(struct lpi2c_imx_struct *lpi2c_imx, static int lpi2c_imx_bus_busy(struct lpi2c_imx_struct *lpi2c_imx) { - unsigned long orig_jiffies = jiffies; + int err; unsigned int temp; - while (1) { - temp = readl(lpi2c_imx->base + LPI2C_MSR); - - /* check for arbitration lost, clear if set */ - if (temp & MSR_ALF) { - writel(temp, lpi2c_imx->base + LPI2C_MSR); - return -EAGAIN; - } + err = lpi2c_imx_read_msr_poll_timeout(temp, + temp & (MSR_ALF | MSR_BBF | MSR_MBF)); - if (temp & (MSR_BBF | MSR_MBF)) - break; + /* check for arbitration lost, clear if set */ + if (temp & MSR_ALF) { + writel(temp, lpi2c_imx->base + LPI2C_MSR); + return -EAGAIN; + } - if (time_after(jiffies, orig_jiffies + msecs_to_jiffies(500))) { - dev_dbg(&lpi2c_imx->adapter.dev, "bus not work\n"); - if (lpi2c_imx->adapter.bus_recovery_info) - i2c_recover_bus(&lpi2c_imx->adapter); - return -ETIMEDOUT; - } - schedule(); + /* check for bus not busy */ + if (err) { + dev_dbg(&lpi2c_imx->adapter.dev, "bus not work\n"); + if (lpi2c_imx->adapter.bus_recovery_info) + i2c_recover_bus(&lpi2c_imx->adapter); + return -ETIMEDOUT; } return 0; } +static u32 lpi2c_imx_txfifo_cnt(struct lpi2c_imx_struct *lpi2c_imx) +{ + return readl(lpi2c_imx->base + LPI2C_MFSR) & 0xff; +} + static void lpi2c_imx_set_mode(struct lpi2c_imx_struct *lpi2c_imx) { unsigned int bitrate = lpi2c_imx->bitrate;
@@ -259,25 +265,18 @@ static int lpi2c_imx_start(struct lpi2c_imx_struct *lpi2c_imx, static void lpi2c_imx_stop(struct lpi2c_imx_struct *lpi2c_imx) { - unsigned long orig_jiffies = jiffies; unsigned int temp; + int err; writel(GEN_STOP << 8, lpi2c_imx->base + LPI2C_MTDR); - do { - temp = readl(lpi2c_imx->base + LPI2C_MSR); - if (temp & MSR_SDF) - break; + err = lpi2c_imx_read_msr_poll_timeout(temp, temp & MSR_SDF); - if (time_after(jiffies, orig_jiffies + msecs_to_jiffies(500))) { - dev_dbg(&lpi2c_imx->adapter.dev, "stop timeout\n"); - if (lpi2c_imx->adapter.bus_recovery_info) - i2c_recover_bus(&lpi2c_imx->adapter); - break; - } - schedule(); - - } while (1); + if (err) { + dev_dbg(&lpi2c_imx->adapter.dev, "stop timeout\n"); + if (lpi2c_imx->adapter.bus_recovery_info) + i2c_recover_bus(&lpi2c_imx->adapter); + } } /* CLKLO = I2C_CLK_RATIO * CLKHI, SETHOLD = CLKHI, DATAVD = CLKHI/2 */
@@ -393,26 +392,23 @@ static int lpi2c_imx_pio_msg_complete(struct lpi2c_imx_struct *lpi2c_imx) static int lpi2c_imx_txfifo_empty(struct lpi2c_imx_struct *lpi2c_imx) { - unsigned long orig_jiffies = jiffies; - u32 txcnt; - - do { - txcnt = readl(lpi2c_imx->base + LPI2C_MFSR) & 0xff; + unsigned int temp; + int err; - if (readl(lpi2c_imx->base + LPI2C_MSR) & MSR_NDF) { - dev_dbg(&lpi2c_imx->adapter.dev, "NDF detected\n"); - return -EIO; - } + err = lpi2c_imx_read_msr_poll_timeout(temp, + (temp & MSR_NDF) || !lpi2c_imx_txfifo_cnt(lpi2c_imx)); - if (time_after(jiffies, orig_jiffies + msecs_to_jiffies(500))) { - dev_dbg(&lpi2c_imx->adapter.dev, "txfifo empty timeout\n"); - if (lpi2c_imx->adapter.bus_recovery_info) - i2c_recover_bus(&lpi2c_imx->adapter); - return -ETIMEDOUT; - } - schedule(); + if (temp & MSR_NDF) { + dev_dbg(&lpi2c_imx->adapter.dev, "NDF detected\n"); + return -EIO; + } - } while (txcnt); + if (err) { + dev_dbg(&lpi2c_imx->adapter.dev, "txfifo empty timeout\n"); + if (lpi2c_imx->adapter.bus_recovery_info) + i2c_recover_bus(&lpi2c_imx->adapter); + return -ETIMEDOUT; + } return 0; }
--
2.39.5