i2c: mlxbf: Use readl_poll_timeout_atomic() for polling

Convert the usage of an open-coded custom tight poll while loop
with the provided readl_poll_timeout_atomic() macro.

Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Reviewed-by: Asmaa Mnebhi <asmaa@nvidia.com>
Link: https://lore.kernel.org/r/20250212165128.2413430-1-andriy.shevchenko@linux.intel.com
Signed-off-by: Andi Shyti <andi.shyti@kernel.org>

diff --git a/drivers/i2c/busses/i2c-mlxbf.c b/drivers/i2c/busses/i2c-mlxbf.c
index 21f67f3b65b6eb2460daa667b2f05832149914c0..280dde53d7f3b655088bafb2b8baa754c1cd338c 100644 (file)
--- a/drivers/i2c/busses/i2c-mlxbf.c
+++ b/drivers/i2c/busses/i2c-mlxbf.c
@@ -12,6 +12,7 @@
 #include <linux/interrupt.h>
 #include <linux/i2c.h>
 #include <linux/io.h>
+#include <linux/iopoll.h>
 #include <linux/kernel.h>
 #include <linux/module.h>
 #include <linux/mutex.h>
@@ -495,65 +496,6 @@ static u8 mlxbf_i2c_bus_count;
 
 static struct mutex mlxbf_i2c_bus_lock;
 
-/*
- * Function to poll a set of bits at a specific address; it checks whether
- * the bits are equal to zero when eq_zero is set to 'true', and not equal
- * to zero when eq_zero is set to 'false'.
- * Note that the timeout is given in microseconds.
- */
-static u32 mlxbf_i2c_poll(void __iomem *io, u32 addr, u32 mask,
-                           bool eq_zero, u32  timeout)
-{
-       u32 bits;
-
-       timeout = (timeout / MLXBF_I2C_POLL_FREQ_IN_USEC) + 1;
-
-       do {
-               bits = readl(io + addr) & mask;
-               if (eq_zero ? bits == 0 : bits != 0)
-                       return eq_zero ? 1 : bits;
-               udelay(MLXBF_I2C_POLL_FREQ_IN_USEC);
-       } while (timeout-- != 0);
-
-       return 0;
-}
-
-/*
- * SW must make sure that the SMBus Master GW is idle before starting
- * a transaction. Accordingly, this function polls the Master FSM stop
- * bit; it returns false when the bit is asserted, true if not.
- */
-static bool mlxbf_i2c_smbus_master_wait_for_idle(struct mlxbf_i2c_priv *priv)
-{
-       u32 mask = MLXBF_I2C_SMBUS_MASTER_FSM_STOP_MASK;
-       u32 addr = priv->chip->smbus_master_fsm_off;
-       u32 timeout = MLXBF_I2C_SMBUS_TIMEOUT;
-
-       if (mlxbf_i2c_poll(priv->mst->io, addr, mask, true, timeout))
-               return true;
-
-       return false;
-}
-
-/*
- * wait for the lock to be released before acquiring it.
- */
-static bool mlxbf_i2c_smbus_master_lock(struct mlxbf_i2c_priv *priv)
-{
-       if (mlxbf_i2c_poll(priv->mst->io, MLXBF_I2C_SMBUS_MASTER_GW,
-                          MLXBF_I2C_MASTER_LOCK_BIT, true,
-                          MLXBF_I2C_SMBUS_LOCK_POLL_TIMEOUT))
-               return true;
-
-       return false;
-}
-
-static void mlxbf_i2c_smbus_master_unlock(struct mlxbf_i2c_priv *priv)
-{
-       /* Clear the gw to clear the lock */
-       writel(0, priv->mst->io + MLXBF_I2C_SMBUS_MASTER_GW);
-}
-
 static bool mlxbf_i2c_smbus_transaction_success(u32 master_status,
                                                u32 cause_status)
 {
@@ -583,6 +525,7 @@ static int mlxbf_i2c_smbus_check_status(struct mlxbf_i2c_priv *priv)
 {
        u32 master_status_bits;
        u32 cause_status_bits;
+       u32 bits;
 
        /*
         * GW busy bit is raised by the driver and cleared by the HW
@@ -591,9 +534,9 @@ static int mlxbf_i2c_smbus_check_status(struct mlxbf_i2c_priv *priv)
         * then read the cause and master status bits to determine if
         * errors occurred during the transaction.
         */
-       mlxbf_i2c_poll(priv->mst->io, MLXBF_I2C_SMBUS_MASTER_GW,
-                        MLXBF_I2C_MASTER_BUSY_BIT, true,
-                        MLXBF_I2C_SMBUS_TIMEOUT);
+       readl_poll_timeout_atomic(priv->mst->io + MLXBF_I2C_SMBUS_MASTER_GW,
+                                 bits, !(bits & MLXBF_I2C_MASTER_BUSY_BIT),
+                                 MLXBF_I2C_POLL_FREQ_IN_USEC, MLXBF_I2C_SMBUS_TIMEOUT);
 
        /* Read cause status bits. */
        cause_status_bits = readl(priv->mst_cause->io +
@@ -740,7 +683,8 @@ mlxbf_i2c_smbus_start_transaction(struct mlxbf_i2c_priv *priv,
        u8 read_en, write_en, block_en, pec_en;
        u8 slave, flags, addr;
        u8 *read_buf;
-       int ret = 0;
+       u32 bits;
+       int ret;
 
        if (request->operation_cnt > MLXBF_I2C_SMBUS_MAX_OP_CNT)
                return -EINVAL;
@@ -760,11 +704,22 @@ mlxbf_i2c_smbus_start_transaction(struct mlxbf_i2c_priv *priv,
         * Try to acquire the smbus gw lock before any reads of the GW register since
         * a read sets the lock.
         */
-       if (WARN_ON(!mlxbf_i2c_smbus_master_lock(priv)))
+       ret = readl_poll_timeout_atomic(priv->mst->io + MLXBF_I2C_SMBUS_MASTER_GW,
+                                       bits, !(bits & MLXBF_I2C_MASTER_LOCK_BIT),
+                                       MLXBF_I2C_POLL_FREQ_IN_USEC,
+                                       MLXBF_I2C_SMBUS_LOCK_POLL_TIMEOUT);
+       if (WARN_ON(ret))
                return -EBUSY;
 
-       /* Check whether the HW is idle */
-       if (WARN_ON(!mlxbf_i2c_smbus_master_wait_for_idle(priv))) {
+       /*
+        * SW must make sure that the SMBus Master GW is idle before starting
+        * a transaction. Accordingly, this call polls the Master FSM stop bit;
+        * it returns -ETIMEDOUT when the bit is asserted, 0 if not.
+        */
+       ret = readl_poll_timeout_atomic(priv->mst->io + priv->chip->smbus_master_fsm_off,
+                                       bits, !(bits & MLXBF_I2C_SMBUS_MASTER_FSM_STOP_MASK),
+                                       MLXBF_I2C_POLL_FREQ_IN_USEC, MLXBF_I2C_SMBUS_TIMEOUT);
+       if (WARN_ON(ret)) {
                ret = -EBUSY;
                goto out_unlock;
        }
@@ -855,7 +810,8 @@ mlxbf_i2c_smbus_start_transaction(struct mlxbf_i2c_priv *priv,
        }
 
 out_unlock:
-       mlxbf_i2c_smbus_master_unlock(priv);
+       /* Clear the gw to clear the lock */
+       writel(0, priv->mst->io + MLXBF_I2C_SMBUS_MASTER_GW);
 
        return ret;
 }
@@ -1829,18 +1785,6 @@ static bool mlxbf_i2c_has_coalesce(struct mlxbf_i2c_priv *priv, bool *read,
        return true;
 }
 
-static bool mlxbf_i2c_slave_wait_for_idle(struct mlxbf_i2c_priv *priv,
-                                           u32 timeout)
-{
-       u32 mask = MLXBF_I2C_CAUSE_S_GW_BUSY_FALL;
-       u32 addr = MLXBF_I2C_CAUSE_ARBITER;
-
-       if (mlxbf_i2c_poll(priv->slv_cause->io, addr, mask, false, timeout))
-               return true;
-
-       return false;
-}
-
 static struct i2c_client *mlxbf_i2c_get_slave_from_addr(
                        struct mlxbf_i2c_priv *priv, u8 addr)
 {
@@ -1943,7 +1887,9 @@ static int mlxbf_i2c_irq_send(struct mlxbf_i2c_priv *priv, u8 recv_bytes)
         * Wait until the transfer is completed; the driver will wait
         * until the GW is idle, a cause will rise on fall of GW busy.
         */
-       mlxbf_i2c_slave_wait_for_idle(priv, MLXBF_I2C_SMBUS_TIMEOUT);
+       readl_poll_timeout_atomic(priv->slv_cause->io + MLXBF_I2C_CAUSE_ARBITER,
+                                 data32, data32 & MLXBF_I2C_CAUSE_S_GW_BUSY_FALL,
+                                 MLXBF_I2C_POLL_FREQ_IN_USEC, MLXBF_I2C_SMBUS_TIMEOUT);
 
 clear_csr:
        /* Release the Slave GW. */