linux-kernel - [PATCH v4 3/3] mfd: arizona: Refactor arizona_poll

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Date:   Wed, 15 Mar 2017 14:58:38 +0000
From:   Charles Keepax <ckeepax@...nsource.wolfsonmicro.com>
To:     <lee.jones@...aro.org>
CC:     <linux-kernel@...r.kernel.org>,
        <patches@...nsource.wolfsonmicro.com>
Subject: [PATCH v4 3/3] mfd: arizona: Refactor arizona_poll_reg

Currently, we specify the timeout in terms of the number of polls but it
is more clear from a user of the functions perspective to specify the
timeout directly in milliseconds, as such update the function to these new
semantics.

Additionally, arizona_poll_reg essentially hard-codes
regmap_read_poll_timeout, update the implementation to use
regmap_read_poll_timeout. We still keep arizona_poll_reg around as
regmap_read_poll_timeout is a macro so rather than expand this for each
caller keep it wrapped in arizona_poll_reg.

Whilst we are doing this make the timeouts a little more generous as
the previous system had a bit more slack as it was done as a delay per
iteration of the loop whereas regmap_read_poll_timeout compares ktime's.

Signed-off-by: Charles Keepax <ckeepax@...nsource.wolfsonmicro.com>
---

Changes since v3:
 - Squashed together patches 3/4 from the v3 chain.

Thanks,
Charles

 drivers/mfd/arizona-core.c | 36 ++++++++++++++++--------------------
 1 file changed, 16 insertions(+), 20 deletions(-)

diff --git a/drivers/mfd/arizona-core.c b/drivers/mfd/arizona-core.c
index 4cb34c3..75488e6 100644
--- a/drivers/mfd/arizona-core.c
+++ b/drivers/mfd/arizona-core.c
@@ -235,29 +235,25 @@ static irqreturn_t arizona_overclocked(int irq, void *data)
 	return IRQ_HANDLED;
 }
 
+#define ARIZONA_REG_POLL_DELAY_US 7500
+
 static int arizona_poll_reg(struct arizona *arizona,
-			    int timeout, unsigned int reg,
+			    int timeout_ms, unsigned int reg,
 			    unsigned int mask, unsigned int target)
 {
 	unsigned int val = 0;
-	int ret, i;
-
-	for (i = 0; i < timeout; i++) {
-		ret = regmap_read(arizona->regmap, reg, &val);
-		if (ret != 0) {
-			dev_err(arizona->dev, "Failed to read reg 0x%x: %d\n",
-				reg, ret);
-			continue;
-		}
-
-		if ((val & mask) == target)
-			return 0;
+	int ret;
 
-		usleep_range(1000, 5000);
-	}
+	ret = regmap_read_poll_timeout(arizona->regmap,
+				       ARIZONA_INTERRUPT_RAW_STATUS_5, val,
+				       ((val & mask) == target),
+				       ARIZONA_REG_POLL_DELAY_US,
+				       timeout_ms * 1000);
+	if (ret)
+		dev_err(arizona->dev, "Polling reg 0x%x timed out: %x\n",
+			reg, val);
 
-	dev_err(arizona->dev, "Polling reg 0x%x timed out: %x\n", reg, val);
-	return -ETIMEDOUT;
+	return ret;
 }
 
 static int arizona_wait_for_boot(struct arizona *arizona)
@@ -269,7 +265,7 @@ static int arizona_wait_for_boot(struct arizona *arizona)
 	 * we won't race with the interrupt handler as it'll be blocked on
 	 * runtime resume.
 	 */
-	ret = arizona_poll_reg(arizona, 5, ARIZONA_INTERRUPT_RAW_STATUS_5,
+	ret = arizona_poll_reg(arizona, 30, ARIZONA_INTERRUPT_RAW_STATUS_5,
 			       ARIZONA_BOOT_DONE_STS, ARIZONA_BOOT_DONE_STS);
 
 	if (!ret)
@@ -339,7 +335,7 @@ static int arizona_enable_freerun_sysclk(struct arizona *arizona,
 			ret);
 		return ret;
 	}
-	ret = arizona_poll_reg(arizona, 25, ARIZONA_INTERRUPT_RAW_STATUS_5,
+	ret = arizona_poll_reg(arizona, 180, ARIZONA_INTERRUPT_RAW_STATUS_5,
 			       ARIZONA_FLL1_CLOCK_OK_STS,
 			       ARIZONA_FLL1_CLOCK_OK_STS);
 	if (ret)
@@ -403,7 +399,7 @@ static int wm5102_apply_hardware_patch(struct arizona *arizona)
 		goto err;
 	}
 
-	ret = arizona_poll_reg(arizona, 5, ARIZONA_WRITE_SEQUENCER_CTRL_1,
+	ret = arizona_poll_reg(arizona, 30, ARIZONA_WRITE_SEQUENCER_CTRL_1,
 			       ARIZONA_WSEQ_BUSY, 0);
 	if (ret)
 		regmap_write(arizona->regmap, ARIZONA_WRITE_SEQUENCER_CTRL_0,
-- 
2.1.4