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authorCharles Keepax <ckeepax@opensource.cirrus.com>2018-06-28 16:49:35 +0100
committerLee Jones <lee.jones@linaro.org>2018-07-27 08:13:25 +0100
commitf99fea949736b6a79cddaaaec7e3b8830fd81c93 (patch)
tree2c89aae51cf88a77f5fd8c7e05cc3e4ea765fdb3 /drivers/mfd
parenta13c93b3a5db87a173b2cdc6c2f2122d9d677808 (diff)
downloadlinux-f99fea949736b6a79cddaaaec7e3b8830fd81c93.tar.bz2
mfd: arizona: Don't use regmap_read_poll_timeout
Some Arizona CODECs have a small timing window where they will NAK an I2C transaction if it happens before the boot done bit is set. This can cause the read of the register containing the boot done bit to fail until it is set. Since regmap_read_poll_timeout will abort polling if a read fails it can't be reliably used to poll the boot done bit over I2C. Do a partial revert of ef84f885e037 ("mfd: arizona: Refactor arizona_poll_reg"), removing the regmap_read_poll_timeout but leaving the refactoring to make the arizona_poll_reg take more sensible arguments. Fixes: ef84f885e037 ("mfd: arizona: Refactor arizona_poll_reg") Signed-off-by: Charles Keepax <ckeepax@opensource.cirrus.com> Signed-off-by: Lee Jones <lee.jones@linaro.org>
Diffstat (limited to 'drivers/mfd')
-rw-r--r--drivers/mfd/arizona-core.c34
1 files changed, 26 insertions, 8 deletions
diff --git a/drivers/mfd/arizona-core.c b/drivers/mfd/arizona-core.c
index 83f1c5a516d9..5f1e37d23943 100644
--- a/drivers/mfd/arizona-core.c
+++ b/drivers/mfd/arizona-core.c
@@ -24,6 +24,7 @@
#include <linux/regulator/consumer.h>
#include <linux/regulator/machine.h>
#include <linux/slab.h>
+#include <linux/ktime.h>
#include <linux/platform_device.h>
#include <linux/mfd/arizona/core.h>
@@ -236,22 +237,39 @@ static irqreturn_t arizona_overclocked(int irq, void *data)
#define ARIZONA_REG_POLL_DELAY_US 7500
+static inline bool arizona_poll_reg_delay(ktime_t timeout)
+{
+ if (ktime_compare(ktime_get(), timeout) > 0)
+ return false;
+
+ usleep_range(ARIZONA_REG_POLL_DELAY_US / 2, ARIZONA_REG_POLL_DELAY_US);
+
+ return true;
+}
+
static int arizona_poll_reg(struct arizona *arizona,
int timeout_ms, unsigned int reg,
unsigned int mask, unsigned int target)
{
+ ktime_t timeout = ktime_add_us(ktime_get(), timeout_ms * USEC_PER_MSEC);
unsigned int val = 0;
int ret;
- ret = regmap_read_poll_timeout(arizona->regmap,
- reg, 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);
+ do {
+ ret = regmap_read(arizona->regmap, reg, &val);
- return ret;
+ if ((val & mask) == target)
+ return 0;
+ } while (arizona_poll_reg_delay(timeout));
+
+ if (ret) {
+ dev_err(arizona->dev, "Failed polling reg 0x%x: %d\n",
+ reg, ret);
+ return ret;
+ }
+
+ dev_err(arizona->dev, "Polling reg 0x%x timed out: %x\n", reg, val);
+ return -ETIMEDOUT;
}
static int arizona_wait_for_boot(struct arizona *arizona)