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[v1,12/17] rockchip: adc: fix the hangups

Message ID 20220508150825.21711-13-jbx6244@gmail.com
State Changes Requested
Delegated to: Kever Yang
Headers show
Series Add rk3066 ADC and USB support | expand

Commit Message

Johan Jonker May 8, 2022, 3:08 p.m. UTC 
The Rockchip saradc behaves strange when doing an "adc scan"
with hang ups. Fix by adding an adc power down before the
settings are made. Similair to what TRM recommands follow
this flow below:

Power-down A/D Converter in SARADC_CTRL[3]
Power-up A/D Converter in SARADC_CTRL[3] and select input channel of A/D
Converter in SARADC_CTRL[2:0] bit
Wait an A/D interrupt or poll the SARADC_STAS register to determine
when the conversion is completed
Read the conversion result in the SARADC_DATA register

Signed-off-by: Johan Jonker <jbx6244@gmail.com>
---
 drivers/adc/rockchip-saradc.c | 5 +++++
 1 file changed, 5 insertions(+)
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Patch

diff --git a/drivers/adc/rockchip-saradc.c b/drivers/adc/rockchip-saradc.c
index e6a0341d..fb0f2e03 100644
--- a/drivers/adc/rockchip-saradc.c
+++ b/drivers/adc/rockchip-saradc.c
@@ -13,6 +13,7 @@ 
 #include <errno.h>
 #include <asm/io.h>
 #include <linux/bitops.h>
+#include <linux/delay.h>
 #include <linux/err.h>
 #include <power/regulator.h>
 
@@ -82,6 +83,10 @@  int rockchip_saradc_start_channel(struct udevice *dev, int channel)
 		return -EINVAL;
 	}
 
+	writel(0, &priv->regs->ctrl);
+
+	udelay(1);
+
 	/* 8 clock periods as delay between power up and start cmd */
 	writel(8, &priv->regs->dly_pu_soc);