CBUS: A workaround for ADC S/H HW bug: always keep ch 8 selected when S/H is used

Signed-off-by: Mikko Ylinen <mikko.k.ylinen@nokia.com>
Signed-off-by: Tony Lindgren <tony@atomide.com>

diff --git a/drivers/cbus/retu.c b/drivers/cbus/retu.c
index 417273a67a4eec3bce1a9fbb7b636dcf06e506b8..ebb86b363de1dce2a2ef9654401049fe27373cc3 100644 (file)
--- a/drivers/cbus/retu.c
+++ b/drivers/cbus/retu.c
@@ -114,9 +114,21 @@ int retu_read_adc(int channel)
                return -EINVAL;
 
        spin_lock_irqsave(&retu_lock, flags);
+
+       if ((channel == 8) && retu_is_vilma) {
+               int scr = retu_read_reg(RETU_REG_ADCSCR);
+               int ch = (retu_read_reg(RETU_REG_ADCR) >> 10) & 0xf;
+               if (((scr & 0xff) != 0) && (ch != 8))
+                       retu_write_reg (RETU_REG_ADCSCR, (scr & ~0xff));
+       }
+
        /* Select the channel and read result */
        retu_write_reg(RETU_REG_ADCR, channel << 10);
        res = retu_read_reg(RETU_REG_ADCR) & 0x3ff;
+
+       if (retu_is_vilma)
+               retu_write_reg(RETU_REG_ADCR, (1 << 13));
+
        /* Unlock retu */
        spin_unlock_irqrestore(&retu_lock, flags);
 

diff --git a/drivers/cbus/retu.h b/drivers/cbus/retu.h
index 49f23e664dcaa56c5034eb22741580096475ccf0..c9e044c1494543003227396a2d273e3f32c2266c 100644 (file)
--- a/drivers/cbus/retu.h
+++ b/drivers/cbus/retu.h
@@ -34,6 +34,7 @@
 #define RETU_REG_RTCHMAR       0x05    /* RTC hours and minutes alarm and time set register */
 #define RETU_REG_RTCCALR       0x06    /* RTC calibration register */
 #define RETU_REG_ADCR          0x08    /* ADC result */
+#define RETU_REG_ADCSCR                0x09    /* ADC sample ctrl */
 #define RETU_REG_CC1           0x0d    /* Common control register 1 */
 #define RETU_REG_CC2           0x0e    /* Common control register 2 */
 #define RETU_REG_CTRL_CLR      0x0f    /* Regulator clear register */