counter: stm32-timer-cnt: Report count function when SLAVE_MODE_DISABLED

[ Upstream commit fae6f62e6a580b663ecf42c2120a0898deae9137 ]

When in SLAVE_MODE_DISABLED mode, the count still increases if the
counter is enabled because an internal clock is used. This patch fixes
the stm32_count_function_get() and stm32_count_function_set() functions
to properly handle this behavior.

Fixes: ad29937e206f ("counter: Add STM32 Timer quadrature encoder")
Cc: Fabrice Gasnier <fabrice.gasnier@st.com>
Cc: Maxime Coquelin <mcoquelin.stm32@gmail.com>
Cc: Alexandre Torgue <alexandre.torgue@st.com>
Signed-off-by: William Breathitt Gray <vilhelm.gray@gmail.com>
Reviewed-by: Fabrice Gasnier <fabrice.gasnier@foss.st.com>
Link: https://lore.kernel.org/r/20210226012931.161429-1-vilhelm.gray@gmail.com
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>

diff --git a/drivers/counter/stm32-timer-cnt.c b/drivers/counter/stm32-timer-cnt.c
index ef2a974..cd50dc1 100644 (file)
--- a/drivers/counter/stm32-timer-cnt.c
+++ b/drivers/counter/stm32-timer-cnt.c
@@ -44,13 +44,14 @@ struct stm32_timer_cnt {
  * @STM32_COUNT_ENCODER_MODE_3: counts on both TI1FP1 and TI2FP2 edges
  */
 enum stm32_count_function {
-       STM32_COUNT_SLAVE_MODE_DISABLED = -1,
+       STM32_COUNT_SLAVE_MODE_DISABLED,
        STM32_COUNT_ENCODER_MODE_1,
        STM32_COUNT_ENCODER_MODE_2,
        STM32_COUNT_ENCODER_MODE_3,
 };
 
 static enum counter_count_function stm32_count_functions[] = {
+       [STM32_COUNT_SLAVE_MODE_DISABLED] = COUNTER_COUNT_FUNCTION_INCREASE,
        [STM32_COUNT_ENCODER_MODE_1] = COUNTER_COUNT_FUNCTION_QUADRATURE_X2_A,
        [STM32_COUNT_ENCODER_MODE_2] = COUNTER_COUNT_FUNCTION_QUADRATURE_X2_B,
        [STM32_COUNT_ENCODER_MODE_3] = COUNTER_COUNT_FUNCTION_QUADRATURE_X4,
@@ -90,6 +91,9 @@ static int stm32_count_function_get(struct counter_device *counter,
        regmap_read(priv->regmap, TIM_SMCR, &smcr);
 
        switch (smcr & TIM_SMCR_SMS) {
+       case 0:
+               *function = STM32_COUNT_SLAVE_MODE_DISABLED;
+               return 0;
        case 1:
                *function = STM32_COUNT_ENCODER_MODE_1;
                return 0;
@@ -99,9 +103,9 @@ static int stm32_count_function_get(struct counter_device *counter,
        case 3:
                *function = STM32_COUNT_ENCODER_MODE_3;
                return 0;
+       default:
+               return -EINVAL;
        }
-
-       return -EINVAL;
 }
 
 static int stm32_count_function_set(struct counter_device *counter,
@@ -112,6 +116,9 @@ static int stm32_count_function_set(struct counter_device *counter,
        u32 cr1, sms;
 
        switch (function) {
+       case STM32_COUNT_SLAVE_MODE_DISABLED:
+               sms = 0;
+               break;
        case STM32_COUNT_ENCODER_MODE_1:
                sms = 1;
                break;
@@ -122,8 +129,7 @@ static int stm32_count_function_set(struct counter_device *counter,
                sms = 3;
                break;
        default:
-               sms = 0;
-               break;
+               return -EINVAL;
        }
 
        /* Store enable status */
@@ -274,31 +280,36 @@ static int stm32_action_get(struct counter_device *counter,
        size_t function;
        int err;
 
-       /* Default action mode (e.g. STM32_COUNT_SLAVE_MODE_DISABLED) */
-       *action = STM32_SYNAPSE_ACTION_NONE;
-
        err = stm32_count_function_get(counter, count, &function);
        if (err)
-               return 0;
+               return err;
 
        switch (function) {
+       case STM32_COUNT_SLAVE_MODE_DISABLED:
+               /* counts on internal clock when CEN=1 */
+               *action = STM32_SYNAPSE_ACTION_NONE;
+               return 0;
        case STM32_COUNT_ENCODER_MODE_1:
                /* counts up/down on TI1FP1 edge depending on TI2FP2 level */
                if (synapse->signal->id == count->synapses[0].signal->id)
                        *action = STM32_SYNAPSE_ACTION_BOTH_EDGES;
-               break;
+               else
+                       *action = STM32_SYNAPSE_ACTION_NONE;
+               return 0;
        case STM32_COUNT_ENCODER_MODE_2:
                /* counts up/down on TI2FP2 edge depending on TI1FP1 level */
                if (synapse->signal->id == count->synapses[1].signal->id)
                        *action = STM32_SYNAPSE_ACTION_BOTH_EDGES;
-               break;
+               else
+                       *action = STM32_SYNAPSE_ACTION_NONE;
+               return 0;
        case STM32_COUNT_ENCODER_MODE_3:
                /* counts up/down on both TI1FP1 and TI2FP2 edges */
                *action = STM32_SYNAPSE_ACTION_BOTH_EDGES;
-               break;
+               return 0;
+       default:
+               return -EINVAL;
        }
-
-       return 0;
 }
 
 static const struct counter_ops stm32_timer_cnt_ops = {