diff options
Diffstat (limited to 'drivers/counter')
| -rw-r--r-- | drivers/counter/stm32-timer-cnt.c | 55 |
1 files changed, 55 insertions, 0 deletions
diff --git a/drivers/counter/stm32-timer-cnt.c b/drivers/counter/stm32-timer-cnt.c index b969d550e90a..17f87ace450d 100644 --- a/drivers/counter/stm32-timer-cnt.c +++ b/drivers/counter/stm32-timer-cnt.c @@ -11,6 +11,7 @@ #include <linux/mfd/stm32-timers.h> #include <linux/mod_devicetable.h> #include <linux/module.h> +#include <linux/of.h> #include <linux/pinctrl/consumer.h> #include <linux/platform_device.h> #include <linux/types.h> @@ -38,6 +39,7 @@ struct stm32_timer_cnt { u32 max_arr; bool enabled; struct stm32_timer_regs bak; + bool has_encoder; }; static const enum counter_function stm32_count_functions[] = { @@ -111,12 +113,18 @@ static int stm32_count_function_write(struct counter_device *counter, sms = TIM_SMCR_SMS_SLAVE_MODE_DISABLED; break; case COUNTER_FUNCTION_QUADRATURE_X2_A: + if (!priv->has_encoder) + return -EOPNOTSUPP; sms = TIM_SMCR_SMS_ENCODER_MODE_1; break; case COUNTER_FUNCTION_QUADRATURE_X2_B: + if (!priv->has_encoder) + return -EOPNOTSUPP; sms = TIM_SMCR_SMS_ENCODER_MODE_2; break; case COUNTER_FUNCTION_QUADRATURE_X4: + if (!priv->has_encoder) + return -EOPNOTSUPP; sms = TIM_SMCR_SMS_ENCODER_MODE_3; break; default: @@ -388,6 +396,49 @@ static struct counter_count stm32_counts = { .num_ext = ARRAY_SIZE(stm32_count_ext) }; +/* encoder supported on TIM1 TIM2 TIM3 TIM4 TIM5 TIM8 */ +#define STM32_TIM_ENCODER_SUPPORTED (BIT(0) | BIT(1) | BIT(2) | BIT(3) | BIT(4) | BIT(7)) + +static const char * const stm32_timer_trigger_compat[] = { + "st,stm32-timer-trigger", + "st,stm32h7-timer-trigger", +}; + +static int stm32_timer_cnt_probe_encoder(struct device *dev, + struct stm32_timer_cnt *priv) +{ + struct device *parent = dev->parent; + struct device_node *tnode = NULL, *pnode = parent->of_node; + int i, ret; + u32 idx; + + /* + * Need to retrieve the trigger node index from DT, to be able + * to determine if the counter supports encoder mode. It also + * enforce backward compatibility, and allow to support other + * counter modes in this driver (when the timer doesn't support + * encoder). + */ + for (i = 0; i < ARRAY_SIZE(stm32_timer_trigger_compat) && !tnode; i++) + tnode = of_get_compatible_child(pnode, stm32_timer_trigger_compat[i]); + if (!tnode) { + dev_err(dev, "Can't find trigger node\n"); + return -ENODATA; + } + + ret = of_property_read_u32(tnode, "reg", &idx); + if (ret) { + dev_err(dev, "Can't get index (%d)\n", ret); + return ret; + } + + priv->has_encoder = !!(STM32_TIM_ENCODER_SUPPORTED & BIT(idx)); + + dev_dbg(dev, "encoder support: %s\n", priv->has_encoder ? "yes" : "no"); + + return 0; +} + static int stm32_timer_cnt_probe(struct platform_device *pdev) { struct stm32_timers *ddata = dev_get_drvdata(pdev->dev.parent); @@ -409,6 +460,10 @@ static int stm32_timer_cnt_probe(struct platform_device *pdev) priv->clk = ddata->clk; priv->max_arr = ddata->max_arr; + ret = stm32_timer_cnt_probe_encoder(dev, priv); + if (ret) + return ret; + counter->name = dev_name(dev); counter->parent = dev; counter->ops = &stm32_timer_cnt_ops; |