From: Fabrice Gasnier Date: Thu, 7 Mar 2024 13:33:04 +0000 (+0100) Subject: counter: stm32-timer-cnt: probe number of channels from registers X-Git-Url: http://git.maquefel.me/?a=commitdiff_plain;h=f7630270b67836bedc518e96fb4c64b11fe3fb5e;p=linux.git counter: stm32-timer-cnt: probe number of channels from registers Probe the number of capture compare channels, by writing CCER register bits and read them back. Take care to restore the register original value. This is a precursor patch to support capture channels. Reviewed-by: William Breathitt Gray Signed-off-by: Fabrice Gasnier Link: https://lore.kernel.org/r/20240307133306.383045-9-fabrice.gasnier@foss.st.com Signed-off-by: William Breathitt Gray --- diff --git a/drivers/counter/stm32-timer-cnt.c b/drivers/counter/stm32-timer-cnt.c index f63d0c3e3f229..e1c0a502b74c0 100644 --- a/drivers/counter/stm32-timer-cnt.c +++ b/drivers/counter/stm32-timer-cnt.c @@ -42,6 +42,7 @@ struct stm32_timer_cnt { bool enabled; struct stm32_timer_regs bak; bool has_encoder; + unsigned int nchannels; }; static const enum counter_function stm32_count_functions[] = { @@ -416,6 +417,20 @@ static struct counter_count stm32_counts = { .num_ext = ARRAY_SIZE(stm32_count_ext) }; +static void stm32_timer_cnt_detect_channels(struct device *dev, + struct stm32_timer_cnt *priv) +{ + u32 ccer, ccer_backup; + + regmap_read(priv->regmap, TIM_CCER, &ccer_backup); + regmap_set_bits(priv->regmap, TIM_CCER, TIM_CCER_CCXE); + regmap_read(priv->regmap, TIM_CCER, &ccer); + regmap_write(priv->regmap, TIM_CCER, ccer_backup); + priv->nchannels = hweight32(ccer & TIM_CCER_CCXE); + + dev_dbg(dev, "has %d cc channels\n", priv->nchannels); +} + /* 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)) @@ -484,6 +499,8 @@ static int stm32_timer_cnt_probe(struct platform_device *pdev) if (ret) return ret; + stm32_timer_cnt_detect_channels(dev, priv); + counter->name = dev_name(dev); counter->parent = dev; counter->ops = &stm32_timer_cnt_ops;