From 229476a4de2e237ebadddca8a82d20afa9298f71 Mon Sep 17 00:00:00 2001 From: Valentin Caron Date: Mon, 22 Jul 2024 18:00:21 +0200 Subject: [PATCH] rtc: stm32: add Low Speed Clock Output (LSCO) support RTC is able to output on a pin the "LSE" internal clock. STM32 RTC is now registered as a clock provider. It provides rtc_lsco clock, that means RTC_LSCO is output on either RTC_OUT1 or RTC_OUT2_RMP, depending on pinmux DT property. The clock is marked as CLK_IGNORE_UNUSED and CLK_IS_CRITICAL because RTC_LSCO can be early required by devices needed it to init. Add LSCO in pinmux functions. Add "stm32_rtc_clean_outs" to disable LSCO. As RTC is part of "backup" power domain, it is not reset during shutdown or reboot. So force LSCO disable at probe. Co-developed-by: Amelie Delaunay Signed-off-by: Amelie Delaunay Signed-off-by: Valentin Caron Link: https://lore.kernel.org/r/20240722160022.454226-4-valentin.caron@foss.st.com Signed-off-by: Alexandre Belloni --- drivers/rtc/Kconfig | 1 + drivers/rtc/rtc-stm32.c | 99 +++++++++++++++++++++++++++++++++++++++++ 2 files changed, 100 insertions(+) --- a/drivers/rtc/Kconfig +++ b/drivers/rtc/Kconfig @@ -1892,6 +1892,7 @@ config RTC_DRV_STM32 select PINMUX select PINCONF select GENERIC_PINCONF + depends on COMMON_CLK help If you say yes here you get support for the STM32 On-Chip Real Time Clock. --- a/drivers/rtc/rtc-stm32.c +++ b/drivers/rtc/rtc-stm32.c @@ -6,6 +6,7 @@ #include #include +#include #include #include #include @@ -44,6 +45,10 @@ #define STM32_RTC_CR_FMT BIT(6) #define STM32_RTC_CR_ALRAE BIT(8) #define STM32_RTC_CR_ALRAIE BIT(12) +#define STM32_RTC_CR_OSEL GENMASK(22, 21) +#define STM32_RTC_CR_COE BIT(23) +#define STM32_RTC_CR_TAMPOE BIT(26) +#define STM32_RTC_CR_OUT2EN BIT(31) /* STM32_RTC_ISR/STM32_RTC_ICSR bit fields */ #define STM32_RTC_ISR_ALRAWF BIT(0) @@ -80,6 +85,12 @@ /* STM32_RTC_SR/_SCR bit fields */ #define STM32_RTC_SR_ALRA BIT(0) +/* STM32_RTC_CFGR bit fields */ +#define STM32_RTC_CFGR_OUT2_RMP BIT(0) +#define STM32_RTC_CFGR_LSCOEN GENMASK(2, 1) +#define STM32_RTC_CFGR_LSCOEN_OUT1 1 +#define STM32_RTC_CFGR_LSCOEN_OUT2_RMP 2 + /* STM32_RTC_VERR bit fields */ #define STM32_RTC_VERR_MINREV_SHIFT 0 #define STM32_RTC_VERR_MINREV GENMASK(3, 0) @@ -117,6 +128,7 @@ struct stm32_rtc_registers { u16 wpr; u16 sr; u16 scr; + u16 cfgr; u16 verr; }; @@ -131,6 +143,7 @@ struct stm32_rtc_data { bool has_pclk; bool need_dbp; bool need_accuracy; + bool has_lsco; }; struct stm32_rtc { @@ -143,6 +156,7 @@ struct stm32_rtc { struct clk *rtc_ck; const struct stm32_rtc_data *data; int irq_alarm; + struct clk *clk_lsco; }; static void stm32_rtc_wpr_unlock(struct stm32_rtc *rtc) @@ -209,7 +223,68 @@ struct stm32_rtc_pinmux_func { int (*action)(struct pinctrl_dev *pctl_dev, unsigned int pin); }; +static int stm32_rtc_pinmux_lsco_available(struct pinctrl_dev *pctldev, unsigned int pin) +{ + struct stm32_rtc *rtc = pinctrl_dev_get_drvdata(pctldev); + struct stm32_rtc_registers regs = rtc->data->regs; + unsigned int cr = readl_relaxed(rtc->base + regs.cr); + unsigned int cfgr = readl_relaxed(rtc->base + regs.cfgr); + unsigned int calib = STM32_RTC_CR_COE; + unsigned int tampalrm = STM32_RTC_CR_TAMPOE | STM32_RTC_CR_OSEL; + + switch (pin) { + case OUT1: + if ((!(cr & STM32_RTC_CR_OUT2EN) && + ((cr & calib) || cr & tampalrm)) || + ((cr & calib) && (cr & tampalrm))) + return -EBUSY; + break; + case OUT2_RMP: + if ((cr & STM32_RTC_CR_OUT2EN) && + (cfgr & STM32_RTC_CFGR_OUT2_RMP) && + ((cr & calib) || (cr & tampalrm))) + return -EBUSY; + break; + default: + return -EINVAL; + } + + if (clk_get_rate(rtc->rtc_ck) != 32768) + return -ERANGE; + + return 0; +} + +static int stm32_rtc_pinmux_action_lsco(struct pinctrl_dev *pctldev, unsigned int pin) +{ + struct stm32_rtc *rtc = pinctrl_dev_get_drvdata(pctldev); + struct stm32_rtc_registers regs = rtc->data->regs; + struct device *dev = rtc->rtc_dev->dev.parent; + u8 lscoen; + int ret; + + if (!rtc->data->has_lsco) + return -EPERM; + + ret = stm32_rtc_pinmux_lsco_available(pctldev, pin); + if (ret) + return ret; + + lscoen = (pin == OUT1) ? STM32_RTC_CFGR_LSCOEN_OUT1 : STM32_RTC_CFGR_LSCOEN_OUT2_RMP; + + rtc->clk_lsco = clk_register_gate(dev, "rtc_lsco", __clk_get_name(rtc->rtc_ck), + CLK_IGNORE_UNUSED | CLK_IS_CRITICAL, + rtc->base + regs.cfgr, lscoen, 0, NULL); + if (IS_ERR(rtc->clk_lsco)) + return PTR_ERR(rtc->clk_lsco); + + of_clk_add_provider(dev->of_node, of_clk_src_simple_get, rtc->clk_lsco); + + return 0; +} + static const struct stm32_rtc_pinmux_func stm32_rtc_pinmux_functions[] = { + STM32_RTC_PINMUX("lsco", &stm32_rtc_pinmux_action_lsco, "out1", "out2_rmp"), }; static int stm32_rtc_pinmux_get_functions_count(struct pinctrl_dev *pctldev) @@ -664,6 +739,7 @@ static const struct stm32_rtc_data stm32 .has_pclk = false, .need_dbp = true, .need_accuracy = false, + .has_lsco = false, .regs = { .tr = 0x00, .dr = 0x04, @@ -674,6 +750,7 @@ static const struct stm32_rtc_data stm32 .wpr = 0x24, .sr = 0x0C, /* set to ISR offset to ease alarm management */ .scr = UNDEF_REG, + .cfgr = UNDEF_REG, .verr = UNDEF_REG, }, .events = { @@ -686,6 +763,7 @@ static const struct stm32_rtc_data stm32 .has_pclk = true, .need_dbp = true, .need_accuracy = false, + .has_lsco = false, .regs = { .tr = 0x00, .dr = 0x04, @@ -696,6 +774,7 @@ static const struct stm32_rtc_data stm32 .wpr = 0x24, .sr = 0x0C, /* set to ISR offset to ease alarm management */ .scr = UNDEF_REG, + .cfgr = UNDEF_REG, .verr = UNDEF_REG, }, .events = { @@ -717,6 +796,7 @@ static const struct stm32_rtc_data stm32 .has_pclk = true, .need_dbp = false, .need_accuracy = true, + .has_lsco = true, .regs = { .tr = 0x00, .dr = 0x04, @@ -727,6 +807,7 @@ static const struct stm32_rtc_data stm32 .wpr = 0x24, .sr = 0x50, .scr = 0x5C, + .cfgr = 0x60, .verr = 0x3F4, }, .events = { @@ -743,6 +824,19 @@ static const struct of_device_id stm32_r }; MODULE_DEVICE_TABLE(of, stm32_rtc_of_match); +static void stm32_rtc_clean_outs(struct stm32_rtc *rtc) +{ + struct stm32_rtc_registers regs = rtc->data->regs; + + if (regs.cfgr != UNDEF_REG) { + unsigned int cfgr = readl_relaxed(rtc->base + regs.cfgr); + + cfgr &= ~STM32_RTC_CFGR_LSCOEN; + cfgr &= ~STM32_RTC_CFGR_OUT2_RMP; + writel_relaxed(cfgr, rtc->base + regs.cfgr); + } +} + static int stm32_rtc_init(struct platform_device *pdev, struct stm32_rtc *rtc) { @@ -946,6 +1040,8 @@ static int stm32_rtc_probe(struct platfo goto err; } + stm32_rtc_clean_outs(rtc); + ret = devm_pinctrl_register_and_init(&pdev->dev, &stm32_rtc_pdesc, rtc, &pctl); if (ret) return dev_err_probe(&pdev->dev, ret, "pinctrl register failed"); @@ -992,6 +1088,9 @@ static void stm32_rtc_remove(struct plat const struct stm32_rtc_registers *regs = &rtc->data->regs; unsigned int cr; + if (!IS_ERR_OR_NULL(rtc->clk_lsco)) + clk_unregister_gate(rtc->clk_lsco); + /* Disable interrupts */ stm32_rtc_wpr_unlock(rtc); cr = readl_relaxed(rtc->base + regs->cr);