[PATCH v3 0/4] rtc: stm32: add pinctrl interface to handle RTC outs

[PATCH v3 0/4] rtc: stm32: add pinctrl interface to handle RTC outs

[Valentin Caron]

This series adds a pinctrl/pinmux interface to control STM32 RTC outputs.

Theses two signals output are possible:
 - LSCO (Low Speed Clock Output) that allow to output LSE clock on a pin.
   On STM32MPU Discovery boards, this feature is used to generate a clock
   to Wifi/Bluetooth module.
 - Alarm out that allow to send a pulse on a pin when alarm A of the RTC
   expires.

First attempt [1] was based on 'st,' vendor properties, this one is based
on pinctrl and pinmux framework.

As device-trees will be upstreamed separately, here is an example:

stm32-pinctrl {
    rtc_rsvd_pins_a: rtc-rsvd-0 {
        pins {
            pinmux = <STM32_PINMUX('B', 2, AF1)>, /* OUT2 */
                     <STM32_PINMUX('I', 8, ANALOG)>; /* OUT2_RMP */
        };
    };
};

stm32-rtc {
    pinctrl-0 = <&rtc_rsvd_pins_a &rtc_alarma_pins_a>;

    /* Enable by foo-device */
    rtc_lsco_pins_a: rtc-lsco-0 {
        pins = "out2_rmp";
        function = "lsco";
    };

    /* Enable by stm32-rtc hog */
    rtc_alarma_pins_a: rtc-alarma-0 {
        pins = "out2";
        function = "alarm-a";
    };
};

foo-device {
    pinctrl-0 = <&rtc_lsco_pins_a>;
};

[1] https://lore.kernel.org/linux-arm-kernel/20220504130617.331290-5-valentin.caron@foss.st.com/t/#m37935e92315e22bbe085775096175afc05b7ff09

Since v2:
 - Modify Kconfig after (a lot of) robots alert:
     + https://lore.kernel.org/oe-kbuild-all/202407190654.I3RI7WfP-lkp@intel.com/
     + https://lore.kernel.org/oe-kbuild-all/202407191258.1oitwwMV-lkp@intel.com/
     + https://lore.kernel.org/oe-kbuild-all/202407200400.NnW2fJ0q-lkp@intel.com/
     + https://lore.kernel.org/oe-kbuild-all/202407181525.BRNKqmNf-lkp@intel.com/
     + https://lore.kernel.org/oe-kbuild-all/202407191830.8bh5dJ09-lkp@intel.com/
   Make RTC_DRV_STM32 depends on OF, PINCTRL and COMMON_CLK as they are menuconfig entry.
   Make RTC_DRV_STM32 select PINCONF, PINCONF_GENERIC and PINMUX as they config entry.
   
Since v1:
 - Select PINMUX and PINCONF_GENERIC to solve:
   https://lore.kernel.org/oe-kbuild-all/202407130943.ie6n2Orh-lkp@intel.com/
 - Make stm32_rtc_pinctrl_pins as static to solve:
   https://lore.kernel.org/oe-kbuild-all/202407130612.OEicZbNE-lkp@intel.com/
 - Change "depends on" to "select" COMMON_CLK config
 - Modify regex in dt-binding to avoid properties like "rtc--123" as valid ones.

Valentin Caron (4):
  dt-bindings: rtc: stm32: describe pinmux nodes
  rtc: stm32: add pinctrl and pinmux interfaces
  rtc: stm32: add Low Speed Clock Output (LSCO) support
  rtc: stm32: add alarm A out feature

 .../devicetree/bindings/rtc/st,stm32-rtc.yaml |  28 ++
 drivers/rtc/Kconfig                           |   6 +
 drivers/rtc/rtc-stm32.c                       | 281 ++++++++++++++++++
 3 files changed, 315 insertions(+)

-- 
2.25.1

[PATCH v3 1/4] dt-bindings: rtc: stm32: describe pinmux nodes

[Valentin Caron]

STM32 RTC is capable to handle 3 specific pins of the soc (out1, out2,
out2_rmp) and to outputs 2 signals (LSCO, alarm-a).

This feature is configured thanks to pinmux nodes and pinctrl framework.
This feature is available with compatible st,stm32mp1-rtc and
st,stm32mp25-rtc only.

Signed-off-by: Valentin Caron <valentin.caron@foss.st.com>
---
 .../devicetree/bindings/rtc/st,stm32-rtc.yaml | 28 +++++++++++++++++++
 1 file changed, 28 insertions(+)

diff --git a/Documentation/devicetree/bindings/rtc/st,stm32-rtc.yaml b/Documentation/devicetree/bindings/rtc/st,stm32-rtc.yaml
index 7a0fab721cf1..aae06e570c22 100644
--- a/Documentation/devicetree/bindings/rtc/st,stm32-rtc.yaml
+++ b/Documentation/devicetree/bindings/rtc/st,stm32-rtc.yaml
@@ -53,6 +53,28 @@ properties:
       override default rtc_ck parent clock phandle of the new parent clock of rtc_ck
     maxItems: 1
 
+patternProperties:
+  "^rtc-[a-z]+-[0-9]+$":
+    type: object
+    $ref: /schemas/pinctrl/pinmux-node.yaml
+    description: |
+      Configuration of STM32 RTC pins description. STM32 RTC is able to output
+      some signals on specific pins:
+      - LSCO (Low Speed Clock Output) that allow to output LSE clock on a pin.
+      - Alarm out that allow to send a pulse on a pin when alarm A of the RTC
+        expires.
+    additionalProperties: false
+    properties:
+      function:
+        enum:
+          - lsco
+          - alarm-a
+      pins:
+        enum:
+          - out1
+          - out2
+          - out2_rmp
+
 allOf:
   - if:
       properties:
@@ -68,6 +90,9 @@ allOf:
 
         clock-names: false
 
+      patternProperties:
+        "^rtc-[a-z]+-[0-9]+$": false
+
       required:
         - st,syscfg
 
@@ -83,6 +108,9 @@ allOf:
           minItems: 2
           maxItems: 2
 
+      patternProperties:
+        "^rtc-[a-z]+-[0-9]+$": false
+
       required:
         - clock-names
         - st,syscfg
-- 
2.25.1

[PATCH v3 2/4] rtc: stm32: add pinctrl and pinmux interfaces

[Valentin Caron]

STM32 RTC is capable to handle 3 specific pins of the soc.
"out1, out2 and out2_rmp". To handle this, we use pinctrl framework.
There is a single pin per group.

Signed-off-by: Valentin Caron <valentin.caron@foss.st.com>
---
 drivers/rtc/Kconfig     |   5 ++
 drivers/rtc/rtc-stm32.c | 120 ++++++++++++++++++++++++++++++++++++++++
 2 files changed, 125 insertions(+)

diff --git a/drivers/rtc/Kconfig b/drivers/rtc/Kconfig
index 2a95b05982ad..4b1a87027a3d 100644
--- a/drivers/rtc/Kconfig
+++ b/drivers/rtc/Kconfig
@@ -1923,6 +1923,11 @@ config RTC_DRV_STM32
 	tristate "STM32 RTC"
 	select REGMAP_MMIO
 	depends on ARCH_STM32 || COMPILE_TEST
+	depends on OF
+	depends on PINCTRL
+	select PINMUX
+	select PINCONF
+	select GENERIC_PINCONF
 	help
 	   If you say yes here you get support for the STM32 On-Chip
 	   Real Time Clock.
diff --git a/drivers/rtc/rtc-stm32.c b/drivers/rtc/rtc-stm32.c
index 98b07969609d..6dfd9dc07e2e 100644
--- a/drivers/rtc/rtc-stm32.c
+++ b/drivers/rtc/rtc-stm32.c
@@ -13,6 +13,9 @@
 #include <linux/mfd/syscon.h>
 #include <linux/module.h>
 #include <linux/of.h>
+#include <linux/pinctrl/pinctrl.h>
+#include <linux/pinctrl/pinconf-generic.h>
+#include <linux/pinctrl/pinmux.h>
 #include <linux/platform_device.h>
 #include <linux/pm_wakeirq.h>
 #include <linux/regmap.h>
@@ -107,6 +110,14 @@
 /* STM32 RTC driver time helpers */
 #define SEC_PER_DAY		(24 * 60 * 60)
 
+/* STM32 RTC pinctrl helpers */
+#define STM32_RTC_PINMUX(_name, _action, ...) { \
+	.name = (_name), \
+	.action = (_action), \
+	.groups = ((const char *[]){ __VA_ARGS__ }), \
+	.num_groups = ARRAY_SIZE(((const char *[]){ __VA_ARGS__ })), \
+}
+
 struct stm32_rtc;
 
 struct stm32_rtc_registers {
@@ -171,6 +182,106 @@ static void stm32_rtc_wpr_lock(struct stm32_rtc *rtc)
 	writel_relaxed(RTC_WPR_WRONG_KEY, rtc->base + regs->wpr);
 }
 
+enum stm32_rtc_pin_name {
+	NONE,
+	OUT1,
+	OUT2,
+	OUT2_RMP
+};
+
+static const struct pinctrl_pin_desc stm32_rtc_pinctrl_pins[] = {
+	PINCTRL_PIN(OUT1, "out1"),
+	PINCTRL_PIN(OUT2, "out2"),
+	PINCTRL_PIN(OUT2_RMP, "out2_rmp"),
+};
+
+static int stm32_rtc_pinctrl_get_groups_count(struct pinctrl_dev *pctldev)
+{
+	return ARRAY_SIZE(stm32_rtc_pinctrl_pins);
+}
+
+static const char *stm32_rtc_pinctrl_get_group_name(struct pinctrl_dev *pctldev,
+						    unsigned int selector)
+{
+	return stm32_rtc_pinctrl_pins[selector].name;
+}
+
+static int stm32_rtc_pinctrl_get_group_pins(struct pinctrl_dev *pctldev,
+					    unsigned int selector,
+					    const unsigned int **pins,
+					    unsigned int *num_pins)
+{
+	*pins = &stm32_rtc_pinctrl_pins[selector].number;
+	*num_pins = 1;
+	return 0;
+}
+
+static const struct pinctrl_ops stm32_rtc_pinctrl_ops = {
+	.dt_node_to_map		= pinconf_generic_dt_node_to_map_all,
+	.dt_free_map		= pinconf_generic_dt_free_map,
+	.get_groups_count	= stm32_rtc_pinctrl_get_groups_count,
+	.get_group_name		= stm32_rtc_pinctrl_get_group_name,
+	.get_group_pins		= stm32_rtc_pinctrl_get_group_pins,
+};
+
+struct stm32_rtc_pinmux_func {
+	const char *name;
+	const char * const *groups;
+	const unsigned int num_groups;
+	int (*action)(struct pinctrl_dev *pctl_dev, unsigned int pin);
+};
+
+static const struct stm32_rtc_pinmux_func stm32_rtc_pinmux_functions[] = {
+};
+
+static int stm32_rtc_pinmux_get_functions_count(struct pinctrl_dev *pctldev)
+{
+	return ARRAY_SIZE(stm32_rtc_pinmux_functions);
+}
+
+static const char *stm32_rtc_pinmux_get_fname(struct pinctrl_dev *pctldev, unsigned int selector)
+{
+	return stm32_rtc_pinmux_functions[selector].name;
+}
+
+static int stm32_rtc_pinmux_get_groups(struct pinctrl_dev *pctldev, unsigned int selector,
+				       const char * const **groups, unsigned int * const num_groups)
+{
+	*groups = stm32_rtc_pinmux_functions[selector].groups;
+	*num_groups = stm32_rtc_pinmux_functions[selector].num_groups;
+	return 0;
+}
+
+static int stm32_rtc_pinmux_set_mux(struct pinctrl_dev *pctldev, unsigned int selector,
+				    unsigned int group)
+{
+	struct stm32_rtc_pinmux_func selected_func = stm32_rtc_pinmux_functions[selector];
+	struct pinctrl_pin_desc pin = stm32_rtc_pinctrl_pins[group];
+
+	/* Call action */
+	if (selected_func.action)
+		return selected_func.action(pctldev, pin.number);
+
+	return -EINVAL;
+}
+
+static const struct pinmux_ops stm32_rtc_pinmux_ops = {
+	.get_functions_count	= stm32_rtc_pinmux_get_functions_count,
+	.get_function_name	= stm32_rtc_pinmux_get_fname,
+	.get_function_groups	= stm32_rtc_pinmux_get_groups,
+	.set_mux		= stm32_rtc_pinmux_set_mux,
+	.strict			= true,
+};
+
+static struct pinctrl_desc stm32_rtc_pdesc = {
+	.name = DRIVER_NAME,
+	.pins = stm32_rtc_pinctrl_pins,
+	.npins = ARRAY_SIZE(stm32_rtc_pinctrl_pins),
+	.owner = THIS_MODULE,
+	.pctlops = &stm32_rtc_pinctrl_ops,
+	.pmxops = &stm32_rtc_pinmux_ops,
+};
+
 static int stm32_rtc_enter_init_mode(struct stm32_rtc *rtc)
 {
 	const struct stm32_rtc_registers *regs = &rtc->data->regs;
@@ -791,6 +902,7 @@ static int stm32_rtc_probe(struct platform_device *pdev)
 {
 	struct stm32_rtc *rtc;
 	const struct stm32_rtc_registers *regs;
+	struct pinctrl_dev *pctl;
 	int ret;
 
 	rtc = devm_kzalloc(&pdev->dev, sizeof(*rtc), GFP_KERNEL);
@@ -912,6 +1024,14 @@ static int stm32_rtc_probe(struct platform_device *pdev)
 		goto err;
 	}
 
+	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");
+
+	ret = pinctrl_enable(pctl);
+	if (ret)
+		return dev_err_probe(&pdev->dev, ret, "pinctrl enable failed");
+
 	/*
 	 * If INITS flag is reset (calendar year field set to 0x00), calendar
 	 * must be initialized
-- 
2.25.1

[PATCH v3 3/4] rtc: stm32: add Low Speed Clock Output (LSCO) support

[Valentin Caron]

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 <amelie.delaunay@foss.st.com>
Signed-off-by: Amelie Delaunay <amelie.delaunay@foss.st.com>
Signed-off-by: Valentin Caron <valentin.caron@foss.st.com>
---
 drivers/rtc/Kconfig     |   1 +
 drivers/rtc/rtc-stm32.c | 101 ++++++++++++++++++++++++++++++++++++++++
 2 files changed, 102 insertions(+)

diff --git a/drivers/rtc/Kconfig b/drivers/rtc/Kconfig
index 4b1a87027a3d..b3469f6986e9 100644
--- a/drivers/rtc/Kconfig
+++ b/drivers/rtc/Kconfig
@@ -1928,6 +1928,7 @@ 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.
diff --git a/drivers/rtc/rtc-stm32.c b/drivers/rtc/rtc-stm32.c
index 6dfd9dc07e2e..675860a13051 100644
--- a/drivers/rtc/rtc-stm32.c
+++ b/drivers/rtc/rtc-stm32.c
@@ -7,6 +7,7 @@
 #include <linux/bcd.h>
 #include <linux/bitfield.h>
 #include <linux/clk.h>
+#include <linux/clk-provider.h>
 #include <linux/errno.h>
 #include <linux/iopoll.h>
 #include <linux/ioport.h>
@@ -45,6 +46,10 @@
 #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)
@@ -81,6 +86,12 @@
 /* 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)
@@ -130,6 +141,7 @@ struct stm32_rtc_registers {
 	u16 wpr;
 	u16 sr;
 	u16 scr;
+	u16 cfgr;
 	u16 verr;
 };
 
@@ -145,6 +157,7 @@ struct stm32_rtc_data {
 	bool need_dbp;
 	bool need_accuracy;
 	bool rif_protected;
+	bool has_lsco;
 };
 
 struct stm32_rtc {
@@ -157,6 +170,7 @@ struct stm32_rtc {
 	struct clk *rtc_ck;
 	const struct stm32_rtc_data *data;
 	int irq_alarm;
+	struct clk *clk_lsco;
 };
 
 struct stm32_rtc_rif_resource {
@@ -231,7 +245,68 @@ 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)
@@ -687,6 +762,7 @@ static const struct stm32_rtc_data stm32_rtc_data = {
 	.need_dbp = true,
 	.need_accuracy = false,
 	.rif_protected = false,
+	.has_lsco = false,
 	.regs = {
 		.tr = 0x00,
 		.dr = 0x04,
@@ -697,6 +773,7 @@ static const struct stm32_rtc_data stm32_rtc_data = {
 		.wpr = 0x24,
 		.sr = 0x0C, /* set to ISR offset to ease alarm management */
 		.scr = UNDEF_REG,
+		.cfgr = UNDEF_REG,
 		.verr = UNDEF_REG,
 	},
 	.events = {
@@ -710,6 +787,7 @@ static const struct stm32_rtc_data stm32h7_rtc_data = {
 	.need_dbp = true,
 	.need_accuracy = false,
 	.rif_protected = false,
+	.has_lsco = false,
 	.regs = {
 		.tr = 0x00,
 		.dr = 0x04,
@@ -720,6 +798,7 @@ static const struct stm32_rtc_data stm32h7_rtc_data = {
 		.wpr = 0x24,
 		.sr = 0x0C, /* set to ISR offset to ease alarm management */
 		.scr = UNDEF_REG,
+		.cfgr = UNDEF_REG,
 		.verr = UNDEF_REG,
 	},
 	.events = {
@@ -742,6 +821,7 @@ static const struct stm32_rtc_data stm32mp1_data = {
 	.need_dbp = false,
 	.need_accuracy = true,
 	.rif_protected = false,
+	.has_lsco = true,
 	.regs = {
 		.tr = 0x00,
 		.dr = 0x04,
@@ -752,6 +832,7 @@ static const struct stm32_rtc_data stm32mp1_data = {
 		.wpr = 0x24,
 		.sr = 0x50,
 		.scr = 0x5C,
+		.cfgr = 0x60,
 		.verr = 0x3F4,
 	},
 	.events = {
@@ -765,6 +846,7 @@ static const struct stm32_rtc_data stm32mp25_data = {
 	.need_dbp = false,
 	.need_accuracy = true,
 	.rif_protected = true,
+	.has_lsco = true,
 	.regs = {
 		.tr = 0x00,
 		.dr = 0x04,
@@ -775,6 +857,7 @@ static const struct stm32_rtc_data stm32mp25_data = {
 		.wpr = 0x24,
 		.sr = 0x50,
 		.scr = 0x5C,
+		.cfgr = 0x60,
 		.verr = 0x3F4,
 	},
 	.events = {
@@ -792,6 +875,19 @@ static const struct of_device_id stm32_rtc_of_match[] = {
 };
 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_check_rif(struct stm32_rtc *stm32_rtc,
 			       struct stm32_rtc_rif_resource res)
 {
@@ -1024,6 +1120,8 @@ static int stm32_rtc_probe(struct platform_device *pdev)
 		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");
@@ -1070,6 +1168,9 @@ static void stm32_rtc_remove(struct platform_device *pdev)
 	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);
-- 
2.25.1

[PATCH v3 4/4] rtc: stm32: add alarm A out feature

[Valentin Caron]

STM32 RTC can pulse some SOC pins when an RTC alarm expires.
This patch adds this functionality for alarm A. The pulse can out on three
pins RTC_OUT1, RTC_OUT2, RTC_OUT2_RMP (PC13, PB2, PI8 on stm32mp15)
(PC13, PB2, PI1 on stm32mp13) (PC13, PF4/PF6, PI8 on stm32mp25).

This patch only adds the functionality for devices which are using
st,stm32mp1-rtc and st,stm32mp25-rtc compatible.

Add "alarm-a" in pinmux functions.

Signed-off-by: Valentin Caron <valentin.caron@foss.st.com>
---
 drivers/rtc/rtc-stm32.c | 60 +++++++++++++++++++++++++++++++++++++++++
 1 file changed, 60 insertions(+)

diff --git a/drivers/rtc/rtc-stm32.c b/drivers/rtc/rtc-stm32.c
index 675860a13051..3e4f2ee22b0b 100644
--- a/drivers/rtc/rtc-stm32.c
+++ b/drivers/rtc/rtc-stm32.c
@@ -47,8 +47,10 @@
 #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_OSEL_ALARM_A	FIELD_PREP(STM32_RTC_CR_OSEL, 0x01)
 #define STM32_RTC_CR_COE		BIT(23)
 #define STM32_RTC_CR_TAMPOE		BIT(26)
+#define STM32_RTC_CR_TAMPALRM_TYPE	BIT(30)
 #define STM32_RTC_CR_OUT2EN		BIT(31)
 
 /* STM32_RTC_ISR/STM32_RTC_ICSR bit fields */
@@ -158,6 +160,7 @@ struct stm32_rtc_data {
 	bool need_accuracy;
 	bool rif_protected;
 	bool has_lsco;
+	bool has_alarm_out;
 };
 
 struct stm32_rtc {
@@ -245,6 +248,47 @@ struct stm32_rtc_pinmux_func {
 	int (*action)(struct pinctrl_dev *pctl_dev, unsigned int pin);
 };
 
+static int stm32_rtc_pinmux_action_alarm(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);
+
+	if (!rtc->data->has_alarm_out)
+		return -EPERM;
+
+	cr &= ~STM32_RTC_CR_OSEL;
+	cr |= STM32_RTC_CR_OSEL_ALARM_A;
+	cr &= ~STM32_RTC_CR_TAMPOE;
+	cr &= ~STM32_RTC_CR_COE;
+	cr &= ~STM32_RTC_CR_TAMPALRM_TYPE;
+
+	switch (pin) {
+	case OUT1:
+		cr &= ~STM32_RTC_CR_OUT2EN;
+		cfgr &= ~STM32_RTC_CFGR_OUT2_RMP;
+		break;
+	case OUT2:
+		cr |= STM32_RTC_CR_OUT2EN;
+		cfgr &= ~STM32_RTC_CFGR_OUT2_RMP;
+		break;
+	case OUT2_RMP:
+		cr |= STM32_RTC_CR_OUT2EN;
+		cfgr |= STM32_RTC_CFGR_OUT2_RMP;
+		break;
+	default:
+		return -EINVAL;
+	}
+
+	stm32_rtc_wpr_unlock(rtc);
+	writel_relaxed(cr, rtc->base + regs.cr);
+	writel_relaxed(cfgr, rtc->base + regs.cfgr);
+	stm32_rtc_wpr_lock(rtc);
+
+	return 0;
+}
+
 static int stm32_rtc_pinmux_lsco_available(struct pinctrl_dev *pctldev, unsigned int pin)
 {
 	struct stm32_rtc *rtc = pinctrl_dev_get_drvdata(pctldev);
@@ -307,6 +351,7 @@ static int stm32_rtc_pinmux_action_lsco(struct pinctrl_dev *pctldev, unsigned in
 
 static const struct stm32_rtc_pinmux_func stm32_rtc_pinmux_functions[] = {
 	STM32_RTC_PINMUX("lsco", &stm32_rtc_pinmux_action_lsco, "out1", "out2_rmp"),
+	STM32_RTC_PINMUX("alarm-a", &stm32_rtc_pinmux_action_alarm, "out1", "out2", "out2_rmp"),
 };
 
 static int stm32_rtc_pinmux_get_functions_count(struct pinctrl_dev *pctldev)
@@ -763,6 +808,7 @@ static const struct stm32_rtc_data stm32_rtc_data = {
 	.need_accuracy = false,
 	.rif_protected = false,
 	.has_lsco = false,
+	.has_alarm_out = false,
 	.regs = {
 		.tr = 0x00,
 		.dr = 0x04,
@@ -788,6 +834,7 @@ static const struct stm32_rtc_data stm32h7_rtc_data = {
 	.need_accuracy = false,
 	.rif_protected = false,
 	.has_lsco = false,
+	.has_alarm_out = false,
 	.regs = {
 		.tr = 0x00,
 		.dr = 0x04,
@@ -822,6 +869,7 @@ static const struct stm32_rtc_data stm32mp1_data = {
 	.need_accuracy = true,
 	.rif_protected = false,
 	.has_lsco = true,
+	.has_alarm_out = true,
 	.regs = {
 		.tr = 0x00,
 		.dr = 0x04,
@@ -847,6 +895,7 @@ static const struct stm32_rtc_data stm32mp25_data = {
 	.need_accuracy = true,
 	.rif_protected = true,
 	.has_lsco = true,
+	.has_alarm_out = true,
 	.regs = {
 		.tr = 0x00,
 		.dr = 0x04,
@@ -878,6 +927,17 @@ 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;
+	unsigned int cr = readl_relaxed(rtc->base + regs.cr);
+
+	cr &= ~STM32_RTC_CR_OSEL;
+	cr &= ~STM32_RTC_CR_TAMPOE;
+	cr &= ~STM32_RTC_CR_COE;
+	cr &= ~STM32_RTC_CR_TAMPALRM_TYPE;
+	cr &= ~STM32_RTC_CR_OUT2EN;
+
+	stm32_rtc_wpr_unlock(rtc);
+	writel_relaxed(cr, rtc->base + regs.cr);
+	stm32_rtc_wpr_lock(rtc);
 
 	if (regs.cfgr != UNDEF_REG) {
 		unsigned int cfgr = readl_relaxed(rtc->base + regs.cfgr);
-- 
2.25.1

Re: [PATCH v3 1/4] dt-bindings: rtc: stm32: describe pinmux nodes

[Krzysztof Kozlowski]

On 22/07/2024 18:00, Valentin Caron wrote:
> STM32 RTC is capable to handle 3 specific pins of the soc (out1, out2,
> out2_rmp) and to outputs 2 signals (LSCO, alarm-a).
> 
> This feature is configured thanks to pinmux nodes and pinctrl framework.
> This feature is available with compatible st,stm32mp1-rtc and
> st,stm32mp25-rtc only.
> 
> Signed-off-by: Valentin Caron <valentin.caron@foss.st.com>

Reviewed-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>

Best regards,
Krzysztof

Re: [PATCH v3 0/4] rtc: stm32: add pinctrl interface to handle RTC outs

[Linus Walleij]

Hi Valentin,

On Mon, Jul 22, 2024 at 6:02 PM Valentin Caron
<valentin.caron@foss.st.com> wrote:

> This series adds a pinctrl/pinmux interface to control STM32 RTC outputs.

Interesting! I think it is the first pin controller outside on
drivers/pinctrl in the kernel tree.

Please include me and the linux-gpio@vger.kernel.org list in
subsequent postings, I want to be sure what gets merged here
and I only noticed this from the LWN driver patches summary.

> As device-trees will be upstreamed separately, here is an example:
>
> stm32-pinctrl {
>     rtc_rsvd_pins_a: rtc-rsvd-0 {
>         pins {
>             pinmux = <STM32_PINMUX('B', 2, AF1)>, /* OUT2 */
>                      <STM32_PINMUX('I', 8, ANALOG)>; /* OUT2_RMP */
>         };
>     };
> };
>
> stm32-rtc {
>     pinctrl-0 = <&rtc_rsvd_pins_a &rtc_alarma_pins_a>;

So the first one is a generic pin control setting and the second
one is a hog for the pins defined by the device itself.

It's clever, and works. Nice work!

(There should probably be a comment in the device tree to say
what is going on so people reading it are not confused.)

>     /* Enable by foo-device */
>     rtc_lsco_pins_a: rtc-lsco-0 {
>         pins = "out2_rmp";
>         function = "lsco";
>     };
>
>     /* Enable by stm32-rtc hog */
>     rtc_alarma_pins_a: rtc-alarma-0 {
>         pins = "out2";
>         function = "alarm-a";
>     };

Yours,
Linus Walleij

Re: [PATCH v3 1/4] dt-bindings: rtc: stm32: describe pinmux nodes

[Linus Walleij]

On Mon, Jul 22, 2024 at 6:02 PM Valentin Caron
<valentin.caron@foss.st.com> wrote:

> STM32 RTC is capable to handle 3 specific pins of the soc (out1, out2,
> out2_rmp) and to outputs 2 signals (LSCO, alarm-a).
>
> This feature is configured thanks to pinmux nodes and pinctrl framework.
> This feature is available with compatible st,stm32mp1-rtc and
> st,stm32mp25-rtc only.
>
> Signed-off-by: Valentin Caron <valentin.caron@foss.st.com>

Reviewed-by: Linus Walleij <linus.walleij@linaro.org>

Yours,
Linus Walleij

Re: [PATCH v3 2/4] rtc: stm32: add pinctrl and pinmux interfaces

[Linus Walleij]

On Mon, Jul 22, 2024 at 6:02 PM Valentin Caron
<valentin.caron@foss.st.com> wrote:

> STM32 RTC is capable to handle 3 specific pins of the soc.
> "out1, out2 and out2_rmp". To handle this, we use pinctrl framework.
> There is a single pin per group.
>
> Signed-off-by: Valentin Caron <valentin.caron@foss.st.com>
(...)

> +/* STM32 RTC pinctrl helpers */
> +#define STM32_RTC_PINMUX(_name, _action, ...) { \
> +       .name = (_name), \
> +       .action = (_action), \
> +       .groups = ((const char *[]){ __VA_ARGS__ }), \
> +       .num_groups = ARRAY_SIZE(((const char *[]){ __VA_ARGS__ })), \
> +}

This is a very clever and clean macro.

We have PINCTRL_PINFUNCTION() in <linux/pinctrl/pinctrl.h> which isn't
smart enough to use VA_ARGS and ARRAY_SIZE.

Now you also need .action but if it wasn't for that I would have asked
for the macro to be made generic.

The implementation is clean and impeccable.
Reviewed-by: Linus Walleij <linus.walleij@linaro.org>

Yours,
Linus Walleij

Re: [PATCH v3 3/4] rtc: stm32: add Low Speed Clock Output (LSCO) support

[Linus Walleij]

Hi Valentin,

On Mon, Jul 22, 2024 at 6:02 PM Valentin Caron
<valentin.caron@foss.st.com> wrote:

> 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 <amelie.delaunay@foss.st.com>
> Signed-off-by: Amelie Delaunay <amelie.delaunay@foss.st.com>
> Signed-off-by: Valentin Caron <valentin.caron@foss.st.com>
(...)

> @@ -1928,6 +1928,7 @@ config RTC_DRV_STM32
>         select PINMUX
>         select PINCONF
>         select GENERIC_PINCONF
> +       depends on COMMON_CLK

Just
select COMMON_CLK

Why not, it will with 100% certainty be needed anyway by the system
clock controller.

Yours,
Linus Walleij

Re: [PATCH v3 4/4] rtc: stm32: add alarm A out feature

[Linus Walleij]

On Mon, Jul 22, 2024 at 6:02 PM Valentin Caron
<valentin.caron@foss.st.com> wrote:

> STM32 RTC can pulse some SOC pins when an RTC alarm expires.
> This patch adds this functionality for alarm A. The pulse can out on three
> pins RTC_OUT1, RTC_OUT2, RTC_OUT2_RMP (PC13, PB2, PI8 on stm32mp15)
> (PC13, PB2, PI1 on stm32mp13) (PC13, PF4/PF6, PI8 on stm32mp25).
>
> This patch only adds the functionality for devices which are using
> st,stm32mp1-rtc and st,stm32mp25-rtc compatible.
>
> Add "alarm-a" in pinmux functions.
>
> Signed-off-by: Valentin Caron <valentin.caron@foss.st.com>

Looks good to me:
Reviewed-by: Linus Walleij <linus.walleij@linaro.org>

Yours,
Linus Walleij

Re: [PATCH v3 0/4] rtc: stm32: add pinctrl interface to handle RTC outs

[Alexandre Belloni]

Hello Linus,

On 26/07/2024 22:37:21+0200, Linus Walleij wrote:
> On Mon, Jul 22, 2024 at 6:02 PM Valentin Caron
> <valentin.caron@foss.st.com> wrote:
> 
> > This series adds a pinctrl/pinmux interface to control STM32 RTC outputs.
> 
> Interesting! I think it is the first pin controller outside on
> drivers/pinctrl in the kernel tree.

Actually, we have rtc-omap which does this too. I've been pushing for
more RTC to do this instead of defining custom dt bindings to do what
boils down to pinmuxing.

> 
> Please include me and the linux-gpio@vger.kernel.org list in
> subsequent postings, I want to be sure what gets merged here
> and I only noticed this from the LWN driver patches summary.


I'll also ensure you get copied on pinctrl related patches.


-- 
Alexandre Belloni, co-owner and COO, Bootlin
Embedded Linux and Kernel engineering
https://bootlin.com

Re: [PATCH v3 0/4] rtc: stm32: add pinctrl interface to handle RTC outs

[Alexandre Belloni]

On Mon, 22 Jul 2024 18:00:18 +0200, Valentin Caron wrote:
> This series adds a pinctrl/pinmux interface to control STM32 RTC outputs.
> 
> Theses two signals output are possible:
>  - LSCO (Low Speed Clock Output) that allow to output LSE clock on a pin.
>    On STM32MPU Discovery boards, this feature is used to generate a clock
>    to Wifi/Bluetooth module.
>  - Alarm out that allow to send a pulse on a pin when alarm A of the RTC
>    expires.
> 
> [...]

Applied, thanks!

[1/4] dt-bindings: rtc: stm32: describe pinmux nodes
      https://git.kernel.org/abelloni/c/5b19519d4e6f
[2/4] rtc: stm32: add pinctrl and pinmux interfaces
      https://git.kernel.org/abelloni/c/16ad2bc09efb
[3/4] rtc: stm32: add Low Speed Clock Output (LSCO) support
      https://git.kernel.org/abelloni/c/bb7b0df2be5c
[4/4] rtc: stm32: add alarm A out feature
      https://git.kernel.org/abelloni/c/04dcadb87da6

Best regards,

-- 
Alexandre Belloni, co-owner and COO, Bootlin
Embedded Linux and Kernel engineering
https://bootlin.com