[PATCH v2 2/8] mfd: stm32-lptimer: add support for stm32mp25

[Fabrice Gasnier]

Add support for STM32MP25 SoC.
A new hardware configuration register (HWCFGR2) has been added, to gather
number of capture/compare channels, autonomous mode and input capture
capability. The full feature set is implemented in LPTIM1/2/3/4. LPTIM5
supports a smaller set of features. This can now be read from HWCFGR
registers.

Add new registers to the stm32-lptimer.h: CCMR1, CCR2, HWCFGR1/2 and VERR.
Update the stm32_lptimer data struct so signal the number of
capture/compare channels to the child devices.
Also Remove some unused bit masks (CMPOK_ARROK / CMPOKCF_ARROKCF).

Signed-off-by: Fabrice Gasnier <fabrice.gasnier@xxxxxxxxxxx>
---
Changes in V2:
- rely on fallback compatible as no specific .data is associated to the
  driver. Compatibility is added by reading hardware configuration
  registers.
- read version register, to be used by clockevent child driver
- rename register/bits definitions
---
 drivers/mfd/stm32-lptimer.c       | 33 ++++++++++++++++++++++++++++-
 include/linux/mfd/stm32-lptimer.h | 35 ++++++++++++++++++++++++++++---
 2 files changed, 64 insertions(+), 4 deletions(-)

diff --git a/drivers/mfd/stm32-lptimer.c b/drivers/mfd/stm32-lptimer.c
index b2704a9809c7..09073dbc9c80 100644
--- a/drivers/mfd/stm32-lptimer.c
+++ b/drivers/mfd/stm32-lptimer.c
@@ -6,6 +6,7 @@
  * Inspired by Benjamin Gaignard's stm32-timers driver
  */
 
+#include <linux/bitfield.h>
 #include <linux/mfd/stm32-lptimer.h>
 #include <linux/module.h>
 #include <linux/of_platform.h>
@@ -49,6 +50,36 @@ static int stm32_lptimer_detect_encoder(struct stm32_lptimer *ddata)
 	return 0;
 }
 
+static int stm32_lptimer_detect_hwcfgr(struct stm32_lptimer *ddata)
+{
+	u32 val;
+	int ret;
+
+	ret = regmap_read(ddata->regmap, STM32_LPTIM_VERR, &ddata->version);
+	if (ret)
+		return ret;
+
+	/* Try to guess parameters from HWCFGR: e.g. encoder mode (STM32MP15) */
+	ret = regmap_read(ddata->regmap, STM32_LPTIM_HWCFGR1, &val);
+	if (ret)
+		return ret;
+
+	/* Fallback to legacy init if HWCFGR isn't present */
+	if (!val)
+		return stm32_lptimer_detect_encoder(ddata);
+
+	ddata->has_encoder = FIELD_GET(STM32_LPTIM_HWCFGR1_ENCODER, val);
+
+	ret = regmap_read(ddata->regmap, STM32_LPTIM_HWCFGR2, &val);
+	if (ret)
+		return ret;
+
+	/* Number of capture/compare channels */
+	ddata->num_cc_chans = FIELD_GET(STM32_LPTIM_HWCFGR2_CHAN_NUM, val);
+
+	return 0;
+}
+
 static int stm32_lptimer_probe(struct platform_device *pdev)
 {
 	struct device *dev = &pdev->dev;
@@ -73,7 +104,7 @@ static int stm32_lptimer_probe(struct platform_device *pdev)
 	if (IS_ERR(ddata->clk))
 		return PTR_ERR(ddata->clk);
 
-	ret = stm32_lptimer_detect_encoder(ddata);
+	ret = stm32_lptimer_detect_hwcfgr(ddata);
 	if (ret)
 		return ret;
 
diff --git a/include/linux/mfd/stm32-lptimer.h b/include/linux/mfd/stm32-lptimer.h
index 06d3f11dc3c9..30ebd3152e1a 100644
--- a/include/linux/mfd/stm32-lptimer.h
+++ b/include/linux/mfd/stm32-lptimer.h
@@ -17,20 +17,28 @@
 #define STM32_LPTIM_IER		0x08	/* Interrupt Enable Reg      */
 #define STM32_LPTIM_CFGR	0x0C	/* Configuration Reg         */
 #define STM32_LPTIM_CR		0x10	/* Control Reg               */
-#define STM32_LPTIM_CMP		0x14	/* Compare Reg               */
+#define STM32_LPTIM_CMP		0x14	/* Compare Reg (MP25 CCR1)   */
 #define STM32_LPTIM_ARR		0x18	/* Autoreload Reg            */
 #define STM32_LPTIM_CNT		0x1C	/* Counter Reg               */
+#define STM32_LPTIM_CCMR1	0x2C	/* Capture/Compare Mode MP25 */
+#define STM32_LPTIM_CCR2	0x34	/* Compare Reg2 MP25         */
+
+#define STM32_LPTIM_HWCFGR2	0x3EC	/* Hardware configuration register 2 - MP25 */
+#define STM32_LPTIM_HWCFGR1	0x3F0	/* Hardware configuration register 1 - MP15 */
+#define STM32_LPTIM_VERR	0x3F4	/* Version identification register - MP15 */
 
 /* STM32_LPTIM_ISR - bit fields */
+#define STM32_LPTIM_CMP2_ARROK		(BIT(19) | BIT(4))
 #define STM32_LPTIM_CMPOK_ARROK		GENMASK(4, 3)
 #define STM32_LPTIM_ARROK		BIT(4)
 #define STM32_LPTIM_CMPOK		BIT(3)
 
 /* STM32_LPTIM_ICR - bit fields */
-#define STM32_LPTIM_ARRMCF		BIT(1)
+#define STM32_LPTIM_CMP2OKCF_ARROKCF	(BIT(19) | BIT(4))
 #define STM32_LPTIM_CMPOKCF_ARROKCF	GENMASK(4, 3)
+#define STM32_LPTIM_ARRMCF		BIT(1)
 
-/* STM32_LPTIM_IER - bit flieds */
+/* STM32_LPTIM_IER - bit fields */
 #define STM32_LPTIM_ARRMIE	BIT(1)
 
 /* STM32_LPTIM_CR - bit fields */
@@ -53,16 +61,37 @@
 /* STM32_LPTIM_ARR */
 #define STM32_LPTIM_MAX_ARR	0xFFFF
 
+/* STM32_LPTIM_CCMR1 */
+#define STM32_LPTIM_CC2P	GENMASK(19, 18)
+#define STM32_LPTIM_CC2E	BIT(17)
+#define STM32_LPTIM_CC2SEL	BIT(16)
+#define STM32_LPTIM_CC1P	GENMASK(3, 2)
+#define STM32_LPTIM_CC1E	BIT(1)
+#define STM32_LPTIM_CC1SEL	BIT(0)
+
+/* STM32_LPTIM_HWCFGR1 */
+#define STM32_LPTIM_HWCFGR1_ENCODER	BIT(16)
+
+/* STM32_LPTIM_HWCFGR2 */
+#define STM32_LPTIM_HWCFGR2_CHAN_NUM	GENMASK(3, 0)
+
+/* STM32_LPTIM_VERR */
+#define STM32_LPTIM_VERR_23	0x23	/* STM32MP25 */
+
 /**
  * struct stm32_lptimer - STM32 Low-Power Timer data assigned by parent device
  * @clk: clock reference for this instance
  * @regmap: register map reference for this instance
  * @has_encoder: indicates this Low-Power Timer supports encoder mode
+ * @num_cc_chans: indicates the number of capture/compare channels
+ * @version: indicates the major and minor revision of the controller
  */
 struct stm32_lptimer {
 	struct clk *clk;
 	struct regmap *regmap;
 	bool has_encoder;
+	unsigned int num_cc_chans;
+	u32 version;
 };
 
 #endif
-- 
2.25.1