[PATCH 1/3] reset: stm32: Add support of MCU HOLD BOOT

[Patrick Delaunay]

Handle the register RCC_MP_GCR without SET/CLR registers
but with a direct access to bit BOOT_MCU:
- deassert => set the bit: The MCU will not be in HOLD_BOOT
- assert => clear the bit: The MCU will be set in HOLD_BOOT

With this patch the RCC driver handles the MCU_HOLD_BOOT_R value
added in binding stm32mp1-resets.h

Cc: Fabien DESSENNE <fabien.desse...@st.com>
Cc: Arnaud POULIQUEN <arnaud.pouliq...@st.com>
Signed-off-by: Patrick Delaunay <patrick.delau...@st.com>
---

 drivers/reset/stm32-reset.c                 | 17 +++++++++++++----
 include/dt-bindings/reset/stm32mp1-resets.h |  1 +
 2 files changed, 14 insertions(+), 4 deletions(-)

diff --git a/drivers/reset/stm32-reset.c b/drivers/reset/stm32-reset.c
index 64a11cfcfc..20c36a99eb 100644
--- a/drivers/reset/stm32-reset.c
+++ b/drivers/reset/stm32-reset.c
@@ -14,6 +14,9 @@
 #include <asm/io.h>
 #include <linux/bitops.h>
 
+/* offset of register without set/clear management */
+#define RCC_MP_GCR_OFFSET 0x10C
+
 /* reset clear offset for STM32MP RCC */
 #define RCC_CL 0x4
 
@@ -40,8 +43,11 @@ static int stm32_reset_assert(struct reset_ctl *reset_ctl)
              reset_ctl->id, bank, offset);
 
        if (dev_get_driver_data(reset_ctl->dev) == STM32MP1)
-               /* reset assert is done in rcc set register */
-               writel(BIT(offset), priv->base + bank);
+               if (bank != RCC_MP_GCR_OFFSET)
+                       /* reset assert is done in rcc set register */
+                       writel(BIT(offset), priv->base + bank);
+               else
+                       clrbits_le32(priv->base + bank, BIT(offset));
        else
                setbits_le32(priv->base + bank, BIT(offset));
 
@@ -57,8 +63,11 @@ static int stm32_reset_deassert(struct reset_ctl *reset_ctl)
              reset_ctl->id, bank, offset);
 
        if (dev_get_driver_data(reset_ctl->dev) == STM32MP1)
-               /* reset deassert is done in rcc clr register */
-               writel(BIT(offset), priv->base + bank + RCC_CL);
+               if (bank != RCC_MP_GCR_OFFSET)
+                       /* reset deassert is done in rcc clr register */
+                       writel(BIT(offset), priv->base + bank + RCC_CL);
+               else
+                       setbits_le32(priv->base + bank, BIT(offset));
        else
                clrbits_le32(priv->base + bank, BIT(offset));
 
diff --git a/include/dt-bindings/reset/stm32mp1-resets.h 
b/include/dt-bindings/reset/stm32mp1-resets.h
index f0c3aaef67..702da37a2e 100644
--- a/include/dt-bindings/reset/stm32mp1-resets.h
+++ b/include/dt-bindings/reset/stm32mp1-resets.h
@@ -7,6 +7,7 @@
 #ifndef _DT_BINDINGS_STM32MP1_RESET_H_
 #define _DT_BINDINGS_STM32MP1_RESET_H_
 
+#define MCU_HOLD_BOOT_R        2144
 #define LTDC_R         3072
 #define DSI_R          3076
 #define DDRPERFM_R     3080
-- 
2.17.1