rtc: add mxc driver for i.MX53 SRTC

From: Patrick Bruenn <[email protected]>

Neither rtc-imxdi, rtc-mxc nor rtc-snvs are compatible with i.MX53.

This is driver enables support for the low power domain SRTC features:
- 32-bit MSB of non-rollover time counter
- 32-bit alarm register

Select the new config option RTC_DRV_MXC_V2 to build this driver

Based on:
http://git.freescale.com/git/cgit.cgi/imx/linux-2.6-imx.git/tree/drivers/rtc/rtc-mxc_v2.c?h=imx_2.6.35_11.09.01

---

v4:
- rename "srtc" node into generic "rtc" keep the label as "srtc" to avoid duplication with imx53-m53.dtsi
- fix Signed-off-by: in bindings-patch

v3:
- introduce new config option with the same patch, which adds the driver
- call rtc_update_irq() only if necessary
- merge mxc_rtc_write_alarm_locked() with mxc_rtc_set_alarm()
- only use clk_enable/disable (without "prepare") during operation
- rebase on v4.15-rc3
- consistently use rtc_tm_to_time64() and time64_t
- refactor mxc_rtc_read_time(): don't lock for readl() only; don't rtc_valid_tm(); use time64_t
- check returncode of mxc_rtc_wait_for_flag()
- restructure mxc_rtc_sync_lp_locked() to replace pr_err() with dev_err_once(); remove explicit 'inline'
- don't touch imx_v4_v5_defconfig, instead add to imx_v6_v7_defconfig

v2:
- have seperate patches for dt-binding, CONFIG option, imx53.dtsi and driver
- add SPDX-License-Identifier and cleanup copyright notice
- replace __raw_readl/writel() with readl/writel()
- fix PM_SLEEP callbacks
- add CONFIG_RTC_DRV_MXC_V2 to build rtc-mxc_v2.c
- remove misleading or obvious comments and fix style of the remaining
- avoid endless loop while waiting for hw
- implement consistent locking; make spinlock a member of dev struct
- enable clk only for register accesses
- remove all udelay() calls since they are obsolete or redundant (we are already waiting for register flags to change)
- init platform_data before registering irq callback
- let set_time() fail, when 32 bit rtc counter exceeded
- make names more consistent
- cleanup and reorder includes
- cleanup and remove unused defines

---

Patrick Bruenn (4):
dt-bindings: rtc: add bindings for i.MX53 SRTC
ARM: dts: imx53: add srtc node
rtc: add mxc driver for i.MX53 SRTC
ARM: imx_v6_v7_defconfig: enable RTC_DRV_MXC_V2

 .../devicetree/bindings/rtc/rtc-mxc_v2.txt         |  17 +
 arch/arm/boot/dts/imx53.dtsi                       |   7 +
 arch/arm/configs/imx_v6_v7_defconfig               |   1 +
 drivers/rtc/Kconfig                                |  10 +
 drivers/rtc/Makefile                               |   1 +
 drivers/rtc/rtc-mxc_v2.c                           | 422 +++++++++++++++++++++
 6 files changed, 458 insertions(+)
 create mode 100644 Documentation/devicetree/bindings/rtc/rtc-mxc_v2.txt
 create mode 100644 drivers/rtc/rtc-mxc_v2.c

2.11.0

From: Patrick Bruenn <[email protected]>

Document the binding for i.MX53 SRTC implemented by rtc-mxc_v2

---

v4:
- replace "srtc" node name with generic "rtc"

v2:
- added "Secure" and (SRTC) to the description

---
 Documentation/devicetree/bindings/rtc/rtc-mxc_v2.txt | 17 +++++++++++++++++
 1 file changed, 17 insertions(+)
 create mode 100644 Documentation/devicetree/bindings/rtc/rtc-mxc_v2.txt

new file mode 100644
index 000000000000..79d7e87b0d91
@@ -0,0 +1,17 @@
+* i.MX53 Secure Real Time Clock (SRTC)
+
+Required properties:
+- compatible: should be: "fsl,imx53-rtc"
+- reg: physical base address of the controller and length of memory mapped
+  region.
+- clocks: should contain the phandle for the rtc clock
+- interrupts: rtc alarm interrupt
+
+Example:
+
+rtc at 53fa4000 {
+	compatible = "fsl,imx53-rtc";
+	reg = <0x53fa4000 0x4000>;
+	interrupts = <24>;
+	clocks = <&clks IMX5_CLK_SRTC_GATE>;
+};

2.11.0

From: Patrick Bruenn <[email protected]>

rtc-mxc_v2 driver will add support for the i.MX53 SRTC

Note: we keep the 'srtc' label to avoid duplicate with imx53-m53.dtsi

---

v4:
- replace "srtc" node name with generic "rtc"

---
 arch/arm/boot/dts/imx53.dtsi | 7 +++++++
 1 file changed, 7 insertions(+)

index 84f17f7abb71..beca1c830623 100644
@@ -433,6 +433,13 @@
 				clock-names = "ipg", "per";
 			};
 
+			srtc: rtc at 53fa4000 {
+				compatible = "fsl,imx53-rtc";
+				reg = <0x53fa4000 0x4000>;
+				interrupts = <24>;
+				clocks = <&clks IMX5_CLK_SRTC_GATE>;
+			};
+
 			iomuxc: iomuxc at 53fa8000 {
 				compatible = "fsl,imx53-iomuxc";
 				reg = <0x53fa8000 0x4000>;

2.11.0

From: Patrick Bruenn <[email protected]>

Neither rtc-imxdi, rtc-mxc nor rtc-snvs are compatible with i.MX53.

This is driver enables support for the low power domain SRTC features:
- 32-bit MSB of non-rollover time counter
- 32-bit alarm register

Select the new config option RTC_DRV_MXC_V2 to build this driver

Based on:
http://git.freescale.com/git/cgit.cgi/imx/linux-2.6-imx.git/tree/drivers/rtc/rtc-mxc_v2.c?h=imx_2.6.35_11.09.01

---

v3:
- introduce new config option with the same patch, which adds the driver
- call rtc_update_irq() only if necessary
- merge mxc_rtc_write_alarm_locked() with mxc_rtc_set_alarm()
- only use clk_enable/disable (without "prepare") during operation
- rebase on v4.15-rc3
- consistently use rtc_tm_to_time64() and time64_t
- refactor mxc_rtc_read_time(): don't lock for readl() only; don't rtc_valid_tm(); use time64_t
- check returncode of mxc_rtc_wait_for_flag()
- restructure mxc_rtc_sync_lp_locked() to replace pr_err() with dev_err_once(); remove explicit 'inline'
- don't touch imx_v4_v5_defconfig, instead add to imx_v6_v7_defconfig

v2:
- have seperate patches for dt-binding, CONFIG option, imx53.dtsi and driver
- add SPDX-License-Identifier and cleanup copyright notice
- replace __raw_readl/writel() with readl/writel()
- fix PM_SLEEP callbacks
- add CONFIG_RTC_DRV_MXC_V2 to build rtc-mxc_v2.c
- remove misleading or obvious comments and fix style of the remaining
- avoid endless loop while waiting for hw
- implement consistent locking; make spinlock a member of dev struct
- enable clk only for register accesses
- remove all udelay() calls since they are obsolete or redundant (we are already waiting for register flags to change)
- init platform_data before registering irq callback
- let set_time() fail, when 32 bit rtc counter exceeded
- make names more consistent
- cleanup and reorder includes
- cleanup and remove unused defines

---
 drivers/rtc/Kconfig      |  10 ++
 drivers/rtc/Makefile     |   1 +
 drivers/rtc/rtc-mxc_v2.c | 422 +++++++++++++++++++++++++++++++++++++++++++++++
 3 files changed, 433 insertions(+)
 create mode 100644 drivers/rtc/rtc-mxc_v2.c

index b59a31b079a5..440edebf5c71 100644
@@ -1689,6 +1689,16 @@ config RTC_DRV_MXC
 	   This driver can also be built as a module, if so, the module
 	   will be called "rtc-mxc".
 
+config RTC_DRV_MXC_V2
+	tristate "Freescale MXC Real Time Clock for i.MX53"
+	depends on ARCH_MXC
+	help
+	   If you say yes here you get support for the Freescale MXC
+	   SRTC module in i.MX53 processor.
+
+	   This driver can also be built as a module, if so, the module
+	   will be called "rtc-mxc_v2".
+
 config RTC_DRV_SNVS
 	tristate "Freescale SNVS RTC support"
 	select REGMAP_MMIO

index f2f50c11dc38..dcf60e61ae5c 100644
@@ -106,6 +106,7 @@ obj-$(CONFIG_RTC_DRV_MT6397)	+= rtc-mt6397.o
 obj-$(CONFIG_RTC_DRV_MT7622)	+= rtc-mt7622.o
 obj-$(CONFIG_RTC_DRV_MV)	+= rtc-mv.o
 obj-$(CONFIG_RTC_DRV_MXC)	+= rtc-mxc.o
+obj-$(CONFIG_RTC_DRV_MXC_V2)	+= rtc-mxc_v2.o
 obj-$(CONFIG_RTC_DRV_NUC900)	+= rtc-nuc900.o
 obj-$(CONFIG_RTC_DRV_OMAP)	+= rtc-omap.o
 obj-$(CONFIG_RTC_DRV_OPAL)	+= rtc-opal.o

2.11.0

From: Patrick Bruenn <[email protected]>

Enable SRTC driver for i.MX53 in default config

---
v3:
- imx_v4_v5_defconfig was the wrong default config for i.MX53

---
 arch/arm/configs/imx_v6_v7_defconfig | 1 +
 1 file changed, 1 insertion(+)

index 0d4494922561..548c11142a4e 100644
@@ -349,6 +349,7 @@ CONFIG_RTC_DRV_PCF8563=y
 CONFIG_RTC_DRV_M41T80=y
 CONFIG_RTC_DRV_MC13XXX=y
 CONFIG_RTC_DRV_MXC=y
+CONFIG_RTC_DRV_MXC_V2=y
 CONFIG_RTC_DRV_SNVS=y
 CONFIG_DMADEVICES=y
 CONFIG_FSL_EDMA=y

2.11.0

For the use of SPDX license tags in this patch set:

Applied 1/4 and 3/4, thanks.

Alexandre Belloni, Free Electrons
Embedded Linux and Kernel engineering
http://free-electrons.com

Applied 2/4 and 4/4, thanks.