[PATCH v7 0/8] Add PWM and IIO timer drivers for STM32

[PATCH v7 0/8] Add PWM and IIO timer drivers for STM32

[Benjamin Gaignard]

version 7:
- rebase on v4.10-rc2
- remove iio_device code from driver and keep only the trigger part

version 6:
- rename stm32-gptimer in stm32-timers.
- change "st,stm32-gptimer" compatible to "st,stm32-timers".
- modify "st,breakinput" parameter in pwm part.
- split DT patch in 2

version 5:
- fix comments done on version 4
- rebased on kernel 4.9-rc8
- change nodes names and re-order then by addresses

version 4:
- fix comments done on version 3
- don't use interrupts anymore in IIO timer
- detect hardware capabilities at probe time to simplify binding

version 3:
- no change on mfd and pwm divers patches
- add cross reference between bindings
- change compatible to "st,stm32-timer-trigger"
- fix attributes access rights
- use string instead of int for master_mode and slave_mode
- document device attributes in sysfs-bus-iio-timer-stm32
- update DT with the new compatible

version 2:
- keep only one compatible per driver
- use DT parameters to describe hardware block configuration:
  - pwm channels, complementary output, counter size, break input
  - triggers accepted and create by IIO timers
- change DT to limite use of reference to the node
- interrupt is now in IIO timer driver
- rename stm32-mfd-timer to stm32-timers (for general purpose timer)

The following patches enable PWM and IIO Timer features for STM32 platforms.

Those two features are mixed into the registers of the same hardware block
(named general purpose timer) which lead to introduce a multifunctions driver 
on the top of them to be able to share the registers.

In STM32f4 14 instances of timer hardware block exist, even if they all have
the same register mapping they could have a different number of pwm channels
and/or different triggers capabilities. We use various parameters in DT to 
describe the differences between hardware blocks

The MFD (stm32-timers.c) takes care of clock and register mapping
by using regmap. stm32_timers structure is provided to its sub-node to
share those information.

PWM driver is implemented into pwm-stm32.c. Depending of the instance we may
have up to 4 channels, sometime with complementary outputs or 32 bits counter
instead of 16 bits. Some hardware blocks may also have a break input function
which allows to stop pwm depending of a level, defined in devicetree, on an
external pin.

IIO timer driver (stm32-timer-trigger.c and stm32-timer-trigger.h) define a list
of hardware triggers usable by hardware blocks like ADC, DAC or other timers. 

The matrix of possible connections between blocks is quite complex so we use 
trigger names and is_stm32_iio_timer_trigger() function to be sure that
triggers are valid and configure the IPs.

At run time IIO timer hardware blocks can configure (through "master_mode" 
IIO device attribute) which internal signal (counter enable, reset,
comparison block, etc...) is used to generate the trigger.

Benjamin Gaignard (8):
  MFD: add bindings for STM32 Timers driver
  MFD: add STM32 Timers driver
  PWM: add pwm-stm32 DT bindings
  PWM: add PWM driver for STM32 plaftorm
  IIO: add bindings for STM32 timer trigger driver
  IIO: add STM32 timer trigger driver
  ARM: dts: stm32: add Timers driver for stm32f429 MCU
  ARM: dts: stm32: Enable pwm1 and pwm3 for stm32f469-disco

 .../ABI/testing/sysfs-bus-iio-timer-stm32          |  29 ++
 .../bindings/iio/timer/stm32-timer-trigger.txt     |  23 ++
 .../devicetree/bindings/mfd/stm32-timers.txt       |  46 +++
 .../devicetree/bindings/pwm/pwm-stm32.txt          |  33 ++
 arch/arm/boot/dts/stm32f429.dtsi                   | 275 +++++++++++++
 arch/arm/boot/dts/stm32f469-disco.dts              |  28 ++
 drivers/iio/Kconfig                                |   1 -
 drivers/iio/trigger/Kconfig                        |  10 +
 drivers/iio/trigger/Makefile                       |   1 +
 drivers/iio/trigger/stm32-timer-trigger.c          | 340 ++++++++++++++++
 drivers/mfd/Kconfig                                |  11 +
 drivers/mfd/Makefile                               |   2 +
 drivers/mfd/stm32-timers.c                         |  80 ++++
 drivers/pwm/Kconfig                                |   9 +
 drivers/pwm/Makefile                               |   1 +
 drivers/pwm/pwm-stm32.c                            | 434 +++++++++++++++++++++
 include/linux/iio/timer/stm32-timer-trigger.h      |  62 +++
 include/linux/mfd/stm32-timers.h                   |  71 ++++
 18 files changed, 1455 insertions(+), 1 deletion(-)
 create mode 100644 Documentation/ABI/testing/sysfs-bus-iio-timer-stm32
 create mode 100644 Documentation/devicetree/bindings/iio/timer/stm32-timer-trigger.txt
 create mode 100644 Documentation/devicetree/bindings/mfd/stm32-timers.txt
 create mode 100644 Documentation/devicetree/bindings/pwm/pwm-stm32.txt
 create mode 100644 drivers/iio/trigger/stm32-timer-trigger.c
 create mode 100644 drivers/mfd/stm32-timers.c
 create mode 100644 drivers/pwm/pwm-stm32.c
 create mode 100644 include/linux/iio/timer/stm32-timer-trigger.h
 create mode 100644 include/linux/mfd/stm32-timers.h

-- 
1.9.1

[PATCH v7 1/8] MFD: add bindings for STM32 Timers driver

[Benjamin Gaignard]

Add bindings information for STM32 Timers

version 6:
- rename stm32-gtimer to stm32-timers
- change compatible
- add description about the IPs

version 2:
- rename stm32-mfd-timer to stm32-gptimer
- only keep one compatible string

Signed-off-by: Benjamin Gaignard <benjamin.gaignard@st.com>
---
 .../devicetree/bindings/mfd/stm32-timers.txt       | 46 ++++++++++++++++++++++
 1 file changed, 46 insertions(+)
 create mode 100644 Documentation/devicetree/bindings/mfd/stm32-timers.txt

diff --git a/Documentation/devicetree/bindings/mfd/stm32-timers.txt b/Documentation/devicetree/bindings/mfd/stm32-timers.txt
new file mode 100644
index 0000000..a73301d
--- /dev/null
+++ b/Documentation/devicetree/bindings/mfd/stm32-timers.txt
@@ -0,0 +1,46 @@
+STM32 Timers driver bindings
+
+This IP provides 3 types of timer along with PWM functionality:
+- advanced-control timers consist of a 16-bit auto-reload counter driven by a programmable
+  prescaler, break input feature, PWM outputs and complementary PWM ouputs channels.
+- general-purpose timers consist of a 16-bit or 32-bit auto-reload counter driven by a
+  programmable prescaler and PWM outputs.
+- basic timers consist of a 16-bit auto-reload counter driven by a programmable prescaler.
+
+Required parameters:
+- compatible: must be "st,stm32-timers"
+
+- reg:			Physical base address and length of the controller's
+			registers.
+- clock-names: 		Set to "int".
+- clocks: 		Phandle to the clock used by the timer module.
+			For Clk properties, please refer to ../clock/clock-bindings.txt
+
+Optional parameters:
+- resets:		Phandle to the parent reset controller.
+			See ../reset/st,stm32-rcc.txt
+
+Optional subnodes:
+- pwm:			See ../pwm/pwm-stm32.txt
+- timer:		See ../iio/timer/stm32-timer-trigger.txt
+
+Example:
+	timers@40010000 {
+		#address-cells = <1>;
+		#size-cells = <0>;
+		compatible = "st,stm32-timers";
+		reg = <0x40010000 0x400>;
+		clocks = <&rcc 0 160>;
+		clock-names = "clk_int";
+
+		pwm {
+			compatible = "st,stm32-pwm";
+			pinctrl-0	= <&pwm1_pins>;
+			pinctrl-names	= "default";
+		};
+
+		timer {
+			compatible = "st,stm32-timer-trigger";
+			reg = <0>;
+		};
+	};
-- 
1.9.1

[PATCH v7 2/8] MFD: add STM32 Timers driver

[Benjamin Gaignard]

This hardware block could at used at same time for PWM generation
and IIO timers.
PWM and IIO timer configuration are mixed in the same registers
so we need a multi fonction driver to be able to share those registers.

version 7:
- rebase on v4.10-rc2

version 6:
- rename files to stm32-timers
- rename functions to stm32_timers_xxx

version 5:
- fix Lee comments about detect function
- add missing dependency on REGMAP_MMIO

version 4:
- add a function to detect Auto Reload Register (ARR) size
- rename the structure shared with other drivers

version 2:
- rename driver "stm32-gptimer" to be align with SoC documentation
- only keep one compatible
- use of_platform_populate() instead of devm_mfd_add_devices()

Signed-off-by: Benjamin Gaignard <benjamin.gaignard@st.com>
---
 .../devicetree/bindings/mfd/stm32-timers.txt       |  2 +-
 drivers/mfd/Kconfig                                | 11 +++
 drivers/mfd/Makefile                               |  2 +
 drivers/mfd/stm32-timers.c                         | 80 ++++++++++++++++++++++
 include/linux/mfd/stm32-timers.h                   | 71 +++++++++++++++++++
 5 files changed, 165 insertions(+), 1 deletion(-)
 create mode 100644 drivers/mfd/stm32-timers.c
 create mode 100644 include/linux/mfd/stm32-timers.h

diff --git a/Documentation/devicetree/bindings/mfd/stm32-timers.txt b/Documentation/devicetree/bindings/mfd/stm32-timers.txt
index a73301d..897e7c2 100644
--- a/Documentation/devicetree/bindings/mfd/stm32-timers.txt
+++ b/Documentation/devicetree/bindings/mfd/stm32-timers.txt
@@ -12,7 +12,7 @@ Required parameters:
 
 - reg:			Physical base address and length of the controller's
 			registers.
-- clock-names: 		Set to "int".
+- clock-names:		Set to "int".
 - clocks: 		Phandle to the clock used by the timer module.
 			For Clk properties, please refer to ../clock/clock-bindings.txt
 
diff --git a/drivers/mfd/Kconfig b/drivers/mfd/Kconfig
index 4ce3b6f..d0c14b8 100644
--- a/drivers/mfd/Kconfig
+++ b/drivers/mfd/Kconfig
@@ -1621,6 +1621,17 @@ config MFD_STW481X
 	  in various ST Microelectronics and ST-Ericsson embedded
 	  Nomadik series.
 
+config MFD_STM32_TIMERS
+	tristate "Support for STM32 Timers"
+	depends on (ARCH_STM32 && OF) || COMPILE_TEST
+	select MFD_CORE
+	select REGMAP
+	select REGMAP_MMIO
+	help
+	  Select this option to enable STM32 timers driver used
+	  for PWM and IIO Timer. This driver allow to share the
+	  registers between the others drivers.
+
 menu "Multimedia Capabilities Port drivers"
 	depends on ARCH_SA1100
 
diff --git a/drivers/mfd/Makefile b/drivers/mfd/Makefile
index dda4d4f..876ca86 100644
--- a/drivers/mfd/Makefile
+++ b/drivers/mfd/Makefile
@@ -212,3 +212,5 @@ obj-$(CONFIG_MFD_MT6397)	+= mt6397-core.o
 
 obj-$(CONFIG_MFD_ALTERA_A10SR)	+= altera-a10sr.o
 obj-$(CONFIG_MFD_SUN4I_GPADC)	+= sun4i-gpadc.o
+
+obj-$(CONFIG_MFD_STM32_TIMERS) 	+= stm32-timers.o
diff --git a/drivers/mfd/stm32-timers.c b/drivers/mfd/stm32-timers.c
new file mode 100644
index 0000000..41bd901
--- /dev/null
+++ b/drivers/mfd/stm32-timers.c
@@ -0,0 +1,80 @@
+/*
+ * Copyright (C) STMicroelectronics 2016
+ *
+ * Author: Benjamin Gaignard <benjamin.gaignard@st.com>
+ *
+ * License terms:  GNU General Public License (GPL), version 2
+ */
+
+#include <linux/mfd/stm32-timers.h>
+#include <linux/module.h>
+#include <linux/of_platform.h>
+#include <linux/reset.h>
+
+static const struct regmap_config stm32_timers_regmap_cfg = {
+	.reg_bits = 32,
+	.val_bits = 32,
+	.reg_stride = sizeof(u32),
+	.max_register = 0x400,
+};
+
+static void stm32_timers_get_arr_size(struct stm32_timers *ddata)
+{
+	/*
+	 * Only the available bits will be written so when readback
+	 * we get the maximum value of auto reload register
+	 */
+	regmap_write(ddata->regmap, TIM_ARR, ~0L);
+	regmap_read(ddata->regmap, TIM_ARR, &ddata->max_arr);
+	regmap_write(ddata->regmap, TIM_ARR, 0x0);
+}
+
+static int stm32_timers_probe(struct platform_device *pdev)
+{
+	struct device *dev = &pdev->dev;
+	struct stm32_timers *ddata;
+	struct resource *res;
+	void __iomem *mmio;
+
+	ddata = devm_kzalloc(dev, sizeof(*ddata), GFP_KERNEL);
+	if (!ddata)
+		return -ENOMEM;
+
+	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+	mmio = devm_ioremap_resource(dev, res);
+	if (IS_ERR(mmio))
+		return PTR_ERR(mmio);
+
+	ddata->regmap = devm_regmap_init_mmio_clk(dev, "int", mmio,
+						  &stm32_timers_regmap_cfg);
+	if (IS_ERR(ddata->regmap))
+		return PTR_ERR(ddata->regmap);
+
+	ddata->clk = devm_clk_get(dev, NULL);
+	if (IS_ERR(ddata->clk))
+		return PTR_ERR(ddata->clk);
+
+	stm32_timers_get_arr_size(ddata);
+
+	platform_set_drvdata(pdev, ddata);
+
+	return of_platform_populate(pdev->dev.of_node, NULL, NULL, &pdev->dev);
+}
+
+static const struct of_device_id stm32_timers_of_match[] = {
+	{ .compatible = "st,stm32-timers", },
+	{ /* end node */ },
+};
+MODULE_DEVICE_TABLE(of, stm32_timers_of_match);
+
+static struct platform_driver stm32_timers_driver = {
+	.probe = stm32_timers_probe,
+	.driver	= {
+		.name = "stm32-timers",
+		.of_match_table = stm32_timers_of_match,
+	},
+};
+module_platform_driver(stm32_timers_driver);
+
+MODULE_DESCRIPTION("STMicroelectronics STM32 Timers");
+MODULE_LICENSE("GPL v2");
diff --git a/include/linux/mfd/stm32-timers.h b/include/linux/mfd/stm32-timers.h
new file mode 100644
index 0000000..d030004
--- /dev/null
+++ b/include/linux/mfd/stm32-timers.h
@@ -0,0 +1,71 @@
+/*
+ * Copyright (C) STMicroelectronics 2016
+ *
+ * Author: Benjamin Gaignard <benjamin.gaignard@st.com>
+ *
+ * License terms:  GNU General Public License (GPL), version 2
+ */
+
+#ifndef _LINUX_STM32_GPTIMER_H_
+#define _LINUX_STM32_GPTIMER_H_
+
+#include <linux/clk.h>
+#include <linux/regmap.h>
+
+#define TIM_CR1		0x00	/* Control Register 1      */
+#define TIM_CR2		0x04	/* Control Register 2      */
+#define TIM_SMCR	0x08	/* Slave mode control reg  */
+#define TIM_DIER	0x0C	/* DMA/interrupt register  */
+#define TIM_SR		0x10	/* Status register	   */
+#define TIM_EGR		0x14	/* Event Generation Reg    */
+#define TIM_CCMR1	0x18	/* Capt/Comp 1 Mode Reg    */
+#define TIM_CCMR2	0x1C	/* Capt/Comp 2 Mode Reg    */
+#define TIM_CCER	0x20	/* Capt/Comp Enable Reg    */
+#define TIM_PSC		0x28	/* Prescaler               */
+#define TIM_ARR		0x2c	/* Auto-Reload Register    */
+#define TIM_CCR1	0x34	/* Capt/Comp Register 1    */
+#define TIM_CCR2	0x38	/* Capt/Comp Register 2    */
+#define TIM_CCR3	0x3C	/* Capt/Comp Register 3    */
+#define TIM_CCR4	0x40	/* Capt/Comp Register 4    */
+#define TIM_BDTR	0x44	/* Break and Dead-Time Reg */
+
+#define TIM_CR1_CEN	BIT(0)	/* Counter Enable	   */
+#define TIM_CR1_ARPE	BIT(7)	/* Auto-reload Preload Ena */
+#define TIM_CR2_MMS	(BIT(4) | BIT(5) | BIT(6)) /* Master mode selection */
+#define TIM_SMCR_SMS	(BIT(0) | BIT(1) | BIT(2)) /* Slave mode selection */
+#define TIM_SMCR_TS	(BIT(4) | BIT(5) | BIT(6)) /* Trigger selection */
+#define TIM_DIER_UIE	BIT(0)	/* Update interrupt	   */
+#define TIM_SR_UIF	BIT(0)	/* Update interrupt flag   */
+#define TIM_EGR_UG	BIT(0)	/* Update Generation       */
+#define TIM_CCMR_PE	BIT(3)	/* Channel Preload Enable  */
+#define TIM_CCMR_M1	(BIT(6) | BIT(5))  /* Channel PWM Mode 1 */
+#define TIM_CCER_CC1E	BIT(0)	/* Capt/Comp 1  out Ena    */
+#define TIM_CCER_CC1P	BIT(1)	/* Capt/Comp 1  Polarity   */
+#define TIM_CCER_CC1NE	BIT(2)	/* Capt/Comp 1N out Ena    */
+#define TIM_CCER_CC1NP	BIT(3)	/* Capt/Comp 1N Polarity   */
+#define TIM_CCER_CC2E	BIT(4)	/* Capt/Comp 2  out Ena    */
+#define TIM_CCER_CC3E	BIT(8)	/* Capt/Comp 3  out Ena    */
+#define TIM_CCER_CC4E	BIT(12)	/* Capt/Comp 4  out Ena    */
+#define TIM_CCER_CCXE	(BIT(0) | BIT(4) | BIT(8) | BIT(12))
+#define TIM_BDTR_BKE	BIT(12) /* Break input enable	   */
+#define TIM_BDTR_BKP	BIT(13) /* Break input polarity	   */
+#define TIM_BDTR_AOE	BIT(14)	/* Automatic Output Enable */
+#define TIM_BDTR_MOE	BIT(15)	/* Main Output Enable      */
+#define TIM_BDTR_BKF	(BIT(16) | BIT(17) | BIT(18) | BIT(19))
+#define TIM_BDTR_BK2F	(BIT(20) | BIT(21) | BIT(22) | BIT(23))
+#define TIM_BDTR_BK2E	BIT(24) /* Break 2 input enable	   */
+#define TIM_BDTR_BK2P	BIT(25) /* Break 2 input polarity  */
+
+#define MAX_TIM_PSC		0xFFFF
+#define TIM_CR2_MMS_SHIFT	4
+#define TIM_SMCR_TS_SHIFT	4
+#define TIM_BDTR_BKF_MASK	0xF
+#define TIM_BDTR_BKF_SHIFT	16
+#define TIM_BDTR_BK2F_SHIFT	20
+
+struct stm32_timers {
+	struct clk *clk;
+	struct regmap *regmap;
+	u32 max_arr;
+};
+#endif
-- 
1.9.1

[PATCH v7 3/8] PWM: add pwm-stm32 DT bindings

[Benjamin Gaignard]

Define bindings for pwm-stm32

version 6:
- change st,breakinput parameter format to make it usuable on stm32f7 too.

version 2:
- use parameters instead of compatible of handle the hardware configuration

Signed-off-by: Benjamin Gaignard <benjamin.gaignard@st.com>
---
 .../devicetree/bindings/pwm/pwm-stm32.txt          | 33 ++++++++++++++++++++++
 1 file changed, 33 insertions(+)
 create mode 100644 Documentation/devicetree/bindings/pwm/pwm-stm32.txt

diff --git a/Documentation/devicetree/bindings/pwm/pwm-stm32.txt b/Documentation/devicetree/bindings/pwm/pwm-stm32.txt
new file mode 100644
index 0000000..866f222
--- /dev/null
+++ b/Documentation/devicetree/bindings/pwm/pwm-stm32.txt
@@ -0,0 +1,33 @@
+STMicroelectronics STM32 Timers PWM bindings
+
+Must be a sub-node of an STM32 Timers device tree node.
+See ../mfd/stm32-timers.txt for details about the parent node.
+
+Required parameters:
+- compatible:		Must be "st,stm32-pwm".
+- pinctrl-names: 	Set to "default".
+- pinctrl-0: 		List of phandles pointing to pin configuration nodes for PWM module.
+			For Pinctrl properties see ../pinctrl/pinctrl-bindings.txt
+
+Optional parameters:
+- st,breakinput:	Arrays of three u32 <index level filter> to describe break input configurations.
+			"index" indicates on which break input the configuration should be applied.
+			"level" gives the active level (0=low or 1=high) for this configuration.
+			"filter" gives the filtering value to be applied.
+
+Example:
+	timers@40010000 {
+		#address-cells = <1>;
+		#size-cells = <0>;
+		compatible = "st,stm32-timers";
+		reg = <0x40010000 0x400>;
+		clocks = <&rcc 0 160>;
+		clock-names = "clk_int";
+
+		pwm {
+			compatible = "st,stm32-pwm";
+			pinctrl-0	= <&pwm1_pins>;
+			pinctrl-names	= "default";
+			st,breakinput = <0 1 5>;
+		};
+	};
-- 
1.9.1

[PATCH v7 4/8] PWM: add PWM driver for STM32 plaftorm

[Benjamin Gaignard]

This driver adds support for PWM driver on STM32 platform.
The SoC have multiple instances of the hardware IP and each
of them could have small differences: number of channels,
complementary output, auto reload register size...

version 6:
- change st,breakinput parameter to make it usuable for stm32f7 too.

version 4:
- detect at probe time hardware capabilities
- fix comments done on v2 and v3
- use PWM atomic ops

version 2:
- only keep one comptatible
- use DT parameters to discover hardware block configuration

Signed-off-by: Benjamin Gaignard <benjamin.gaignard@st.com>
---
 drivers/pwm/Kconfig     |   9 +
 drivers/pwm/Makefile    |   1 +
 drivers/pwm/pwm-stm32.c | 434 ++++++++++++++++++++++++++++++++++++++++++++++++
 3 files changed, 444 insertions(+)
 create mode 100644 drivers/pwm/pwm-stm32.c

diff --git a/drivers/pwm/Kconfig b/drivers/pwm/Kconfig
index f92dd41..88035c0 100644
--- a/drivers/pwm/Kconfig
+++ b/drivers/pwm/Kconfig
@@ -397,6 +397,15 @@ config PWM_STI
 	  To compile this driver as a module, choose M here: the module
 	  will be called pwm-sti.
 
+config PWM_STM32
+	tristate "STMicroelectronics STM32 PWM"
+	depends on (ARCH_STM32 && OF && MFD_STM32_TIMERS) || COMPILE_TEST
+	help
+	  Generic PWM framework driver for STM32 SoCs.
+
+	  To compile this driver as a module, choose M here: the module
+	  will be called pwm-stm32.
+
 config PWM_STMPE
 	bool "STMPE expander PWM export"
 	depends on MFD_STMPE
diff --git a/drivers/pwm/Makefile b/drivers/pwm/Makefile
index a48bdb5..346a83b 100644
--- a/drivers/pwm/Makefile
+++ b/drivers/pwm/Makefile
@@ -38,6 +38,7 @@ obj-$(CONFIG_PWM_ROCKCHIP)	+= pwm-rockchip.o
 obj-$(CONFIG_PWM_SAMSUNG)	+= pwm-samsung.o
 obj-$(CONFIG_PWM_SPEAR)		+= pwm-spear.o
 obj-$(CONFIG_PWM_STI)		+= pwm-sti.o
+obj-$(CONFIG_PWM_STM32)		+= pwm-stm32.o
 obj-$(CONFIG_PWM_STMPE)		+= pwm-stmpe.o
 obj-$(CONFIG_PWM_SUN4I)		+= pwm-sun4i.o
 obj-$(CONFIG_PWM_TEGRA)		+= pwm-tegra.o
diff --git a/drivers/pwm/pwm-stm32.c b/drivers/pwm/pwm-stm32.c
new file mode 100644
index 0000000..fcf0a78
--- /dev/null
+++ b/drivers/pwm/pwm-stm32.c
@@ -0,0 +1,434 @@
+/*
+ * Copyright (C) STMicroelectronics 2016
+ *
+ * Author: Gerald Baeza <gerald.baeza@st.com>
+ *
+ * License terms: GNU General Public License (GPL), version 2
+ *
+ * Inspired by timer-stm32.c from Maxime Coquelin
+ *             pwm-atmel.c from Bo Shen
+ */
+
+#include <linux/mfd/stm32-timers.h>
+#include <linux/module.h>
+#include <linux/platform_device.h>
+#include <linux/pwm.h>
+#include <linux/of.h>
+
+#define CCMR_CHANNEL_SHIFT 8
+#define CCMR_CHANNEL_MASK  0xFF
+#define MAX_BREAKINPUT 2
+
+struct stm32_pwm {
+	struct pwm_chip chip;
+	struct device *dev;
+	struct clk *clk;
+	struct regmap *regmap;
+	unsigned int caps;
+	unsigned int npwm;
+	u32 max_arr;
+	bool have_complementary_output;
+};
+
+struct stm32_breakinput {
+	u32 index;
+	u32 level;
+	u32 filter;
+};
+
+static inline struct stm32_pwm *to_stm32_pwm_dev(struct pwm_chip *chip)
+{
+	return container_of(chip, struct stm32_pwm, chip);
+}
+
+static u32 active_channels(struct stm32_pwm *dev)
+{
+	u32 ccer;
+
+	regmap_read(dev->regmap, TIM_CCER, &ccer);
+
+	return ccer & TIM_CCER_CCXE;
+}
+
+static int write_ccrx(struct stm32_pwm *dev, struct pwm_device *pwm,
+		      u32 value)
+{
+	switch (pwm->hwpwm) {
+	case 0:
+		return regmap_write(dev->regmap, TIM_CCR1, value);
+	case 1:
+		return regmap_write(dev->regmap, TIM_CCR2, value);
+	case 2:
+		return regmap_write(dev->regmap, TIM_CCR3, value);
+	case 3:
+		return regmap_write(dev->regmap, TIM_CCR4, value);
+	}
+	return -EINVAL;
+}
+
+static int stm32_pwm_config(struct pwm_chip *chip, struct pwm_device *pwm,
+			    int duty_ns, int period_ns)
+{
+	struct stm32_pwm *priv = to_stm32_pwm_dev(chip);
+	unsigned long long prd, div, dty;
+	unsigned int prescaler = 0;
+	u32 ccmr, mask, shift;
+
+	/* Period and prescaler values depends on clock rate */
+	div = (unsigned long long)clk_get_rate(priv->clk) * period_ns;
+
+	do_div(div, NSEC_PER_SEC);
+	prd = div;
+
+	while (div > priv->max_arr) {
+		prescaler++;
+		div = prd;
+		do_div(div, (prescaler + 1));
+	}
+
+	prd = div;
+
+	if (prescaler > MAX_TIM_PSC) {
+		dev_err(chip->dev, "prescaler exceeds the maximum value\n");
+		return -EINVAL;
+	}
+
+	/*
+	 * All channels share the same prescaler and counter so when two
+	 * channels are active at the same we can't change them
+	 */
+	if (active_channels(priv) & ~(1 << pwm->hwpwm * 4)) {
+		u32 psc, arr;
+
+		regmap_read(priv->regmap, TIM_PSC, &psc);
+		regmap_read(priv->regmap, TIM_ARR, &arr);
+
+		if ((psc != prescaler) || (arr != prd - 1))
+			return -EBUSY;
+	}
+
+	regmap_write(priv->regmap, TIM_PSC, prescaler);
+	regmap_write(priv->regmap, TIM_ARR, prd - 1);
+	regmap_update_bits(priv->regmap, TIM_CR1, TIM_CR1_ARPE, TIM_CR1_ARPE);
+
+	/* Calculate the duty cycles */
+	dty = prd * duty_ns;
+	do_div(dty, period_ns);
+
+	write_ccrx(priv, pwm, dty);
+
+	/* Configure output mode */
+	shift = (pwm->hwpwm & 0x1) * CCMR_CHANNEL_SHIFT;
+	ccmr = (TIM_CCMR_PE | TIM_CCMR_M1) << shift;
+	mask = CCMR_CHANNEL_MASK << shift;
+
+	if (pwm->hwpwm < 2)
+		regmap_update_bits(priv->regmap, TIM_CCMR1, mask, ccmr);
+	else
+		regmap_update_bits(priv->regmap, TIM_CCMR2, mask, ccmr);
+
+	regmap_update_bits(priv->regmap, TIM_BDTR,
+			   TIM_BDTR_MOE | TIM_BDTR_AOE,
+			   TIM_BDTR_MOE | TIM_BDTR_AOE);
+
+	return 0;
+}
+
+static int stm32_pwm_set_polarity(struct pwm_chip *chip, struct pwm_device *pwm,
+				  enum pwm_polarity polarity)
+{
+	u32 mask;
+	struct stm32_pwm *priv = to_stm32_pwm_dev(chip);
+
+	mask = TIM_CCER_CC1P << (pwm->hwpwm * 4);
+	if (priv->have_complementary_output)
+		mask |= TIM_CCER_CC1NP << (pwm->hwpwm * 4);
+
+	regmap_update_bits(priv->regmap, TIM_CCER, mask,
+			   polarity == PWM_POLARITY_NORMAL ? 0 : mask);
+
+	return 0;
+}
+
+static int stm32_pwm_enable(struct pwm_chip *chip, struct pwm_device *pwm)
+{
+	u32 mask;
+	struct stm32_pwm *priv = to_stm32_pwm_dev(chip);
+
+	clk_enable(priv->clk);
+
+	/* Enable channel */
+	mask = TIM_CCER_CC1E << (pwm->hwpwm * 4);
+	if (priv->have_complementary_output)
+		mask |= TIM_CCER_CC1NE << (pwm->hwpwm * 4);
+
+	regmap_update_bits(priv->regmap, TIM_CCER, mask, mask);
+
+	/* Make sure that registers are updated */
+	regmap_update_bits(priv->regmap, TIM_EGR, TIM_EGR_UG, TIM_EGR_UG);
+
+	/* Enable controller */
+	regmap_update_bits(priv->regmap, TIM_CR1, TIM_CR1_CEN, TIM_CR1_CEN);
+
+	return 0;
+}
+
+static void stm32_pwm_disable(struct pwm_chip *chip, struct pwm_device *pwm)
+{
+	u32 mask;
+	struct stm32_pwm *priv = to_stm32_pwm_dev(chip);
+
+	/* Disable channel */
+	mask = TIM_CCER_CC1E << (pwm->hwpwm * 4);
+	if (priv->have_complementary_output)
+		mask |= TIM_CCER_CC1NE << (pwm->hwpwm * 4);
+
+	regmap_update_bits(priv->regmap, TIM_CCER, mask, 0);
+
+	/* When all channels are disabled, we can disable the controller */
+	if (!active_channels(priv))
+		regmap_update_bits(priv->regmap, TIM_CR1, TIM_CR1_CEN, 0);
+
+	clk_disable(priv->clk);
+}
+
+static int stm32_pwm_apply(struct pwm_chip *chip, struct pwm_device *pwm,
+			   struct pwm_state *state)
+{
+	struct pwm_state curstate;
+	bool enabled;
+	int ret;
+
+	pwm_get_state(pwm, &curstate);
+	enabled = curstate.enabled;
+
+	if (enabled && !state->enabled) {
+		stm32_pwm_disable(chip, pwm);
+		return 0;
+	}
+
+	if (state->polarity != curstate.polarity && enabled)
+		stm32_pwm_set_polarity(chip, pwm, state->polarity);
+
+	ret = stm32_pwm_config(chip, pwm, state->duty_cycle, state->period);
+	if (ret)
+		return ret;
+
+	if (!enabled && state->enabled)
+		ret = stm32_pwm_enable(chip, pwm);
+
+	return ret;
+}
+
+static const struct pwm_ops stm32pwm_ops = {
+	.owner = THIS_MODULE,
+	.apply = stm32_pwm_apply,
+};
+
+static int stm32_pwm_set_breakinput(struct stm32_pwm *priv,
+				    int level, int filter)
+{
+	u32 bdtr = TIM_BDTR_BKE;
+
+	if (level)
+		bdtr |= TIM_BDTR_BKP;
+
+	bdtr |= (filter & TIM_BDTR_BKF_MASK) << TIM_BDTR_BKF_SHIFT;
+
+	regmap_update_bits(priv->regmap,
+			   TIM_BDTR, TIM_BDTR_BKE | TIM_BDTR_BKP | TIM_BDTR_BKF,
+			   bdtr);
+
+	regmap_read(priv->regmap, TIM_BDTR, &bdtr);
+
+	return (bdtr & TIM_BDTR_BKE) ? 0 : -EINVAL;
+}
+
+static int stm32_pwm_set_breakinput2(struct stm32_pwm *priv,
+				     int level, int filter)
+{
+	u32 bdtr = TIM_BDTR_BK2E;
+
+	if (level)
+		bdtr |= TIM_BDTR_BK2P;
+
+	bdtr |= (filter & TIM_BDTR_BKF_MASK) << TIM_BDTR_BK2F_SHIFT;
+
+	regmap_update_bits(priv->regmap,
+			   TIM_BDTR, TIM_BDTR_BK2E |
+			   TIM_BDTR_BK2P |
+			   TIM_BDTR_BK2F,
+			   bdtr);
+
+	regmap_read(priv->regmap, TIM_BDTR, &bdtr);
+
+	return (bdtr & TIM_BDTR_BK2E) ? 0 : -EINVAL;
+}
+
+static int stm32_pwm_apply_breakinputs(struct stm32_pwm *priv,
+				       struct device_node *np)
+{
+	struct stm32_breakinput breakinput[MAX_BREAKINPUT];
+	int nb, ret, i, array_size;
+
+	nb = of_property_count_elems_of_size(np, "st,breakinput",
+					     sizeof(struct stm32_breakinput));
+
+	/*
+	 * Because "st,breakinput" parameter is optional do not make probe
+	 * failed if it doesn't exist.
+	 */
+	if (nb <= 0)
+		return 0;
+
+	if (nb > MAX_BREAKINPUT)
+		return -EINVAL;
+
+	array_size = nb * sizeof(struct stm32_breakinput) / sizeof(u32);
+	ret = of_property_read_u32_array(np, "st,breakinput",
+					 &breakinput[0].index, array_size);
+	if (ret)
+		return ret;
+
+	for (i = 0; i < nb && !ret; i++) {
+		switch (breakinput[i].index) {
+		case 0:
+		{
+			ret = stm32_pwm_set_breakinput(priv,
+						       breakinput[i].level,
+						       breakinput[i].filter);
+			break;
+		}
+		case 1:
+		{
+			ret = stm32_pwm_set_breakinput2(priv,
+							breakinput[i].level,
+							breakinput[i].filter);
+
+			break;
+		}
+		default:
+		{
+			ret = -EINVAL;
+			break;
+		}
+		}
+	}
+
+	return ret;
+}
+
+static void stm32_pwm_detect_complementary(struct stm32_pwm *priv)
+{
+	u32 ccer;
+
+	/*
+	 * If complementary bit doesn't exist writing 1 will have no
+	 * effect so we can detect it.
+	 */
+	regmap_update_bits(priv->regmap,
+			   TIM_CCER, TIM_CCER_CC1NE, TIM_CCER_CC1NE);
+	regmap_read(priv->regmap, TIM_CCER, &ccer);
+	regmap_update_bits(priv->regmap, TIM_CCER, TIM_CCER_CCXE, 0);
+
+	priv->have_complementary_output = (ccer != 0);
+}
+
+static void stm32_pwm_detect_channels(struct stm32_pwm *priv)
+{
+	u32 ccer;
+
+	/*
+	 * If channels enable bits don't exist writing 1 will have no
+	 * effect so we can detect and count them.
+	 */
+	regmap_update_bits(priv->regmap,
+			   TIM_CCER, TIM_CCER_CCXE, TIM_CCER_CCXE);
+	regmap_read(priv->regmap, TIM_CCER, &ccer);
+	regmap_update_bits(priv->regmap, TIM_CCER, TIM_CCER_CCXE, 0);
+
+	if (ccer & TIM_CCER_CC1E)
+		priv->npwm++;
+
+	if (ccer & TIM_CCER_CC2E)
+		priv->npwm++;
+
+	if (ccer & TIM_CCER_CC3E)
+		priv->npwm++;
+
+	if (ccer & TIM_CCER_CC4E)
+		priv->npwm++;
+}
+
+static int stm32_pwm_probe(struct platform_device *pdev)
+{
+	struct device *dev = &pdev->dev;
+	struct device_node *np = dev->of_node;
+	struct stm32_timers *ddata = dev_get_drvdata(pdev->dev.parent);
+	struct stm32_pwm *priv;
+	int ret;
+
+	priv = devm_kzalloc(dev, sizeof(*priv), GFP_KERNEL);
+	if (!priv)
+		return -ENOMEM;
+
+	priv->regmap = ddata->regmap;
+	priv->clk = ddata->clk;
+	priv->max_arr = ddata->max_arr;
+
+	if (!priv->regmap || !priv->clk)
+		return -EINVAL;
+
+	ret = stm32_pwm_apply_breakinputs(priv, np);
+	if (ret)
+		return ret;
+
+	stm32_pwm_detect_complementary(priv);
+	stm32_pwm_detect_channels(priv);
+
+	priv->chip.base = -1;
+	priv->chip.dev = dev;
+	priv->chip.ops = &stm32pwm_ops;
+	priv->chip.npwm = priv->npwm;
+
+	ret = pwmchip_add(&priv->chip);
+	if (ret < 0)
+		return ret;
+
+	platform_set_drvdata(pdev, priv);
+
+	return 0;
+}
+
+static int stm32_pwm_remove(struct platform_device *pdev)
+{
+	struct stm32_pwm *priv = platform_get_drvdata(pdev);
+	unsigned int i;
+
+	for (i = 0; i < priv->npwm; i++)
+		pwm_disable(&priv->chip.pwms[i]);
+
+	pwmchip_remove(&priv->chip);
+
+	return 0;
+}
+
+static const struct of_device_id stm32_pwm_of_match[] = {
+	{ .compatible = "st,stm32-pwm",	},
+	{ /* end node */ },
+};
+MODULE_DEVICE_TABLE(of, stm32_pwm_of_match);
+
+static struct platform_driver stm32_pwm_driver = {
+	.probe	= stm32_pwm_probe,
+	.remove	= stm32_pwm_remove,
+	.driver	= {
+		.name = "stm32-pwm",
+		.of_match_table = stm32_pwm_of_match,
+	},
+};
+module_platform_driver(stm32_pwm_driver);
+
+MODULE_ALIAS("platform: stm32-pwm");
+MODULE_DESCRIPTION("STMicroelectronics STM32 PWM driver");
+MODULE_LICENSE("GPL v2");
-- 
1.9.1

[PATCH v7 5/8] IIO: add bindings for STM32 timer trigger driver

[Benjamin Gaignard]

Define bindings for STM32 timer trigger

version 4:
- remove triggers enumeration from DT
- add reg parameter

version 3:
- change file name
- add cross reference with mfd bindings

version 2:
- only keep one compatible
- add DT parameters to set lists of the triggers:
  one list describe the triggers created by the device
  another one give the triggers accepted by the device

Signed-off-by: Benjamin Gaignard <benjamin.gaignard@st.com>
---
 .../bindings/iio/timer/stm32-timer-trigger.txt     | 23 ++++++++++++++++++++++
 1 file changed, 23 insertions(+)
 create mode 100644 Documentation/devicetree/bindings/iio/timer/stm32-timer-trigger.txt

diff --git a/Documentation/devicetree/bindings/iio/timer/stm32-timer-trigger.txt b/Documentation/devicetree/bindings/iio/timer/stm32-timer-trigger.txt
new file mode 100644
index 0000000..36a6c4a
--- /dev/null
+++ b/Documentation/devicetree/bindings/iio/timer/stm32-timer-trigger.txt
@@ -0,0 +1,23 @@
+STMicroelectronics STM32 Timers IIO timer bindings
+
+Must be a sub-node of an STM32 Timers device tree node.
+See ../mfd/stm32-timers.txt for details about the parent node.
+
+Required parameters:
+- compatible:	Must be "st,stm32-timer-trigger".
+- reg:		Define triggers configuration of the hardware IP.
+
+Example:
+	timers@40010000 {
+		#address-cells = <1>;
+		#size-cells = <0>;
+		compatible = "st,stm32-timers";
+		reg = <0x40010000 0x400>;
+		clocks = <&rcc 0 160>;
+		clock-names = "clk_int";
+
+		timer {
+			compatible = "st,stm32-timer-trigger";
+			reg = <0>;
+		};
+	};
-- 
1.9.1

[PATCH v7 6/8] IIO: add STM32 timer trigger driver

[Benjamin Gaignard]

Timers IPs can be used to generate triggers for other IPs like
DAC or ADC.
Each trigger may result of timer internals signals like counter enable,
reset or edge, this configuration could be done through "master_mode"
device attribute.

Since triggers could be used by DAC or ADC their names are defined
in include/ nux/iio/timer/stm32-timer-trigger.h and is_stm32_iio_timer_trigger
function could be used to check if the trigger is valid or not.

"trgo" trigger have a "sampling_frequency" attribute which allow to configure
timer sampling frequency.

version 7:
- remove all iio_device related code
- move driver into trigger directory

version 5:
- simplify tables of triggers
- only create an IIO device when needed

version 4:
- get triggers configuration from "reg" in DT
- add tables of triggers
- sampling frequency is enable/disable when writing in trigger
  sampling_frequency attribute
- no more use of interruptions

version 3:
- change compatible to "st,stm32-timer-trigger"
- fix attributes access right
- use string instead of int for master_mode and slave_mode
- document device attributes in sysfs-bus-iio-timer-stm32

version 2:
- keep only one compatible
- use st,input-triggers-names and st,output-triggers-names
  to know which triggers are accepted and/or create by the device

Signed-off-by: Benjamin Gaignard <benjamin.gaignard@st.com>
---
 .../ABI/testing/sysfs-bus-iio-timer-stm32          |  29 ++
 drivers/iio/Kconfig                                |   1 -
 drivers/iio/trigger/Kconfig                        |  10 +
 drivers/iio/trigger/Makefile                       |   1 +
 drivers/iio/trigger/stm32-timer-trigger.c          | 340 +++++++++++++++++++++
 include/linux/iio/timer/stm32-timer-trigger.h      |  62 ++++
 6 files changed, 442 insertions(+), 1 deletion(-)
 create mode 100644 Documentation/ABI/testing/sysfs-bus-iio-timer-stm32
 create mode 100644 drivers/iio/trigger/stm32-timer-trigger.c
 create mode 100644 include/linux/iio/timer/stm32-timer-trigger.h

diff --git a/Documentation/ABI/testing/sysfs-bus-iio-timer-stm32 b/Documentation/ABI/testing/sysfs-bus-iio-timer-stm32
new file mode 100644
index 0000000..a7f5177
--- /dev/null
+++ b/Documentation/ABI/testing/sysfs-bus-iio-timer-stm32
@@ -0,0 +1,29 @@
+What:		/sys/bus/iio/devices/triggerX/master_mode_available
+KernelVersion:	4.10
+Contact:	benjamin.gaignard@st.com
+Description:
+		Reading returns the list possible master modes which are:
+		- "reset"     :	The UG bit from the TIMx_EGR register is used as trigger output (TRGO).
+		- "enable"    : The Counter Enable signal CNT_EN is used as trigger output.
+		- "update"    : The update event is selected as trigger output.
+				For instance a master timer can then be used as a prescaler for a slave timer.
+		- "compare_pulse" : The trigger output send a positive pulse when the CC1IF flag is to be set.
+		- "OC1REF"    : OC1REF signal is used as trigger output.
+		- "OC2REF"    : OC2REF signal is used as trigger output.
+		- "OC3REF"    : OC3REF signal is used as trigger output.
+		- "OC4REF"    : OC4REF signal is used as trigger output.
+
+What:		/sys/bus/iio/devices/triggerX/master_mode
+KernelVersion:	4.10
+Contact:	benjamin.gaignard@st.com
+Description:
+		Reading returns the current master modes.
+		Writing set the master mode
+
+What:		/sys/bus/iio/devices/triggerX/sampling_frequency
+KernelVersion:	4.10
+Contact:	benjamin.gaignard@st.com
+Description:
+		Reading returns the current sampling frequency.
+		Writing an value different of 0 set and start sampling.
+		Writing 0 stop sampling.
diff --git a/drivers/iio/Kconfig b/drivers/iio/Kconfig
index a918270..6b0c427 100644
--- a/drivers/iio/Kconfig
+++ b/drivers/iio/Kconfig
@@ -92,5 +92,4 @@ source "drivers/iio/potentiostat/Kconfig"
 source "drivers/iio/pressure/Kconfig"
 source "drivers/iio/proximity/Kconfig"
 source "drivers/iio/temperature/Kconfig"
-
 endif # IIO
diff --git a/drivers/iio/trigger/Kconfig b/drivers/iio/trigger/Kconfig
index 809b2e7..72d3a32 100644
--- a/drivers/iio/trigger/Kconfig
+++ b/drivers/iio/trigger/Kconfig
@@ -24,6 +24,16 @@ config IIO_INTERRUPT_TRIGGER
 	  To compile this driver as a module, choose M here: the
 	  module will be called iio-trig-interrupt.
 
+config IIO_STM32_TIMER_TRIGGER
+	tristate "STM32 Timer Trigger"
+	depends on (ARCH_STM32 && OF && MFD_STM32_TIMERS) || COMPILE_TEST
+	help
+	  Select this option to enable STM32 Timer Trigger
+
+	  To compile this driver as a module, choose M here: the
+	  module will be called stm32-timer-trigger.
+
+
 config IIO_TIGHTLOOP_TRIGGER
 	tristate "A kthread based hammering loop trigger"
 	depends on IIO_SW_TRIGGER
diff --git a/drivers/iio/trigger/Makefile b/drivers/iio/trigger/Makefile
index aab4dc2..5c4ecd3 100644
--- a/drivers/iio/trigger/Makefile
+++ b/drivers/iio/trigger/Makefile
@@ -6,5 +6,6 @@
 
 obj-$(CONFIG_IIO_HRTIMER_TRIGGER) += iio-trig-hrtimer.o
 obj-$(CONFIG_IIO_INTERRUPT_TRIGGER) += iio-trig-interrupt.o
+obj-$(CONFIG_IIO_STM32_TIMER_TRIGGER) += stm32-timer-trigger.o
 obj-$(CONFIG_IIO_SYSFS_TRIGGER) += iio-trig-sysfs.o
 obj-$(CONFIG_IIO_TIGHTLOOP_TRIGGER) += iio-trig-loop.o
diff --git a/drivers/iio/trigger/stm32-timer-trigger.c b/drivers/iio/trigger/stm32-timer-trigger.c
new file mode 100644
index 0000000..409fb0c
--- /dev/null
+++ b/drivers/iio/trigger/stm32-timer-trigger.c
@@ -0,0 +1,340 @@
+/*
+ * Copyright (C) STMicroelectronics 2016
+ *
+ * Author: Benjamin Gaignard <benjamin.gaignard@st.com>
+ *
+ * License terms:  GNU General Public License (GPL), version 2
+ */
+
+#include <linux/iio/iio.h>
+#include <linux/iio/sysfs.h>
+#include <linux/iio/timer/stm32-timer-trigger.h>
+#include <linux/iio/trigger.h>
+#include <linux/mfd/stm32-timers.h>
+#include <linux/module.h>
+#include <linux/platform_device.h>
+
+#define MAX_TRIGGERS 6
+
+/* List the triggers created by each timer */
+static const void *triggers_table[][MAX_TRIGGERS] = {
+	{ TIM1_TRGO, TIM1_CH1, TIM1_CH2, TIM1_CH3, TIM1_CH4,},
+	{ TIM2_TRGO, TIM2_CH1, TIM2_CH2, TIM2_CH3, TIM2_CH4,},
+	{ TIM3_TRGO, TIM3_CH1, TIM3_CH2, TIM3_CH3, TIM3_CH4,},
+	{ TIM4_TRGO, TIM4_CH1, TIM4_CH2, TIM4_CH3, TIM4_CH4,},
+	{ TIM5_TRGO, TIM5_CH1, TIM5_CH2, TIM5_CH3, TIM5_CH4,},
+	{ TIM6_TRGO,},
+	{ TIM7_TRGO,},
+	{ TIM8_TRGO, TIM8_CH1, TIM8_CH2, TIM8_CH3, TIM8_CH4,},
+	{ TIM9_TRGO, TIM9_CH1, TIM9_CH2,},
+	{ TIM12_TRGO, TIM12_CH1, TIM12_CH2,},
+};
+
+struct stm32_timer_trigger {
+	struct device *dev;
+	struct regmap *regmap;
+	struct clk *clk;
+	u32 max_arr;
+	const void *triggers;
+};
+
+static int stm32_timer_start(struct stm32_timer_trigger *priv,
+			     unsigned int frequency)
+{
+	unsigned long long prd, div;
+	int prescaler = 0;
+	u32 ccer, cr1;
+
+	/* Period and prescaler values depends of clock rate */
+	div = (unsigned long long)clk_get_rate(priv->clk);
+
+	do_div(div, frequency);
+
+	prd = div;
+
+	/*
+	 * Increase prescaler value until we get a result that fit
+	 * with auto reload register maximum value.
+	 */
+	while (div > priv->max_arr) {
+		prescaler++;
+		div = prd;
+		do_div(div, (prescaler + 1));
+	}
+	prd = div;
+
+	if (prescaler > MAX_TIM_PSC) {
+		dev_err(priv->dev, "prescaler exceeds the maximum value\n");
+		return -EINVAL;
+	}
+
+	/* Check if nobody else use the timer */
+	regmap_read(priv->regmap, TIM_CCER, &ccer);
+	if (ccer & TIM_CCER_CCXE)
+		return -EBUSY;
+
+	regmap_read(priv->regmap, TIM_CR1, &cr1);
+	if (!(cr1 & TIM_CR1_CEN))
+		clk_enable(priv->clk);
+
+	regmap_write(priv->regmap, TIM_PSC, prescaler);
+	regmap_write(priv->regmap, TIM_ARR, prd - 1);
+	regmap_update_bits(priv->regmap, TIM_CR1, TIM_CR1_ARPE, TIM_CR1_ARPE);
+
+	/* Force master mode to update mode */
+	regmap_update_bits(priv->regmap, TIM_CR2, TIM_CR2_MMS, 0x20);
+
+	/* Make sure that registers are updated */
+	regmap_update_bits(priv->regmap, TIM_EGR, TIM_EGR_UG, TIM_EGR_UG);
+
+	/* Enable controller */
+	regmap_update_bits(priv->regmap, TIM_CR1, TIM_CR1_CEN, TIM_CR1_CEN);
+
+	return 0;
+}
+
+static void stm32_timer_stop(struct stm32_timer_trigger *priv)
+{
+	u32 ccer, cr1;
+
+	regmap_read(priv->regmap, TIM_CCER, &ccer);
+	if (ccer & TIM_CCER_CCXE)
+		return;
+
+	regmap_read(priv->regmap, TIM_CR1, &cr1);
+	if (cr1 & TIM_CR1_CEN)
+		clk_disable(priv->clk);
+
+	/* Stop timer */
+	regmap_update_bits(priv->regmap, TIM_CR1, TIM_CR1_CEN, 0);
+	regmap_write(priv->regmap, TIM_PSC, 0);
+	regmap_write(priv->regmap, TIM_ARR, 0);
+
+	/* Make sure that registers are updated */
+	regmap_update_bits(priv->regmap, TIM_EGR, TIM_EGR_UG, TIM_EGR_UG);
+}
+
+static ssize_t stm32_tt_store_frequency(struct device *dev,
+					struct device_attribute *attr,
+					const char *buf, size_t len)
+{
+	struct iio_trigger *trig = to_iio_trigger(dev);
+	struct stm32_timer_trigger *priv = iio_trigger_get_drvdata(trig);
+	unsigned int freq;
+	int ret;
+
+	ret = kstrtouint(buf, 10, &freq);
+	if (ret)
+		return ret;
+
+	if (freq == 0) {
+		stm32_timer_stop(priv);
+	} else {
+		ret = stm32_timer_start(priv, freq);
+		if (ret)
+			return ret;
+	}
+
+	return len;
+}
+
+static ssize_t stm32_tt_read_frequency(struct device *dev,
+				       struct device_attribute *attr, char *buf)
+{
+	struct iio_trigger *trig = to_iio_trigger(dev);
+	struct stm32_timer_trigger *priv = iio_trigger_get_drvdata(trig);
+	u32 psc, arr, cr1;
+	unsigned long long freq = 0;
+
+	regmap_read(priv->regmap, TIM_CR1, &cr1);
+	regmap_read(priv->regmap, TIM_PSC, &psc);
+	regmap_read(priv->regmap, TIM_ARR, &arr);
+
+	if (psc && arr && (cr1 & TIM_CR1_CEN)) {
+		freq = (unsigned long long)clk_get_rate(priv->clk);
+		do_div(freq, psc);
+		do_div(freq, arr);
+	}
+
+	return sprintf(buf, "%d\n", (unsigned int)freq);
+}
+
+static IIO_DEV_ATTR_SAMP_FREQ(0660,
+			      stm32_tt_read_frequency,
+			      stm32_tt_store_frequency);
+
+static char *master_mode_table[] = {
+	"reset",
+	"enable",
+	"update",
+	"compare_pulse",
+	"OC1REF",
+	"OC2REF",
+	"OC3REF",
+	"OC4REF"
+};
+
+static ssize_t stm32_tt_show_master_mode(struct device *dev,
+					 struct device_attribute *attr,
+					 char *buf)
+{
+	struct iio_dev *indio_dev = dev_to_iio_dev(dev);
+	struct stm32_timer_trigger *priv = iio_priv(indio_dev);
+	u32 cr2;
+
+	regmap_read(priv->regmap, TIM_CR2, &cr2);
+	cr2 = (cr2 & TIM_CR2_MMS) >> TIM_CR2_MMS_SHIFT;
+
+	return snprintf(buf, PAGE_SIZE, "%s\n", master_mode_table[cr2]);
+}
+
+static ssize_t stm32_tt_store_master_mode(struct device *dev,
+					  struct device_attribute *attr,
+					  const char *buf, size_t len)
+{
+	struct iio_dev *indio_dev = dev_to_iio_dev(dev);
+	struct stm32_timer_trigger *priv = iio_priv(indio_dev);
+	int i;
+
+	for (i = 0; i < ARRAY_SIZE(master_mode_table); i++) {
+		if (!strncmp(master_mode_table[i], buf,
+			     strlen(master_mode_table[i]))) {
+			regmap_update_bits(priv->regmap, TIM_CR2,
+					   TIM_CR2_MMS, i << TIM_CR2_MMS_SHIFT);
+			/* Make sure that registers are updated */
+			regmap_update_bits(priv->regmap, TIM_EGR,
+					   TIM_EGR_UG, TIM_EGR_UG);
+			return len;
+		}
+	}
+
+	return -EINVAL;
+}
+
+static IIO_CONST_ATTR(master_mode_available,
+	"reset enable update compare_pulse OC1REF OC2REF OC3REF OC4REF");
+
+static IIO_DEVICE_ATTR(master_mode, 0660,
+		       stm32_tt_show_master_mode,
+		       stm32_tt_store_master_mode,
+		       0);
+
+static struct attribute *stm32_trigger_attrs[] = {
+	&iio_dev_attr_sampling_frequency.dev_attr.attr,
+	&iio_dev_attr_master_mode.dev_attr.attr,
+	&iio_const_attr_master_mode_available.dev_attr.attr,
+	NULL,
+};
+
+static const struct attribute_group stm32_trigger_attr_group = {
+	.attrs = stm32_trigger_attrs,
+};
+
+static const struct attribute_group *stm32_trigger_attr_groups[] = {
+	&stm32_trigger_attr_group,
+	NULL,
+};
+
+static const struct iio_trigger_ops timer_trigger_ops = {
+	.owner = THIS_MODULE,
+};
+
+static int stm32_setup_iio_triggers(struct stm32_timer_trigger *priv)
+{
+	int ret;
+	const char * const *cur = priv->triggers;
+
+	while (cur && *cur) {
+		struct iio_trigger *trig;
+
+		trig = devm_iio_trigger_alloc(priv->dev, "%s", *cur);
+		if  (!trig)
+			return -ENOMEM;
+
+		trig->dev.parent = priv->dev->parent;
+		trig->ops = &timer_trigger_ops;
+
+		/*
+		 * sampling frequency and master mode attributes
+		 * should only be available on trgo trigger which
+		 * is always the first in the list.
+		 */
+		if (cur == priv->triggers)
+			trig->dev.groups = stm32_trigger_attr_groups;
+
+		iio_trigger_set_drvdata(trig, priv);
+
+		ret = devm_iio_trigger_register(priv->dev, trig);
+		if (ret)
+			return ret;
+		cur++;
+	}
+
+	return 0;
+}
+
+/**
+ * is_stm32_timer_trigger
+ * @trig: trigger to be checked
+ *
+ * return true if the trigger is a valid stm32 iio timer trigger
+ * either return false
+ */
+bool is_stm32_timer_trigger(struct iio_trigger *trig)
+{
+	return (trig->ops == &timer_trigger_ops);
+}
+EXPORT_SYMBOL(is_stm32_timer_trigger);
+
+static int stm32_timer_trigger_probe(struct platform_device *pdev)
+{
+	struct device *dev = &pdev->dev;
+	struct stm32_timer_trigger *priv;
+	struct stm32_timers *ddata = dev_get_drvdata(pdev->dev.parent);
+	unsigned int index;
+	int ret;
+
+	if (of_property_read_u32(dev->of_node, "reg", &index))
+		return -EINVAL;
+
+	if (index >= ARRAY_SIZE(triggers_table))
+		return -EINVAL;
+
+	priv = devm_kzalloc(dev, sizeof(*priv), GFP_KERNEL);
+
+	if (!priv)
+		return -ENOMEM;
+
+	priv->dev = dev;
+	priv->regmap = ddata->regmap;
+	priv->clk = ddata->clk;
+	priv->max_arr = ddata->max_arr;
+	priv->triggers = triggers_table[index];
+
+	ret = stm32_setup_iio_triggers(priv);
+	if (ret)
+		return ret;
+
+	platform_set_drvdata(pdev, priv);
+
+	return 0;
+}
+
+static const struct of_device_id stm32_trig_of_match[] = {
+	{ .compatible = "st,stm32-timer-trigger", },
+	{ /* end node */ },
+};
+MODULE_DEVICE_TABLE(of, stm32_trig_of_match);
+
+static struct platform_driver stm32_timer_trigger_driver = {
+	.probe = stm32_timer_trigger_probe,
+	.driver = {
+		.name = "stm32-timer-trigger",
+		.of_match_table = stm32_trig_of_match,
+	},
+};
+module_platform_driver(stm32_timer_trigger_driver);
+
+MODULE_ALIAS("platform: stm32-timer-trigger");
+MODULE_DESCRIPTION("STMicroelectronics STM32 Timer Trigger driver");
+MODULE_LICENSE("GPL v2");
diff --git a/include/linux/iio/timer/stm32-timer-trigger.h b/include/linux/iio/timer/stm32-timer-trigger.h
new file mode 100644
index 0000000..55535ae
--- /dev/null
+++ b/include/linux/iio/timer/stm32-timer-trigger.h
@@ -0,0 +1,62 @@
+/*
+ * Copyright (C) STMicroelectronics 2016
+ *
+ * Author: Benjamin Gaignard <benjamin.gaignard@st.com>
+ *
+ * License terms:  GNU General Public License (GPL), version 2
+ */
+
+#ifndef _STM32_TIMER_TRIGGER_H_
+#define _STM32_TIMER_TRIGGER_H_
+
+#define TIM1_TRGO	"tim1_trgo"
+#define TIM1_CH1	"tim1_ch1"
+#define TIM1_CH2	"tim1_ch2"
+#define TIM1_CH3	"tim1_ch3"
+#define TIM1_CH4	"tim1_ch4"
+
+#define TIM2_TRGO	"tim2_trgo"
+#define TIM2_CH1	"tim2_ch1"
+#define TIM2_CH2	"tim2_ch2"
+#define TIM2_CH3	"tim2_ch3"
+#define TIM2_CH4	"tim2_ch4"
+
+#define TIM3_TRGO	"tim3_trgo"
+#define TIM3_CH1	"tim3_ch1"
+#define TIM3_CH2	"tim3_ch2"
+#define TIM3_CH3	"tim3_ch3"
+#define TIM3_CH4	"tim3_ch4"
+
+#define TIM4_TRGO	"tim4_trgo"
+#define TIM4_CH1	"tim4_ch1"
+#define TIM4_CH2	"tim4_ch2"
+#define TIM4_CH3	"tim4_ch3"
+#define TIM4_CH4	"tim4_ch4"
+
+#define TIM5_TRGO	"tim5_trgo"
+#define TIM5_CH1	"tim5_ch1"
+#define TIM5_CH2	"tim5_ch2"
+#define TIM5_CH3	"tim5_ch3"
+#define TIM5_CH4	"tim5_ch4"
+
+#define TIM6_TRGO	"tim6_trgo"
+
+#define TIM7_TRGO	"tim7_trgo"
+
+#define TIM8_TRGO	"tim8_trgo"
+#define TIM8_CH1	"tim8_ch1"
+#define TIM8_CH2	"tim8_ch2"
+#define TIM8_CH3	"tim8_ch3"
+#define TIM8_CH4	"tim8_ch4"
+
+#define TIM9_TRGO	"tim9_trgo"
+#define TIM9_CH1	"tim9_ch1"
+#define TIM9_CH2	"tim9_ch2"
+
+#define TIM12_TRGO	"tim12_trgo"
+#define TIM12_CH1	"tim12_ch1"
+#define TIM12_CH2	"tim12_ch2"
+
+bool is_stm32_timer_trigger(struct iio_trigger *trig);
+
+#endif
-- 
1.9.1

[PATCH v7 7/8] ARM: dts: stm32: add Timers driver for stm32f429 MCU

[Benjamin Gaignard]

Add Timers and it sub-nodes into DT for stm32f429 family.

version 6:
- split patch in two: one for SoC family and one for stm32f469
  discovery board.

version 5:
- rename gptimer node to timers
- re-order timers node par addresses

version 4:
- remove unwanted indexing in pwm@ and timer@ node name
- use "reg" instead of additional parameters to set timer
  configuration

version 3:
- use "st,stm32-timer-trigger" in DT

version 2:
- use parameters to describe hardware capabilities
- do not use references for pwm and iio timer subnodes

Signed-off-by: Benjamin Gaignard <benjamin.gaignard@st.com>
---
 arch/arm/boot/dts/stm32f429.dtsi | 275 +++++++++++++++++++++++++++++++++++++++
 1 file changed, 275 insertions(+)

diff --git a/arch/arm/boot/dts/stm32f429.dtsi b/arch/arm/boot/dts/stm32f429.dtsi
index e4dae0e..35e9b23 100644
--- a/arch/arm/boot/dts/stm32f429.dtsi
+++ b/arch/arm/boot/dts/stm32f429.dtsi
@@ -355,6 +355,21 @@
 					slew-rate = <2>;
 				};
 			};
+
+			pwm1_pins: pwm@1 {
+				pins {
+					pinmux = <STM32F429_PA8_FUNC_TIM1_CH1>,
+						 <STM32F429_PB13_FUNC_TIM1_CH1N>,
+						 <STM32F429_PB12_FUNC_TIM1_BKIN>;
+				};
+			};
+
+			pwm3_pins: pwm@3 {
+				pins {
+					pinmux = <STM32F429_PB4_FUNC_TIM3_CH1>,
+						 <STM32F429_PB5_FUNC_TIM3_CH2>;
+				};
+			};
 		};
 
 		rcc: rcc@40023810 {
@@ -426,6 +441,266 @@
 			interrupts = <80>;
 			clocks = <&rcc 0 38>;
 		};
+
+		timers2: timers@40000000 {
+			#address-cells = <1>;
+			#size-cells = <0>;
+			compatible = "st,stm32-timers";
+			reg = <0x40000000 0x400>;
+			clocks = <&rcc 0 128>;
+			clock-names = "int";
+			status = "disabled";
+
+			pwm {
+				compatible = "st,stm32-pwm";
+				status = "disabled";
+			};
+
+			timer@1 {
+				compatible = "st,stm32-timer-trigger";
+				reg = <1>;
+				status = "disabled";
+			};
+		};
+
+		timers3: timers@40000400 {
+			#address-cells = <1>;
+			#size-cells = <0>;
+			compatible = "st,stm32-timers";
+			reg = <0x40000400 0x400>;
+			clocks = <&rcc 0 129>;
+			clock-names = "int";
+			status = "disabled";
+
+			pwm {
+				compatible = "st,stm32-pwm";
+				status = "disabled";
+			};
+
+			timer@2 {
+				compatible = "st,stm32-timer-trigger";
+				reg = <2>;
+				status = "disabled";
+			};
+		};
+
+		timers4: timers@40000800 {
+			#address-cells = <1>;
+			#size-cells = <0>;
+			compatible = "st,stm32-timers";
+			reg = <0x40000800 0x400>;
+			clocks = <&rcc 0 130>;
+			clock-names = "int";
+			status = "disabled";
+
+			pwm {
+				compatible = "st,stm32-pwm";
+				status = "disabled";
+			};
+
+			timer@3 {
+				compatible = "st,stm32-timer-trigger";
+				reg = <3>;
+				status = "disabled";
+			};
+		};
+
+		timers5: timers@40000c00 {
+			#address-cells = <1>;
+			#size-cells = <0>;
+			compatible = "st,stm32-timers";
+			reg = <0x40000C00 0x400>;
+			clocks = <&rcc 0 131>;
+			clock-names = "int";
+			status = "disabled";
+
+			pwm {
+				compatible = "st,stm32-pwm";
+				status = "disabled";
+			};
+
+			timer@4 {
+				compatible = "st,stm32-timer-trigger";
+				reg = <4>;
+				status = "disabled";
+			};
+		};
+
+		timers6: timers@40001000 {
+			#address-cells = <1>;
+			#size-cells = <0>;
+			compatible = "st,stm32-timers";
+			reg = <0x40001000 0x400>;
+			clocks = <&rcc 0 132>;
+			clock-names = "int";
+			status = "disabled";
+
+			timer@5 {
+				compatible = "st,stm32-timer-trigger";
+				reg = <5>;
+				status = "disabled";
+			};
+		};
+
+		timers7: timers@40001400 {
+			#address-cells = <1>;
+			#size-cells = <0>;
+			compatible = "st,stm32-timers";
+			reg = <0x40001400 0x400>;
+			clocks = <&rcc 0 133>;
+			clock-names = "int";
+			status = "disabled";
+
+			timer@6 {
+				compatible = "st,stm32-timer-trigger";
+				reg = <6>;
+				status = "disabled";
+			};
+		};
+
+		timers12: timers@40001800 {
+			#address-cells = <1>;
+			#size-cells = <0>;
+			compatible = "st,stm32-timers";
+			reg = <0x40001800 0x400>;
+			clocks = <&rcc 0 134>;
+			clock-names = "int";
+			status = "disabled";
+
+			pwm {
+				compatible = "st,stm32-pwm";
+				status = "disabled";
+			};
+
+			timer@9 {
+				compatible = "st,stm32-timer-trigger";
+				reg = <9>;
+				status = "disabled";
+			};
+		};
+
+		timers13: timers@40001c00 {
+			#address-cells = <1>;
+			#size-cells = <0>;
+			compatible = "st,stm32-timers";
+			reg = <0x40001C00 0x400>;
+			clocks = <&rcc 0 135>;
+			clock-names = "int";
+			status = "disabled";
+
+			pwm {
+				compatible = "st,stm32-pwm";
+				status = "disabled";
+			};
+		};
+
+		timers14: timers@40002000 {
+			#address-cells = <1>;
+			#size-cells = <0>;
+			compatible = "st,stm32-timers";
+			reg = <0x40002000 0x400>;
+			clocks = <&rcc 0 136>;
+			clock-names = "int";
+			status = "disabled";
+
+			pwm {
+				compatible = "st,stm32-pwm";
+				status = "disabled";
+			};
+		};
+
+		timers1: timers@40010000 {
+			#address-cells = <1>;
+			#size-cells = <0>;
+			compatible = "st,stm32-timers";
+			reg = <0x40010000 0x400>;
+			clocks = <&rcc 0 160>;
+			clock-names = "int";
+			status = "disabled";
+
+			pwm {
+				compatible = "st,stm32-pwm";
+				status = "disabled";
+			};
+
+			timer@0 {
+				compatible = "st,stm32-timer-trigger";
+				reg = <0>;
+				status = "disabled";
+			};
+		};
+
+		timers8: timers@40010400 {
+			#address-cells = <1>;
+			#size-cells = <0>;
+			compatible = "st,stm32-timers";
+			reg = <0x40010400 0x400>;
+			clocks = <&rcc 0 161>;
+			clock-names = "int";
+			status = "disabled";
+
+			pwm {
+				compatible = "st,stm32-pwm";
+				status = "disabled";
+			};
+
+			timer@7 {
+				compatible = "st,stm32-timer-trigger";
+				reg = <7>;
+				status = "disabled";
+			};
+		};
+
+		timers9: timers@40014000 {
+			#address-cells = <1>;
+			#size-cells = <0>;
+			compatible = "st,stm32-timers";
+			reg = <0x40014000 0x400>;
+			clocks = <&rcc 0 176>;
+			clock-names = "int";
+			status = "disabled";
+
+			pwm {
+				compatible = "st,stm32-pwm";
+				status = "disabled";
+			};
+
+			timer@8 {
+				compatible = "st,stm32-timer-trigger";
+				reg = <8>;
+				status = "disabled";
+			};
+		};
+
+		timers10: timers@40014400 {
+			#address-cells = <1>;
+			#size-cells = <0>;
+			compatible = "st,stm32-timers";
+			reg = <0x40014400 0x400>;
+			clocks = <&rcc 0 177>;
+			clock-names = "int";
+			status = "disabled";
+
+			pwm {
+				compatible = "st,stm32-pwm";
+				status = "disabled";
+			};
+		};
+
+		timers11: timers@40014800 {
+			#address-cells = <1>;
+			#size-cells = <0>;
+			compatible = "st,stm32-timers";
+			reg = <0x40014800 0x400>;
+			clocks = <&rcc 0 178>;
+			clock-names = "int";
+			status = "disabled";
+
+			pwm {
+				compatible = "st,stm32-pwm";
+				status = "disabled";
+			};
+		};
 	};
 };
 
-- 
1.9.1

[PATCH v7 8/8] ARM: dts: stm32: Enable pwm1 and pwm3 for stm32f469-disco

[Benjamin Gaignard]

Define and enable pwm1 and pwm3 for stm32f469 discovery board

Signed-off-by: Benjamin Gaignard <benjamin.gaignard@st.com>
---
 arch/arm/boot/dts/stm32f469-disco.dts | 28 ++++++++++++++++++++++++++++
 1 file changed, 28 insertions(+)

diff --git a/arch/arm/boot/dts/stm32f469-disco.dts b/arch/arm/boot/dts/stm32f469-disco.dts
index 8a163d7..92552d3 100644
--- a/arch/arm/boot/dts/stm32f469-disco.dts
+++ b/arch/arm/boot/dts/stm32f469-disco.dts
@@ -81,3 +81,31 @@
 &usart3 {
 	status = "okay";
 };
+
+&timers1 {
+	status = "okay";
+
+	pwm {
+		pinctrl-0 = <&pwm1_pins>;
+		pinctrl-names = "default";
+		status = "okay";
+	};
+
+	timer@0 {
+		status = "okay";
+	};
+};
+
+&timers3 {
+	status = "okay";
+
+	pwm {
+		pinctrl-0 = <&pwm3_pins>;
+		pinctrl-names = "default";
+		status = "okay";
+	};
+
+	timer@2 {
+		status = "okay";
+	};
+};
-- 
1.9.1

Re: [PATCH v7 0/8] Add PWM and IIO timer drivers for STM32

[Lee Jones]

On Thu, 05 Jan 2017, Benjamin Gaignard wrote:

> version 7:
> - rebase on v4.10-rc2
> - remove iio_device code from driver and keep only the trigger part
> 
> version 6:
> - rename stm32-gptimer in stm32-timers.
> - change "st,stm32-gptimer" compatible to "st,stm32-timers".
> - modify "st,breakinput" parameter in pwm part.
> - split DT patch in 2
> 
> version 5:
> - fix comments done on version 4
> - rebased on kernel 4.9-rc8
> - change nodes names and re-order then by addresses
> 
> version 4:
> - fix comments done on version 3
> - don't use interrupts anymore in IIO timer
> - detect hardware capabilities at probe time to simplify binding
> 
> version 3:
> - no change on mfd and pwm divers patches
> - add cross reference between bindings
> - change compatible to "st,stm32-timer-trigger"
> - fix attributes access rights
> - use string instead of int for master_mode and slave_mode
> - document device attributes in sysfs-bus-iio-timer-stm32
> - update DT with the new compatible
> 
> version 2:
> - keep only one compatible per driver
> - use DT parameters to describe hardware block configuration:
>   - pwm channels, complementary output, counter size, break input
>   - triggers accepted and create by IIO timers
> - change DT to limite use of reference to the node
> - interrupt is now in IIO timer driver
> - rename stm32-mfd-timer to stm32-timers (for general purpose timer)
> 
> The following patches enable PWM and IIO Timer features for STM32 platforms.
> 
> Those two features are mixed into the registers of the same hardware block
> (named general purpose timer) which lead to introduce a multifunctions driver 
> on the top of them to be able to share the registers.
> 
> In STM32f4 14 instances of timer hardware block exist, even if they all have
> the same register mapping they could have a different number of pwm channels
> and/or different triggers capabilities. We use various parameters in DT to 
> describe the differences between hardware blocks
> 
> The MFD (stm32-timers.c) takes care of clock and register mapping
> by using regmap. stm32_timers structure is provided to its sub-node to
> share those information.
> 
> PWM driver is implemented into pwm-stm32.c. Depending of the instance we may
> have up to 4 channels, sometime with complementary outputs or 32 bits counter
> instead of 16 bits. Some hardware blocks may also have a break input function
> which allows to stop pwm depending of a level, defined in devicetree, on an
> external pin.
> 
> IIO timer driver (stm32-timer-trigger.c and stm32-timer-trigger.h) define a list
> of hardware triggers usable by hardware blocks like ADC, DAC or other timers. 
> 
> The matrix of possible connections between blocks is quite complex so we use 
> trigger names and is_stm32_iio_timer_trigger() function to be sure that
> triggers are valid and configure the IPs.
> 
> At run time IIO timer hardware blocks can configure (through "master_mode" 
> IIO device attribute) which internal signal (counter enable, reset,
> comparison block, etc...) is used to generate the trigger.
> 
> Benjamin Gaignard (8):
>   MFD: add bindings for STM32 Timers driver
>   MFD: add STM32 Timers driver
>   PWM: add pwm-stm32 DT bindings
>   PWM: add PWM driver for STM32 plaftorm
>   IIO: add bindings for STM32 timer trigger driver
>   IIO: add STM32 timer trigger driver
>   ARM: dts: stm32: add Timers driver for stm32f429 MCU
>   ARM: dts: stm32: Enable pwm1 and pwm3 for stm32f469-disco

Any reason why you've dropped all your Acks?

I don't really want to review it again if little is different.

How much MFD related code has changed since the last review?

>  .../ABI/testing/sysfs-bus-iio-timer-stm32          |  29 ++
>  .../bindings/iio/timer/stm32-timer-trigger.txt     |  23 ++
>  .../devicetree/bindings/mfd/stm32-timers.txt       |  46 +++
>  .../devicetree/bindings/pwm/pwm-stm32.txt          |  33 ++
>  arch/arm/boot/dts/stm32f429.dtsi                   | 275 +++++++++++++
>  arch/arm/boot/dts/stm32f469-disco.dts              |  28 ++
>  drivers/iio/Kconfig                                |   1 -
>  drivers/iio/trigger/Kconfig                        |  10 +
>  drivers/iio/trigger/Makefile                       |   1 +
>  drivers/iio/trigger/stm32-timer-trigger.c          | 340 ++++++++++++++++
>  drivers/mfd/Kconfig                                |  11 +
>  drivers/mfd/Makefile                               |   2 +
>  drivers/mfd/stm32-timers.c                         |  80 ++++
>  drivers/pwm/Kconfig                                |   9 +
>  drivers/pwm/Makefile                               |   1 +
>  drivers/pwm/pwm-stm32.c                            | 434 +++++++++++++++++++++
>  include/linux/iio/timer/stm32-timer-trigger.h      |  62 +++
>  include/linux/mfd/stm32-timers.h                   |  71 ++++
>  18 files changed, 1455 insertions(+), 1 deletion(-)
>  create mode 100644 Documentation/ABI/testing/sysfs-bus-iio-timer-stm32
>  create mode 100644 Documentation/devicetree/bindings/iio/timer/stm32-timer-trigger.txt
>  create mode 100644 Documentation/devicetree/bindings/mfd/stm32-timers.txt
>  create mode 100644 Documentation/devicetree/bindings/pwm/pwm-stm32.txt
>  create mode 100644 drivers/iio/trigger/stm32-timer-trigger.c
>  create mode 100644 drivers/mfd/stm32-timers.c
>  create mode 100644 drivers/pwm/pwm-stm32.c
>  create mode 100644 include/linux/iio/timer/stm32-timer-trigger.h
>  create mode 100644 include/linux/mfd/stm32-timers.h
> 

-- 
Lee Jones
Linaro STMicroelectronics Landing Team Lead
Linaro.org │ Open source software for ARM SoCs
Follow Linaro: Facebook | Twitter | Blog

Re: [PATCH v7 0/8] Add PWM and IIO timer drivers for STM32

[Benjamin Gaignard]

2017-01-05 15:49 GMT+01:00 Lee Jones <lee.jones@linaro.org>:
> On Thu, 05 Jan 2017, Benjamin Gaignard wrote:
>
>> version 7:
>> - rebase on v4.10-rc2
>> - remove iio_device code from driver and keep only the trigger part
>>
>> version 6:
>> - rename stm32-gptimer in stm32-timers.
>> - change "st,stm32-gptimer" compatible to "st,stm32-timers".
>> - modify "st,breakinput" parameter in pwm part.
>> - split DT patch in 2
>>
>> version 5:
>> - fix comments done on version 4
>> - rebased on kernel 4.9-rc8
>> - change nodes names and re-order then by addresses
>>
>> version 4:
>> - fix comments done on version 3
>> - don't use interrupts anymore in IIO timer
>> - detect hardware capabilities at probe time to simplify binding
>>
>> version 3:
>> - no change on mfd and pwm divers patches
>> - add cross reference between bindings
>> - change compatible to "st,stm32-timer-trigger"
>> - fix attributes access rights
>> - use string instead of int for master_mode and slave_mode
>> - document device attributes in sysfs-bus-iio-timer-stm32
>> - update DT with the new compatible
>>
>> version 2:
>> - keep only one compatible per driver
>> - use DT parameters to describe hardware block configuration:
>>   - pwm channels, complementary output, counter size, break input
>>   - triggers accepted and create by IIO timers
>> - change DT to limite use of reference to the node
>> - interrupt is now in IIO timer driver
>> - rename stm32-mfd-timer to stm32-timers (for general purpose timer)
>>
>> The following patches enable PWM and IIO Timer features for STM32 platforms.
>>
>> Those two features are mixed into the registers of the same hardware block
>> (named general purpose timer) which lead to introduce a multifunctions driver
>> on the top of them to be able to share the registers.
>>
>> In STM32f4 14 instances of timer hardware block exist, even if they all have
>> the same register mapping they could have a different number of pwm channels
>> and/or different triggers capabilities. We use various parameters in DT to
>> describe the differences between hardware blocks
>>
>> The MFD (stm32-timers.c) takes care of clock and register mapping
>> by using regmap. stm32_timers structure is provided to its sub-node to
>> share those information.
>>
>> PWM driver is implemented into pwm-stm32.c. Depending of the instance we may
>> have up to 4 channels, sometime with complementary outputs or 32 bits counter
>> instead of 16 bits. Some hardware blocks may also have a break input function
>> which allows to stop pwm depending of a level, defined in devicetree, on an
>> external pin.
>>
>> IIO timer driver (stm32-timer-trigger.c and stm32-timer-trigger.h) define a list
>> of hardware triggers usable by hardware blocks like ADC, DAC or other timers.
>>
>> The matrix of possible connections between blocks is quite complex so we use
>> trigger names and is_stm32_iio_timer_trigger() function to be sure that
>> triggers are valid and configure the IPs.
>>
>> At run time IIO timer hardware blocks can configure (through "master_mode"
>> IIO device attribute) which internal signal (counter enable, reset,
>> comparison block, etc...) is used to generate the trigger.
>>
>> Benjamin Gaignard (8):
>>   MFD: add bindings for STM32 Timers driver
>>   MFD: add STM32 Timers driver
>>   PWM: add pwm-stm32 DT bindings
>>   PWM: add PWM driver for STM32 plaftorm
>>   IIO: add bindings for STM32 timer trigger driver
>>   IIO: add STM32 timer trigger driver
>>   ARM: dts: stm32: add Timers driver for stm32f429 MCU
>>   ARM: dts: stm32: Enable pwm1 and pwm3 for stm32f469-disco
>
> Any reason why you've dropped all your Acks?
>
> I don't really want to review it again if little is different.
>
> How much MFD related code has changed since the last review?

All my apologies I forgot to add your Acks for MFD parts.

Sorry for that

>
>>  .../ABI/testing/sysfs-bus-iio-timer-stm32          |  29 ++
>>  .../bindings/iio/timer/stm32-timer-trigger.txt     |  23 ++
>>  .../devicetree/bindings/mfd/stm32-timers.txt       |  46 +++
>>  .../devicetree/bindings/pwm/pwm-stm32.txt          |  33 ++
>>  arch/arm/boot/dts/stm32f429.dtsi                   | 275 +++++++++++++
>>  arch/arm/boot/dts/stm32f469-disco.dts              |  28 ++
>>  drivers/iio/Kconfig                                |   1 -
>>  drivers/iio/trigger/Kconfig                        |  10 +
>>  drivers/iio/trigger/Makefile                       |   1 +
>>  drivers/iio/trigger/stm32-timer-trigger.c          | 340 ++++++++++++++++
>>  drivers/mfd/Kconfig                                |  11 +
>>  drivers/mfd/Makefile                               |   2 +
>>  drivers/mfd/stm32-timers.c                         |  80 ++++
>>  drivers/pwm/Kconfig                                |   9 +
>>  drivers/pwm/Makefile                               |   1 +
>>  drivers/pwm/pwm-stm32.c                            | 434 +++++++++++++++++++++
>>  include/linux/iio/timer/stm32-timer-trigger.h      |  62 +++
>>  include/linux/mfd/stm32-timers.h                   |  71 ++++
>>  18 files changed, 1455 insertions(+), 1 deletion(-)
>>  create mode 100644 Documentation/ABI/testing/sysfs-bus-iio-timer-stm32
>>  create mode 100644 Documentation/devicetree/bindings/iio/timer/stm32-timer-trigger.txt
>>  create mode 100644 Documentation/devicetree/bindings/mfd/stm32-timers.txt
>>  create mode 100644 Documentation/devicetree/bindings/pwm/pwm-stm32.txt
>>  create mode 100644 drivers/iio/trigger/stm32-timer-trigger.c
>>  create mode 100644 drivers/mfd/stm32-timers.c
>>  create mode 100644 drivers/pwm/pwm-stm32.c
>>  create mode 100644 include/linux/iio/timer/stm32-timer-trigger.h
>>  create mode 100644 include/linux/mfd/stm32-timers.h
>>
>
> --
> Lee Jones
> Linaro STMicroelectronics Landing Team Lead
> Linaro.org │ Open source software for ARM SoCs
> Follow Linaro: Facebook | Twitter | Blog



-- 
Benjamin Gaignard

Graphic Study Group

Linaro.org │ Open source software for ARM SoCs

Follow Linaro: Facebook | Twitter | Blog

Re: [PATCH v7 5/8] IIO: add bindings for STM32 timer trigger driver

[Jonathan Cameron]

On 05/01/17 09:25, Benjamin Gaignard wrote:
> Define bindings for STM32 timer trigger
> 
> version 4:
> - remove triggers enumeration from DT
> - add reg parameter
> 
> version 3:
> - change file name
> - add cross reference with mfd bindings
> 
> version 2:
> - only keep one compatible
> - add DT parameters to set lists of the triggers:
>   one list describe the triggers created by the device
>   another one give the triggers accepted by the device
> 
> Signed-off-by: Benjamin Gaignard <benjamin.gaignard@st.com>
Acked-by: Jonathan Cameron <jic23@kernel.org>
> ---
>  .../bindings/iio/timer/stm32-timer-trigger.txt     | 23 ++++++++++++++++++++++
>  1 file changed, 23 insertions(+)
>  create mode 100644 Documentation/devicetree/bindings/iio/timer/stm32-timer-trigger.txt
> 
> diff --git a/Documentation/devicetree/bindings/iio/timer/stm32-timer-trigger.txt b/Documentation/devicetree/bindings/iio/timer/stm32-timer-trigger.txt
> new file mode 100644
> index 0000000..36a6c4a
> --- /dev/null
> +++ b/Documentation/devicetree/bindings/iio/timer/stm32-timer-trigger.txt
> @@ -0,0 +1,23 @@
> +STMicroelectronics STM32 Timers IIO timer bindings
> +
> +Must be a sub-node of an STM32 Timers device tree node.
> +See ../mfd/stm32-timers.txt for details about the parent node.
> +
> +Required parameters:
> +- compatible:	Must be "st,stm32-timer-trigger".
> +- reg:		Define triggers configuration of the hardware IP.
> +
> +Example:
> +	timers@40010000 {
> +		#address-cells = <1>;
> +		#size-cells = <0>;
> +		compatible = "st,stm32-timers";
> +		reg = <0x40010000 0x400>;
> +		clocks = <&rcc 0 160>;
> +		clock-names = "clk_int";
> +
> +		timer {
> +			compatible = "st,stm32-timer-trigger";
> +			reg = <0>;
> +		};
> +	};
> 

Re: [PATCH v7 6/8] IIO: add STM32 timer trigger driver

[Jonathan Cameron]

On 05/01/17 09:25, Benjamin Gaignard wrote:
> Timers IPs can be used to generate triggers for other IPs like
> DAC or ADC.
> Each trigger may result of timer internals signals like counter enable,
> reset or edge, this configuration could be done through "master_mode"
> device attribute.
> 
> Since triggers could be used by DAC or ADC their names are defined
> in include/ nux/iio/timer/stm32-timer-trigger.h and is_stm32_iio_timer_trigger
> function could be used to check if the trigger is valid or not.
> 
> "trgo" trigger have a "sampling_frequency" attribute which allow to configure
> timer sampling frequency.
> 
> version 7:
> - remove all iio_device related code
> - move driver into trigger directory
> 
> version 5:
> - simplify tables of triggers
> - only create an IIO device when needed
> 
> version 4:
> - get triggers configuration from "reg" in DT
> - add tables of triggers
> - sampling frequency is enable/disable when writing in trigger
>   sampling_frequency attribute
> - no more use of interruptions
> 
> version 3:
> - change compatible to "st,stm32-timer-trigger"
> - fix attributes access right
> - use string instead of int for master_mode and slave_mode
> - document device attributes in sysfs-bus-iio-timer-stm32
> 
> version 2:
> - keep only one compatible
> - use st,input-triggers-names and st,output-triggers-names
>   to know which triggers are accepted and/or create by the device
> 
> Signed-off-by: Benjamin Gaignard <benjamin.gaignard@st.com>
One line snuck in that shouldn't be there (the one in iio/Kconfig).
Other than that

Acked-by: Jonathan Cameron <jic23@kernel.org>

I didn't get a chance to look at doing trigger trees unfortunately.
Not sure when I'll next get a window to work on new stuff.

Thanks,

Jonathan

> ---
>  .../ABI/testing/sysfs-bus-iio-timer-stm32          |  29 ++
>  drivers/iio/Kconfig                                |   1 -
>  drivers/iio/trigger/Kconfig                        |  10 +
>  drivers/iio/trigger/Makefile                       |   1 +
>  drivers/iio/trigger/stm32-timer-trigger.c          | 340 +++++++++++++++++++++
>  include/linux/iio/timer/stm32-timer-trigger.h      |  62 ++++
>  6 files changed, 442 insertions(+), 1 deletion(-)
>  create mode 100644 Documentation/ABI/testing/sysfs-bus-iio-timer-stm32
>  create mode 100644 drivers/iio/trigger/stm32-timer-trigger.c
>  create mode 100644 include/linux/iio/timer/stm32-timer-trigger.h
> 
> diff --git a/Documentation/ABI/testing/sysfs-bus-iio-timer-stm32 b/Documentation/ABI/testing/sysfs-bus-iio-timer-stm32
> new file mode 100644
> index 0000000..a7f5177
> --- /dev/null
> +++ b/Documentation/ABI/testing/sysfs-bus-iio-timer-stm32
> @@ -0,0 +1,29 @@
> +What:		/sys/bus/iio/devices/triggerX/master_mode_available
> +KernelVersion:	4.10
> +Contact:	benjamin.gaignard@st.com
> +Description:
> +		Reading returns the list possible master modes which are:
> +		- "reset"     :	The UG bit from the TIMx_EGR register is used as trigger output (TRGO).
> +		- "enable"    : The Counter Enable signal CNT_EN is used as trigger output.
> +		- "update"    : The update event is selected as trigger output.
> +				For instance a master timer can then be used as a prescaler for a slave timer.
> +		- "compare_pulse" : The trigger output send a positive pulse when the CC1IF flag is to be set.
> +		- "OC1REF"    : OC1REF signal is used as trigger output.
> +		- "OC2REF"    : OC2REF signal is used as trigger output.
> +		- "OC3REF"    : OC3REF signal is used as trigger output.
> +		- "OC4REF"    : OC4REF signal is used as trigger output.
> +
> +What:		/sys/bus/iio/devices/triggerX/master_mode
> +KernelVersion:	4.10
> +Contact:	benjamin.gaignard@st.com
> +Description:
> +		Reading returns the current master modes.
> +		Writing set the master mode
> +
> +What:		/sys/bus/iio/devices/triggerX/sampling_frequency
> +KernelVersion:	4.10
> +Contact:	benjamin.gaignard@st.com
> +Description:
> +		Reading returns the current sampling frequency.
> +		Writing an value different of 0 set and start sampling.
> +		Writing 0 stop sampling.
> diff --git a/drivers/iio/Kconfig b/drivers/iio/Kconfig
> index a918270..6b0c427 100644
> --- a/drivers/iio/Kconfig
> +++ b/drivers/iio/Kconfig
> @@ -92,5 +92,4 @@ source "drivers/iio/potentiostat/Kconfig"
>  source "drivers/iio/pressure/Kconfig"
>  source "drivers/iio/proximity/Kconfig"
>  source "drivers/iio/temperature/Kconfig"
> -
Please fix this!!
>  endif # IIO
> diff --git a/drivers/iio/trigger/Kconfig b/drivers/iio/trigger/Kconfig
> index 809b2e7..72d3a32 100644
> --- a/drivers/iio/trigger/Kconfig
> +++ b/drivers/iio/trigger/Kconfig
> @@ -24,6 +24,16 @@ config IIO_INTERRUPT_TRIGGER
>  	  To compile this driver as a module, choose M here: the
>  	  module will be called iio-trig-interrupt.
>  
> +config IIO_STM32_TIMER_TRIGGER
> +	tristate "STM32 Timer Trigger"
> +	depends on (ARCH_STM32 && OF && MFD_STM32_TIMERS) || COMPILE_TEST
> +	help
> +	  Select this option to enable STM32 Timer Trigger
> +
> +	  To compile this driver as a module, choose M here: the
> +	  module will be called stm32-timer-trigger.
> +
> +
>  config IIO_TIGHTLOOP_TRIGGER
>  	tristate "A kthread based hammering loop trigger"
>  	depends on IIO_SW_TRIGGER
> diff --git a/drivers/iio/trigger/Makefile b/drivers/iio/trigger/Makefile
> index aab4dc2..5c4ecd3 100644
> --- a/drivers/iio/trigger/Makefile
> +++ b/drivers/iio/trigger/Makefile
> @@ -6,5 +6,6 @@
>  
>  obj-$(CONFIG_IIO_HRTIMER_TRIGGER) += iio-trig-hrtimer.o
>  obj-$(CONFIG_IIO_INTERRUPT_TRIGGER) += iio-trig-interrupt.o
> +obj-$(CONFIG_IIO_STM32_TIMER_TRIGGER) += stm32-timer-trigger.o
>  obj-$(CONFIG_IIO_SYSFS_TRIGGER) += iio-trig-sysfs.o
>  obj-$(CONFIG_IIO_TIGHTLOOP_TRIGGER) += iio-trig-loop.o
> diff --git a/drivers/iio/trigger/stm32-timer-trigger.c b/drivers/iio/trigger/stm32-timer-trigger.c
> new file mode 100644
> index 0000000..409fb0c
> --- /dev/null
> +++ b/drivers/iio/trigger/stm32-timer-trigger.c
> @@ -0,0 +1,340 @@
> +/*
> + * Copyright (C) STMicroelectronics 2016
> + *
> + * Author: Benjamin Gaignard <benjamin.gaignard@st.com>
> + *
> + * License terms:  GNU General Public License (GPL), version 2
> + */
> +
> +#include <linux/iio/iio.h>
> +#include <linux/iio/sysfs.h>
> +#include <linux/iio/timer/stm32-timer-trigger.h>
> +#include <linux/iio/trigger.h>
> +#include <linux/mfd/stm32-timers.h>
> +#include <linux/module.h>
> +#include <linux/platform_device.h>
> +
> +#define MAX_TRIGGERS 6
> +
> +/* List the triggers created by each timer */
> +static const void *triggers_table[][MAX_TRIGGERS] = {
> +	{ TIM1_TRGO, TIM1_CH1, TIM1_CH2, TIM1_CH3, TIM1_CH4,},
> +	{ TIM2_TRGO, TIM2_CH1, TIM2_CH2, TIM2_CH3, TIM2_CH4,},
> +	{ TIM3_TRGO, TIM3_CH1, TIM3_CH2, TIM3_CH3, TIM3_CH4,},
> +	{ TIM4_TRGO, TIM4_CH1, TIM4_CH2, TIM4_CH3, TIM4_CH4,},
> +	{ TIM5_TRGO, TIM5_CH1, TIM5_CH2, TIM5_CH3, TIM5_CH4,},
> +	{ TIM6_TRGO,},
> +	{ TIM7_TRGO,},
> +	{ TIM8_TRGO, TIM8_CH1, TIM8_CH2, TIM8_CH3, TIM8_CH4,},
> +	{ TIM9_TRGO, TIM9_CH1, TIM9_CH2,},
> +	{ TIM12_TRGO, TIM12_CH1, TIM12_CH2,},
> +};
> +
> +struct stm32_timer_trigger {
> +	struct device *dev;
> +	struct regmap *regmap;
> +	struct clk *clk;
> +	u32 max_arr;
> +	const void *triggers;
> +};
> +
> +static int stm32_timer_start(struct stm32_timer_trigger *priv,
> +			     unsigned int frequency)
> +{
> +	unsigned long long prd, div;
> +	int prescaler = 0;
> +	u32 ccer, cr1;
> +
> +	/* Period and prescaler values depends of clock rate */
> +	div = (unsigned long long)clk_get_rate(priv->clk);
> +
> +	do_div(div, frequency);
> +
> +	prd = div;
> +
> +	/*
> +	 * Increase prescaler value until we get a result that fit
> +	 * with auto reload register maximum value.
> +	 */
> +	while (div > priv->max_arr) {
> +		prescaler++;
> +		div = prd;
> +		do_div(div, (prescaler + 1));
> +	}
> +	prd = div;
> +
> +	if (prescaler > MAX_TIM_PSC) {
> +		dev_err(priv->dev, "prescaler exceeds the maximum value\n");
> +		return -EINVAL;
> +	}
> +
> +	/* Check if nobody else use the timer */
> +	regmap_read(priv->regmap, TIM_CCER, &ccer);
> +	if (ccer & TIM_CCER_CCXE)
> +		return -EBUSY;
> +
> +	regmap_read(priv->regmap, TIM_CR1, &cr1);
> +	if (!(cr1 & TIM_CR1_CEN))
> +		clk_enable(priv->clk);
> +
> +	regmap_write(priv->regmap, TIM_PSC, prescaler);
> +	regmap_write(priv->regmap, TIM_ARR, prd - 1);
> +	regmap_update_bits(priv->regmap, TIM_CR1, TIM_CR1_ARPE, TIM_CR1_ARPE);
> +
> +	/* Force master mode to update mode */
> +	regmap_update_bits(priv->regmap, TIM_CR2, TIM_CR2_MMS, 0x20);
> +
> +	/* Make sure that registers are updated */
> +	regmap_update_bits(priv->regmap, TIM_EGR, TIM_EGR_UG, TIM_EGR_UG);
> +
> +	/* Enable controller */
> +	regmap_update_bits(priv->regmap, TIM_CR1, TIM_CR1_CEN, TIM_CR1_CEN);
> +
> +	return 0;
> +}
> +
> +static void stm32_timer_stop(struct stm32_timer_trigger *priv)
> +{
> +	u32 ccer, cr1;
> +
> +	regmap_read(priv->regmap, TIM_CCER, &ccer);
> +	if (ccer & TIM_CCER_CCXE)
> +		return;
> +
> +	regmap_read(priv->regmap, TIM_CR1, &cr1);
> +	if (cr1 & TIM_CR1_CEN)
> +		clk_disable(priv->clk);
> +
> +	/* Stop timer */
> +	regmap_update_bits(priv->regmap, TIM_CR1, TIM_CR1_CEN, 0);
> +	regmap_write(priv->regmap, TIM_PSC, 0);
> +	regmap_write(priv->regmap, TIM_ARR, 0);
> +
> +	/* Make sure that registers are updated */
> +	regmap_update_bits(priv->regmap, TIM_EGR, TIM_EGR_UG, TIM_EGR_UG);
> +}
> +
> +static ssize_t stm32_tt_store_frequency(struct device *dev,
> +					struct device_attribute *attr,
> +					const char *buf, size_t len)
> +{
> +	struct iio_trigger *trig = to_iio_trigger(dev);
> +	struct stm32_timer_trigger *priv = iio_trigger_get_drvdata(trig);
> +	unsigned int freq;
> +	int ret;
> +
> +	ret = kstrtouint(buf, 10, &freq);
> +	if (ret)
> +		return ret;
> +
> +	if (freq == 0) {
> +		stm32_timer_stop(priv);
> +	} else {
> +		ret = stm32_timer_start(priv, freq);
> +		if (ret)
> +			return ret;
> +	}
> +
> +	return len;
> +}
> +
> +static ssize_t stm32_tt_read_frequency(struct device *dev,
> +				       struct device_attribute *attr, char *buf)
> +{
> +	struct iio_trigger *trig = to_iio_trigger(dev);
> +	struct stm32_timer_trigger *priv = iio_trigger_get_drvdata(trig);
> +	u32 psc, arr, cr1;
> +	unsigned long long freq = 0;
> +
> +	regmap_read(priv->regmap, TIM_CR1, &cr1);
> +	regmap_read(priv->regmap, TIM_PSC, &psc);
> +	regmap_read(priv->regmap, TIM_ARR, &arr);
> +
> +	if (psc && arr && (cr1 & TIM_CR1_CEN)) {
> +		freq = (unsigned long long)clk_get_rate(priv->clk);
> +		do_div(freq, psc);
> +		do_div(freq, arr);
> +	}
> +
> +	return sprintf(buf, "%d\n", (unsigned int)freq);
> +}
> +
> +static IIO_DEV_ATTR_SAMP_FREQ(0660,
> +			      stm32_tt_read_frequency,
> +			      stm32_tt_store_frequency);
> +
> +static char *master_mode_table[] = {
> +	"reset",
> +	"enable",
> +	"update",
> +	"compare_pulse",
> +	"OC1REF",
> +	"OC2REF",
> +	"OC3REF",
> +	"OC4REF"
> +};
> +
> +static ssize_t stm32_tt_show_master_mode(struct device *dev,
> +					 struct device_attribute *attr,
> +					 char *buf)
> +{
> +	struct iio_dev *indio_dev = dev_to_iio_dev(dev);
> +	struct stm32_timer_trigger *priv = iio_priv(indio_dev);
> +	u32 cr2;
> +
> +	regmap_read(priv->regmap, TIM_CR2, &cr2);
> +	cr2 = (cr2 & TIM_CR2_MMS) >> TIM_CR2_MMS_SHIFT;
> +
> +	return snprintf(buf, PAGE_SIZE, "%s\n", master_mode_table[cr2]);
> +}
> +
> +static ssize_t stm32_tt_store_master_mode(struct device *dev,
> +					  struct device_attribute *attr,
> +					  const char *buf, size_t len)
> +{
> +	struct iio_dev *indio_dev = dev_to_iio_dev(dev);
> +	struct stm32_timer_trigger *priv = iio_priv(indio_dev);
> +	int i;
> +
> +	for (i = 0; i < ARRAY_SIZE(master_mode_table); i++) {
> +		if (!strncmp(master_mode_table[i], buf,
> +			     strlen(master_mode_table[i]))) {
> +			regmap_update_bits(priv->regmap, TIM_CR2,
> +					   TIM_CR2_MMS, i << TIM_CR2_MMS_SHIFT);
> +			/* Make sure that registers are updated */
> +			regmap_update_bits(priv->regmap, TIM_EGR,
> +					   TIM_EGR_UG, TIM_EGR_UG);
> +			return len;
> +		}
> +	}
> +
> +	return -EINVAL;
> +}
> +
> +static IIO_CONST_ATTR(master_mode_available,
> +	"reset enable update compare_pulse OC1REF OC2REF OC3REF OC4REF");
> +
> +static IIO_DEVICE_ATTR(master_mode, 0660,
> +		       stm32_tt_show_master_mode,
> +		       stm32_tt_store_master_mode,
> +		       0);
> +
> +static struct attribute *stm32_trigger_attrs[] = {
> +	&iio_dev_attr_sampling_frequency.dev_attr.attr,
> +	&iio_dev_attr_master_mode.dev_attr.attr,
> +	&iio_const_attr_master_mode_available.dev_attr.attr,
> +	NULL,
> +};
> +
> +static const struct attribute_group stm32_trigger_attr_group = {
> +	.attrs = stm32_trigger_attrs,
> +};
> +
> +static const struct attribute_group *stm32_trigger_attr_groups[] = {
> +	&stm32_trigger_attr_group,
> +	NULL,
> +};
> +
> +static const struct iio_trigger_ops timer_trigger_ops = {
> +	.owner = THIS_MODULE,
> +};
> +
> +static int stm32_setup_iio_triggers(struct stm32_timer_trigger *priv)
> +{
> +	int ret;
> +	const char * const *cur = priv->triggers;
> +
> +	while (cur && *cur) {
> +		struct iio_trigger *trig;
> +
> +		trig = devm_iio_trigger_alloc(priv->dev, "%s", *cur);
> +		if  (!trig)
> +			return -ENOMEM;
> +
> +		trig->dev.parent = priv->dev->parent;
> +		trig->ops = &timer_trigger_ops;
> +
> +		/*
> +		 * sampling frequency and master mode attributes
> +		 * should only be available on trgo trigger which
> +		 * is always the first in the list.
> +		 */
> +		if (cur == priv->triggers)
> +			trig->dev.groups = stm32_trigger_attr_groups;
> +
> +		iio_trigger_set_drvdata(trig, priv);
> +
> +		ret = devm_iio_trigger_register(priv->dev, trig);
> +		if (ret)
> +			return ret;
> +		cur++;
> +	}
> +
> +	return 0;
> +}
> +
> +/**
> + * is_stm32_timer_trigger
> + * @trig: trigger to be checked
> + *
> + * return true if the trigger is a valid stm32 iio timer trigger
> + * either return false
> + */
> +bool is_stm32_timer_trigger(struct iio_trigger *trig)
> +{
> +	return (trig->ops == &timer_trigger_ops);
> +}
> +EXPORT_SYMBOL(is_stm32_timer_trigger);
> +
> +static int stm32_timer_trigger_probe(struct platform_device *pdev)
> +{
> +	struct device *dev = &pdev->dev;
> +	struct stm32_timer_trigger *priv;
> +	struct stm32_timers *ddata = dev_get_drvdata(pdev->dev.parent);
> +	unsigned int index;
> +	int ret;
> +
> +	if (of_property_read_u32(dev->of_node, "reg", &index))
> +		return -EINVAL;
> +
> +	if (index >= ARRAY_SIZE(triggers_table))
> +		return -EINVAL;
> +
> +	priv = devm_kzalloc(dev, sizeof(*priv), GFP_KERNEL);
> +
> +	if (!priv)
> +		return -ENOMEM;
> +
> +	priv->dev = dev;
> +	priv->regmap = ddata->regmap;
> +	priv->clk = ddata->clk;
> +	priv->max_arr = ddata->max_arr;
> +	priv->triggers = triggers_table[index];
> +
> +	ret = stm32_setup_iio_triggers(priv);
> +	if (ret)
> +		return ret;
> +
> +	platform_set_drvdata(pdev, priv);
> +
> +	return 0;
> +}
> +
> +static const struct of_device_id stm32_trig_of_match[] = {
> +	{ .compatible = "st,stm32-timer-trigger", },
> +	{ /* end node */ },
> +};
> +MODULE_DEVICE_TABLE(of, stm32_trig_of_match);
> +
> +static struct platform_driver stm32_timer_trigger_driver = {
> +	.probe = stm32_timer_trigger_probe,
> +	.driver = {
> +		.name = "stm32-timer-trigger",
> +		.of_match_table = stm32_trig_of_match,
> +	},
> +};
> +module_platform_driver(stm32_timer_trigger_driver);
> +
> +MODULE_ALIAS("platform: stm32-timer-trigger");
> +MODULE_DESCRIPTION("STMicroelectronics STM32 Timer Trigger driver");
> +MODULE_LICENSE("GPL v2");
> diff --git a/include/linux/iio/timer/stm32-timer-trigger.h b/include/linux/iio/timer/stm32-timer-trigger.h
> new file mode 100644
> index 0000000..55535ae
> --- /dev/null
> +++ b/include/linux/iio/timer/stm32-timer-trigger.h
> @@ -0,0 +1,62 @@
> +/*
> + * Copyright (C) STMicroelectronics 2016
> + *
> + * Author: Benjamin Gaignard <benjamin.gaignard@st.com>
> + *
> + * License terms:  GNU General Public License (GPL), version 2
> + */
> +
> +#ifndef _STM32_TIMER_TRIGGER_H_
> +#define _STM32_TIMER_TRIGGER_H_
> +
> +#define TIM1_TRGO	"tim1_trgo"
> +#define TIM1_CH1	"tim1_ch1"
> +#define TIM1_CH2	"tim1_ch2"
> +#define TIM1_CH3	"tim1_ch3"
> +#define TIM1_CH4	"tim1_ch4"
> +
> +#define TIM2_TRGO	"tim2_trgo"
> +#define TIM2_CH1	"tim2_ch1"
> +#define TIM2_CH2	"tim2_ch2"
> +#define TIM2_CH3	"tim2_ch3"
> +#define TIM2_CH4	"tim2_ch4"
> +
> +#define TIM3_TRGO	"tim3_trgo"
> +#define TIM3_CH1	"tim3_ch1"
> +#define TIM3_CH2	"tim3_ch2"
> +#define TIM3_CH3	"tim3_ch3"
> +#define TIM3_CH4	"tim3_ch4"
> +
> +#define TIM4_TRGO	"tim4_trgo"
> +#define TIM4_CH1	"tim4_ch1"
> +#define TIM4_CH2	"tim4_ch2"
> +#define TIM4_CH3	"tim4_ch3"
> +#define TIM4_CH4	"tim4_ch4"
> +
> +#define TIM5_TRGO	"tim5_trgo"
> +#define TIM5_CH1	"tim5_ch1"
> +#define TIM5_CH2	"tim5_ch2"
> +#define TIM5_CH3	"tim5_ch3"
> +#define TIM5_CH4	"tim5_ch4"
> +
> +#define TIM6_TRGO	"tim6_trgo"
> +
> +#define TIM7_TRGO	"tim7_trgo"
> +
> +#define TIM8_TRGO	"tim8_trgo"
> +#define TIM8_CH1	"tim8_ch1"
> +#define TIM8_CH2	"tim8_ch2"
> +#define TIM8_CH3	"tim8_ch3"
> +#define TIM8_CH4	"tim8_ch4"
> +
> +#define TIM9_TRGO	"tim9_trgo"
> +#define TIM9_CH1	"tim9_ch1"
> +#define TIM9_CH2	"tim9_ch2"
> +
> +#define TIM12_TRGO	"tim12_trgo"
> +#define TIM12_CH1	"tim12_ch1"
> +#define TIM12_CH2	"tim12_ch2"
> +
> +bool is_stm32_timer_trigger(struct iio_trigger *trig);
> +
> +#endif
> 

Re: [PATCH v7 1/8] MFD: add bindings for STM32 Timers driver

[Rob Herring]

On Thu, Jan 05, 2017 at 10:25:37AM +0100, Benjamin Gaignard wrote:
> Add bindings information for STM32 Timers
> 
> version 6:
> - rename stm32-gtimer to stm32-timers
> - change compatible
> - add description about the IPs
> 
> version 2:
> - rename stm32-mfd-timer to stm32-gptimer
> - only keep one compatible string
> 
> Signed-off-by: Benjamin Gaignard <benjamin.gaignard@st.com>
> ---
>  .../devicetree/bindings/mfd/stm32-timers.txt       | 46 ++++++++++++++++++++++
>  1 file changed, 46 insertions(+)
>  create mode 100644 Documentation/devicetree/bindings/mfd/stm32-timers.txt

Acked-by: Rob Herring <robh@kernel.org>

Re: [PATCH v7 2/8] MFD: add STM32 Timers driver

[Rob Herring]

On Thu, Jan 05, 2017 at 10:25:38AM +0100, Benjamin Gaignard wrote:
> This hardware block could at used at same time for PWM generation
> and IIO timers.
> PWM and IIO timer configuration are mixed in the same registers
> so we need a multi fonction driver to be able to share those registers.
> 
> version 7:
> - rebase on v4.10-rc2
> 
> version 6:
> - rename files to stm32-timers
> - rename functions to stm32_timers_xxx
> 
> version 5:
> - fix Lee comments about detect function
> - add missing dependency on REGMAP_MMIO
> 
> version 4:
> - add a function to detect Auto Reload Register (ARR) size
> - rename the structure shared with other drivers
> 
> version 2:
> - rename driver "stm32-gptimer" to be align with SoC documentation
> - only keep one compatible
> - use of_platform_populate() instead of devm_mfd_add_devices()
> 
> Signed-off-by: Benjamin Gaignard <benjamin.gaignard@st.com>
> ---
>  .../devicetree/bindings/mfd/stm32-timers.txt       |  2 +-
>  drivers/mfd/Kconfig                                | 11 +++
>  drivers/mfd/Makefile                               |  2 +
>  drivers/mfd/stm32-timers.c                         | 80 ++++++++++++++++++++++
>  include/linux/mfd/stm32-timers.h                   | 71 +++++++++++++++++++
>  5 files changed, 165 insertions(+), 1 deletion(-)
>  create mode 100644 drivers/mfd/stm32-timers.c
>  create mode 100644 include/linux/mfd/stm32-timers.h
> 
> diff --git a/Documentation/devicetree/bindings/mfd/stm32-timers.txt b/Documentation/devicetree/bindings/mfd/stm32-timers.txt
> index a73301d..897e7c2 100644
> --- a/Documentation/devicetree/bindings/mfd/stm32-timers.txt
> +++ b/Documentation/devicetree/bindings/mfd/stm32-timers.txt
> @@ -12,7 +12,7 @@ Required parameters:
>  
>  - reg:			Physical base address and length of the controller's
>  			registers.
> -- clock-names: 		Set to "int".
> +- clock-names:		Set to "int".

This hunk should be dropped or moved to previous patch.

>  - clocks: 		Phandle to the clock used by the timer module.
>  			For Clk properties, please refer to ../clock/clock-bindings.txt
>  

Re: [PATCH v7 3/8] PWM: add pwm-stm32 DT bindings

[Rob Herring]

On Thu, Jan 05, 2017 at 10:25:39AM +0100, Benjamin Gaignard wrote:
> Define bindings for pwm-stm32
> 
> version 6:
> - change st,breakinput parameter format to make it usuable on stm32f7 too.
> 
> version 2:
> - use parameters instead of compatible of handle the hardware configuration
> 
> Signed-off-by: Benjamin Gaignard <benjamin.gaignard@st.com>
> ---
>  .../devicetree/bindings/pwm/pwm-stm32.txt          | 33 ++++++++++++++++++++++
>  1 file changed, 33 insertions(+)
>  create mode 100644 Documentation/devicetree/bindings/pwm/pwm-stm32.txt

Acked-by: Rob Herring <robh@kernel.org>

Re: [PATCH v7 5/8] IIO: add bindings for STM32 timer trigger driver

[Rob Herring]

On Thu, Jan 05, 2017 at 10:25:41AM +0100, Benjamin Gaignard wrote:
> Define bindings for STM32 timer trigger
> 
> version 4:
> - remove triggers enumeration from DT
> - add reg parameter
> 
> version 3:
> - change file name
> - add cross reference with mfd bindings
> 
> version 2:
> - only keep one compatible
> - add DT parameters to set lists of the triggers:
>   one list describe the triggers created by the device
>   another one give the triggers accepted by the device
> 
> Signed-off-by: Benjamin Gaignard <benjamin.gaignard@st.com>
> ---
>  .../bindings/iio/timer/stm32-timer-trigger.txt     | 23 ++++++++++++++++++++++
>  1 file changed, 23 insertions(+)
>  create mode 100644 Documentation/devicetree/bindings/iio/timer/stm32-timer-trigger.txt
> 
> diff --git a/Documentation/devicetree/bindings/iio/timer/stm32-timer-trigger.txt b/Documentation/devicetree/bindings/iio/timer/stm32-timer-trigger.txt
> new file mode 100644
> index 0000000..36a6c4a
> --- /dev/null
> +++ b/Documentation/devicetree/bindings/iio/timer/stm32-timer-trigger.txt
> @@ -0,0 +1,23 @@
> +STMicroelectronics STM32 Timers IIO timer bindings
> +
> +Must be a sub-node of an STM32 Timers device tree node.
> +See ../mfd/stm32-timers.txt for details about the parent node.
> +
> +Required parameters:
> +- compatible:	Must be "st,stm32-timer-trigger".
> +- reg:		Define triggers configuration of the hardware IP.

Valid values? Not sure this makes sense for use of reg. reg should be 
how you address or id a device.

> +
> +Example:
> +	timers@40010000 {
> +		#address-cells = <1>;
> +		#size-cells = <0>;
> +		compatible = "st,stm32-timers";
> +		reg = <0x40010000 0x400>;
> +		clocks = <&rcc 0 160>;
> +		clock-names = "clk_int";
> +
> +		timer {

This would also need an unit address.

> +			compatible = "st,stm32-timer-trigger";
> +			reg = <0>;
> +		};
> +	};
> -- 
> 1.9.1
> 

Re: [PATCH v7 5/8] IIO: add bindings for STM32 timer trigger driver

[Benjamin Gaignard]

2017-01-09 19:04 GMT+01:00 Rob Herring <robh@kernel.org>:
> On Thu, Jan 05, 2017 at 10:25:41AM +0100, Benjamin Gaignard wrote:
>> Define bindings for STM32 timer trigger
>>
>> version 4:
>> - remove triggers enumeration from DT
>> - add reg parameter
>>
>> version 3:
>> - change file name
>> - add cross reference with mfd bindings
>>
>> version 2:
>> - only keep one compatible
>> - add DT parameters to set lists of the triggers:
>>   one list describe the triggers created by the device
>>   another one give the triggers accepted by the device
>>
>> Signed-off-by: Benjamin Gaignard <benjamin.gaignard@st.com>
>> ---
>>  .../bindings/iio/timer/stm32-timer-trigger.txt     | 23 ++++++++++++++++++++++
>>  1 file changed, 23 insertions(+)
>>  create mode 100644 Documentation/devicetree/bindings/iio/timer/stm32-timer-trigger.txt
>>
>> diff --git a/Documentation/devicetree/bindings/iio/timer/stm32-timer-trigger.txt b/Documentation/devicetree/bindings/iio/timer/stm32-timer-trigger.txt
>> new file mode 100644
>> index 0000000..36a6c4a
>> --- /dev/null
>> +++ b/Documentation/devicetree/bindings/iio/timer/stm32-timer-trigger.txt
>> @@ -0,0 +1,23 @@
>> +STMicroelectronics STM32 Timers IIO timer bindings
>> +
>> +Must be a sub-node of an STM32 Timers device tree node.
>> +See ../mfd/stm32-timers.txt for details about the parent node.
>> +
>> +Required parameters:
>> +- compatible:        Must be "st,stm32-timer-trigger".
>> +- reg:               Define triggers configuration of the hardware IP.
>
> Valid values? Not sure this makes sense for use of reg. reg should be
> how you address or id a device.

I use reg like an id to distinguish device and get the right
configuration inside
the driver.

>
>> +
>> +Example:
>> +     timers@40010000 {
>> +             #address-cells = <1>;
>> +             #size-cells = <0>;
>> +             compatible = "st,stm32-timers";
>> +             reg = <0x40010000 0x400>;
>> +             clocks = <&rcc 0 160>;
>> +             clock-names = "clk_int";
>> +
>> +             timer {
>
> This would also need an unit address.

Ok I will fix that

>
>> +                     compatible = "st,stm32-timer-trigger";
>> +                     reg = <0>;
>> +             };
>> +     };
>> --
>> 1.9.1
>>



-- 
Benjamin Gaignard

Graphic Study Group

Linaro.org │ Open source software for ARM SoCs

Follow Linaro: Facebook | Twitter | Blog

Re: [PATCH v7 2/8] MFD: add STM32 Timers driver

[Benjamin Gaignard]

2017-01-09 19:00 GMT+01:00 Rob Herring <robh@kernel.org>:
> On Thu, Jan 05, 2017 at 10:25:38AM +0100, Benjamin Gaignard wrote:
>> This hardware block could at used at same time for PWM generation
>> and IIO timers.
>> PWM and IIO timer configuration are mixed in the same registers
>> so we need a multi fonction driver to be able to share those registers.
>>
>> version 7:
>> - rebase on v4.10-rc2
>>
>> version 6:
>> - rename files to stm32-timers
>> - rename functions to stm32_timers_xxx
>>
>> version 5:
>> - fix Lee comments about detect function
>> - add missing dependency on REGMAP_MMIO
>>
>> version 4:
>> - add a function to detect Auto Reload Register (ARR) size
>> - rename the structure shared with other drivers
>>
>> version 2:
>> - rename driver "stm32-gptimer" to be align with SoC documentation
>> - only keep one compatible
>> - use of_platform_populate() instead of devm_mfd_add_devices()
>>
>> Signed-off-by: Benjamin Gaignard <benjamin.gaignard@st.com>
>> ---
>>  .../devicetree/bindings/mfd/stm32-timers.txt       |  2 +-
>>  drivers/mfd/Kconfig                                | 11 +++
>>  drivers/mfd/Makefile                               |  2 +
>>  drivers/mfd/stm32-timers.c                         | 80 ++++++++++++++++++++++
>>  include/linux/mfd/stm32-timers.h                   | 71 +++++++++++++++++++
>>  5 files changed, 165 insertions(+), 1 deletion(-)
>>  create mode 100644 drivers/mfd/stm32-timers.c
>>  create mode 100644 include/linux/mfd/stm32-timers.h
>>
>> diff --git a/Documentation/devicetree/bindings/mfd/stm32-timers.txt b/Documentation/devicetree/bindings/mfd/stm32-timers.txt
>> index a73301d..897e7c2 100644
>> --- a/Documentation/devicetree/bindings/mfd/stm32-timers.txt
>> +++ b/Documentation/devicetree/bindings/mfd/stm32-timers.txt
>> @@ -12,7 +12,7 @@ Required parameters:
>>
>>  - reg:                       Physical base address and length of the controller's
>>                       registers.
>> -- clock-names:               Set to "int".
>> +- clock-names:               Set to "int".
>
> This hunk should be dropped or moved to previous patch.

I will move it in the previous patch

>
>>  - clocks:            Phandle to the clock used by the timer module.
>>                       For Clk properties, please refer to ../clock/clock-bindings.txt
>>



-- 
Benjamin Gaignard

Graphic Study Group

Linaro.org │ Open source software for ARM SoCs

Follow Linaro: Facebook | Twitter | Blog

Re: [PATCH v7 0/8] Add PWM and IIO timer drivers for STM32

[Benjamin Gaignard]

2017-01-06 8:58 GMT+01:00 Benjamin Gaignard <benjamin.gaignard@linaro.org>:
> 2017-01-05 15:49 GMT+01:00 Lee Jones <lee.jones@linaro.org>:
>> On Thu, 05 Jan 2017, Benjamin Gaignard wrote:
>>
>>> version 7:
>>> - rebase on v4.10-rc2
>>> - remove iio_device code from driver and keep only the trigger part

Version 7 got ACK for MFD (binding and driver), PWM (bindings), IIO (driver).

I would like to progress on this series but I there is still 2 blocking points:
1) usage of reg in IIO driver as an hardware block index, Rob does it
sound reasonable for you ?
2) PWM driver haven't receive comments (neither ack), Thierry do you
think you will be able to find time to review it ?

Benjamin

>>>
>>> version 6:
>>> - rename stm32-gptimer in stm32-timers.
>>> - change "st,stm32-gptimer" compatible to "st,stm32-timers".
>>> - modify "st,breakinput" parameter in pwm part.
>>> - split DT patch in 2
>>>
>>> version 5:
>>> - fix comments done on version 4
>>> - rebased on kernel 4.9-rc8
>>> - change nodes names and re-order then by addresses
>>>
>>> version 4:
>>> - fix comments done on version 3
>>> - don't use interrupts anymore in IIO timer
>>> - detect hardware capabilities at probe time to simplify binding
>>>
>>> version 3:
>>> - no change on mfd and pwm divers patches
>>> - add cross reference between bindings
>>> - change compatible to "st,stm32-timer-trigger"
>>> - fix attributes access rights
>>> - use string instead of int for master_mode and slave_mode
>>> - document device attributes in sysfs-bus-iio-timer-stm32
>>> - update DT with the new compatible
>>>
>>> version 2:
>>> - keep only one compatible per driver
>>> - use DT parameters to describe hardware block configuration:
>>>   - pwm channels, complementary output, counter size, break input
>>>   - triggers accepted and create by IIO timers
>>> - change DT to limite use of reference to the node
>>> - interrupt is now in IIO timer driver
>>> - rename stm32-mfd-timer to stm32-timers (for general purpose timer)
>>>
>>> The following patches enable PWM and IIO Timer features for STM32 platforms.
>>>
>>> Those two features are mixed into the registers of the same hardware block
>>> (named general purpose timer) which lead to introduce a multifunctions driver
>>> on the top of them to be able to share the registers.
>>>
>>> In STM32f4 14 instances of timer hardware block exist, even if they all have
>>> the same register mapping they could have a different number of pwm channels
>>> and/or different triggers capabilities. We use various parameters in DT to
>>> describe the differences between hardware blocks
>>>
>>> The MFD (stm32-timers.c) takes care of clock and register mapping
>>> by using regmap. stm32_timers structure is provided to its sub-node to
>>> share those information.
>>>
>>> PWM driver is implemented into pwm-stm32.c. Depending of the instance we may
>>> have up to 4 channels, sometime with complementary outputs or 32 bits counter
>>> instead of 16 bits. Some hardware blocks may also have a break input function
>>> which allows to stop pwm depending of a level, defined in devicetree, on an
>>> external pin.
>>>
>>> IIO timer driver (stm32-timer-trigger.c and stm32-timer-trigger.h) define a list
>>> of hardware triggers usable by hardware blocks like ADC, DAC or other timers.
>>>
>>> The matrix of possible connections between blocks is quite complex so we use
>>> trigger names and is_stm32_iio_timer_trigger() function to be sure that
>>> triggers are valid and configure the IPs.
>>>
>>> At run time IIO timer hardware blocks can configure (through "master_mode"
>>> IIO device attribute) which internal signal (counter enable, reset,
>>> comparison block, etc...) is used to generate the trigger.
>>>
>>> Benjamin Gaignard (8):
>>>   MFD: add bindings for STM32 Timers driver
>>>   MFD: add STM32 Timers driver
>>>   PWM: add pwm-stm32 DT bindings
>>>   PWM: add PWM driver for STM32 plaftorm
>>>   IIO: add bindings for STM32 timer trigger driver
>>>   IIO: add STM32 timer trigger driver
>>>   ARM: dts: stm32: add Timers driver for stm32f429 MCU
>>>   ARM: dts: stm32: Enable pwm1 and pwm3 for stm32f469-disco
>>
>> Any reason why you've dropped all your Acks?
>>
>> I don't really want to review it again if little is different.
>>
>> How much MFD related code has changed since the last review?
>
> All my apologies I forgot to add your Acks for MFD parts.
>
> Sorry for that
>
>>
>>>  .../ABI/testing/sysfs-bus-iio-timer-stm32          |  29 ++
>>>  .../bindings/iio/timer/stm32-timer-trigger.txt     |  23 ++
>>>  .../devicetree/bindings/mfd/stm32-timers.txt       |  46 +++
>>>  .../devicetree/bindings/pwm/pwm-stm32.txt          |  33 ++
>>>  arch/arm/boot/dts/stm32f429.dtsi                   | 275 +++++++++++++
>>>  arch/arm/boot/dts/stm32f469-disco.dts              |  28 ++
>>>  drivers/iio/Kconfig                                |   1 -
>>>  drivers/iio/trigger/Kconfig                        |  10 +
>>>  drivers/iio/trigger/Makefile                       |   1 +
>>>  drivers/iio/trigger/stm32-timer-trigger.c          | 340 ++++++++++++++++
>>>  drivers/mfd/Kconfig                                |  11 +
>>>  drivers/mfd/Makefile                               |   2 +
>>>  drivers/mfd/stm32-timers.c                         |  80 ++++
>>>  drivers/pwm/Kconfig                                |   9 +
>>>  drivers/pwm/Makefile                               |   1 +
>>>  drivers/pwm/pwm-stm32.c                            | 434 +++++++++++++++++++++
>>>  include/linux/iio/timer/stm32-timer-trigger.h      |  62 +++
>>>  include/linux/mfd/stm32-timers.h                   |  71 ++++
>>>  18 files changed, 1455 insertions(+), 1 deletion(-)
>>>  create mode 100644 Documentation/ABI/testing/sysfs-bus-iio-timer-stm32
>>>  create mode 100644 Documentation/devicetree/bindings/iio/timer/stm32-timer-trigger.txt
>>>  create mode 100644 Documentation/devicetree/bindings/mfd/stm32-timers.txt
>>>  create mode 100644 Documentation/devicetree/bindings/pwm/pwm-stm32.txt
>>>  create mode 100644 drivers/iio/trigger/stm32-timer-trigger.c
>>>  create mode 100644 drivers/mfd/stm32-timers.c
>>>  create mode 100644 drivers/pwm/pwm-stm32.c
>>>  create mode 100644 include/linux/iio/timer/stm32-timer-trigger.h
>>>  create mode 100644 include/linux/mfd/stm32-timers.h
>>>
>>
>> --
>> Lee Jones
>> Linaro STMicroelectronics Landing Team Lead
>> Linaro.org │ Open source software for ARM SoCs
>> Follow Linaro: Facebook | Twitter | Blog
>
>
>
> --
> Benjamin Gaignard
>
> Graphic Study Group
>
> Linaro.org │ Open source software for ARM SoCs
>
> Follow Linaro: Facebook | Twitter | Blog



-- 
Benjamin Gaignard

Graphic Study Group

Linaro.org │ Open source software for ARM SoCs

Follow Linaro: Facebook | Twitter | Blog

Re: [PATCH v7 3/8] PWM: add pwm-stm32 DT bindings

[Thierry Reding]

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On Thu, Jan 05, 2017 at 10:25:39AM +0100, Benjamin Gaignard wrote:
> Define bindings for pwm-stm32
> 
> version 6:
> - change st,breakinput parameter format to make it usuable on stm32f7 too.
> 
> version 2:
> - use parameters instead of compatible of handle the hardware configuration
> 
> Signed-off-by: Benjamin Gaignard <benjamin.gaignard@st.com>
> ---
>  .../devicetree/bindings/pwm/pwm-stm32.txt          | 33 ++++++++++++++++++++++
>  1 file changed, 33 insertions(+)
>  create mode 100644 Documentation/devicetree/bindings/pwm/pwm-stm32.txt
> 
> diff --git a/Documentation/devicetree/bindings/pwm/pwm-stm32.txt b/Documentation/devicetree/bindings/pwm/pwm-stm32.txt
> new file mode 100644
> index 0000000..866f222
> --- /dev/null
> +++ b/Documentation/devicetree/bindings/pwm/pwm-stm32.txt
> @@ -0,0 +1,33 @@
> +STMicroelectronics STM32 Timers PWM bindings
> +
> +Must be a sub-node of an STM32 Timers device tree node.
> +See ../mfd/stm32-timers.txt for details about the parent node.
> +
> +Required parameters:
> +- compatible:		Must be "st,stm32-pwm".
> +- pinctrl-names: 	Set to "default".
> +- pinctrl-0: 		List of phandles pointing to pin configuration nodes for PWM module.
> +			For Pinctrl properties see ../pinctrl/pinctrl-bindings.txt
> +
> +Optional parameters:
> +- st,breakinput:	Arrays of three u32 <index level filter> to describe break input configurations.
> +			"index" indicates on which break input the configuration should be applied.

It might be useful to specify what the valid values are for the break
input index.

Also, u32 is kind of a Linuxism, perhaps "Arrays of three cells"? Also,
does this mean there can be multiple entries? Such as 6 cells for two
configurations? What's the maximum number of such configurations?

If it's possible to specify multiple configurations, maybe a slightly
clearer wording would be: "One or more <index level filter> triplets to
describe..."

> +			"level" gives the active level (0=low or 1=high) for this configuration.

So how does this work exactly? "level" specifies the output level if the
filter value is matched?

> +			"filter" gives the filtering value to be applied.

Is this a single value at which "level" will be applied? Or is it an
upper/lower bound that can be used to restrict the output to "level" if
the signal goes beyond/below a certain threshold?

Maybe an example would clarify this. Or perhaps a reference to a manual
where a more in-depth description of this functionality can be found.

Thierry

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Re: [PATCH v7 3/8] PWM: add pwm-stm32 DT bindings

[Benjamin Gaignard]

2017-01-18 10:20 GMT+01:00 Thierry Reding <thierry.reding@gmail.com>:
> On Thu, Jan 05, 2017 at 10:25:39AM +0100, Benjamin Gaignard wrote:
>> Define bindings for pwm-stm32
>>
>> version 6:
>> - change st,breakinput parameter format to make it usuable on stm32f7 too.
>>
>> version 2:
>> - use parameters instead of compatible of handle the hardware configuration
>>
>> Signed-off-by: Benjamin Gaignard <benjamin.gaignard@st.com>
>> ---
>>  .../devicetree/bindings/pwm/pwm-stm32.txt          | 33 ++++++++++++++++++++++
>>  1 file changed, 33 insertions(+)
>>  create mode 100644 Documentation/devicetree/bindings/pwm/pwm-stm32.txt
>>
>> diff --git a/Documentation/devicetree/bindings/pwm/pwm-stm32.txt b/Documentation/devicetree/bindings/pwm/pwm-stm32.txt
>> new file mode 100644
>> index 0000000..866f222
>> --- /dev/null
>> +++ b/Documentation/devicetree/bindings/pwm/pwm-stm32.txt
>> @@ -0,0 +1,33 @@
>> +STMicroelectronics STM32 Timers PWM bindings
>> +
>> +Must be a sub-node of an STM32 Timers device tree node.
>> +See ../mfd/stm32-timers.txt for details about the parent node.
>> +
>> +Required parameters:
>> +- compatible:                Must be "st,stm32-pwm".
>> +- pinctrl-names:     Set to "default".
>> +- pinctrl-0:                 List of phandles pointing to pin configuration nodes for PWM module.
>> +                     For Pinctrl properties see ../pinctrl/pinctrl-bindings.txt
>> +
>> +Optional parameters:
>> +- st,breakinput:     Arrays of three u32 <index level filter> to describe break input configurations.
>> +                     "index" indicates on which break input the configuration should be applied.
>
> It might be useful to specify what the valid values are for the break
> input index.

It could 0 and 1, I will add this information.

>
> Also, u32 is kind of a Linuxism, perhaps "Arrays of three cells"? Also,
> does this mean there can be multiple entries? Such as 6 cells for two
> configurations? What's the maximum number of such configurations?
>
> If it's possible to specify multiple configurations, maybe a slightly
> clearer wording would be: "One or more <index level filter> triplets to
> describe..."
>

You can have one configuration per index so I will rephrase it like that:
One or two <index level filter> to describe break input configurations.
"index" indicates on which break input (0 or 1 ) the configuration
should be applied.


>> +                     "level" gives the active level (0=low or 1=high) for this configuration.
>
> So how does this work exactly? "level" specifies the output level if the
> filter value is matched?

No it specify on which input level the break event is generated

>
>> +                     "filter" gives the filtering value to be applied.
>
> Is this a single value at which "level" will be applied? Or is it an
> upper/lower bound that can be used to restrict the output to "level" if
> the signal goes beyond/below a certain threshold?

Very very basically filter is more a debounce value set on the signal
to avoid glitches.
The goal of break input feature is to stop PWM generation in hardware
errors failure case.

For a more completed description you can read "using break input
function" (starting page 645) in this doc:

http://www.st.com/content/ccc/resource/technical/document/reference_manual/c5/cf/ef/52/c0/f1/4b/fa/DM00124865.pdf/files/DM00124865.pdf/jcr:content/translations/en.DM00124865.pdf

>
> Maybe an example would clarify this. Or perhaps a reference to a manual
> where a more in-depth description of this functionality can be found.
>
> Thierry



-- 
Benjamin Gaignard

Graphic Study Group

Linaro.org │ Open source software for ARM SoCs

Follow Linaro: Facebook | Twitter | Blog

Re: [PATCH v7 4/8] PWM: add PWM driver for STM32 plaftorm

[Thierry Reding]

[-- Attachment #1: Type: text/plain, Size: 14942 bytes --]

On Thu, Jan 05, 2017 at 10:25:40AM +0100, Benjamin Gaignard wrote:
> This driver adds support for PWM driver on STM32 platform.
> The SoC have multiple instances of the hardware IP and each
> of them could have small differences: number of channels,
> complementary output, auto reload register size...
> 
> version 6:
> - change st,breakinput parameter to make it usuable for stm32f7 too.
> 
> version 4:
> - detect at probe time hardware capabilities
> - fix comments done on v2 and v3
> - use PWM atomic ops
> 
> version 2:
> - only keep one comptatible
> - use DT parameters to discover hardware block configuration
> 
> Signed-off-by: Benjamin Gaignard <benjamin.gaignard@st.com>
> ---
>  drivers/pwm/Kconfig     |   9 +
>  drivers/pwm/Makefile    |   1 +
>  drivers/pwm/pwm-stm32.c | 434 ++++++++++++++++++++++++++++++++++++++++++++++++
>  3 files changed, 444 insertions(+)
>  create mode 100644 drivers/pwm/pwm-stm32.c
> 
> diff --git a/drivers/pwm/Kconfig b/drivers/pwm/Kconfig
> index f92dd41..88035c0 100644
> --- a/drivers/pwm/Kconfig
> +++ b/drivers/pwm/Kconfig
> @@ -397,6 +397,15 @@ config PWM_STI
>  	  To compile this driver as a module, choose M here: the module
>  	  will be called pwm-sti.
>  
> +config PWM_STM32
> +	tristate "STMicroelectronics STM32 PWM"
> +	depends on (ARCH_STM32 && OF && MFD_STM32_TIMERS) || COMPILE_TEST
> +	help
> +	  Generic PWM framework driver for STM32 SoCs.
> +
> +	  To compile this driver as a module, choose M here: the module
> +	  will be called pwm-stm32.
> +
>  config PWM_STMPE
>  	bool "STMPE expander PWM export"
>  	depends on MFD_STMPE
> diff --git a/drivers/pwm/Makefile b/drivers/pwm/Makefile
> index a48bdb5..346a83b 100644
> --- a/drivers/pwm/Makefile
> +++ b/drivers/pwm/Makefile
> @@ -38,6 +38,7 @@ obj-$(CONFIG_PWM_ROCKCHIP)	+= pwm-rockchip.o
>  obj-$(CONFIG_PWM_SAMSUNG)	+= pwm-samsung.o
>  obj-$(CONFIG_PWM_SPEAR)		+= pwm-spear.o
>  obj-$(CONFIG_PWM_STI)		+= pwm-sti.o
> +obj-$(CONFIG_PWM_STM32)		+= pwm-stm32.o
>  obj-$(CONFIG_PWM_STMPE)		+= pwm-stmpe.o
>  obj-$(CONFIG_PWM_SUN4I)		+= pwm-sun4i.o
>  obj-$(CONFIG_PWM_TEGRA)		+= pwm-tegra.o
> diff --git a/drivers/pwm/pwm-stm32.c b/drivers/pwm/pwm-stm32.c
> new file mode 100644
> index 0000000..fcf0a78
> --- /dev/null
> +++ b/drivers/pwm/pwm-stm32.c
> @@ -0,0 +1,434 @@
> +/*
> + * Copyright (C) STMicroelectronics 2016
> + *
> + * Author: Gerald Baeza <gerald.baeza@st.com>
> + *
> + * License terms: GNU General Public License (GPL), version 2
> + *
> + * Inspired by timer-stm32.c from Maxime Coquelin
> + *             pwm-atmel.c from Bo Shen
> + */
> +
> +#include <linux/mfd/stm32-timers.h>
> +#include <linux/module.h>
> +#include <linux/platform_device.h>
> +#include <linux/pwm.h>
> +#include <linux/of.h>

Can you please sort these alphabetically?

> +
> +#define CCMR_CHANNEL_SHIFT 8
> +#define CCMR_CHANNEL_MASK  0xFF
> +#define MAX_BREAKINPUT 2

Okay, this answers my question regarding the st,breakinput property. I
still think it'd be good to have this in the binding documentation just
to avoid having to look at implementation to find out.

> +
> +struct stm32_pwm {
> +	struct pwm_chip chip;
> +	struct device *dev;
> +	struct clk *clk;
> +	struct regmap *regmap;
> +	unsigned int caps;

This seems completely unused?

> +	unsigned int npwm;

It's somewhat redundant to have this here, since the same information is
already contained in struct pwm_chip.npwm.

Since you use this primarily for detection, how about you make the
stm32_pwm_detect_channels() function return the value and store it in a
local variable in ->probe()? That might be useful also because you
need to check the return value of regmap_update_bits() which technically
could fail.

> +	u32 max_arr;
> +	bool have_complementary_output;
> +};
> +
> +struct stm32_breakinput {
> +	u32 index;
> +	u32 level;
> +	u32 filter;
> +};
> +
> +static inline struct stm32_pwm *to_stm32_pwm_dev(struct pwm_chip *chip)
> +{
> +	return container_of(chip, struct stm32_pwm, chip);
> +}
> +
> +static u32 active_channels(struct stm32_pwm *dev)
> +{
> +	u32 ccer;
> +
> +	regmap_read(dev->regmap, TIM_CCER, &ccer);
> +
> +	return ccer & TIM_CCER_CCXE;
> +}

This looks like something that you could track in software, but this is
probably fine, too. Again, technically regmap_read() could fail, so you
might want to consider adding some code to handle it. In practice it
probably won't, so maybe you don't.

> +
> +static int write_ccrx(struct stm32_pwm *dev, struct pwm_device *pwm,
> +		      u32 value)
> +{
> +	switch (pwm->hwpwm) {
> +	case 0:
> +		return regmap_write(dev->regmap, TIM_CCR1, value);
> +	case 1:
> +		return regmap_write(dev->regmap, TIM_CCR2, value);
> +	case 2:
> +		return regmap_write(dev->regmap, TIM_CCR3, value);
> +	case 3:
> +		return regmap_write(dev->regmap, TIM_CCR4, value);
> +	}
> +	return -EINVAL;
> +}
> +
> +static int stm32_pwm_config(struct pwm_chip *chip, struct pwm_device *pwm,
> +			    int duty_ns, int period_ns)
> +{
> +	struct stm32_pwm *priv = to_stm32_pwm_dev(chip);
> +	unsigned long long prd, div, dty;
> +	unsigned int prescaler = 0;
> +	u32 ccmr, mask, shift;
> +
> +	/* Period and prescaler values depends on clock rate */
> +	div = (unsigned long long)clk_get_rate(priv->clk) * period_ns;
> +
> +	do_div(div, NSEC_PER_SEC);
> +	prd = div;
> +
> +	while (div > priv->max_arr) {
> +		prescaler++;
> +		div = prd;
> +		do_div(div, (prescaler + 1));

Nit: there's no need for the parentheses here.

> +	}
> +
> +	prd = div;
> +
> +	if (prescaler > MAX_TIM_PSC) {
> +		dev_err(chip->dev, "prescaler exceeds the maximum value\n");
> +		return -EINVAL;
> +	}
> +
> +	/*
> +	 * All channels share the same prescaler and counter so when two
> +	 * channels are active at the same we can't change them

Nit: "at the same time"?

> +	 */
> +	if (active_channels(priv) & ~(1 << pwm->hwpwm * 4)) {
> +		u32 psc, arr;
> +
> +		regmap_read(priv->regmap, TIM_PSC, &psc);
> +		regmap_read(priv->regmap, TIM_ARR, &arr);
> +
> +		if ((psc != prescaler) || (arr != prd - 1))
> +			return -EBUSY;
> +	}
> +
> +	regmap_write(priv->regmap, TIM_PSC, prescaler);
> +	regmap_write(priv->regmap, TIM_ARR, prd - 1);
> +	regmap_update_bits(priv->regmap, TIM_CR1, TIM_CR1_ARPE, TIM_CR1_ARPE);
> +
> +	/* Calculate the duty cycles */
> +	dty = prd * duty_ns;
> +	do_div(dty, period_ns);
> +
> +	write_ccrx(priv, pwm, dty);
> +
> +	/* Configure output mode */
> +	shift = (pwm->hwpwm & 0x1) * CCMR_CHANNEL_SHIFT;
> +	ccmr = (TIM_CCMR_PE | TIM_CCMR_M1) << shift;
> +	mask = CCMR_CHANNEL_MASK << shift;
> +
> +	if (pwm->hwpwm < 2)
> +		regmap_update_bits(priv->regmap, TIM_CCMR1, mask, ccmr);
> +	else
> +		regmap_update_bits(priv->regmap, TIM_CCMR2, mask, ccmr);
> +
> +	regmap_update_bits(priv->regmap, TIM_BDTR,
> +			   TIM_BDTR_MOE | TIM_BDTR_AOE,
> +			   TIM_BDTR_MOE | TIM_BDTR_AOE);
> +
> +	return 0;
> +}
> +
> +static int stm32_pwm_set_polarity(struct pwm_chip *chip, struct pwm_device *pwm,
> +				  enum pwm_polarity polarity)
> +{
> +	u32 mask;
> +	struct stm32_pwm *priv = to_stm32_pwm_dev(chip);
> +
> +	mask = TIM_CCER_CC1P << (pwm->hwpwm * 4);
> +	if (priv->have_complementary_output)
> +		mask |= TIM_CCER_CC1NP << (pwm->hwpwm * 4);
> +
> +	regmap_update_bits(priv->regmap, TIM_CCER, mask,
> +			   polarity == PWM_POLARITY_NORMAL ? 0 : mask);
> +
> +	return 0;
> +}
> +
> +static int stm32_pwm_enable(struct pwm_chip *chip, struct pwm_device *pwm)
> +{
> +	u32 mask;
> +	struct stm32_pwm *priv = to_stm32_pwm_dev(chip);
> +
> +	clk_enable(priv->clk);

This can fail, so its return value should be checked. Also, I don't see
a clk_prepare() anywhere. Is that something that maybe the MFD driver
should be doing? It currently isn't.

> +
> +	/* Enable channel */
> +	mask = TIM_CCER_CC1E << (pwm->hwpwm * 4);
> +	if (priv->have_complementary_output)
> +		mask |= TIM_CCER_CC1NE << (pwm->hwpwm * 4);
> +
> +	regmap_update_bits(priv->regmap, TIM_CCER, mask, mask);
> +
> +	/* Make sure that registers are updated */
> +	regmap_update_bits(priv->regmap, TIM_EGR, TIM_EGR_UG, TIM_EGR_UG);
> +
> +	/* Enable controller */
> +	regmap_update_bits(priv->regmap, TIM_CR1, TIM_CR1_CEN, TIM_CR1_CEN);
> +
> +	return 0;
> +}
> +
> +static void stm32_pwm_disable(struct pwm_chip *chip, struct pwm_device *pwm)
> +{
> +	u32 mask;
> +	struct stm32_pwm *priv = to_stm32_pwm_dev(chip);
> +
> +	/* Disable channel */
> +	mask = TIM_CCER_CC1E << (pwm->hwpwm * 4);
> +	if (priv->have_complementary_output)
> +		mask |= TIM_CCER_CC1NE << (pwm->hwpwm * 4);
> +
> +	regmap_update_bits(priv->regmap, TIM_CCER, mask, 0);
> +
> +	/* When all channels are disabled, we can disable the controller */
> +	if (!active_channels(priv))
> +		regmap_update_bits(priv->regmap, TIM_CR1, TIM_CR1_CEN, 0);
> +
> +	clk_disable(priv->clk);
> +}
> +
> +static int stm32_pwm_apply(struct pwm_chip *chip, struct pwm_device *pwm,
> +			   struct pwm_state *state)
> +{
> +	struct pwm_state curstate;
> +	bool enabled;
> +	int ret;
> +
> +	pwm_get_state(pwm, &curstate);
> +	enabled = curstate.enabled;

There should be no need to do this in drivers. pwm_get_state() is for
PWM API users. Drivers can directly dereference pwm->state.

> +
> +	if (enabled && !state->enabled) {
> +		stm32_pwm_disable(chip, pwm);
> +		return 0;
> +	}
> +
> +	if (state->polarity != curstate.polarity && enabled)
> +		stm32_pwm_set_polarity(chip, pwm, state->polarity);

So that's kind of a violation of atomic API semantics. The above means
that if you have a PWM in the following state:

	enabled: no
	polarity: normal

and want to set this:

	enabled: yes
	polarity: inversed

then you will ignore the new polarity setting. What's the reason for
"&& enabled) in the conditional above?

> +
> +	ret = stm32_pwm_config(chip, pwm, state->duty_cycle, state->period);
> +	if (ret)
> +		return ret;
> +
> +	if (!enabled && state->enabled)
> +		ret = stm32_pwm_enable(chip, pwm);
> +
> +	return ret;
> +}

Would it be possible to merge stm32_pwm_disable(), stm32_pwm_enable(),
stm32_pwm_set_polarity() and stm32_pwm_config() into stm32_pwm_apply()?
Part of the reason for the atomic API was to make it easier to write
these drivers, but your implementation effectively copies what the
transitional helpers do.

It might not make a difference technically in your case, but I think
it'd make the implementation more compact and set a better example for
future reference.

> +
> +static const struct pwm_ops stm32pwm_ops = {
> +	.owner = THIS_MODULE,
> +	.apply = stm32_pwm_apply,
> +};
> +
> +static int stm32_pwm_set_breakinput(struct stm32_pwm *priv,
> +				    int level, int filter)
> +{
> +	u32 bdtr = TIM_BDTR_BKE;
> +
> +	if (level)
> +		bdtr |= TIM_BDTR_BKP;
> +
> +	bdtr |= (filter & TIM_BDTR_BKF_MASK) << TIM_BDTR_BKF_SHIFT;
> +
> +	regmap_update_bits(priv->regmap,
> +			   TIM_BDTR, TIM_BDTR_BKE | TIM_BDTR_BKP | TIM_BDTR_BKF,
> +			   bdtr);
> +
> +	regmap_read(priv->regmap, TIM_BDTR, &bdtr);
> +
> +	return (bdtr & TIM_BDTR_BKE) ? 0 : -EINVAL;
> +}
> +
> +static int stm32_pwm_set_breakinput2(struct stm32_pwm *priv,
> +				     int level, int filter)
> +{
> +	u32 bdtr = TIM_BDTR_BK2E;
> +
> +	if (level)
> +		bdtr |= TIM_BDTR_BK2P;
> +
> +	bdtr |= (filter & TIM_BDTR_BKF_MASK) << TIM_BDTR_BK2F_SHIFT;
> +
> +	regmap_update_bits(priv->regmap,
> +			   TIM_BDTR, TIM_BDTR_BK2E |
> +			   TIM_BDTR_BK2P |
> +			   TIM_BDTR_BK2F,
> +			   bdtr);
> +
> +	regmap_read(priv->regmap, TIM_BDTR, &bdtr);
> +
> +	return (bdtr & TIM_BDTR_BK2E) ? 0 : -EINVAL;
> +}

As far as I can tell the only difference here is the various bit
positions. Can you collapse the above two functions and add a new
parameter to unify some code?

> +
> +static int stm32_pwm_apply_breakinputs(struct stm32_pwm *priv,
> +				       struct device_node *np)
> +{
> +	struct stm32_breakinput breakinput[MAX_BREAKINPUT];
> +	int nb, ret, i, array_size;
> +
> +	nb = of_property_count_elems_of_size(np, "st,breakinput",
> +					     sizeof(struct stm32_breakinput));
> +
> +	/*
> +	 * Because "st,breakinput" parameter is optional do not make probe
> +	 * failed if it doesn't exist.
> +	 */
> +	if (nb <= 0)
> +		return 0;
> +
> +	if (nb > MAX_BREAKINPUT)
> +		return -EINVAL;
> +
> +	array_size = nb * sizeof(struct stm32_breakinput) / sizeof(u32);
> +	ret = of_property_read_u32_array(np, "st,breakinput",
> +					 &breakinput[0].index, array_size);

Maybe (u32 *)breakinput? That would make it more resilient against
changes in ordering of fields in the struct. Granted, that's not likely
to change, but I think it's a good idea in general to write code in a
way that's safe in a more general case. That way if somebody ever were
to copy from your code and then decide to reorder fields in their code
things wouldn't fall apart.

> +	if (ret)
> +		return ret;
> +
> +	for (i = 0; i < nb && !ret; i++) {
> +		switch (breakinput[i].index) {
> +		case 0:
> +		{
> +			ret = stm32_pwm_set_breakinput(priv,
> +						       breakinput[i].level,
> +						       breakinput[i].filter);
> +			break;
> +		}

Curly braces are unnecessary here.

> +		case 1:
> +		{
> +			ret = stm32_pwm_set_breakinput2(priv,
> +							breakinput[i].level,
> +							breakinput[i].filter);
> +
> +			break;
> +		}
> +		default:
> +		{
> +			ret = -EINVAL;
> +			break;
> +		}
> +		}
> +	}
> +
> +	return ret;
> +}
> +
> +static void stm32_pwm_detect_complementary(struct stm32_pwm *priv)
> +{
> +	u32 ccer;
> +
> +	/*
> +	 * If complementary bit doesn't exist writing 1 will have no
> +	 * effect so we can detect it.
> +	 */
> +	regmap_update_bits(priv->regmap,
> +			   TIM_CCER, TIM_CCER_CC1NE, TIM_CCER_CC1NE);
> +	regmap_read(priv->regmap, TIM_CCER, &ccer);
> +	regmap_update_bits(priv->regmap, TIM_CCER, TIM_CCER_CCXE, 0);

This is strange: why are we disabling outputs here? Shouldn't the last
line here undo the first instead?

> +
> +	priv->have_complementary_output = (ccer != 0);
> +}
> +
> +static void stm32_pwm_detect_channels(struct stm32_pwm *priv)
> +{
> +	u32 ccer;
> +
> +	/*
> +	 * If channels enable bits don't exist writing 1 will have no
> +	 * effect so we can detect and count them.
> +	 */
> +	regmap_update_bits(priv->regmap,
> +			   TIM_CCER, TIM_CCER_CCXE, TIM_CCER_CCXE);
> +	regmap_read(priv->regmap, TIM_CCER, &ccer);
> +	regmap_update_bits(priv->regmap, TIM_CCER, TIM_CCER_CCXE, 0);

Does this have the potential to glitch? I suspect that the clock may not
be on at this point and therefore no PWM outputs will be generated, but
is that guaranteed to always be the case?

Thierry

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Re: [PATCH v7 4/8] PWM: add PWM driver for STM32 plaftorm

[Thierry Reding]

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On Thu, Jan 05, 2017 at 10:25:40AM +0100, Benjamin Gaignard wrote:
[...]
> diff --git a/drivers/pwm/Kconfig b/drivers/pwm/Kconfig
> index f92dd41..88035c0 100644
> --- a/drivers/pwm/Kconfig
> +++ b/drivers/pwm/Kconfig
> @@ -397,6 +397,15 @@ config PWM_STI
>  	  To compile this driver as a module, choose M here: the module
>  	  will be called pwm-sti.
>  
> +config PWM_STM32
> +	tristate "STMicroelectronics STM32 PWM"
> +	depends on (ARCH_STM32 && OF && MFD_STM32_TIMERS) || COMPILE_TEST

One other thing: is the dependency on ARCH_STM32 and OF necessary here?
ARCH_STM32 and OF are both pulled in by MFD_STM32_TIMERS. The dependency
is probably fine for MFD_STM32_TIMERS, though even there && OF seems too
much, since it's already pulled in via ARCH_STM32 -> ARM_SINGLE_ARMV7M
-> USE_OF.

Thierry

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Re: [PATCH v7 4/8] PWM: add PWM driver for STM32 plaftorm

[Benjamin Gaignard]

2017-01-18 11:08 GMT+01:00 Thierry Reding <thierry.reding@gmail.com>:
> On Thu, Jan 05, 2017 at 10:25:40AM +0100, Benjamin Gaignard wrote:
>> This driver adds support for PWM driver on STM32 platform.
>> The SoC have multiple instances of the hardware IP and each
>> of them could have small differences: number of channels,
>> complementary output, auto reload register size...
>>
>> version 6:
>> - change st,breakinput parameter to make it usuable for stm32f7 too.
>>
>> version 4:
>> - detect at probe time hardware capabilities
>> - fix comments done on v2 and v3
>> - use PWM atomic ops
>>
>> version 2:
>> - only keep one comptatible
>> - use DT parameters to discover hardware block configuration
>>
>> Signed-off-by: Benjamin Gaignard <benjamin.gaignard@st.com>
>> ---
>>  drivers/pwm/Kconfig     |   9 +
>>  drivers/pwm/Makefile    |   1 +
>>  drivers/pwm/pwm-stm32.c | 434 ++++++++++++++++++++++++++++++++++++++++++++++++
>>  3 files changed, 444 insertions(+)
>>  create mode 100644 drivers/pwm/pwm-stm32.c
>>
>> diff --git a/drivers/pwm/Kconfig b/drivers/pwm/Kconfig
>> index f92dd41..88035c0 100644
>> --- a/drivers/pwm/Kconfig
>> +++ b/drivers/pwm/Kconfig
>> @@ -397,6 +397,15 @@ config PWM_STI
>>         To compile this driver as a module, choose M here: the module
>>         will be called pwm-sti.
>>
>> +config PWM_STM32
>> +     tristate "STMicroelectronics STM32 PWM"
>> +     depends on (ARCH_STM32 && OF && MFD_STM32_TIMERS) || COMPILE_TEST
>> +     help
>> +       Generic PWM framework driver for STM32 SoCs.
>> +
>> +       To compile this driver as a module, choose M here: the module
>> +       will be called pwm-stm32.
>> +
>>  config PWM_STMPE
>>       bool "STMPE expander PWM export"
>>       depends on MFD_STMPE
>> diff --git a/drivers/pwm/Makefile b/drivers/pwm/Makefile
>> index a48bdb5..346a83b 100644
>> --- a/drivers/pwm/Makefile
>> +++ b/drivers/pwm/Makefile
>> @@ -38,6 +38,7 @@ obj-$(CONFIG_PWM_ROCKCHIP)  += pwm-rockchip.o
>>  obj-$(CONFIG_PWM_SAMSUNG)    += pwm-samsung.o
>>  obj-$(CONFIG_PWM_SPEAR)              += pwm-spear.o
>>  obj-$(CONFIG_PWM_STI)                += pwm-sti.o
>> +obj-$(CONFIG_PWM_STM32)              += pwm-stm32.o
>>  obj-$(CONFIG_PWM_STMPE)              += pwm-stmpe.o
>>  obj-$(CONFIG_PWM_SUN4I)              += pwm-sun4i.o
>>  obj-$(CONFIG_PWM_TEGRA)              += pwm-tegra.o
>> diff --git a/drivers/pwm/pwm-stm32.c b/drivers/pwm/pwm-stm32.c
>> new file mode 100644
>> index 0000000..fcf0a78
>> --- /dev/null
>> +++ b/drivers/pwm/pwm-stm32.c
>> @@ -0,0 +1,434 @@
>> +/*
>> + * Copyright (C) STMicroelectronics 2016
>> + *
>> + * Author: Gerald Baeza <gerald.baeza@st.com>
>> + *
>> + * License terms: GNU General Public License (GPL), version 2
>> + *
>> + * Inspired by timer-stm32.c from Maxime Coquelin
>> + *             pwm-atmel.c from Bo Shen
>> + */
>> +
>> +#include <linux/mfd/stm32-timers.h>
>> +#include <linux/module.h>
>> +#include <linux/platform_device.h>
>> +#include <linux/pwm.h>
>> +#include <linux/of.h>
>
> Can you please sort these alphabetically?

sure

>
>> +
>> +#define CCMR_CHANNEL_SHIFT 8
>> +#define CCMR_CHANNEL_MASK  0xFF
>> +#define MAX_BREAKINPUT 2
>
> Okay, this answers my question regarding the st,breakinput property. I
> still think it'd be good to have this in the binding documentation just
> to avoid having to look at implementation to find out.
>
>> +
>> +struct stm32_pwm {
>> +     struct pwm_chip chip;
>> +     struct device *dev;
>> +     struct clk *clk;
>> +     struct regmap *regmap;
>> +     unsigned int caps;
>
> This seems completely unused?

Yes I will remove it

>
>> +     unsigned int npwm;
>
> It's somewhat redundant to have this here, since the same information is
> already contained in struct pwm_chip.npwm.
>
> Since you use this primarily for detection, how about you make the
> stm32_pwm_detect_channels() function return the value and store it in a
> local variable in ->probe()? That might be useful also because you
> need to check the return value of regmap_update_bits() which technically
> could fail.
>

I will remove npwm field and put the result of stm32_pwm_detect_channels()
directly on chip.npwm.

regmap functions could failed (even if I haven't experiment that case)
but testing all
return make the code unreadable so I have decide to not test it....

>> +     u32 max_arr;
>> +     bool have_complementary_output;
>> +};
>> +
>> +struct stm32_breakinput {
>> +     u32 index;
>> +     u32 level;
>> +     u32 filter;
>> +};
>> +
>> +static inline struct stm32_pwm *to_stm32_pwm_dev(struct pwm_chip *chip)
>> +{
>> +     return container_of(chip, struct stm32_pwm, chip);
>> +}
>> +
>> +static u32 active_channels(struct stm32_pwm *dev)
>> +{
>> +     u32 ccer;
>> +
>> +     regmap_read(dev->regmap, TIM_CCER, &ccer);
>> +
>> +     return ccer & TIM_CCER_CCXE;
>> +}
>
> This looks like something that you could track in software, but this is
> probably fine, too. Again, technically regmap_read() could fail, so you
> might want to consider adding some code to handle it. In practice it
> probably won't, so maybe you don't.

TIM_CCER_CCXE is a value that IIO timer can also read (not write) so
I have keep the same logic for pwm driver.

>
>> +
>> +static int write_ccrx(struct stm32_pwm *dev, struct pwm_device *pwm,
>> +                   u32 value)
>> +{
>> +     switch (pwm->hwpwm) {
>> +     case 0:
>> +             return regmap_write(dev->regmap, TIM_CCR1, value);
>> +     case 1:
>> +             return regmap_write(dev->regmap, TIM_CCR2, value);
>> +     case 2:
>> +             return regmap_write(dev->regmap, TIM_CCR3, value);
>> +     case 3:
>> +             return regmap_write(dev->regmap, TIM_CCR4, value);
>> +     }
>> +     return -EINVAL;
>> +}
>> +
>> +static int stm32_pwm_config(struct pwm_chip *chip, struct pwm_device *pwm,
>> +                         int duty_ns, int period_ns)
>> +{
>> +     struct stm32_pwm *priv = to_stm32_pwm_dev(chip);
>> +     unsigned long long prd, div, dty;
>> +     unsigned int prescaler = 0;
>> +     u32 ccmr, mask, shift;
>> +
>> +     /* Period and prescaler values depends on clock rate */
>> +     div = (unsigned long long)clk_get_rate(priv->clk) * period_ns;
>> +
>> +     do_div(div, NSEC_PER_SEC);
>> +     prd = div;
>> +
>> +     while (div > priv->max_arr) {
>> +             prescaler++;
>> +             div = prd;
>> +             do_div(div, (prescaler + 1));
>
> Nit: there's no need for the parentheses here.

okay

>> +     }
>> +
>> +     prd = div;
>> +
>> +     if (prescaler > MAX_TIM_PSC) {
>> +             dev_err(chip->dev, "prescaler exceeds the maximum value\n");
>> +             return -EINVAL;
>> +     }
>> +
>> +     /*
>> +      * All channels share the same prescaler and counter so when two
>> +      * channels are active at the same we can't change them
>
> Nit: "at the same time"?

okay

>
>> +      */
>> +     if (active_channels(priv) & ~(1 << pwm->hwpwm * 4)) {
>> +             u32 psc, arr;
>> +
>> +             regmap_read(priv->regmap, TIM_PSC, &psc);
>> +             regmap_read(priv->regmap, TIM_ARR, &arr);
>> +
>> +             if ((psc != prescaler) || (arr != prd - 1))
>> +                     return -EBUSY;
>> +     }
>> +
>> +     regmap_write(priv->regmap, TIM_PSC, prescaler);
>> +     regmap_write(priv->regmap, TIM_ARR, prd - 1);
>> +     regmap_update_bits(priv->regmap, TIM_CR1, TIM_CR1_ARPE, TIM_CR1_ARPE);
>> +
>> +     /* Calculate the duty cycles */
>> +     dty = prd * duty_ns;
>> +     do_div(dty, period_ns);
>> +
>> +     write_ccrx(priv, pwm, dty);
>> +
>> +     /* Configure output mode */
>> +     shift = (pwm->hwpwm & 0x1) * CCMR_CHANNEL_SHIFT;
>> +     ccmr = (TIM_CCMR_PE | TIM_CCMR_M1) << shift;
>> +     mask = CCMR_CHANNEL_MASK << shift;
>> +
>> +     if (pwm->hwpwm < 2)
>> +             regmap_update_bits(priv->regmap, TIM_CCMR1, mask, ccmr);
>> +     else
>> +             regmap_update_bits(priv->regmap, TIM_CCMR2, mask, ccmr);
>> +
>> +     regmap_update_bits(priv->regmap, TIM_BDTR,
>> +                        TIM_BDTR_MOE | TIM_BDTR_AOE,
>> +                        TIM_BDTR_MOE | TIM_BDTR_AOE);
>> +
>> +     return 0;
>> +}
>> +
>> +static int stm32_pwm_set_polarity(struct pwm_chip *chip, struct pwm_device *pwm,
>> +                               enum pwm_polarity polarity)
>> +{
>> +     u32 mask;
>> +     struct stm32_pwm *priv = to_stm32_pwm_dev(chip);
>> +
>> +     mask = TIM_CCER_CC1P << (pwm->hwpwm * 4);
>> +     if (priv->have_complementary_output)
>> +             mask |= TIM_CCER_CC1NP << (pwm->hwpwm * 4);
>> +
>> +     regmap_update_bits(priv->regmap, TIM_CCER, mask,
>> +                        polarity == PWM_POLARITY_NORMAL ? 0 : mask);
>> +
>> +     return 0;
>> +}
>> +
>> +static int stm32_pwm_enable(struct pwm_chip *chip, struct pwm_device *pwm)
>> +{
>> +     u32 mask;
>> +     struct stm32_pwm *priv = to_stm32_pwm_dev(chip);
>> +
>> +     clk_enable(priv->clk);
>
> This can fail, so its return value should be checked. Also, I don't see
> a clk_prepare() anywhere. Is that something that maybe the MFD driver
> should be doing? It currently isn't.

I will check the return value.
You are right clk_prepare() is done in mfd driver when calling
devm_regmap_init_mmio_clk()

>
>> +
>> +     /* Enable channel */
>> +     mask = TIM_CCER_CC1E << (pwm->hwpwm * 4);
>> +     if (priv->have_complementary_output)
>> +             mask |= TIM_CCER_CC1NE << (pwm->hwpwm * 4);
>> +
>> +     regmap_update_bits(priv->regmap, TIM_CCER, mask, mask);
>> +
>> +     /* Make sure that registers are updated */
>> +     regmap_update_bits(priv->regmap, TIM_EGR, TIM_EGR_UG, TIM_EGR_UG);
>> +
>> +     /* Enable controller */
>> +     regmap_update_bits(priv->regmap, TIM_CR1, TIM_CR1_CEN, TIM_CR1_CEN);
>> +
>> +     return 0;
>> +}
>> +
>> +static void stm32_pwm_disable(struct pwm_chip *chip, struct pwm_device *pwm)
>> +{
>> +     u32 mask;
>> +     struct stm32_pwm *priv = to_stm32_pwm_dev(chip);
>> +
>> +     /* Disable channel */
>> +     mask = TIM_CCER_CC1E << (pwm->hwpwm * 4);
>> +     if (priv->have_complementary_output)
>> +             mask |= TIM_CCER_CC1NE << (pwm->hwpwm * 4);
>> +
>> +     regmap_update_bits(priv->regmap, TIM_CCER, mask, 0);
>> +
>> +     /* When all channels are disabled, we can disable the controller */
>> +     if (!active_channels(priv))
>> +             regmap_update_bits(priv->regmap, TIM_CR1, TIM_CR1_CEN, 0);
>> +
>> +     clk_disable(priv->clk);
>> +}
>> +
>> +static int stm32_pwm_apply(struct pwm_chip *chip, struct pwm_device *pwm,
>> +                        struct pwm_state *state)
>> +{
>> +     struct pwm_state curstate;
>> +     bool enabled;
>> +     int ret;
>> +
>> +     pwm_get_state(pwm, &curstate);
>> +     enabled = curstate.enabled;
>
> There should be no need to do this in drivers. pwm_get_state() is for
> PWM API users. Drivers can directly dereference pwm->state.

ok

>
>> +
>> +     if (enabled && !state->enabled) {
>> +             stm32_pwm_disable(chip, pwm);
>> +             return 0;
>> +     }
>> +
>> +     if (state->polarity != curstate.polarity && enabled)
>> +             stm32_pwm_set_polarity(chip, pwm, state->polarity);
>
> So that's kind of a violation of atomic API semantics. The above means
> that if you have a PWM in the following state:
>
>         enabled: no
>         polarity: normal
>
> and want to set this:
>
>         enabled: yes
>         polarity: inversed
>
> then you will ignore the new polarity setting. What's the reason for
> "&& enabled) in the conditional above?

There is no reason, I will remove it.

>> +
>> +     ret = stm32_pwm_config(chip, pwm, state->duty_cycle, state->period);
>> +     if (ret)
>> +             return ret;
>> +
>> +     if (!enabled && state->enabled)
>> +             ret = stm32_pwm_enable(chip, pwm);
>> +
>> +     return ret;
>> +}
>
> Would it be possible to merge stm32_pwm_disable(), stm32_pwm_enable(),
> stm32_pwm_set_polarity() and stm32_pwm_config() into stm32_pwm_apply()?
> Part of the reason for the atomic API was to make it easier to write
> these drivers, but your implementation effectively copies what the
> transitional helpers do.
>
> It might not make a difference technically in your case, but I think
> it'd make the implementation more compact and set a better example for
> future reference.

hmm... it will create a fat function with lot of where
enabling/disabling/configuration
will be mixed I'm really not convince that will more compact and readable.

>
>> +
>> +static const struct pwm_ops stm32pwm_ops = {
>> +     .owner = THIS_MODULE,
>> +     .apply = stm32_pwm_apply,
>> +};
>> +
>> +static int stm32_pwm_set_breakinput(struct stm32_pwm *priv,
>> +                                 int level, int filter)
>> +{
>> +     u32 bdtr = TIM_BDTR_BKE;
>> +
>> +     if (level)
>> +             bdtr |= TIM_BDTR_BKP;
>> +
>> +     bdtr |= (filter & TIM_BDTR_BKF_MASK) << TIM_BDTR_BKF_SHIFT;
>> +
>> +     regmap_update_bits(priv->regmap,
>> +                        TIM_BDTR, TIM_BDTR_BKE | TIM_BDTR_BKP | TIM_BDTR_BKF,
>> +                        bdtr);
>> +
>> +     regmap_read(priv->regmap, TIM_BDTR, &bdtr);
>> +
>> +     return (bdtr & TIM_BDTR_BKE) ? 0 : -EINVAL;
>> +}
>> +
>> +static int stm32_pwm_set_breakinput2(struct stm32_pwm *priv,
>> +                                  int level, int filter)
>> +{
>> +     u32 bdtr = TIM_BDTR_BK2E;
>> +
>> +     if (level)
>> +             bdtr |= TIM_BDTR_BK2P;
>> +
>> +     bdtr |= (filter & TIM_BDTR_BKF_MASK) << TIM_BDTR_BK2F_SHIFT;
>> +
>> +     regmap_update_bits(priv->regmap,
>> +                        TIM_BDTR, TIM_BDTR_BK2E |
>> +                        TIM_BDTR_BK2P |
>> +                        TIM_BDTR_BK2F,
>> +                        bdtr);
>> +
>> +     regmap_read(priv->regmap, TIM_BDTR, &bdtr);
>> +
>> +     return (bdtr & TIM_BDTR_BK2E) ? 0 : -EINVAL;
>> +}
>
> As far as I can tell the only difference here is the various bit
> positions. Can you collapse the above two functions and add a new
> parameter to unify some code?

Yes it is all about bit shifting, I had try unify those two functions
with index has additional parameter
but it just add if() before each lines so no real benefit for code size.

>
>> +
>> +static int stm32_pwm_apply_breakinputs(struct stm32_pwm *priv,
>> +                                    struct device_node *np)
>> +{
>> +     struct stm32_breakinput breakinput[MAX_BREAKINPUT];
>> +     int nb, ret, i, array_size;
>> +
>> +     nb = of_property_count_elems_of_size(np, "st,breakinput",
>> +                                          sizeof(struct stm32_breakinput));
>> +
>> +     /*
>> +      * Because "st,breakinput" parameter is optional do not make probe
>> +      * failed if it doesn't exist.
>> +      */
>> +     if (nb <= 0)
>> +             return 0;
>> +
>> +     if (nb > MAX_BREAKINPUT)
>> +             return -EINVAL;
>> +
>> +     array_size = nb * sizeof(struct stm32_breakinput) / sizeof(u32);
>> +     ret = of_property_read_u32_array(np, "st,breakinput",
>> +                                      &breakinput[0].index, array_size);
>
> Maybe (u32 *)breakinput? That would make it more resilient against
> changes in ordering of fields in the struct. Granted, that's not likely
> to change, but I think it's a good idea in general to write code in a
> way that's safe in a more general case. That way if somebody ever were
> to copy from your code and then decide to reorder fields in their code
> things wouldn't fall apart.

Yes it is not suppose to change but I will use (u32 *)breakinput.

>> +     if (ret)
>> +             return ret;
>> +
>> +     for (i = 0; i < nb && !ret; i++) {
>> +             switch (breakinput[i].index) {
>> +             case 0:
>> +             {
>> +                     ret = stm32_pwm_set_breakinput(priv,
>> +                                                    breakinput[i].level,
>> +                                                    breakinput[i].filter);
>> +                     break;
>> +             }
>
> Curly braces are unnecessary here.

removed

>
>> +             case 1:
>> +             {
>> +                     ret = stm32_pwm_set_breakinput2(priv,
>> +                                                     breakinput[i].level,
>> +                                                     breakinput[i].filter);
>> +
>> +                     break;
>> +             }
>> +             default:
>> +             {
>> +                     ret = -EINVAL;
>> +                     break;
>> +             }
>> +             }
>> +     }
>> +
>> +     return ret;
>> +}
>> +
>> +static void stm32_pwm_detect_complementary(struct stm32_pwm *priv)
>> +{
>> +     u32 ccer;
>> +
>> +     /*
>> +      * If complementary bit doesn't exist writing 1 will have no
>> +      * effect so we can detect it.
>> +      */
>> +     regmap_update_bits(priv->regmap,
>> +                        TIM_CCER, TIM_CCER_CC1NE, TIM_CCER_CC1NE);
>> +     regmap_read(priv->regmap, TIM_CCER, &ccer);
>> +     regmap_update_bits(priv->regmap, TIM_CCER, TIM_CCER_CCXE, 0);
>
> This is strange: why are we disabling outputs here? Shouldn't the last
> line here undo the first instead?

Yes it should TIM_CCER_CC1NE not TIM_CCER_CCXE, I will fix it, thanks

>
>> +
>> +     priv->have_complementary_output = (ccer != 0);
>> +}
>> +
>> +static void stm32_pwm_detect_channels(struct stm32_pwm *priv)
>> +{
>> +     u32 ccer;
>> +
>> +     /*
>> +      * If channels enable bits don't exist writing 1 will have no
>> +      * effect so we can detect and count them.
>> +      */
>> +     regmap_update_bits(priv->regmap,
>> +                        TIM_CCER, TIM_CCER_CCXE, TIM_CCER_CCXE);
>> +     regmap_read(priv->regmap, TIM_CCER, &ccer);
>> +     regmap_update_bits(priv->regmap, TIM_CCER, TIM_CCER_CCXE, 0);
>
> Does this have the potential to glitch? I suspect that the clock may not
> be on at this point and therefore no PWM outputs will be generated, but
> is that guaranteed to always be the case?

Set TIM_CCER_CCXE isn't enough to enable PWM generation, TIM_CR1_CEN
in TIM_CR1 register must also to set so no risk of glitch here

>
> Thierry



-- 
Benjamin Gaignard

Graphic Study Group

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Re: [PATCH v7 4/8] PWM: add PWM driver for STM32 plaftorm

[Benjamin Gaignard]

2017-01-18 11:16 GMT+01:00 Thierry Reding <thierry.reding@gmail.com>:
> On Thu, Jan 05, 2017 at 10:25:40AM +0100, Benjamin Gaignard wrote:
> [...]
>> diff --git a/drivers/pwm/Kconfig b/drivers/pwm/Kconfig
>> index f92dd41..88035c0 100644
>> --- a/drivers/pwm/Kconfig
>> +++ b/drivers/pwm/Kconfig
>> @@ -397,6 +397,15 @@ config PWM_STI
>>         To compile this driver as a module, choose M here: the module
>>         will be called pwm-sti.
>>
>> +config PWM_STM32
>> +     tristate "STMicroelectronics STM32 PWM"
>> +     depends on (ARCH_STM32 && OF && MFD_STM32_TIMERS) || COMPILE_TEST
>
> One other thing: is the dependency on ARCH_STM32 and OF necessary here?
> ARCH_STM32 and OF are both pulled in by MFD_STM32_TIMERS. The dependency
> is probably fine for MFD_STM32_TIMERS, though even there && OF seems too
> much, since it's already pulled in via ARCH_STM32 -> ARM_SINGLE_ARMV7M
> -> USE_OF.

Said like that MFD_STM32_TIMERS is enough so I will keep this one

Thanks

>
> Thierry



-- 
Benjamin Gaignard

Graphic Study Group

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Re: [PATCH v7 4/8] PWM: add PWM driver for STM32 plaftorm

[Thierry Reding]

[-- Attachment #1: Type: text/plain, Size: 4616 bytes --]

On Wed, Jan 18, 2017 at 12:15:58PM +0100, Benjamin Gaignard wrote:
> 2017-01-18 11:08 GMT+01:00 Thierry Reding <thierry.reding@gmail.com>:
> > On Thu, Jan 05, 2017 at 10:25:40AM +0100, Benjamin Gaignard wrote:
[...]
> >> +static u32 active_channels(struct stm32_pwm *dev)
> >> +{
> >> +     u32 ccer;
> >> +
> >> +     regmap_read(dev->regmap, TIM_CCER, &ccer);
> >> +
> >> +     return ccer & TIM_CCER_CCXE;
> >> +}
> >
> > This looks like something that you could track in software, but this is
> > probably fine, too. Again, technically regmap_read() could fail, so you
> > might want to consider adding some code to handle it. In practice it
> > probably won't, so maybe you don't.
> 
> TIM_CCER_CCXE is a value that IIO timer can also read (not write) so
> I have keep the same logic for pwm driver.

Would that not be racy? What happens if after active_channels() here,
the IIO timer modifies the TIM_CCER register?

> >> +     ret = stm32_pwm_config(chip, pwm, state->duty_cycle, state->period);
> >> +     if (ret)
> >> +             return ret;
> >> +
> >> +     if (!enabled && state->enabled)
> >> +             ret = stm32_pwm_enable(chip, pwm);
> >> +
> >> +     return ret;
> >> +}
> >
> > Would it be possible to merge stm32_pwm_disable(), stm32_pwm_enable(),
> > stm32_pwm_set_polarity() and stm32_pwm_config() into stm32_pwm_apply()?
> > Part of the reason for the atomic API was to make it easier to write
> > these drivers, but your implementation effectively copies what the
> > transitional helpers do.
> >
> > It might not make a difference technically in your case, but I think
> > it'd make the implementation more compact and set a better example for
> > future reference.
> 
> hmm... it will create a fat function with lot of where
> enabling/disabling/configuration
> will be mixed I'm really not convince that will more compact and readable.

I don't object to splitting this up into separate functions, I just
don't think the functions should correspond to the legacy ones. One
variant that I think could work out nicely would be to have one
function that precomputes the various values, call in from ->apply()
and then do only the register writes along with a couple of
conditionals depending on enable state, for example.

> >> +static const struct pwm_ops stm32pwm_ops = {
> >> +     .owner = THIS_MODULE,
> >> +     .apply = stm32_pwm_apply,
> >> +};
> >> +
> >> +static int stm32_pwm_set_breakinput(struct stm32_pwm *priv,
> >> +                                 int level, int filter)
> >> +{
> >> +     u32 bdtr = TIM_BDTR_BKE;
> >> +
> >> +     if (level)
> >> +             bdtr |= TIM_BDTR_BKP;
> >> +
> >> +     bdtr |= (filter & TIM_BDTR_BKF_MASK) << TIM_BDTR_BKF_SHIFT;
> >> +
> >> +     regmap_update_bits(priv->regmap,
> >> +                        TIM_BDTR, TIM_BDTR_BKE | TIM_BDTR_BKP | TIM_BDTR_BKF,
> >> +                        bdtr);
> >> +
> >> +     regmap_read(priv->regmap, TIM_BDTR, &bdtr);
> >> +
> >> +     return (bdtr & TIM_BDTR_BKE) ? 0 : -EINVAL;
> >> +}
> >> +
> >> +static int stm32_pwm_set_breakinput2(struct stm32_pwm *priv,
> >> +                                  int level, int filter)
> >> +{
> >> +     u32 bdtr = TIM_BDTR_BK2E;
> >> +
> >> +     if (level)
> >> +             bdtr |= TIM_BDTR_BK2P;
> >> +
> >> +     bdtr |= (filter & TIM_BDTR_BKF_MASK) << TIM_BDTR_BK2F_SHIFT;
> >> +
> >> +     regmap_update_bits(priv->regmap,
> >> +                        TIM_BDTR, TIM_BDTR_BK2E |
> >> +                        TIM_BDTR_BK2P |
> >> +                        TIM_BDTR_BK2F,
> >> +                        bdtr);
> >> +
> >> +     regmap_read(priv->regmap, TIM_BDTR, &bdtr);
> >> +
> >> +     return (bdtr & TIM_BDTR_BK2E) ? 0 : -EINVAL;
> >> +}
> >
> > As far as I can tell the only difference here is the various bit
> > positions. Can you collapse the above two functions and add a new
> > parameter to unify some code?
> 
> Yes it is all about bit shifting, I had try unify those two functions
> with index has additional parameter
> but it just add if() before each lines so no real benefit for code size.

How about if you precompute the values and masks? Something like:

	u32 bke = (index == 0) ? ... : ...;
	u32 bkp = (index == 0) ? ... : ...;
	u32 bkf = (index == 0) ? ... : ...;
	u32 mask = (index == 0) ? ... : ...;

	bdtr = bke | bkf;

	if (level)
		bdtr |= bkp;

	regmap_update_bits(priv->regmap, TIM_BDTR, mask, bdtr);

	regmap_read(priv->regmap, TIM_BDTR, &bdtr);

	return (bdtr & bke) ? 0 : -EINVAL;

?

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Re: [PATCH v7 4/8] PWM: add PWM driver for STM32 plaftorm

[Benjamin Gaignard]

2017-01-18 12:37 GMT+01:00 Thierry Reding <thierry.reding@gmail.com>:
> On Wed, Jan 18, 2017 at 12:15:58PM +0100, Benjamin Gaignard wrote:
>> 2017-01-18 11:08 GMT+01:00 Thierry Reding <thierry.reding@gmail.com>:
>> > On Thu, Jan 05, 2017 at 10:25:40AM +0100, Benjamin Gaignard wrote:
> [...]
>> >> +static u32 active_channels(struct stm32_pwm *dev)
>> >> +{
>> >> +     u32 ccer;
>> >> +
>> >> +     regmap_read(dev->regmap, TIM_CCER, &ccer);
>> >> +
>> >> +     return ccer & TIM_CCER_CCXE;
>> >> +}
>> >
>> > This looks like something that you could track in software, but this is
>> > probably fine, too. Again, technically regmap_read() could fail, so you
>> > might want to consider adding some code to handle it. In practice it
>> > probably won't, so maybe you don't.
>>
>> TIM_CCER_CCXE is a value that IIO timer can also read (not write) so
>> I have keep the same logic for pwm driver.
>
> Would that not be racy? What happens if after active_channels() here,
> the IIO timer modifies the TIM_CCER register?

IIO timer only read this register not write it so no racy condition here

>
>> >> +     ret = stm32_pwm_config(chip, pwm, state->duty_cycle, state->period);
>> >> +     if (ret)
>> >> +             return ret;
>> >> +
>> >> +     if (!enabled && state->enabled)
>> >> +             ret = stm32_pwm_enable(chip, pwm);
>> >> +
>> >> +     return ret;
>> >> +}
>> >
>> > Would it be possible to merge stm32_pwm_disable(), stm32_pwm_enable(),
>> > stm32_pwm_set_polarity() and stm32_pwm_config() into stm32_pwm_apply()?
>> > Part of the reason for the atomic API was to make it easier to write
>> > these drivers, but your implementation effectively copies what the
>> > transitional helpers do.
>> >
>> > It might not make a difference technically in your case, but I think
>> > it'd make the implementation more compact and set a better example for
>> > future reference.
>>
>> hmm... it will create a fat function with lot of where
>> enabling/disabling/configuration
>> will be mixed I'm really not convince that will more compact and readable.
>
> I don't object to splitting this up into separate functions, I just
> don't think the functions should correspond to the legacy ones. One
> variant that I think could work out nicely would be to have one
> function that precomputes the various values, call in from ->apply()
> and then do only the register writes along with a couple of
> conditionals depending on enable state, for example.

Ok I will change functions prototype so they will not be like legacy ones
but I will keep the current split.

>
>> >> +static const struct pwm_ops stm32pwm_ops = {
>> >> +     .owner = THIS_MODULE,
>> >> +     .apply = stm32_pwm_apply,
>> >> +};
>> >> +
>> >> +static int stm32_pwm_set_breakinput(struct stm32_pwm *priv,
>> >> +                                 int level, int filter)
>> >> +{
>> >> +     u32 bdtr = TIM_BDTR_BKE;
>> >> +
>> >> +     if (level)
>> >> +             bdtr |= TIM_BDTR_BKP;
>> >> +
>> >> +     bdtr |= (filter & TIM_BDTR_BKF_MASK) << TIM_BDTR_BKF_SHIFT;
>> >> +
>> >> +     regmap_update_bits(priv->regmap,
>> >> +                        TIM_BDTR, TIM_BDTR_BKE | TIM_BDTR_BKP | TIM_BDTR_BKF,
>> >> +                        bdtr);
>> >> +
>> >> +     regmap_read(priv->regmap, TIM_BDTR, &bdtr);
>> >> +
>> >> +     return (bdtr & TIM_BDTR_BKE) ? 0 : -EINVAL;
>> >> +}
>> >> +
>> >> +static int stm32_pwm_set_breakinput2(struct stm32_pwm *priv,
>> >> +                                  int level, int filter)
>> >> +{
>> >> +     u32 bdtr = TIM_BDTR_BK2E;
>> >> +
>> >> +     if (level)
>> >> +             bdtr |= TIM_BDTR_BK2P;
>> >> +
>> >> +     bdtr |= (filter & TIM_BDTR_BKF_MASK) << TIM_BDTR_BK2F_SHIFT;
>> >> +
>> >> +     regmap_update_bits(priv->regmap,
>> >> +                        TIM_BDTR, TIM_BDTR_BK2E |
>> >> +                        TIM_BDTR_BK2P |
>> >> +                        TIM_BDTR_BK2F,
>> >> +                        bdtr);
>> >> +
>> >> +     regmap_read(priv->regmap, TIM_BDTR, &bdtr);
>> >> +
>> >> +     return (bdtr & TIM_BDTR_BK2E) ? 0 : -EINVAL;
>> >> +}
>> >
>> > As far as I can tell the only difference here is the various bit
>> > positions. Can you collapse the above two functions and add a new
>> > parameter to unify some code?
>>
>> Yes it is all about bit shifting, I had try unify those two functions
>> with index has additional parameter
>> but it just add if() before each lines so no real benefit for code size.
>
> How about if you precompute the values and masks? Something like:
>
>         u32 bke = (index == 0) ? ... : ...;
>         u32 bkp = (index == 0) ? ... : ...;
>         u32 bkf = (index == 0) ? ... : ...;
>         u32 mask = (index == 0) ? ... : ...;
>
>         bdtr = bke | bkf;
>
>         if (level)
>                 bdtr |= bkp;
>
>         regmap_update_bits(priv->regmap, TIM_BDTR, mask, bdtr);
>
>         regmap_read(priv->regmap, TIM_BDTR, &bdtr);
>
>         return (bdtr & bke) ? 0 : -EINVAL;
>
> ?

ok done


-- 
Benjamin Gaignard

Graphic Study Group

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