Re: [PATCH v8 02/11] mfd: sy7636a: Initial commit

On Wed, 04 Aug 2021, Alistair Francis wrote:

On Wed, Aug 4, 2021 at 7:06 PM Lee Jones [off-list ref] wrote:

quoted

On Wed, 04 Aug 2021, Alistair Francis wrote:

quoted

On Tue, Aug 3, 2021 at 11:16 PM Lee Jones [off-list ref] wrote:

quoted

On Tue, 03 Aug 2021, Alistair Francis wrote:

quoted

Initial support for the Silergy SY7636A Power Management chip.

Signed-off-by: Alistair Francis <redacted>
---
 drivers/mfd/Kconfig         |  9 +++++
 drivers/mfd/Makefile        |  1 +
 drivers/mfd/sy7636a.c       | 72 +++++++++++++++++++++++++++++++++++++
 include/linux/mfd/sy7636a.h | 45 +++++++++++++++++++++++
 4 files changed, 127 insertions(+)
 create mode 100644 drivers/mfd/sy7636a.c
 create mode 100644 include/linux/mfd/sy7636a.h

diff --git a/drivers/mfd/Kconfig b/drivers/mfd/Kconfig
index 6a3fd2d75f96..b82208f0c79c 100644
--- a/drivers/mfd/Kconfig
+++ b/drivers/mfd/Kconfig

@@ -1352,6 +1352,15 @@ config MFD_SYSCON
        Select this option to enable accessing system control registers
        via regmap.

+config MFD_SY7636A
+     tristate "Silergy SY7636A Power Management IC"
+     select MFD_CORE
+     select REGMAP_I2C
+     depends on I2C
+     help
+       Select this option to enable support for the Silergy SY7636A
+       Power Management IC.
+
 config MFD_DAVINCI_VOICECODEC
      tristate
      select MFD_CORE

diff --git a/drivers/mfd/Makefile b/drivers/mfd/Makefile
index 8116c19d5fd4..cbe581e87fa9 100644
--- a/drivers/mfd/Makefile
+++ b/drivers/mfd/Makefile

@@ -266,6 +266,7 @@ obj-$(CONFIG_MFD_KHADAS_MCU)      += khadas-mcu.o
 obj-$(CONFIG_MFD_ACER_A500_EC)       += acer-ec-a500.o
 obj-$(CONFIG_MFD_QCOM_PM8008)        += qcom-pm8008.o

+obj-$(CONFIG_MFD_SY7636A)    += sy7636a.o
 obj-$(CONFIG_SGI_MFD_IOC3)   += ioc3.o
 obj-$(CONFIG_MFD_SIMPLE_MFD_I2C)     += simple-mfd-i2c.o
 obj-$(CONFIG_MFD_INTEL_M10_BMC)   += intel-m10-bmc.o

diff --git a/drivers/mfd/sy7636a.c b/drivers/mfd/sy7636a.c
new file mode 100644
index 000000000000..f3ff93c7395d
--- /dev/null
+++ b/drivers/mfd/sy7636a.c

@@ -0,0 +1,72 @@
+// SPDX-License-Identifier: GPL-2.0+
+/*
+ * MFD parent driver for SY7636A chip
+ *
+ * Copyright (C) 2021 reMarkable AS - http://www.remarkable.com/
+ *
+ * Authors: Lars Ivar Miljeteig <lars.ivar.miljeteig@remarkable.com>
+ *          Alistair Francis <alistair@alistair23.me>
+ *
+ * Based on the lp87565 driver by Keerthy <j-keerthy@ti.com>
+ */
+
+#include <linux/interrupt.h>
+#include <linux/mfd/core.h>
+#include <linux/module.h>
+#include <linux/of_device.h>
+
+#include <linux/mfd/sy7636a.h>
+
+static const struct regmap_config sy7636a_regmap_config = {
+     .reg_bits = 8,
+     .val_bits = 8,
+};
+
+static const struct mfd_cell sy7636a_cells[] = {
+     { .name = "sy7636a-regulator", },

What kind of regulator is 'vcom'? LDO? DCDC?

Both I guess:

"SY7636A is a single-chip power management IC (PMIC) designed for
electronic paper display (EPD) applications. The device supports panel
sizes up to 9.7 inches and larger. The device integrates two
high-efficiency DC-DC boost converters, which are boosted to 25V and
-20V by two charge pumps to provide gate driver power for the panel.
Two tracking LDOs create a ±15V source driver power supply that
supports output currents up to 200mA. SY7636A also provides I2C
interface control for specific panel requirements"

Is there a datasheet I could look at?

I have managed to find this:

https://www.silergy.com/cn/productsview/SY7636ARMC

which is in Chinese. The datasheet is behind a login page unfortunately.

Where did the snippet above come from then?

What documentation are you working to?

-- 
Lee Jones [李琼斯]
Senior Technical Lead - Developer Services
Linaro.org │ Open source software for Arm SoCs
Follow Linaro: Facebook | Twitter | Blog