This adds a driver that supports the GPIO block found in
MStar/SigmaStar ARMv7 SoCs.

The controller seems to support 128 lines but where they
are wired up differs between chips and no currently known
chip uses anywhere near 128 lines so there needs to be some
per-chip data to collect together what lines actually have
physical pins attached and map the right names to them.

The core peripherals seem to use the same lines on the
currently known chips but the lines used for the sensor
interface, lcd controller etc pins seem to be totally
different between the infinity and mercury chips

The code tries to collect all of the re-usable names,
offsets etc together so that it's easy to build the extra
per-chip data for other chips in the future.

So far this only supports the MSC313 and MSC313E chips.

Support for the SSC8336N (mercury5) is trivial to add once
all of the lines have been mapped out.

Signed-off-by: Daniel Palmer <dan...@0x0f.com>
---
 MAINTAINERS                |   1 +
 drivers/gpio/Kconfig       |   9 +
 drivers/gpio/Makefile      |   1 +
 drivers/gpio/gpio-msc313.c | 341 +++++++++++++++++++++++++++++++++++++
 4 files changed, 352 insertions(+)
 create mode 100644 drivers/gpio/gpio-msc313.c

diff --git a/MAINTAINERS b/MAINTAINERS
index ec5b49b9955f..d20e8935dd4c 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -2158,6 +2158,7 @@ F:        Documentation/devicetree/bindings/arm/mstar/*
 F:     Documentation/devicetree/bindings/gpio/mstar,msc313-gpio.yaml
 F:     arch/arm/boot/dts/mstar-*
 F:     arch/arm/mach-mstar/
+F:     drivers/gpio/gpio-msc313.c
 F:     include/dt-bindings/gpio/msc313-gpio.h
 
 ARM/NEC MOBILEPRO 900/c MACHINE SUPPORT
diff --git a/drivers/gpio/Kconfig b/drivers/gpio/Kconfig
index 8030fd91a3cc..d85226cb2a07 100644
--- a/drivers/gpio/Kconfig
+++ b/drivers/gpio/Kconfig
@@ -712,6 +712,15 @@ config GPIO_AMD_FCH
          Note: This driver doesn't registers itself automatically, as it
          needs to be provided with platform specific configuration.
          (See eg. CONFIG_PCENGINES_APU2.)
+
+config GPIO_MSC313
+       bool "MStar MSC313 GPIO support"
+       default y if ARCH_MSTARV7
+       depends on ARCH_MSTARV7
+       select GPIO_GENERIC
+       help
+         Say Y here to support GPIO on MStar MSC313 and later SoCs.
+
 endmenu
 
 menu "Port-mapped I/O GPIO drivers"
diff --git a/drivers/gpio/Makefile b/drivers/gpio/Makefile
index 4f9abff4f2dc..7c675b502cc4 100644
--- a/drivers/gpio/Makefile
+++ b/drivers/gpio/Makefile
@@ -102,6 +102,7 @@ obj-$(CONFIG_GPIO_MOCKUP)           += gpio-mockup.o
 obj-$(CONFIG_GPIO_MOXTET)              += gpio-moxtet.o
 obj-$(CONFIG_GPIO_MPC5200)             += gpio-mpc5200.o
 obj-$(CONFIG_GPIO_MPC8XXX)             += gpio-mpc8xxx.o
+obj-$(CONFIG_GPIO_MSC313)              += gpio-msc313.o
 obj-$(CONFIG_GPIO_MSIC)                        += gpio-msic.o
 obj-$(CONFIG_GPIO_MT7621)              += gpio-mt7621.o
 obj-$(CONFIG_GPIO_MVEBU)               += gpio-mvebu.o
diff --git a/drivers/gpio/gpio-msc313.c b/drivers/gpio/gpio-msc313.c
new file mode 100644
index 000000000000..6bdab77674ae
--- /dev/null
+++ b/drivers/gpio/gpio-msc313.c
@@ -0,0 +1,341 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Copyright (C) 2020 Daniel Palmer<dan...@thingy.jp>
+ */
+
+#include <linux/of_device.h>
+#include <linux/of_irq.h>
+#include <linux/gpio/driver.h>
+
+#include <dt-bindings/gpio/msc313-gpio.h>
+
+#define DRIVER_NAME "gpio-msc313"
+
+#define MSC313_GPIO_IN  BIT(0)
+#define MSC313_GPIO_OUT BIT(4)
+#define MSC313_GPIO_OEN BIT(5)
+
+#define MSC313_GPIO_BITSTOSAVE (MSC313_GPIO_OUT | MSC313_GPIO_OEN)
+
+#define FUART_NAMES                    \
+       MSC313_PINNAME_FUART_RX,        \
+       MSC313_PINNAME_FUART_TX,        \
+       MSC313_PINNAME_FUART_CTS,       \
+       MSC313_PINNAME_FUART_RTS
+
+#define OFF_FUART_RX   0x50
+#define OFF_FUART_TX   0x54
+#define OFF_FUART_CTS  0x58
+#define OFF_FUART_RTS  0x5c
+
+#define FUART_OFFSETS  \
+       OFF_FUART_RX,   \
+       OFF_FUART_TX,   \
+       OFF_FUART_CTS,  \
+       OFF_FUART_RTS
+
+#define SR_NAMES               \
+       MSC313_PINNAME_SR_IO2,  \
+       MSC313_PINNAME_SR_IO3,  \
+       MSC313_PINNAME_SR_IO4,  \
+       MSC313_PINNAME_SR_IO5,  \
+       MSC313_PINNAME_SR_IO6,  \
+       MSC313_PINNAME_SR_IO7,  \
+       MSC313_PINNAME_SR_IO8,  \
+       MSC313_PINNAME_SR_IO9,  \
+       MSC313_PINNAME_SR_IO10, \
+       MSC313_PINNAME_SR_IO11, \
+       MSC313_PINNAME_SR_IO12, \
+       MSC313_PINNAME_SR_IO13, \
+       MSC313_PINNAME_SR_IO14, \
+       MSC313_PINNAME_SR_IO15, \
+       MSC313_PINNAME_SR_IO16, \
+       MSC313_PINNAME_SR_IO17
+
+#define OFF_SR_IO2     0x88
+#define OFF_SR_IO3     0x8c
+#define OFF_SR_IO4     0x90
+#define OFF_SR_IO5     0x94
+#define OFF_SR_IO6     0x98
+#define OFF_SR_IO7     0x9c
+#define OFF_SR_IO8     0xa0
+#define OFF_SR_IO9     0xa4
+#define OFF_SR_IO10    0xa8
+#define OFF_SR_IO11    0xac
+#define OFF_SR_IO12    0xb0
+#define OFF_SR_IO13    0xb4
+#define OFF_SR_IO14    0xb8
+#define OFF_SR_IO15    0xbc
+#define OFF_SR_IO16    0xc0
+#define OFF_SR_IO17    0xc4
+
+#define SR_OFFSETS     \
+       OFF_SR_IO2,     \
+       OFF_SR_IO3,     \
+       OFF_SR_IO4,     \
+       OFF_SR_IO5,     \
+       OFF_SR_IO6,     \
+       OFF_SR_IO7,     \
+       OFF_SR_IO8,     \
+       OFF_SR_IO9,     \
+       OFF_SR_IO10,    \
+       OFF_SR_IO11,    \
+       OFF_SR_IO12,    \
+       OFF_SR_IO13,    \
+       OFF_SR_IO14,    \
+       OFF_SR_IO15,    \
+       OFF_SR_IO16,    \
+       OFF_SR_IO17
+
+#define SD_NAMES               \
+       MSC313_PINNAME_SD_CLK,  \
+       MSC313_PINNAME_SD_CMD,  \
+       MSC313_PINNAME_SD_D0,   \
+       MSC313_PINNAME_SD_D1,   \
+       MSC313_PINNAME_SD_D2,   \
+       MSC313_PINNAME_SD_D3
+
+#define OFF_SD_CLK     0x140
+#define OFF_SD_CMD     0x144
+#define OFF_SD_D0      0x148
+#define OFF_SD_D1      0x14c
+#define OFF_SD_D2      0x150
+#define OFF_SD_D3      0x154
+
+#define SD_OFFSETS     \
+       OFF_SD_CLK,     \
+       OFF_SD_CMD,     \
+       OFF_SD_D0,      \
+       OFF_SD_D1,      \
+       OFF_SD_D2,      \
+       OFF_SD_D3
+
+#define I2C1_NAMES                     \
+       MSC313_PINNAME_I2C1_SCL,        \
+       MSC313_PINNAME_I2C1_SCA
+
+#define OFF_I2C1_SCL   0x188
+#define OFF_I2C1_SCA   0x18c
+
+#define I2C1_OFFSETS   \
+       OFF_I2C1_SCL,   \
+       OFF_I2C1_SCA
+
+#define SPI0_NAMES             \
+       MSC313_PINNAME_SPI0_CZ, \
+       MSC313_PINNAME_SPI0_CK, \
+       MSC313_PINNAME_SPI0_DI, \
+       MSC313_PINNAME_SPI0_DO
+
+#define OFF_SPI0_CZ    0x1c0
+#define OFF_SPI0_CK    0x1c4
+#define OFF_SPI0_DI    0x1c8
+#define OFF_SPI0_DO    0x1cc
+
+#define SPI0_OFFSETS   \
+       OFF_SPI0_CZ,    \
+       OFF_SPI0_CK,    \
+       OFF_SPI0_DI,    \
+       OFF_SPI0_DO
+
+struct msc313_gpio_data {
+       const char * const *names;
+       const unsigned int *offsets;
+       const unsigned int num;
+};
+
+#define MSC313_GPIO_CHIPDATA(_chip) \
+static const struct msc313_gpio_data _chip##_data = { \
+       .names = _chip##_names, \
+       .offsets = _chip##_offsets, \
+       .num = ARRAY_SIZE(_chip##_offsets), \
+}
+
+#ifdef CONFIG_MACH_INFINITY
+static const char * const msc313_names[] = {
+       FUART_NAMES,
+       SR_NAMES,
+       SD_NAMES,
+       I2C1_NAMES,
+       SPI0_NAMES,
+};
+
+static const unsigned int msc313_offsets[] = {
+       FUART_OFFSETS,
+       SR_OFFSETS,
+       SD_OFFSETS,
+       I2C1_OFFSETS,
+       SPI0_OFFSETS,
+};
+
+MSC313_GPIO_CHIPDATA(msc313);
+#endif
+
+struct msc313_gpio {
+       void __iomem *base;
+       const struct msc313_gpio_data *gpio_data;
+       int *irqs;
+       u8 *saved;
+};
+
+static void msc313_gpio_set(struct gpio_chip *chip, unsigned int offset, int 
value)
+{
+       struct msc313_gpio *gpio = gpiochip_get_data(chip);
+       u8 gpioreg = readb_relaxed(gpio->base + 
gpio->gpio_data->offsets[offset]);
+
+       if (value)
+               gpioreg |= MSC313_GPIO_OUT;
+       else
+               gpioreg &= ~MSC313_GPIO_OUT;
+
+       writeb_relaxed(gpioreg, gpio->base + gpio->gpio_data->offsets[offset]);
+}
+
+static int msc313_gpio_get(struct gpio_chip *chip, unsigned int offset)
+{
+       struct msc313_gpio *gpio = gpiochip_get_data(chip);
+
+       return readb_relaxed(gpio->base + gpio->gpio_data->offsets[offset])
+                       & MSC313_GPIO_IN;
+}
+
+static int msc313_gpio_direction_input(struct gpio_chip *chip, unsigned int 
offset)
+{
+       struct msc313_gpio *gpio = gpiochip_get_data(chip);
+       u8 gpioreg = readb_relaxed(gpio->base + 
gpio->gpio_data->offsets[offset]);
+
+       gpioreg |= MSC313_GPIO_OEN;
+       writeb_relaxed(gpioreg, gpio->base + gpio->gpio_data->offsets[offset]);
+
+       return 0;
+}
+
+static int msc313_gpio_direction_output(struct gpio_chip *chip, unsigned int 
offset, int value)
+{
+       struct msc313_gpio *gpio = gpiochip_get_data(chip);
+       u8 gpioreg = readb_relaxed(gpio->base + 
gpio->gpio_data->offsets[offset]);
+
+       gpioreg &= ~MSC313_GPIO_OEN;
+       if (value)
+               gpioreg |= MSC313_GPIO_OUT;
+       else
+               gpioreg &= ~MSC313_GPIO_OUT;
+       writeb_relaxed(gpioreg, gpio->base + gpio->gpio_data->offsets[offset]);
+
+       return 0;
+}
+
+static int msc313_gpio_to_irq(struct gpio_chip *chip, unsigned int offset)
+{
+       struct msc313_gpio *gpio = gpiochip_get_data(chip);
+
+       return gpio->irqs[offset];
+}
+
+static int msc313_gpio_probe(struct platform_device *pdev)
+{
+       int i, ret;
+       const struct msc313_gpio_data *match_data;
+       struct msc313_gpio *gpio;
+       struct resource *res;
+       struct gpio_chip *gpiochip;
+
+       match_data = of_device_get_match_data(&pdev->dev);
+       if (!match_data)
+               return -EINVAL;
+
+       gpio = devm_kzalloc(&pdev->dev, sizeof(*gpio), GFP_KERNEL);
+       if (!gpio)
+               return -ENOMEM;
+
+       gpio->gpio_data = match_data;
+
+       gpio->irqs = devm_kzalloc(&pdev->dev, gpio->gpio_data->num * 
sizeof(*gpio->irqs), GFP_KERNEL);
+       if (!gpio->irqs)
+               return -ENOMEM;
+
+       gpio->saved = devm_kzalloc(&pdev->dev, gpio->gpio_data->num * 
sizeof(*gpio->saved), GFP_KERNEL);
+       if (!gpio->saved)
+               return -ENOMEM;
+
+       platform_set_drvdata(pdev, gpio);
+
+       res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+       gpio->base = devm_ioremap_resource(&pdev->dev, res);
+       if (IS_ERR(gpio->base))
+               return PTR_ERR(gpio->base);
+
+       gpiochip = devm_kzalloc(&pdev->dev, sizeof(*gpiochip), GFP_KERNEL);
+       if (!gpiochip)
+               return -ENOMEM;
+
+       gpiochip->label = DRIVER_NAME;
+       gpiochip->parent = &pdev->dev;
+       gpiochip->request = gpiochip_generic_request;
+       gpiochip->free = gpiochip_generic_free;
+       gpiochip->direction_input = msc313_gpio_direction_input;
+       gpiochip->direction_output = msc313_gpio_direction_output;
+       gpiochip->get = msc313_gpio_get;
+       gpiochip->set = msc313_gpio_set;
+       gpiochip->to_irq = msc313_gpio_to_irq;
+       gpiochip->base = -1;
+       gpiochip->ngpio = gpio->gpio_data->num;
+       gpiochip->names = gpio->gpio_data->names;
+
+       for (i = 0; i < gpiochip->ngpio; i++)
+               gpio->irqs[i] = of_irq_get_byname(pdev->dev.of_node, 
gpio->gpio_data->names[i]);
+
+       ret = gpiochip_add_data(gpiochip, gpio);
+       return ret;
+}
+
+static const struct of_device_id msc313_gpio_of_match[] = {
+#ifdef CONFIG_MACH_INFINITY
+       {
+               .compatible = "mstar,msc313-gpio",
+               .data = &msc313_data,
+       },
+#endif
+       { }
+};
+
+/* The GPIO controller loses the state of the registers when the
+ * SoC goes into "DRAM self-refresh low power" mode so we need to
+ * save the direction and value before suspending and put it back
+ * when resuming.
+ */
+
+static int __maybe_unused msc313_gpio_suspend(struct device *dev)
+{
+       struct msc313_gpio *gpio = dev_get_drvdata(dev);
+       int i;
+
+       for (i = 0; i < gpio->gpio_data->num; i++)
+               gpio->saved[i] = readb_relaxed(gpio->base + 
gpio->gpio_data->offsets[i]) & MSC313_GPIO_BITSTOSAVE;
+
+       return 0;
+}
+
+static int __maybe_unused msc313_gpio_resume(struct device *dev)
+{
+       struct msc313_gpio *gpio = dev_get_drvdata(dev);
+       int i;
+
+       for (i = 0; i < gpio->gpio_data->num; i++)
+               writeb_relaxed(gpio->saved[i], gpio->base + 
gpio->gpio_data->offsets[i]);
+
+       return 0;
+}
+
+static SIMPLE_DEV_PM_OPS(msc313_gpio_ops, msc313_gpio_suspend, 
msc313_gpio_resume);
+
+static struct platform_driver msc313_gpio_driver = {
+       .driver = {
+               .name = DRIVER_NAME,
+               .of_match_table = msc313_gpio_of_match,
+               .pm = &msc313_gpio_ops,
+       },
+       .probe = msc313_gpio_probe,
+};
+
+builtin_platform_driver(msc313_gpio_driver);
-- 
2.27.0

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