[PATCH V8 1/3] mfd: Add support for UP board CPLD/FPGA

From: larry.lai
Date: Thu Dec 28 2023 - 10:16:46 EST


The UP Squared board <http://www.upboard.com> implements certain
features (pin control, onboard LEDs or CEC) through an on-board CPLD/FPGA.

This driver implements the line protocol to read and write registers
from the FPGA through regmap. The register address map is also included.

The UP Boards provide a few I/O pin headers (for both GPIO and
functions), including a 40-pin Raspberry Pi compatible header.

This patch implements the FPGA-based pin controller that manages direction
and enable state for those header pins.

Partial supported boards:
* UP core + CREX
* UP core + CRST02

Signed-off-by: Gary Wang <garywang@xxxxxxxxxxxx>
Signed-off-by: larry.lai <larry.lai@xxxxxxxxxxxxxxx>
---
PATCH V7 -> PATCH V8
(1) Refer 2023/11/14 Andy Shevchenko review, cleaned up coding style
and addressed review comments.
PATCH V6 -> PATCH V7
(1) Refer 2023/09/15 Lee Jones review, cleaned up coding style
and addressed review comments.
PATCH V5 -> PATCH V6
(1) Fixed kernel test robot compiler warning.
PATCH V4 -> PATCH V5
(1) Refer 2023/05/25 Lee Jones review, cleaned up coding style
and addressed review comments.
(2) Synchronizing upboard github to v1.0.5 tag.
RFC 2023/04/25 -> PATCH V4
(1) Fixed kernel test robot compiler warning.
(2) Remove mistakes with wrong Reviewed-by tags.
RFC 2022/11/23 -> RFC 2023/04/25
(1) Refer 2022/12/08 Andy Shevchenko review, cleaned up coding style
and addressed review comments.
PATCH V3 -> RFC 2022/11/23:
(1) Refer 2022/11/16 Lee Jones review, cleaned up coding style and
addressed review comments.
(2) Description on the UP Boards FPGA register read/write protocols
PATCH V2 -> V3:
(1) fixed kernel test robot compiler warning.
PATCH V1 -> V2:
(1) Synchronizing upboard github to rc2.
(2) Refer 2022/10/31 Lee Jones review, fixed some of the issues.
---
drivers/mfd/Kconfig | 12 +
drivers/mfd/Makefile | 1 +
drivers/mfd/upboard-fpga.c | 364 +++++++++++++++++++++++++++++++
include/linux/mfd/upboard-fpga.h | 59 +++++
4 files changed, 436 insertions(+)
create mode 100644 drivers/mfd/upboard-fpga.c
create mode 100644 include/linux/mfd/upboard-fpga.h

diff --git a/drivers/mfd/Kconfig b/drivers/mfd/Kconfig
index abb58ab1a1a4..54b5ddf782e3 100644
--- a/drivers/mfd/Kconfig
+++ b/drivers/mfd/Kconfig
@@ -2104,6 +2104,18 @@ config MFD_QCOM_PM8008
under it in the device tree. Additional drivers must be enabled in
order to use the functionality of the device.

+config MFD_UPBOARD_FPGA
+ tristate "Support for the Intel platform foundation kit UP board FPGA"
+ select MFD_CORE
+ depends on (X86 && ACPI) || COMPILE_TEST
+ help
+ Select this option to enable the AAEON UP and UP^2 on-board FPGA.
+ This is core driver for the UP board that implements certain (pin
+ control, onboard LEDs or CEC) through an on-board FPGA.
+
+ To compile this driver as a module, choose M here: the module will be
+ called upboard-fpga.
+
menu "Multimedia Capabilities Port drivers"
depends on ARCH_SA1100

diff --git a/drivers/mfd/Makefile b/drivers/mfd/Makefile
index 858cacf659d6..d9d10e3664f7 100644
--- a/drivers/mfd/Makefile
+++ b/drivers/mfd/Makefile
@@ -250,6 +250,7 @@ obj-$(CONFIG_MFD_ALTERA_A10SR) += altera-a10sr.o
obj-$(CONFIG_MFD_ALTERA_SYSMGR) += altera-sysmgr.o
obj-$(CONFIG_MFD_STPMIC1) += stpmic1.o
obj-$(CONFIG_MFD_SUN4I_GPADC) += sun4i-gpadc.o
+obj-$(CONFIG_MFD_UPBOARD_FPGA) += upboard-fpga.o

obj-$(CONFIG_MFD_STM32_LPTIMER) += stm32-lptimer.o
obj-$(CONFIG_MFD_STM32_TIMERS) += stm32-timers.o
diff --git a/drivers/mfd/upboard-fpga.c b/drivers/mfd/upboard-fpga.c
new file mode 100644
index 000000000000..03158025b57f
--- /dev/null
+++ b/drivers/mfd/upboard-fpga.c
@@ -0,0 +1,364 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * UP Board multifunction device driver.
+ * CPLD provide more GPIO driving power, LEDs and pin mux function.
+ * HID AANT0F00 ~ AAANT0F04 in ACPI namespace.
+ *
+ * Copyright (c) AAEON. All rights reserved.
+ *
+ * Author: Gary Wang <garywang@xxxxxxxxxxxx>
+ */
+
+#include <linux/acpi.h>
+#include <linux/gpio/consumer.h>
+#include <linux/leds.h>
+#include <linux/mfd/core.h>
+#include <linux/mfd/upboard-fpga.h>
+#include <linux/module.h>
+#include <linux/regmap.h>
+
+#define ENABLE_DEVICE 1
+
+#define AAEON_MANUFACTURER_ID 0x01
+#define SUPPORTED_FW_MAJOR 0x0
+#define MENUFACTURER_ID_MASK GENMASK(7, 0)
+
+#define FIRMWARE_ID_BUILD_OFFSET 12
+#define FIRMWARE_ID_MAJOR_OFFSET 8
+#define FIRMWARE_ID_MINOR_OFFSET 4
+#define FIRMWARE_ID_PATCH_OFFSET 0
+#define FIRMWARE_ID_MASK GENMASK(3, 0)
+
+/*
+ * read CPLD register on custom protocol
+ * send clock and addr bit in strobe and datain pins then read from dataout pin
+ */
+static int upboard_cpld_read(void *context, unsigned int reg, unsigned int *val)
+{
+ struct upboard_fpga * const fpga = context;
+ int i;
+
+ /* clear to start new transcation */
+ gpiod_set_value(fpga->clear_gpio, 0);
+ gpiod_set_value(fpga->clear_gpio, 1);
+
+ reg |= UPFPGA_READ_FLAG;
+
+ /* send clock and data from strobe & datain */
+ for (i = UPFPGA_ADDRESS_SIZE; i >= 0; i--) {
+ gpiod_set_value(fpga->strobe_gpio, 0);
+ gpiod_set_value(fpga->datain_gpio, !!(reg & BIT(i)));
+ gpiod_set_value(fpga->strobe_gpio, 1);
+ }
+
+ gpiod_set_value(fpga->strobe_gpio, 0);
+ *val = 0;
+
+ /* read from dataout */
+ for (i = UPFPGA_REGISTER_SIZE - 1; i >= 0; i--) {
+ gpiod_set_value(fpga->strobe_gpio, 1);
+ gpiod_set_value(fpga->strobe_gpio, 0);
+ *val |= gpiod_get_value(fpga->dataout_gpio) << i;
+ }
+
+ gpiod_set_value(fpga->strobe_gpio, 1);
+
+ return 0;
+}
+
+/*
+ * write CPLD register on custom protocol
+ * send clock and addr bit in strobe and datain pins then write to datain pin
+ */
+static int upboard_cpld_write(void *context, unsigned int reg, unsigned int val)
+{
+ struct upboard_fpga * const fpga = context;
+ int i;
+
+ /* clear to start new transcation */
+ gpiod_set_value(fpga->clear_gpio, 0);
+ gpiod_set_value(fpga->clear_gpio, 1);
+
+ /* send clock and data from strobe & datain */
+ for (i = UPFPGA_ADDRESS_SIZE; i >= 0; i--) {
+ gpiod_set_value(fpga->strobe_gpio, 0);
+ gpiod_set_value(fpga->datain_gpio, !!(reg & BIT(i)));
+ gpiod_set_value(fpga->strobe_gpio, 1);
+ }
+
+ gpiod_set_value(fpga->strobe_gpio, 0);
+
+ /* write to datain pin */
+ for (i = UPFPGA_REGISTER_SIZE - 1; i >= 0; i--) {
+ gpiod_set_value(fpga->datain_gpio, !!(val & BIT(i)));
+ gpiod_set_value(fpga->strobe_gpio, 1);
+ gpiod_set_value(fpga->strobe_gpio, 0);
+ }
+
+ gpiod_set_value(fpga->strobe_gpio, 1);
+
+ return 0;
+}
+
+static const struct regmap_range upboard_up_readable_ranges[] = {
+ regmap_reg_range(UPFPGA_REG_PLATFORM_ID, UPFPGA_REG_FIRMWARE_ID),
+ regmap_reg_range(UPFPGA_REG_FUNC_EN0, UPFPGA_REG_FUNC_EN0),
+ regmap_reg_range(UPFPGA_REG_GPIO_DIR0, UPFPGA_REG_GPIO_DIR1),
+};
+
+static const struct regmap_range upboard_up_writable_ranges[] = {
+ regmap_reg_range(UPFPGA_REG_FUNC_EN0, UPFPGA_REG_FUNC_EN0),
+ regmap_reg_range(UPFPGA_REG_GPIO_DIR0, UPFPGA_REG_GPIO_DIR1),
+};
+
+static const struct regmap_access_table upboard_up_readable_table = {
+ .yes_ranges = upboard_up_readable_ranges,
+ .n_yes_ranges = ARRAY_SIZE(upboard_up_readable_ranges),
+};
+
+static const struct regmap_access_table upboard_up_writable_table = {
+ .yes_ranges = upboard_up_writable_ranges,
+ .n_yes_ranges = ARRAY_SIZE(upboard_up_writable_ranges),
+};
+
+static struct regmap_config upboard_up_regmap_config = {
+ .reg_bits = UPFPGA_ADDRESS_SIZE,
+ .val_bits = UPFPGA_REGISTER_SIZE,
+ .max_register = UPFPGA_REG_MAX,
+ .reg_read = upboard_cpld_read,
+ .reg_write = upboard_cpld_write,
+ .fast_io = false,
+ .cache_type = REGCACHE_NONE,
+ .rd_table = &upboard_up_readable_table,
+ .wr_table = &upboard_up_writable_table,
+};
+
+static struct upboard_led_data upboard_gpio_led_data[] = {
+ { .bit = 0, .colour = "gpio" },
+};
+
+/* 3 LEDs controlled by CPLD */
+static struct upboard_led_data upboard_up_led_data[] = {
+ { .bit = 0, .colour = "yellow" },
+ { .bit = 1, .colour = "green" },
+ { .bit = 2, .colour = "red" },
+};
+
+static const struct mfd_cell upboard_up_mfd_cells[] = {
+ MFD_CELL_NAME("upboard-pinctrl"),
+ MFD_CELL_BASIC("upboard-led", NULL, &upboard_up_led_data[0],
+ sizeof(*upboard_up_led_data), 0),
+ MFD_CELL_BASIC("upboard-led", NULL, &upboard_up_led_data[1],
+ sizeof(*upboard_up_led_data), 1),
+ MFD_CELL_BASIC("upboard-led", NULL, &upboard_up_led_data[2],
+ sizeof(*upboard_up_led_data), 2),
+ MFD_CELL_BASIC("upboard-led", NULL, &upboard_gpio_led_data[0],
+ sizeof(*upboard_gpio_led_data), 0),
+};
+
+static const struct upboard_fpga_data upboard_up_fpga_data = {
+ .cpld_config = &upboard_up_regmap_config,
+ .cells = upboard_up_mfd_cells,
+ .ncells = ARRAY_SIZE(upboard_up_mfd_cells),
+};
+
+/* UP^2 board */
+static const struct regmap_range upboard_up2_readable_ranges[] = {
+ regmap_reg_range(UPFPGA_REG_PLATFORM_ID, UPFPGA_REG_FIRMWARE_ID),
+ regmap_reg_range(UPFPGA_REG_FUNC_EN0, UPFPGA_REG_FUNC_EN1),
+ regmap_reg_range(UPFPGA_REG_GPIO_EN0, UPFPGA_REG_GPIO_EN2),
+ regmap_reg_range(UPFPGA_REG_GPIO_DIR0, UPFPGA_REG_GPIO_DIR2),
+};
+
+static const struct regmap_range upboard_up2_writable_ranges[] = {
+ regmap_reg_range(UPFPGA_REG_FUNC_EN0, UPFPGA_REG_FUNC_EN1),
+ regmap_reg_range(UPFPGA_REG_GPIO_EN0, UPFPGA_REG_GPIO_EN2),
+ regmap_reg_range(UPFPGA_REG_GPIO_DIR0, UPFPGA_REG_GPIO_DIR2),
+};
+
+static const struct regmap_access_table upboard_up2_readable_table = {
+ .yes_ranges = upboard_up2_readable_ranges,
+ .n_yes_ranges = ARRAY_SIZE(upboard_up2_readable_ranges),
+};
+
+static const struct regmap_access_table upboard_up2_writable_table = {
+ .yes_ranges = upboard_up2_writable_ranges,
+ .n_yes_ranges = ARRAY_SIZE(upboard_up2_writable_ranges),
+};
+
+static struct regmap_config upboard_up2_regmap_config = {
+ .reg_bits = UPFPGA_ADDRESS_SIZE,
+ .val_bits = UPFPGA_REGISTER_SIZE,
+ .max_register = UPFPGA_REG_MAX,
+ .reg_read = upboard_cpld_read,
+ .reg_write = upboard_cpld_write,
+ .fast_io = false,
+ .cache_type = REGCACHE_NONE,
+ .rd_table = &upboard_up2_readable_table,
+ .wr_table = &upboard_up2_writable_table,
+};
+
+static struct upboard_led_data upboard_up2_led_data[] = {
+ { .bit = 0, .colour = "blue" },
+ { .bit = 1, .colour = "yellow" },
+ { .bit = 2, .colour = "green" },
+ { .bit = 3, .colour = "red" },
+};
+
+static const struct mfd_cell upboard_up2_mfd_cells[] = {
+ MFD_CELL_NAME("upboard-pinctrl"),
+ MFD_CELL_BASIC("upboard-led", NULL, &upboard_up2_led_data[0],
+ sizeof(*upboard_up2_led_data), 0),
+ MFD_CELL_BASIC("upboard-led", NULL, &upboard_up2_led_data[1],
+ sizeof(*upboard_up2_led_data), 1),
+ MFD_CELL_BASIC("upboard-led", NULL, &upboard_up2_led_data[2],
+ sizeof(*upboard_up2_led_data), 2),
+ MFD_CELL_BASIC("upboard-led", NULL, &upboard_up2_led_data[3],
+ sizeof(*upboard_up2_led_data), 3),
+ MFD_CELL_BASIC("upboard-led", NULL, &upboard_gpio_led_data[0],
+ sizeof(*upboard_gpio_led_data), 0),
+};
+
+static const struct upboard_fpga_data upboard_up2_fpga_data = {
+ .cpld_config = &upboard_up2_regmap_config,
+ .cells = upboard_up2_mfd_cells,
+ .ncells = ARRAY_SIZE(upboard_up2_mfd_cells),
+};
+
+/* UP-CREX carrier board for UP Core */
+
+/* same MAXV config as UP1 (proto2 release) */
+#define upboard_upcore_crex_fpga_data upboard_up_fpga_data
+
+/* UP-CRST02 carrier board for UP Core */
+
+/* same MAX10 config as UP2, but same LED cells as UP1 */
+static const struct upboard_fpga_data upboard_upcore_crst02_fpga_data = {
+ .cpld_config = &upboard_up2_regmap_config,
+ .cells = upboard_up_mfd_cells,
+ .ncells = ARRAY_SIZE(upboard_up_mfd_cells),
+};
+
+static int upboard_cpld_gpio_init(struct upboard_fpga *fpga)
+{
+ fpga->enable_gpio = devm_gpiod_get(fpga->dev, "enable", GPIOD_ASIS);
+ if (IS_ERR(fpga->enable_gpio))
+ return PTR_ERR(fpga->enable_gpio);
+
+ fpga->clear_gpio = devm_gpiod_get(fpga->dev, "clear", GPIOD_OUT_LOW);
+ if (IS_ERR(fpga->clear_gpio))
+ return PTR_ERR(fpga->clear_gpio);
+
+ fpga->strobe_gpio = devm_gpiod_get(fpga->dev, "strobe", GPIOD_OUT_LOW);
+ if (IS_ERR(fpga->strobe_gpio))
+ return PTR_ERR(fpga->strobe_gpio);
+
+ fpga->datain_gpio = devm_gpiod_get(fpga->dev, "datain", GPIOD_OUT_LOW);
+ if (IS_ERR(fpga->datain_gpio))
+ return PTR_ERR(fpga->datain_gpio);
+
+ fpga->dataout_gpio = devm_gpiod_get(fpga->dev, "dataout", GPIOD_IN);
+ if (IS_ERR(fpga->dataout_gpio))
+ return PTR_ERR(fpga->dataout_gpio);
+
+ gpiod_set_value(fpga->enable_gpio, ENABLE_DEVICE);
+
+ return 0;
+}
+
+/* This function is for debugging with user for showing firmware information. */
+static int upboard_fpga_verify_device(struct upboard_fpga *fpga)
+{
+ unsigned int platform_id, manufacturer_id;
+ unsigned int firmware_id, build, major, minor, patch;
+ int ret;
+
+ ret = regmap_read(fpga->regmap, UPFPGA_REG_PLATFORM_ID, &platform_id);
+ if (ret)
+ return ret;
+
+ manufacturer_id = platform_id & MENUFACTURER_ID_MASK;
+ if (manufacturer_id != AAEON_MANUFACTURER_ID) {
+ dev_err(fpga->dev,
+ "Manufacturer ID 0x%02x not supported\n",
+ manufacturer_id);
+
+ return -ENODEV;
+ }
+
+ ret = regmap_read(fpga->regmap, UPFPGA_REG_FIRMWARE_ID, &firmware_id);
+ if (ret)
+ return ret;
+
+ build = (firmware_id >> FIRMWARE_ID_BUILD_OFFSET) & FIRMWARE_ID_MASK;
+ major = (firmware_id >> FIRMWARE_ID_MAJOR_OFFSET) & FIRMWARE_ID_MASK;
+ minor = (firmware_id >> FIRMWARE_ID_MINOR_OFFSET) & FIRMWARE_ID_MASK;
+ patch = (firmware_id >> FIRMWARE_ID_PATCH_OFFSET) & FIRMWARE_ID_MASK;
+
+ if (major != SUPPORTED_FW_MAJOR) {
+ dev_err(fpga->dev, "Manufacturer ID 0x%02x not supported\n", build);
+
+ return -ENODEV;
+ }
+
+ dev_info(fpga->dev, "Compatible FPGA FW v%u.%u.%u build 0x%02x",
+ major, minor, patch, build);
+
+ return 0;
+}
+
+static const struct acpi_device_id upboard_fpga_acpi_match[] = {
+ { "AANT0F00", (kernel_ulong_t)&upboard_up_fpga_data },
+ { "AANT0F01", (kernel_ulong_t)&upboard_up2_fpga_data },
+ { "AANT0F02", (kernel_ulong_t)&upboard_upcore_crex_fpga_data },
+ { "AANT0F03", (kernel_ulong_t)&upboard_upcore_crst02_fpga_data },
+ { "AANT0F04", (kernel_ulong_t)&upboard_up_fpga_data },
+ { }
+};
+MODULE_DEVICE_TABLE(acpi, upboard_fpga_acpi_match);
+
+static int upboard_fpga_probe(struct platform_device *pdev)
+{
+ struct device *dev = &pdev->dev;
+ struct upboard_fpga *ddata;
+ int ret;
+
+ ddata = devm_kzalloc(dev, sizeof(ddata), GFP_KERNEL);
+ if (!ddata)
+ return -ENOMEM;
+
+ ddata->fpga_data = device_get_match_data(dev);
+ if (!ddata->fpga_data)
+ return -ENODEV;
+
+ platform_set_drvdata(pdev, ddata);
+ ddata->dev = dev;
+ ddata->regmap = devm_regmap_init(dev, NULL, ddata, ddata->fpga_data->cpld_config);
+ if (IS_ERR(ddata->regmap))
+ return PTR_ERR(ddata->regmap);
+
+ ret = upboard_cpld_gpio_init(ddata);
+ if (ret) {
+ /* Not FPGA firmware, abort FPGA GPIO initialize process */
+ dev_warn(dev, "Failed to initialize CPLD common GPIOs: %d", ret);
+ } else {
+ upboard_fpga_verify_device(ddata);
+ }
+
+ return devm_mfd_add_devices(dev, PLATFORM_DEVID_AUTO,
+ ddata->fpga_data->cells,
+ ddata->fpga_data->ncells,
+ NULL, 0, NULL);
+}
+
+static struct platform_driver upboard_fpga_driver = {
+ .driver = {
+ .name = "upboard-cpld",
+ .acpi_match_table = upboard_fpga_acpi_match,
+ },
+};
+module_platform_driver_probe(upboard_fpga_driver, upboard_fpga_probe);
+
+MODULE_AUTHOR("Gary Wang <garywang@xxxxxxxxxxxx>");
+MODULE_DESCRIPTION("UP Board CPLD/FPGA driver");
+MODULE_LICENSE("GPL v2");
diff --git a/include/linux/mfd/upboard-fpga.h b/include/linux/mfd/upboard-fpga.h
new file mode 100644
index 000000000000..b25bf02e79aa
--- /dev/null
+++ b/include/linux/mfd/upboard-fpga.h
@@ -0,0 +1,59 @@
+/* SPDX-License-Identifier: GPL-2.0-only */
+/*
+ * UP Board CPLD/FPGA driver
+ *
+ * Copyright (c) AAEON. All rights reserved.
+ *
+ * Author: Gary Wang <garywang@xxxxxxxxxxxx>
+ */
+
+#ifndef __MFD_UPBOARD_FPGA_H
+#define __MFD_UPBOARD_FPGA_H
+
+/* CPLD/FPGA protocol version */
+#define UPFPGA_PROTOCOL_V1_HRV 1
+#define UPFPGA_PROTOCOL_V2_HRV 2
+
+#define UPFPGA_ADDRESS_SIZE 7
+#define UPFPGA_REGISTER_SIZE 16
+
+#define UPFPGA_READ_FLAG BIT(UPFPGA_ADDRESS_SIZE)
+
+enum upboard_fpgareg {
+ UPFPGA_REG_PLATFORM_ID = 0x10,
+ UPFPGA_REG_FIRMWARE_ID = 0x11,
+ UPFPGA_REG_FUNC_EN0 = 0x20,
+ UPFPGA_REG_FUNC_EN1 = 0x21,
+ UPFPGA_REG_GPIO_EN0 = 0x30,
+ UPFPGA_REG_GPIO_EN1 = 0x31,
+ UPFPGA_REG_GPIO_EN2 = 0x32,
+ UPFPGA_REG_GPIO_DIR0 = 0x40,
+ UPFPGA_REG_GPIO_DIR1 = 0x41,
+ UPFPGA_REG_GPIO_DIR2 = 0x42,
+ UPFPGA_REG_MAX
+};
+
+struct upboard_fpga_data {
+ struct regmap_config *cpld_config;
+ const struct mfd_cell *cells;
+ size_t ncells;
+};
+
+struct upboard_fpga {
+ struct device *dev;
+ struct regmap *regmap;
+ struct gpio_desc *enable_gpio;
+ struct gpio_desc *reset_gpio;
+ struct gpio_desc *clear_gpio;
+ struct gpio_desc *strobe_gpio;
+ struct gpio_desc *datain_gpio;
+ struct gpio_desc *dataout_gpio;
+ const struct upboard_fpga_data *fpga_data;
+};
+
+struct upboard_led_data {
+ unsigned int bit;
+ const char *colour;
+};
+
+#endif /* __MFD_UPBOARD_FPGA_H */
--
2.17.1