[PATCH 1/2] GPIO: add single-register gpio via creg driver
From: Eugeniy Paltsev
Date: Thu Aug 23 2018 - 11:00:31 EST
Add single-register MMIO gpio driver for complex cases where
only several fields in register belong to GPIO and each GPIO
owns field with different length and on/off values.
Here is the example:
31 11 8 7 5 0 < bit number
| | | | | |
[ not used | gpio-1 | shift-1 | gpio-0 | shift-0 ] < 32 bit MMIO
^ ^
(3 bit) (2 bit)
| |
| |
| write 0x2 == set output to "1" (on)
| write 0x3 == set output to "0" (off)
|
write 0x1 == set output to "1" (on)
write 0x4 == set output to "0" (off)
This is different from gpio-reg, gpio-mmio and gpio-74xx-mmio:
* They all don't support cases when GPIO output register have
more than one bit per GPIO line.
* They don't support holes in MMIO register.
* They don't support cases when GPIO lines have different on/off
values.
Signed-off-by: Eugeniy Paltsev <Eugeniy.Paltsev@xxxxxxxxxxxx>
---
MAINTAINERS | 6 ++
drivers/gpio/Kconfig | 9 ++
drivers/gpio/Makefile | 1 +
drivers/gpio/gpio-creg-snps.c | 242 ++++++++++++++++++++++++++++++++++++++++++
4 files changed, 258 insertions(+)
create mode 100644 drivers/gpio/gpio-creg-snps.c
diff --git a/MAINTAINERS b/MAINTAINERS
index 544cac829cf4..e731f2f9648a 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -13734,6 +13734,12 @@ S: Supported
F: drivers/reset/reset-axs10x.c
F: Documentation/devicetree/bindings/reset/snps,axs10x-reset.txt
+SYNOPSYS CREG GPIO DRIVER
+M: Eugeniy Paltsev <Eugeniy.Paltsev@xxxxxxxxxxxx>
+S: Maintained
+F: drivers/gpio/gpio-creg-snps.c
+F: Documentation/devicetree/bindings/gpio/snps,creg-gpio.txt
+
SYNOPSYS DESIGNWARE 8250 UART DRIVER
R: Andy Shevchenko <andriy.shevchenko@xxxxxxxxxxxxxxx>
S: Maintained
diff --git a/drivers/gpio/Kconfig b/drivers/gpio/Kconfig
index 71c0ab46f216..0f9cc1582cab 100644
--- a/drivers/gpio/Kconfig
+++ b/drivers/gpio/Kconfig
@@ -430,6 +430,15 @@ config GPIO_REG
A 32-bit single register GPIO fixed in/out implementation. This
can be used to represent any register as a set of GPIO signals.
+config GPIO_SNPS_CREG
+ bool "GPIO via CREG (Control REGisers) driver"
+ select OF_GPIO
+ help
+ This driver supports GPIOs via CREG on various Synopsys SoCs.
+ This is is single-register MMIO gpio driver for complex cases
+ where only several fields in register belong to GPIO and
+ each GPIO owns field with different length and on/off values.
+
config GPIO_SPEAR_SPICS
bool "ST SPEAr13xx SPI Chip Select as GPIO support"
depends on PLAT_SPEAR
diff --git a/drivers/gpio/Makefile b/drivers/gpio/Makefile
index 1324c8f966a7..993f8ad54a19 100644
--- a/drivers/gpio/Makefile
+++ b/drivers/gpio/Makefile
@@ -109,6 +109,7 @@ obj-$(CONFIG_GPIO_REG) += gpio-reg.o
obj-$(CONFIG_ARCH_SA1100) += gpio-sa1100.o
obj-$(CONFIG_GPIO_SCH) += gpio-sch.o
obj-$(CONFIG_GPIO_SCH311X) += gpio-sch311x.o
+obj-$(CONFIG_GPIO_SNPS_CREG) += gpio-creg-snps.o
obj-$(CONFIG_GPIO_SODAVILLE) += gpio-sodaville.o
obj-$(CONFIG_GPIO_SPEAR_SPICS) += gpio-spear-spics.o
obj-$(CONFIG_GPIO_SPRD) += gpio-sprd.o
diff --git a/drivers/gpio/gpio-creg-snps.c b/drivers/gpio/gpio-creg-snps.c
new file mode 100644
index 000000000000..b684b7257aae
--- /dev/null
+++ b/drivers/gpio/gpio-creg-snps.c
@@ -0,0 +1,242 @@
+// SPDX-License-Identifier: GPL-2.0+
+//
+// Synopsys CREG (Control REGisers) GPIO driver
+//
+// Copyright (C) 2018 Synopsys
+// Author: Eugeniy Paltsev <Eugeniy.Paltsev@xxxxxxxxxxxx>
+
+#include <linux/of.h>
+#include <linux/kernel.h>
+#include <linux/slab.h>
+#include <linux/of_gpio.h>
+#include <linux/io.h>
+#include <linux/of_platform.h>
+#include <linux/module.h>
+
+#include "gpiolib.h"
+
+/*
+ * GPIO via CREG (Control REGisers) driver
+ *
+ * 31 11 8 7 5 0 < bit number
+ * | | | | | |
+ * [ not used | gpio-1 | shift-1 | gpio-0 | shift-0 ] < 32 bit register
+ * ^ ^
+ * | |
+ * | write 0x2 == set output to "1" (on)
+ * | write 0x3 == set output to "0" (off)
+ * |
+ * write 0x1 == set output to "1" (on)
+ * write 0x4 == set output to "0" (off)
+ */
+
+#define MAX_GPIO 32
+
+struct creg_gpio {
+ struct of_mm_gpio_chip mmchip;
+ spinlock_t lock;
+
+ u32 shift[MAX_GPIO];
+ u32 on[MAX_GPIO];
+ u32 off[MAX_GPIO];
+ u32 bit_per_gpio[MAX_GPIO];
+};
+
+static void _creg_gpio_set(struct creg_gpio *hcg, unsigned int gpio, u32 val)
+{
+ u32 reg, reg_shift;
+ unsigned long flags;
+ int i;
+
+ reg_shift = hcg->shift[gpio];
+ for (i = 0; i < gpio; i++)
+ reg_shift += hcg->bit_per_gpio[i] + hcg->shift[i];
+
+ spin_lock_irqsave(&hcg->lock, flags);
+ reg = readl(hcg->mmchip.regs);
+ reg &= ~(GENMASK(hcg->bit_per_gpio[i] - 1, 0) << reg_shift);
+ reg |= (val << reg_shift);
+ writel(reg, hcg->mmchip.regs);
+ spin_unlock_irqrestore(&hcg->lock, flags);
+}
+
+static void creg_gpio_set(struct gpio_chip *gc, unsigned int gpio, int val)
+{
+ struct creg_gpio *hcg = gpiochip_get_data(gc);
+ u32 value = val ? hcg->on[gpio] : hcg->off[gpio];
+
+ _creg_gpio_set(hcg, gpio, value);
+}
+
+static int creg_gpio_dir_out(struct gpio_chip *gc, unsigned int gpio, int val)
+{
+ creg_gpio_set(gc, gpio, val);
+
+ return 0;
+}
+
+static int creg_gpio_get_direction(struct gpio_chip *gc, unsigned int offset)
+{
+ return 0; /* output */
+}
+
+static int creg_gpio_xlate(struct gpio_chip *gc,
+ const struct of_phandle_args *gpiospec, u32 *flags)
+{
+ if (gpiospec->args_count != 1) {
+ dev_err(&gc->gpiodev->dev, "invalid args_count: %d\n",
+ gpiospec->args_count);
+ return -EINVAL;
+ }
+
+ if (gpiospec->args[0] >= gc->ngpio) {
+ dev_err(&gc->gpiodev->dev, "gpio number is too big: %d\n",
+ gpiospec->args[0]);
+ return -EINVAL;
+ }
+
+ return gpiospec->args[0];
+}
+
+static int creg_gpio_validate_pgv(struct device *dev, struct creg_gpio *hcg,
+ int i, u32 *defaults, bool use_defaults)
+{
+ if (hcg->bit_per_gpio[i] < 1 || hcg->bit_per_gpio[i] > 8) {
+ dev_err(dev, "'bit-per-line[%d]' is out of bounds\n", i);
+ return -EINVAL;
+ }
+
+ /* Check that on valiue suits it's placeholder */
+ if (GENMASK(31, hcg->bit_per_gpio[i]) & hcg->on[i]) {
+ dev_err(dev, "'on-val[%d]' can't be more than %lu\n",
+ i, GENMASK(hcg->bit_per_gpio[i] - 1, 0));
+ return -EINVAL;
+ }
+
+ /* Check that off valiue suits it's placeholder */
+ if (GENMASK(31, hcg->bit_per_gpio[i]) & hcg->off[i]) {
+ dev_err(dev, "'off-val[%d]' can't be more than %lu\n",
+ i, GENMASK(hcg->bit_per_gpio[i] - 1, 0));
+ return -EINVAL;
+ }
+
+ /* Check that default valiue suits it's placeholder */
+ if (use_defaults && (GENMASK(31, hcg->bit_per_gpio[i]) & defaults[i])) {
+ dev_err(dev, "'default-val[%d]' can't be more than %lu\n",
+ i, GENMASK(hcg->bit_per_gpio[i] - 1, 0));
+ return -EINVAL;
+ }
+
+ if (hcg->on[i] == hcg->off[i]) {
+ dev_err(dev, "'off-val[%d]' and 'on-val[%d]' can't be equal\n",
+ i, i);
+ return -EINVAL;
+ }
+
+ return 0;
+}
+
+static int creg_gpio_probe(struct platform_device *pdev)
+{
+ struct device_node *np = pdev->dev.of_node;
+ struct device *dev = &pdev->dev;
+ struct creg_gpio *hcg;
+
+ u32 defaults[MAX_GPIO];
+ bool use_defaults;
+ u32 ngpio, reg_len = 0;
+ int ret, i;
+
+ hcg = devm_kzalloc(dev, sizeof(struct creg_gpio), GFP_KERNEL);
+ if (!hcg)
+ return -ENOMEM;
+
+ if (of_property_read_u32(np, "snps,ngpios", &ngpio)) {
+ dev_err(dev, "'ngpios' isn't set\n");
+ return -EINVAL;
+ }
+
+ if (ngpio < 1 || ngpio > MAX_GPIO) {
+ dev_err(dev, "'ngpios' is out of bounds\n");
+ return -EINVAL;
+ }
+
+ if (of_property_read_u32_array(np, "snps,shift", hcg->shift, ngpio)) {
+ dev_err(dev, "'shift' is set incorrectly\n");
+ return -EINVAL;
+ }
+
+ if (of_property_read_u32_array(np, "snps,bit-per-line",
+ hcg->bit_per_gpio, ngpio)) {
+ dev_err(dev, "'bit-per-line' is set incorrectly\n");
+ return -EINVAL;
+ }
+
+ if (of_property_read_u32_array(np, "snps,on-val", hcg->on, ngpio)) {
+ dev_err(dev, "'on-val' is set incorrectly\n");
+ return -EINVAL;
+ }
+
+ if (of_property_read_u32_array(np, "snps,off-val", hcg->off, ngpio)) {
+ dev_err(dev, "'off-val' is set incorrectly\n");
+ return -EINVAL;
+ }
+
+ ret = of_property_read_u32_array(np, "snps,default-val", defaults, ngpio);
+ if (ret && ret != -EINVAL) {
+ dev_err(dev, "'default-val' is set incorrectly\n");
+ return ret;
+ }
+ use_defaults = !ret;
+
+ for (i = 0; i < ngpio; i++) {
+ if (creg_gpio_validate_pgv(dev, hcg, i, defaults, use_defaults))
+ return -EINVAL;
+
+ reg_len += hcg->shift[i] + hcg->bit_per_gpio[i];
+ }
+
+ /* Check that we suit in 32 bit register */
+ if (reg_len > 32) {
+ dev_err(dev,
+ "32-bit io register overflow: attempt to use %u bits\n",
+ reg_len);
+ return -EINVAL;
+ }
+
+ spin_lock_init(&hcg->lock);
+
+ hcg->mmchip.gc.ngpio = ngpio;
+ hcg->mmchip.gc.set = creg_gpio_set;
+ hcg->mmchip.gc.get_direction = creg_gpio_get_direction;
+ hcg->mmchip.gc.direction_output = creg_gpio_dir_out;
+ hcg->mmchip.gc.of_xlate = creg_gpio_xlate;
+ hcg->mmchip.gc.of_gpio_n_cells = 1;
+
+ ret = of_mm_gpiochip_add_data(pdev->dev.of_node, &hcg->mmchip, hcg);
+ if (ret)
+ return ret;
+
+ /* Setup default GPIO value if we have "snps,default-val" array */
+ if (use_defaults)
+ for (i = 0; i < ngpio; i++)
+ _creg_gpio_set(hcg, i, defaults[i]);
+
+ dev_info(dev, "GPIO controller with %d gpios probed\n", ngpio);
+
+ return 0;
+}
+
+static const struct of_device_id creg_gpio_ids[] = {
+ { .compatible = "snps,creg-gpio" },
+ { }
+};
+
+static struct platform_driver creg_gpio_snps_driver = {
+ .driver = {
+ .name = "snps-creg-gpio",
+ .of_match_table = creg_gpio_ids,
+ },
+ .probe = creg_gpio_probe,
+};
+builtin_platform_driver(creg_gpio_snps_driver);
--
2.14.4