gpio: Add driver for Nomadik GPIO

Nomadik GPIO is a fairly simple GPIO module used in the ST-Ericsson
Ux500 SoCs (and some older Nomadik SoCs). It uses registers where
each GPIO is represented as a single bit, plus "set" and "clear"
registers that allow updating the state without having to read the
existing state.

The driver implements support for it for use together with DM_GPIO
and the existing ste-dbx5x0.dtsi device tree.

Cc: Linus Walleij <linus.walleij@linaro.org>
Signed-off-by: Stephan Gerhold <stephan@gerhold.net>
Reviewed-by: Linus Walleij <linus.walleij@linaro.org>

diff --git a/drivers/gpio/Kconfig b/drivers/gpio/Kconfig
index de4dc51..0817b12 100644 (file)
--- a/drivers/gpio/Kconfig
+++ b/drivers/gpio/Kconfig
@@ -495,4 +495,12 @@ config NX_GPIO
          The GPIOs for a device are defined in the device tree with one node
          for each bank.
 
+config NOMADIK_GPIO
+       bool "Nomadik GPIO driver"
+       depends on DM_GPIO
+       help
+         Support GPIO access on ST-Ericsson Ux500 SoCs. The GPIOs are arranged
+         into a number of banks each with 32 GPIOs. The GPIOs for a device are
+         defined in the device tree with one node for each bank.
+
 endmenu

diff --git a/drivers/gpio/Makefile b/drivers/gpio/Makefile
index d01c117..16b09fb 100644 (file)
--- a/drivers/gpio/Makefile
+++ b/drivers/gpio/Makefile
@@ -67,3 +67,4 @@ obj-$(CONFIG_MT7621_GPIO)     += mt7621_gpio.o
 obj-$(CONFIG_MSCC_SGPIO)       += mscc_sgpio.o
 obj-$(CONFIG_NX_GPIO)          += nx_gpio.o
 obj-$(CONFIG_SIFIVE_GPIO)      += sifive-gpio.o
+obj-$(CONFIG_NOMADIK_GPIO)     += nmk_gpio.o

diff --git a/drivers/gpio/nmk_gpio.c b/drivers/gpio/nmk_gpio.c
new file mode 100644 (file)
index 0000000..e1bb41b
--- /dev/null
+++ b/drivers/gpio/nmk_gpio.c
@@ -0,0 +1,125 @@
+// SPDX-License-Identifier: GPL-2.0+
+/* Copyright (C) 2019 Stephan Gerhold */
+
+#include <common.h>
+#include <dm.h>
+#include <asm/gpio.h>
+#include <asm/io.h>
+
+struct nmk_gpio_regs {
+       u32 dat;        /* data */
+       u32 dats;       /* data set */
+       u32 datc;       /* data clear */
+       u32 pdis;       /* pull disable */
+       u32 dir;        /* direction */
+       u32 dirs;       /* direction set */
+       u32 dirc;       /* direction clear */
+       u32 slpm;       /* sleep mode */
+       u32 afsla;      /* alternate function select A */
+       u32 afslb;      /* alternate function select B */
+       u32 lowemi;     /* low EMI mode */
+};
+
+struct nmk_gpio {
+       struct nmk_gpio_regs *regs;
+};
+
+static int nmk_gpio_get_value(struct udevice *dev, unsigned offset)
+{
+       struct nmk_gpio *priv = dev_get_priv(dev);
+
+       return !!(readl(&priv->regs->dat) & BIT(offset));
+}
+
+static int nmk_gpio_set_value(struct udevice *dev, unsigned offset, int value)
+{
+       struct nmk_gpio *priv = dev_get_priv(dev);
+
+       if (value)
+               writel(BIT(offset), &priv->regs->dats);
+       else
+               writel(BIT(offset), &priv->regs->datc);
+
+       return 0;
+}
+
+static int nmk_gpio_get_function(struct udevice *dev, unsigned offset)
+{
+       struct nmk_gpio *priv = dev_get_priv(dev);
+
+       if (readl(&priv->regs->afsla) & BIT(offset) ||
+           readl(&priv->regs->afslb) & BIT(offset))
+               return GPIOF_FUNC;
+
+       if (readl(&priv->regs->dir) & BIT(offset))
+               return GPIOF_OUTPUT;
+       else
+               return GPIOF_INPUT;
+}
+
+static int nmk_gpio_direction_input(struct udevice *dev, unsigned offset)
+{
+       struct nmk_gpio *priv = dev_get_priv(dev);
+
+       writel(BIT(offset), &priv->regs->dirc);
+       return 0;
+}
+
+static int nmk_gpio_direction_output(struct udevice *dev, unsigned offset,
+                                    int value)
+{
+       struct nmk_gpio *priv = dev_get_priv(dev);
+
+       writel(BIT(offset), &priv->regs->dirs);
+       return nmk_gpio_set_value(dev, offset, value);
+}
+
+static const struct dm_gpio_ops nmk_gpio_ops = {
+       .get_value              = nmk_gpio_get_value,
+       .set_value              = nmk_gpio_set_value,
+       .get_function           = nmk_gpio_get_function,
+       .direction_input        = nmk_gpio_direction_input,
+       .direction_output       = nmk_gpio_direction_output,
+};
+
+static int nmk_gpio_probe(struct udevice *dev)
+{
+       struct nmk_gpio *priv = dev_get_priv(dev);
+       struct gpio_dev_priv *uc_priv = dev_get_uclass_priv(dev);
+       char buf[20];
+       u32 bank;
+       int ret;
+
+       priv->regs = dev_read_addr_ptr(dev);
+       if (!priv->regs)
+               return -EINVAL;
+
+       ret = dev_read_u32(dev, "gpio-bank", &bank);
+       if (ret < 0) {
+               printf("nmk_gpio(%s): Failed to read gpio-bank\n", dev->name);
+               return ret;
+       }
+
+       sprintf(buf, "nmk%u-gpio", bank);
+       uc_priv->bank_name = strdup(buf);
+       if (!uc_priv->bank_name)
+               return -ENOMEM;
+
+       uc_priv->gpio_count = sizeof(priv->regs->dat) * BITS_PER_BYTE;
+
+       return 0;
+}
+
+static const struct udevice_id nmk_gpio_ids[] = {
+       { .compatible = "st,nomadik-gpio" },
+       { }
+};
+
+U_BOOT_DRIVER(gpio_nmk) = {
+       .name           = "nmk_gpio",
+       .id             = UCLASS_GPIO,
+       .of_match       = nmk_gpio_ids,
+       .probe          = nmk_gpio_probe,
+       .ops            = &nmk_gpio_ops,
+       .priv_auto      = sizeof(struct nmk_gpio),
+};