[PATCH 2/3] gpio: Add GPIO support for Broadcom STB SoCs

Gregory Fong
2015-05-06T08:39:16Z

This adds support for the GPIO IP "UPG GIO" used on Broadcom STB SoCs
(BCM7XXX and some others). Uses basic_mmio_gpio to instantiate a
gpio_chip for each bank. The driver assumes that it handles the base
set of GPIOs on the system and that it can start its numbering sequence
from 0, so any GPIO expanders used with it must dynamically assign GPIO
numbers after this driver has finished registering its GPIOs.

Does not implement the interrupt-controller portion yet, will be done in a
future commit.

List-usage-fixed-by: Brian Norris <computersforpeace@gmail.com>
Signed-off-by: Gregory Fong <gregory.0xf0@gmail.com>
---
MAINTAINERS | 7 ++
arch/arm/mach-bcm/Kconfig | 1 +
drivers/gpio/Kconfig | 8 ++
drivers/gpio/Makefile | 1 +
drivers/gpio/gpio-brcmstb.c | 243 +++++++++++++++++++++++++++++++++++++++++++
5 files changed, 260 insertions(+)
create mode 100644 drivers/gpio/gpio-brcmstb.c

diff --git a/MAINTAINERS b/MAINTAINERS
index b399b34..781806a 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -2235,6 +2235,13 @@ N: bcm9583*
N: bcm583*
N: bcm113*

+BROADCOM BRCMSTB GPIO DRIVER
+M: Gregory Fong <gregory.0xf0@gmail.com>
+L: bcm-kernel-feedback-list@broadcom.com>
+S: Supported
+F: drivers/gpio/gpio-brcmstb.c
+F: Documentation/devicetree/bindings/gpio/brcm,brcmstb-gpio.txt
+
BROADCOM KONA GPIO DRIVER
M: Ray Jui <rjui@broadcom.com>
L: bcm-kernel-feedback-list@broadcom.com
diff --git a/arch/arm/mach-bcm/Kconfig b/arch/arm/mach-bcm/Kconfig
index 8b11f44..0ac9e4b3 100644
--- a/arch/arm/mach-bcm/Kconfig
+++ b/arch/arm/mach-bcm/Kconfig
@@ -144,6 +144,7 @@ config ARCH_BRCMSTB
select BRCMSTB_GISB_ARB
select BRCMSTB_L2_IRQ
select BCM7120_L2_IRQ
+ select ARCH_WANT_OPTIONAL_GPIOLIB
help
Say Y if you intend to run the kernel on a Broadcom ARM-based STB
chipset.
diff --git a/drivers/gpio/Kconfig b/drivers/gpio/Kconfig
index caefe80..5f79b7f 100644
--- a/drivers/gpio/Kconfig
+++ b/drivers/gpio/Kconfig
@@ -126,6 +126,14 @@ config GPIO_BCM_KONA
help
Turn on GPIO support for Broadcom "Kona" chips.

+config GPIO_BRCMSTB
+ tristate "BRCMSTB GPIO support"
+ default y if ARCH_BRCMSTB
+ depends on OF_GPIO && (ARCH_BRCMSTB || COMPILE_TEST)
+ select GPIO_GENERIC
+ help
+ Say yes here to enable GPIO support for Broadcom STB (BCM7XXX) SoCs.
+
config GPIO_CLPS711X
tristate "CLPS711X GPIO support"
depends on ARCH_CLPS711X || COMPILE_TEST
diff --git a/drivers/gpio/Makefile b/drivers/gpio/Makefile
index f71bb97..9bfaaa8 100644
--- a/drivers/gpio/Makefile
+++ b/drivers/gpio/Makefile
@@ -21,6 +21,7 @@ obj-$(CONFIG_GPIO_ALTERA) += gpio-altera.o
obj-$(CONFIG_GPIO_AMD8111) += gpio-amd8111.o
obj-$(CONFIG_GPIO_ARIZONA) += gpio-arizona.o
obj-$(CONFIG_GPIO_BCM_KONA) += gpio-bcm-kona.o
+obj-$(CONFIG_GPIO_BRCMSTB) += gpio-brcmstb.o
obj-$(CONFIG_GPIO_BT8XX) += gpio-bt8xx.o
obj-$(CONFIG_GPIO_CLPS711X) += gpio-clps711x.o
obj-$(CONFIG_GPIO_CS5535) += gpio-cs5535.o
diff --git a/drivers/gpio/gpio-brcmstb.c b/drivers/gpio/gpio-brcmstb.c
new file mode 100644
index 0000000..c8f9014
--- /dev/null
+++ b/drivers/gpio/gpio-brcmstb.c
@@ -0,0 +1,243 @@
+/*
+ * Copyright (C) 2015 Broadcom Corporation
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License as
+ * published by the Free Software Foundation version 2.
+ *
+ * This program is distributed "as is" WITHOUT ANY WARRANTY of any
+ * kind, whether express or implied; without even the implied warranty
+ * of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ */
+
+#include <linux/bitops.h>
+#include <linux/gpio.h>
+#include <linux/of_device.h>
+#include <linux/of_irq.h>
+#include <linux/module.h>
+#include <linux/basic_mmio_gpio.h>
+
+#define GIO_BANK_SIZE 0x20
+#define GIO_ODEN(bank) (((bank) * GIO_BANK_SIZE) + 0x00)
+#define GIO_DATA(bank) (((bank) * GIO_BANK_SIZE) + 0x04)
+#define GIO_IODIR(bank) (((bank) * GIO_BANK_SIZE) + 0x08)
+#define GIO_EC(bank) (((bank) * GIO_BANK_SIZE) + 0x0c)
+#define GIO_EI(bank) (((bank) * GIO_BANK_SIZE) + 0x10)
+#define GIO_MASK(bank) (((bank) * GIO_BANK_SIZE) + 0x14)
+#define GIO_LEVEL(bank) (((bank) * GIO_BANK_SIZE) + 0x18)
+#define GIO_STAT(bank) (((bank) * GIO_BANK_SIZE) + 0x1c)
+
+struct brcmstb_gpio_bank {
+ struct list_head node;
+ int id;
+ struct bgpio_chip bgc;
+ u32 imask; /* irq mask shadow register */
+ struct brcmstb_gpio_priv *parent_priv; /* used in interrupt handler */
+};
+
+struct brcmstb_gpio_priv {
+ struct list_head bank_list;
+ void __iomem *reg_base;
+ int num_banks;
+ struct platform_device *pdev;
+ int gpio_base;
+};
+
+#define GPIO_PER_BANK 32
+#define GPIO_BANK(gpio) ((gpio) >> 5)
+/* assumes GPIO_PER_BANK is a multiple of 2 */
+#define GPIO_BIT(gpio) ((gpio) & (GPIO_PER_BANK - 1))
+
+static inline struct brcmstb_gpio_priv *
+brcmstb_gpio_gc_to_priv(struct gpio_chip *gc)
+{
+ struct bgpio_chip *bgc = to_bgpio_chip(gc);
+ struct brcmstb_gpio_bank *bank =
+ container_of(bgc, struct brcmstb_gpio_bank, bgc);
+
+ return bank->parent_priv;
+}
+
+/* Make sure that the number of banks matches up between properties */
+static int brcmstb_gpio_sanity_check_banks(struct device *dev,
+ struct device_node *np, struct resource *res)
+{
+ int res_num_banks = resource_size(res) / GIO_BANK_SIZE;
+ int num_banks = of_property_count_u32_elems(np, "brcm,gpio-bank-widths");
+
+ if (res_num_banks != num_banks) {
+ dev_err(dev, "Mismatch in banks: res had %d, bank-widths had %d\n",
+ res_num_banks, num_banks);
+ return -EINVAL;
+ } else {
+ return 0;
+ }
+}
+
+static int brcmstb_gpio_remove(struct platform_device *pdev)
+{
+ struct brcmstb_gpio_priv *priv = platform_get_drvdata(pdev);
+ struct list_head *pos;
+ struct brcmstb_gpio_bank *bank;
+ int ret = 0;
+
+ list_for_each(pos, &priv->bank_list) {
+ bank = list_entry(pos, struct brcmstb_gpio_bank, node);
+ ret = bgpio_remove(&bank->bgc);
+ if (ret)
+ dev_err(&pdev->dev, "gpiochip_remove fail in cleanup");
+ }
+ return ret;
+}
+
+static int brcmstb_gpio_of_xlate(struct gpio_chip *gc,
+ const struct of_phandle_args *gpiospec, u32 *flags)
+{
+ struct brcmstb_gpio_priv *priv = brcmstb_gpio_gc_to_priv(gc);
+ int offset;
+
+ if (gc->of_gpio_n_cells != 2) {
+ WARN_ON(1);
+ return -EINVAL;
+ }
+
+ if (WARN_ON(gpiospec->args_count < gc->of_gpio_n_cells))
+ return -EINVAL;
+
+ offset = gpiospec->args[0] - (gc->base - priv->gpio_base);
+ if (offset >= gc->ngpio)
+ return -EINVAL;
+
+ if (flags)
+ *flags = gpiospec->args[1];
+
+ return offset;
+}
+
+static int brcmstb_gpio_probe(struct platform_device *pdev)
+{
+ struct device *dev = &pdev->dev;
+ struct device_node *np = dev->of_node;
+ void __iomem *reg_base;
+ struct brcmstb_gpio_priv *priv;
+ struct resource *res;
+ struct property *prop;
+ const __be32 *p;
+ u32 bank_width;
+ int err;
+ static int gpio_base;
+
+ priv = devm_kzalloc(dev, sizeof(*priv), GFP_KERNEL);
+ if (!priv)
+ return -ENOMEM;
+
+ res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+ reg_base = devm_ioremap_resource(dev, res);
+ if (IS_ERR(reg_base))
+ return PTR_ERR(reg_base);
+
+ priv->gpio_base = gpio_base;
+ priv->reg_base = reg_base;
+ priv->pdev = pdev;
+
+ INIT_LIST_HEAD(&priv->bank_list);
+ if (brcmstb_gpio_sanity_check_banks(dev, np, res))
+ return -EINVAL;
+
+ of_property_for_each_u32(np, "brcm,gpio-bank-widths", prop, p,
+ bank_width) {
+ struct brcmstb_gpio_bank *bank;
+ struct bgpio_chip *bgc;
+ struct gpio_chip *gc;
+
+ bank = devm_kzalloc(dev, sizeof(*bank), GFP_KERNEL);
+ if (!bank) {
+ err = -ENOMEM;
+ goto fail;
+ }
+
+ bank->parent_priv = priv;
+ bank->id = priv->num_banks;
+
+ /*
+ * Regs are 4 bytes wide, have data reg, no set/clear regs,
+ * and direction bits have 0 = output and 1 = input
+ */
+ bgc = &bank->bgc;
+ err = bgpio_init(bgc, dev, 4,
+ reg_base + GIO_DATA(bank->id),
+ NULL, NULL, NULL,
+ reg_base + GIO_IODIR(bank->id), 0);
+ if (err) {
+ dev_err(dev, "bgpio_init() failed\n");
+ goto fail;
+ }
+
+ gc = &bgc->gc;
+ gc->of_node = np;
+ gc->owner = THIS_MODULE;
+ gc->label = np->full_name;
+ gc->base = gpio_base;
+ gc->of_gpio_n_cells = 2;
+ gc->of_xlate = brcmstb_gpio_of_xlate;
+
+ if (bank_width <= 0 || bank_width > GPIO_PER_BANK) {
+ gc->ngpio = GPIO_PER_BANK;
+ dev_warn(dev, "Invalid bank width %d, assume %d\n",
+ bank_width, gc->ngpio);
+ } else {
+ gc->ngpio = bank_width;
+ }
+
+ bank->imask =
+ bgc->read_reg(reg_base + GIO_MASK(bank->id));
+
+ err = gpiochip_add(gc);
+ if (err) {
+ dev_err(dev, "Could not add gpiochip for bank %d\n",
+ bank->id);
+ goto fail;
+ }
+ gpio_base += gc->ngpio;
+ dev_dbg(dev, "bank=%d, base=%d, ngpio=%d\n", bank->id,
+ gc->base, gc->ngpio);
+
+ /* Everything looks good, so add bank to list */
+ list_add(&bank->node, &priv->bank_list);
+
+ priv->num_banks++;
+ }
+
+ dev_info(dev, "Registered %d banks (GPIO(s): %d-%d)\n",
+ priv->num_banks, priv->gpio_base, gpio_base - 1);
+
+ platform_set_drvdata(pdev, priv);
+
+ return 0;
+
+fail:
+ (void) brcmstb_gpio_remove(pdev);
+ return err;
+}
+
+static struct of_device_id brcmstb_gpio_of_match[] = {
+ { .compatible = "brcm,brcmstb-gpio" },
+ {},
+};
+
+MODULE_DEVICE_TABLE(of, brcmstb_gpio_of_match);
+
+static struct platform_driver brcmstb_gpio_driver = {
+ .driver = {
+ .name = "brcmstb-gpio",
+ .of_match_table = brcmstb_gpio_of_match,
+ },
+ .probe = brcmstb_gpio_probe,
+ .remove = brcmstb_gpio_remove,
+};
+module_platform_driver(brcmstb_gpio_driver);
+
+MODULE_AUTHOR("Broadcom");
+MODULE_DESCRIPTION("Driver for BRCMSTB UPG GPIO");
+MODULE_LICENSE("GPL");
--
1.7.9.5