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Message-Id: <20210304034141.7062-2-brad@pensando.io>
Date: Wed, 3 Mar 2021 19:41:34 -0800
From: Brad Larson <brad@...sando.io>
To: linux-arm-kernel@...ts.infradead.org
Cc: arnd@...db.de, linus.walleij@...aro.org, bgolaszewski@...libre.com,
broonie@...nel.org, fancer.lancer@...il.com,
adrian.hunter@...el.com, ulf.hansson@...aro.org, olof@...om.net,
brad@...sando.io, linux-gpio@...r.kernel.org,
linux-spi@...r.kernel.org, linux-mmc@...r.kernel.org,
devicetree@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: [PATCH 1/8] gpio: Add Elba SoC gpio driver for spi cs control
This GPIO driver is for the Pensando Elba SoC which
provides control of four chip selects on two SPI busses.
Signed-off-by: Brad Larson <brad@...sando.io>
---
drivers/gpio/Kconfig | 6 ++
drivers/gpio/Makefile | 1 +
drivers/gpio/gpio-elba-spics.c | 120 +++++++++++++++++++++++++++++++++
3 files changed, 127 insertions(+)
create mode 100644 drivers/gpio/gpio-elba-spics.c
diff --git a/drivers/gpio/Kconfig b/drivers/gpio/Kconfig
index e3607ec4c2e8..d99bc82aa8fa 100644
--- a/drivers/gpio/Kconfig
+++ b/drivers/gpio/Kconfig
@@ -241,6 +241,12 @@ config GPIO_EIC_SPRD
help
Say yes here to support Spreadtrum EIC device.
+config GPIO_ELBA_SPICS
+ bool "Pensando Elba SPI chip-select"
+ depends on ARCH_PENSANDO_ELBA_SOC
+ help
+ Say yes here to support the Pensndo Elba SoC SPI chip-select driver
+
config GPIO_EM
tristate "Emma Mobile GPIO"
depends on (ARCH_EMEV2 || COMPILE_TEST) && OF_GPIO
diff --git a/drivers/gpio/Makefile b/drivers/gpio/Makefile
index c58a90a3c3b1..c5c7acad371b 100644
--- a/drivers/gpio/Makefile
+++ b/drivers/gpio/Makefile
@@ -54,6 +54,7 @@ obj-$(CONFIG_GPIO_DAVINCI) += gpio-davinci.o
obj-$(CONFIG_GPIO_DLN2) += gpio-dln2.o
obj-$(CONFIG_GPIO_DWAPB) += gpio-dwapb.o
obj-$(CONFIG_GPIO_EIC_SPRD) += gpio-eic-sprd.o
+obj-$(CONFIG_GPIO_ELBA_SPICS) += gpio-elba-spics.o
obj-$(CONFIG_GPIO_EM) += gpio-em.o
obj-$(CONFIG_GPIO_EP93XX) += gpio-ep93xx.o
obj-$(CONFIG_GPIO_EXAR) += gpio-exar.o
diff --git a/drivers/gpio/gpio-elba-spics.c b/drivers/gpio/gpio-elba-spics.c
new file mode 100644
index 000000000000..a845525cf2a3
--- /dev/null
+++ b/drivers/gpio/gpio-elba-spics.c
@@ -0,0 +1,120 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Pensando Elba ASIC SPI chip select driver
+ *
+ * Copyright (c) 2020-2021, Pensando Systems Inc.
+ */
+
+#include <linux/err.h>
+#include <linux/gpio.h>
+#include <linux/module.h>
+#include <linux/io.h>
+#include <linux/init.h>
+#include <linux/of.h>
+#include <linux/platform_device.h>
+#include <linux/spinlock.h>
+#include <linux/types.h>
+
+/*
+ * pin: 3 2 | 1 0
+ * bit: 7------6------5------4----|---3------2------1------0
+ * cs1 cs1_ovr cs0 cs0_ovr | cs1 cs1_ovr cs0 cs0_ovr
+ * ssi1 | ssi0
+ */
+#define SPICS_PIN_SHIFT(pin) (2 * (pin))
+#define SPICS_MASK(pin) (0x3 << SPICS_PIN_SHIFT(pin))
+#define SPICS_SET(pin, val) ((((val) << 1) | 0x1) << SPICS_PIN_SHIFT(pin))
+
+struct elba_spics_priv {
+ void __iomem *base;
+ spinlock_t lock;
+ struct gpio_chip chip;
+};
+
+static int elba_spics_get_value(struct gpio_chip *chip, unsigned int pin)
+{
+ return -ENXIO;
+}
+
+static void elba_spics_set_value(struct gpio_chip *chip,
+ unsigned int pin, int value)
+{
+ struct elba_spics_priv *p = gpiochip_get_data(chip);
+ unsigned long flags;
+ u32 tmp;
+
+ /* select chip select from register */
+ spin_lock_irqsave(&p->lock, flags);
+ tmp = readl_relaxed(p->base);
+ tmp = (tmp & ~SPICS_MASK(pin)) | SPICS_SET(pin, value);
+ writel_relaxed(tmp, p->base);
+ spin_unlock_irqrestore(&p->lock, flags);
+}
+
+static int elba_spics_direction_input(struct gpio_chip *chip, unsigned int pin)
+{
+ return -ENXIO;
+}
+
+static int elba_spics_direction_output(struct gpio_chip *chip,
+ unsigned int pin, int value)
+{
+ elba_spics_set_value(chip, pin, value);
+ return 0;
+}
+
+static int elba_spics_probe(struct platform_device *pdev)
+{
+ struct elba_spics_priv *p;
+ struct resource *res;
+ int ret;
+
+ p = devm_kzalloc(&pdev->dev, sizeof(*p), GFP_KERNEL);
+ if (!p)
+ return -ENOMEM;
+
+ res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+ p->base = devm_ioremap_resource(&pdev->dev, res);
+ if (IS_ERR(p->base)) {
+ dev_err(&pdev->dev, "failed to remap I/O memory\n");
+ return PTR_ERR(p->base);
+ }
+ spin_lock_init(&p->lock);
+ platform_set_drvdata(pdev, p);
+
+ p->chip.ngpio = 4; /* 2 cs pins for spi0, and 2 for spi1 */
+ p->chip.base = -1;
+ p->chip.direction_input = elba_spics_direction_input;
+ p->chip.direction_output = elba_spics_direction_output;
+ p->chip.get = elba_spics_get_value;
+ p->chip.set = elba_spics_set_value;
+ p->chip.label = dev_name(&pdev->dev);
+ p->chip.parent = &pdev->dev;
+ p->chip.owner = THIS_MODULE;
+
+ ret = devm_gpiochip_add_data(&pdev->dev, &p->chip, p);
+ if (ret) {
+ dev_err(&pdev->dev, "unable to add gpio chip\n");
+ return ret;
+ }
+
+ dev_info(&pdev->dev, "elba spics registered\n");
+ return 0;
+}
+
+static const struct of_device_id ebla_spics_of_match[] = {
+ { .compatible = "pensando,elba-spics" },
+ {}
+};
+
+static struct platform_driver elba_spics_driver = {
+ .probe = elba_spics_probe,
+ .driver = {
+ .name = "pensando-elba-spics",
+ .of_match_table = ebla_spics_of_match,
+ },
+};
+module_platform_driver(elba_spics_driver);
+
+MODULE_LICENSE("GPL v2");
+MODULE_DESCRIPTION("Elba SPI chip-select driver");
--
2.17.1
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