[U-Boot] [PATCH v7 4/9] lpc32xx: add GPIO support
Albert ARIBAUD (3ADEV)
albert.aribaud at 3adev.fr
Tue Mar 31 11:40:46 CEST 2015
This driver only supports Driver Model, not legacy model.
Signed-off-by: Albert ARIBAUD (3ADEV) <albert.aribaud at 3adev.fr>
---
Changes in v7: None
Changes in v6: None
Changes in v5: None
Changes in v4: None
Changes in v3:
- move DM dependency constraint into Kconfig
- move regs pointer and function cache into private struct
- discourage readers from using functions implementation as an example
Changes in v2:
- move from legacy to Driver Model support
arch/arm/cpu/arm926ejs/lpc32xx/devices.c | 5 +
arch/arm/include/asm/arch-lpc32xx/gpio.h | 43 +++++
drivers/gpio/Kconfig | 7 +
drivers/gpio/Makefile | 1 +
drivers/gpio/lpc32xx_gpio.c | 293 +++++++++++++++++++++++++++++++
5 files changed, 349 insertions(+)
create mode 100644 arch/arm/include/asm/arch-lpc32xx/gpio.h
create mode 100644 drivers/gpio/lpc32xx_gpio.c
diff --git a/arch/arm/cpu/arm926ejs/lpc32xx/devices.c b/arch/arm/cpu/arm926ejs/lpc32xx/devices.c
index 81b53ea..a407098 100644
--- a/arch/arm/cpu/arm926ejs/lpc32xx/devices.c
+++ b/arch/arm/cpu/arm926ejs/lpc32xx/devices.c
@@ -9,6 +9,7 @@
#include <asm/arch/clk.h>
#include <asm/arch/uart.h>
#include <asm/io.h>
+#include <dm.h>
static struct clk_pm_regs *clk = (struct clk_pm_regs *)CLK_PM_BASE;
static struct uart_ctrl_regs *ctrl = (struct uart_ctrl_regs *)UART_CTRL_BASE;
@@ -61,3 +62,7 @@ void lpc32xx_i2c_init(unsigned int devnum)
ctrl |= CLK_I2C2_ENABLE;
writel(ctrl, &clk->i2cclk_ctrl);
}
+
+U_BOOT_DEVICE(lpc32xx_gpios) = {
+ .name = "gpio_lpc32xx"
+};
diff --git a/arch/arm/include/asm/arch-lpc32xx/gpio.h b/arch/arm/include/asm/arch-lpc32xx/gpio.h
new file mode 100644
index 0000000..3bd94e3
--- /dev/null
+++ b/arch/arm/include/asm/arch-lpc32xx/gpio.h
@@ -0,0 +1,43 @@
+/*
+ * LPC32xx GPIO interface
+ *
+ * (C) Copyright 2014 DENX Software Engineering GmbH
+ * Written-by: Albert ARIBAUD <albert.aribaud at 3adev.fr>
+ *
+ * SPDX-License-Identifier: GPL-2.0+
+ */
+
+/**
+ * GPIO Register map for LPC32xx
+ */
+
+struct gpio_regs {
+ u32 p3_inp_state;
+ u32 p3_outp_set;
+ u32 p3_outp_clr;
+ u32 p3_outp_state;
+ /* Watch out! the following are shared between p2 and p3 */
+ u32 p2_p3_dir_set;
+ u32 p2_p3_dir_clr;
+ u32 p2_p3_dir_state;
+ /* Now back to 'one register for one port' */
+ u32 p2_inp_state;
+ u32 p2_outp_set;
+ u32 p2_outp_clr;
+ u32 reserved1[6];
+ u32 p0_inp_state;
+ u32 p0_outp_set;
+ u32 p0_outp_clr;
+ u32 p0_outp_state;
+ u32 p0_dir_set;
+ u32 p0_dir_clr;
+ u32 p0_dir_state;
+ u32 reserved2;
+ u32 p1_inp_state;
+ u32 p1_outp_set;
+ u32 p1_outp_clr;
+ u32 p1_outp_state;
+ u32 p1_dir_set;
+ u32 p1_dir_clr;
+ u32 p1_dir_state;
+};
diff --git a/drivers/gpio/Kconfig b/drivers/gpio/Kconfig
index b609e73..7b5178a 100644
--- a/drivers/gpio/Kconfig
+++ b/drivers/gpio/Kconfig
@@ -7,3 +7,10 @@ config DM_GPIO
the GPIO uclass. Drivers provide methods to query the
particular GPIOs that they provide. The uclass interface
is defined in include/asm-generic/gpio.h.
+
+config LPC32XX_GPIO
+ bool "LPC32XX GPIO driver"
+ depends on DM
+ default n
+ help
+ Support for the LPC32XX GPIO driver.
diff --git a/drivers/gpio/Makefile b/drivers/gpio/Makefile
index fe9a3b2..85f71c5 100644
--- a/drivers/gpio/Makefile
+++ b/drivers/gpio/Makefile
@@ -41,3 +41,4 @@ obj-$(CONFIG_ADI_GPIO2) += adi_gpio2.o
obj-$(CONFIG_TCA642X) += tca642x.o
oby-$(CONFIG_SX151X) += sx151x.o
obj-$(CONFIG_SUNXI_GPIO) += sunxi_gpio.o
+obj-$(CONFIG_LPC32XX_GPIO) += lpc32xx_gpio.o
diff --git a/drivers/gpio/lpc32xx_gpio.c b/drivers/gpio/lpc32xx_gpio.c
new file mode 100644
index 0000000..96b3125
--- /dev/null
+++ b/drivers/gpio/lpc32xx_gpio.c
@@ -0,0 +1,293 @@
+/*
+ * LPC32xxGPIO driver
+ *
+ * (C) Copyright 2014 DENX Software Engineering GmbH
+ * Written-by: Albert ARIBAUD <albert.aribaud at 3adev.fr>
+ *
+ * SPDX-License-Identifier: GPL-2.0+
+ */
+
+#include <asm/io.h>
+#include <asm/arch-lpc32xx/cpu.h>
+#include <asm/arch-lpc32xx/gpio.h>
+#include <asm-generic/gpio.h>
+#include <dm.h>
+
+/**
+ * LPC32xx GPIOs work in banks but are non-homogeneous:
+ * - each bank holds a different number of GPIOs
+ * - some GPIOs are input/ouput, some input only, some output only;
+ * - some GPIOs have different meanings as an input and as an output;
+ * - some GPIOs are controlled on a given port and bit index, but
+ * read on another one.
+*
+ * In order to keep this code simple, GPIOS are considered here as
+ * homogeneous and linear, from 0 to 127.
+ *
+ * ** WARNING #1 **
+ *
+ * Client code is responsible for properly using valid GPIO numbers,
+ * including cases where a single physical GPIO has differing numbers
+ * for setting its direction, reading it and/or writing to it.
+ *
+ * ** WARNING #2 **
+ *
+ * Please read NOTE in description of lpc32xx_gpio_get_function().
+ */
+
+#define LPC32XX_GPIOS 128
+
+struct lpc32xx_gpio_platdata {
+ struct gpio_regs *regs;
+ /* GPIO FUNCTION: SEE WARNING #2 */
+ signed char function[LPC32XX_GPIOS];
+};
+
+/**
+ * We have 4 GPIO ports of 32 bits each
+ */
+
+#define MAX_GPIO 128
+
+#define GPIO_TO_PORT(gpio) ((gpio / 32) & 3)
+#define GPIO_TO_RANK(gpio) (gpio % 32)
+#define GPIO_TO_MASK(gpio) (1 << (gpio % 32))
+
+/**
+ * Configure a GPIO number 'offset' as input
+ */
+
+static int lpc32xx_gpio_direction_input(struct udevice *dev, unsigned offset)
+{
+ int port, mask;
+ struct lpc32xx_gpio_platdata *gpio_platdata = dev_get_platdata(dev);
+ struct gpio_regs *regs = gpio_platdata->regs;
+
+ port = GPIO_TO_PORT(offset);
+ mask = GPIO_TO_MASK(offset);
+
+ switch (port) {
+ case 0:
+ writel(mask, ®s->p0_dir_clr);
+ break;
+ case 1:
+ writel(mask, ®s->p1_dir_clr);
+ break;
+ case 2:
+ /* ports 2 and 3 share a common direction */
+ case 3:
+ writel(mask, ®s->p2_p3_dir_clr);
+ break;
+ default:
+ return -1;
+ }
+
+ /* GPIO FUNCTION: SEE WARNING #2 */
+ gpio_platdata->function[offset] = GPIOF_INPUT;
+
+ return 0;
+}
+
+/**
+ * Get the value of a GPIO
+ */
+
+static int lpc32xx_gpio_get_value(struct udevice *dev, unsigned offset)
+{
+ int port, rank, mask, value;
+ struct lpc32xx_gpio_platdata *gpio_platdata = dev_get_platdata(dev);
+ struct gpio_regs *regs = gpio_platdata->regs;
+
+ port = GPIO_TO_PORT(offset);
+
+ switch (port) {
+ case 0:
+ value = readl(®s->p0_inp_state);
+ break;
+ case 1:
+ value = readl(®s->p1_inp_state);
+ break;
+ case 2:
+ value = readl(®s->p2_inp_state);
+ break;
+ case 3:
+ value = readl(®s->p3_inp_state);
+ break;
+ default:
+ return -1;
+ }
+
+ rank = GPIO_TO_RANK(offset);
+ mask = GPIO_TO_MASK(offset);
+
+ return (value & mask) >> rank;
+}
+
+/**
+ * Set a GPIO
+ */
+
+static int gpio_set(struct udevice *dev, unsigned gpio)
+{
+ int port, mask;
+ struct lpc32xx_gpio_platdata *gpio_platdata = dev_get_platdata(dev);
+ struct gpio_regs *regs = gpio_platdata->regs;
+
+ port = GPIO_TO_PORT(gpio);
+ mask = GPIO_TO_MASK(gpio);
+
+ switch (port) {
+ case 0:
+ writel(mask, ®s->p0_outp_set);
+ break;
+ case 1:
+ writel(mask, ®s->p1_outp_set);
+ break;
+ case 2:
+ writel(mask, ®s->p2_outp_set);
+ break;
+ case 3:
+ writel(mask, ®s->p3_outp_set);
+ break;
+ default:
+ return -1;
+ }
+ return 0;
+}
+
+/**
+ * Clear a GPIO
+ */
+
+static int gpio_clr(struct udevice *dev, unsigned gpio)
+{
+ int port, mask;
+ struct lpc32xx_gpio_platdata *gpio_platdata = dev_get_platdata(dev);
+ struct gpio_regs *regs = gpio_platdata->regs;
+
+ port = GPIO_TO_PORT(gpio);
+ mask = GPIO_TO_MASK(gpio);
+
+ switch (port) {
+ case 0:
+ writel(mask, ®s->p0_outp_clr);
+ break;
+ case 1:
+ writel(mask, ®s->p1_outp_clr);
+ break;
+ case 2:
+ writel(mask, ®s->p2_outp_clr);
+ break;
+ case 3:
+ writel(mask, ®s->p3_outp_clr);
+ break;
+ default:
+ return -1;
+ }
+ return 0;
+}
+
+/**
+ * Set the value of a GPIO
+ */
+
+static int lpc32xx_gpio_set_value(struct udevice *dev, unsigned offset,
+ int value)
+{
+ if (value)
+ return gpio_set(dev, offset);
+ else
+ return gpio_clr(dev, offset);
+}
+
+/**
+ * Configure a GPIO number 'offset' as output with given initial value.
+ */
+
+static int lpc32xx_gpio_direction_output(struct udevice *dev, unsigned offset,
+ int value)
+{
+ int port, mask;
+ struct lpc32xx_gpio_platdata *gpio_platdata = dev_get_platdata(dev);
+ struct gpio_regs *regs = gpio_platdata->regs;
+
+ port = GPIO_TO_PORT(offset);
+ mask = GPIO_TO_MASK(offset);
+
+ switch (port) {
+ case 0:
+ writel(mask, ®s->p0_dir_set);
+ break;
+ case 1:
+ writel(mask, ®s->p1_dir_set);
+ break;
+ case 2:
+ /* ports 2 and 3 share a common direction */
+ case 3:
+ writel(mask, ®s->p2_p3_dir_set);
+ break;
+ default:
+ return -1;
+ }
+
+ /* GPIO FUNCTION: SEE WARNING #2 */
+ gpio_platdata->function[offset] = GPIOF_OUTPUT;
+
+ return lpc32xx_gpio_set_value(dev, offset, value);
+}
+
+/**
+ * GPIO functions are supposed to be computed from their current
+ * configuration, but that's way too complicated in LPC32XX. A simpler
+ * approach is used, where the GPIO functions are cached in an array.
+ * When the GPIO is in use, its function is either "input" or "output"
+ * depending on its direction, otherwise its function is "unknown".
+ *
+ * ** NOTE **
+ *
+ * THIS APPROACH WAS CHOSEN DU TO THE COMPLEX NATURE OF THE LPC32XX
+ * GPIOS; DO NOT TAKE THIS AS AN EXAMPLE FOR NEW CODE.
+ */
+
+static int lpc32xx_gpio_get_function(struct udevice *dev, unsigned offset)
+{
+ struct lpc32xx_gpio_platdata *gpio_platdata = dev_get_platdata(dev);
+ return gpio_platdata->function[offset];
+}
+
+static const struct dm_gpio_ops gpio_lpc32xx_ops = {
+ .direction_input = lpc32xx_gpio_direction_input,
+ .direction_output = lpc32xx_gpio_direction_output,
+ .get_value = lpc32xx_gpio_get_value,
+ .set_value = lpc32xx_gpio_set_value,
+ .get_function = lpc32xx_gpio_get_function,
+};
+
+static int lpc32xx_gpio_probe(struct udevice *dev)
+{
+ struct lpc32xx_gpio_platdata *gpio_platdata = dev_get_platdata(dev);
+ struct gpio_dev_priv *uc_priv = dev->uclass_priv;
+
+ if (dev->of_offset == -1) {
+ /* Tell the uclass how many GPIOs we have */
+ uc_priv->gpio_count = LPC32XX_GPIOS;
+ }
+
+ /* set base address for GPIO registers */
+ gpio_platdata->regs = (struct gpio_regs *)GPIO_BASE;
+
+ /* all GPIO functions are unknown until requested */
+ /* GPIO FUNCTION: SEE WARNING #2 */
+ memset(gpio_platdata->function, GPIOF_UNKNOWN,
+ sizeof(gpio_platdata->function));
+
+ return 0;
+}
+
+U_BOOT_DRIVER(gpio_lpc32xx) = {
+ .name = "gpio_lpc32xx",
+ .id = UCLASS_GPIO,
+ .ops = &gpio_lpc32xx_ops,
+ .probe = lpc32xx_gpio_probe,
+ .priv_auto_alloc_size = sizeof(struct lpc32xx_gpio_platdata),
+};
--
2.1.0
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