Patchwork [U-Boot,v3,1/2] gpio: bcm2835: Add GPIO driver

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Submitter Vikram Narayanan
Date July 31, 2012, 5:48 p.m.
Message ID <50181A8A.9090604@gmail.com>
Download mbox | patch
Permalink /patch/174296/
State Superseded
Delegated to: Tom Rini
Headers show

Comments

Vikram Narayanan - July 31, 2012, 5:48 p.m.
Driver for BCM2835 SoC. This gives the basic functionality of
setting/clearing the output.

Signed-off-by: Vikram Narayanan <vikram186@gmail.com>
---
 arch/arm/include/asm/arch-bcm2835/gpio.h |   71 ++++++++++++++++++++++++
 drivers/gpio/Makefile                    |    1 +
 drivers/gpio/bcm2835_gpio.c              |   88 ++++++++++++++++++++++++++++++
 3 files changed, 160 insertions(+), 0 deletions(-)
 create mode 100644 arch/arm/include/asm/arch-bcm2835/gpio.h
 create mode 100644 drivers/gpio/bcm2835_gpio.c
Vikram Narayanan - Aug. 1, 2012, 2:31 a.m.
On 7/31/2012 11:18 PM, Vikram Narayanan wrote:
> Driver for BCM2835 SoC. This gives the basic functionality of
> setting/clearing the output.
>
> Signed-off-by: Vikram Narayanan<vikram186@gmail.com>
> ---
>   arch/arm/include/asm/arch-bcm2835/gpio.h |   71 ++++++++++++++++++++++++
>   drivers/gpio/Makefile                    |    1 +
>   drivers/gpio/bcm2835_gpio.c              |   88 ++++++++++++++++++++++++++++++
>   3 files changed, 160 insertions(+), 0 deletions(-)
>   create mode 100644 arch/arm/include/asm/arch-bcm2835/gpio.h
>   create mode 100644 drivers/gpio/bcm2835_gpio.c
>
> diff --git a/arch/arm/include/asm/arch-bcm2835/gpio.h b/arch/arm/include/asm/arch-bcm2835/gpio.h
> new file mode 100644
> index 0000000..515456a
> --- /dev/null
> +++ b/arch/arm/include/asm/arch-bcm2835/gpio.h
> @@ -0,0 +1,71 @@
> +/*
> + * Copyright (C) 2012 Vikram Narayananan
> + *<vikram186@gmail.com>
> + *
> + * See file CREDITS for list of people who contributed to this
> + * project.
> + *
> + * 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; either version 2 of
> + * the License, or (at your option) any later version.
> + *
> + * This program is distributed in the hope that it will be useful,
> + * but WITHOUT ANY WARRANTY; without even the implied warranty of
> + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
> + * GNU General Public License for more details.
> + *
> + * You should have received a copy of the GNU General Public License
> + * along with this program; if not, write to the Free Software
> + * Foundation, Inc., 59 Temple Place, Suite 330, Boston,
> + * MA 02111-1307 USA
> + */
> +
> +#ifndef _BCM2835_GPIO_H_
> +#define _BCM2835_GPIO_H_
> +
> +#define BCM2835_GPIO_BASE	0x7E200000
> +#define BCM2835_GPIO_COUNT	53

GPIO count should be 54 to make the gpio_is_valid work correctly when 
the gpio is 53.
Will fix in v4.

Any other comments?

> +
> +#define BCM2835_GPIO_FSEL_MASK	0x7
> +#define BCM2835_GPIO_INPUT		0x0
> +#define BCM2835_GPIO_OUTPUT		0x1
> +#define BCM2835_GPIO_ALT0		0x2
> +#define BCM2835_GPIO_ALT1		0x3
> +#define BCM2835_GPIO_ALT2		0x4
> +#define BCM2835_GPIO_ALT3		0x5
> +#define BCM2835_GPIO_ALT4		0x6
> +#define BCM2835_GPIO_ALT5		0x7
> +
> +#define BCM2835_GPIO_COMMON_BANK(gpio)			((gpio<  32) ? 0 : 1)
> +#define BCM2835_GPIO_COMMON_SHIFT(gpio)		(gpio&  0x1f)
> +
> +#define BCM2835_GPIO_FSEL_BANK(gpio)	(gpio / 10)
> +#define BCM2835_GPIO_FSEL_SHIFT(gpio)	((gpio % 10) * 3)
> +
> +struct bcm_gpio_regs {
> +	u32 gpfsel[6];
> +	u32 reserved1;
> +	u32 gpset[2];
> +	u32 reserved2;
> +	u32 gpclr[2];
> +	u32 reserved3;
> +	u32 gplev[2];
> +	u32 reserved4;
> +	u32 gpeds[2];
> +	u32 reserved5;
> +	u32 gpren[2];
> +	u32 reserved6;
> +	u32 gpfen[2];
> +	u32 reserved7;
> +	u32 gphen[2];
> +	u32 reserved8;
> +	u32 gplen[2];
> +	u32 reserved9;
> +	u32 gparen[2];
> +	u32 reserved10;
> +	u32 gppud;
> +	u32 gppudclk[2];
> +};
> +
> +#endif /* _BCM2835_GPIO_H_ */
> diff --git a/drivers/gpio/Makefile b/drivers/gpio/Makefile
> index 32a2474..8d2f2b2 100644
> --- a/drivers/gpio/Makefile
> +++ b/drivers/gpio/Makefile
> @@ -40,6 +40,7 @@ COBJS-$(CONFIG_TEGRA_GPIO)	+= tegra_gpio.o
>   COBJS-$(CONFIG_DA8XX_GPIO)	+= da8xx_gpio.o
>   COBJS-$(CONFIG_ALTERA_PIO)	+= altera_pio.o
>   COBJS-$(CONFIG_MPC83XX_GPIO)	+= mpc83xx_gpio.o
> +COBJS-$(CONFIG_BCM2835_GPIO)	+= bcm2835_gpio.o
>
>   COBJS	:= $(COBJS-y)
>   SRCS 	:= $(COBJS:.o=.c)
> diff --git a/drivers/gpio/bcm2835_gpio.c b/drivers/gpio/bcm2835_gpio.c
> new file mode 100644
> index 0000000..eb02efa
> --- /dev/null
> +++ b/drivers/gpio/bcm2835_gpio.c
> @@ -0,0 +1,88 @@
> +/*
> + * Copyright (C) 2012 Vikram Narayananan
> + *<vikram186@gmail.com>
> + *
> + * See file CREDITS for list of people who contributed to this
> + * project.
> + *
> + * 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; either version 2 of
> + * the License, or (at your option) any later version.
> + *
> + * This program is distributed in the hope that it will be useful,
> + * but WITHOUT ANY WARRANTY; without even the implied warranty of
> + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
> + * GNU General Public License for more details.
> + *
> + * You should have received a copy of the GNU General Public License
> + * along with this program; if not, write to the Free Software
> + * Foundation, Inc., 59 Temple Place, Suite 330, Boston,
> + * MA 02111-1307 USA
> + */
> +
> +#include<common.h>
> +#include<asm/gpio.h>
> +#include<asm/io.h>
> +
> +inline int gpio_is_valid(unsigned gpio)
> +{
> +	return (gpio<  BCM2835_GPIO_COUNT);
> +}
> +
> +int gpio_request(unsigned gpio, const char *label)
> +{
> +	return gpio_is_valid(gpio);
> +}
> +
> +int gpio_free(unsigned gpio)
> +{
> +	return 0;
> +}
> +
> +int gpio_direction_input(unsigned gpio)
> +{
> +	struct bcm_gpio_regs *reg = (struct bcm_gpio_regs *)BCM2835_GPIO_BASE;
> +	unsigned val;
> +
> +	val = readl(&reg->gpfsel[BCM2835_GPIO_FSEL_BANK(gpio)]);
> +	val&= ~(BCM2835_GPIO_FSEL_MASK<<  BCM2835_GPIO_FSEL_SHIFT(gpio));
> +	val |= (BCM2835_GPIO_INPUT<<  BCM2835_GPIO_FSEL_SHIFT(gpio));
> +	writel(val, reg->gpfsel[BCM2835_GPIO_FSEL_BANK(gpio)]);
> +	}
> +
> +int gpio_direction_output(unsigned gpio, int value)
> +{
> +	struct bcm_gpio_regs *reg = (struct bcm_gpio_regs *)BCM2835_GPIO_BASE;
> +	unsigned val;
> +
> +	if (value)
> +		gpio_set_value(gpio, value);
> +
> +	val = readl(&reg->gpfsel[BCM2835_GPIO_FSEL_BANK(gpio)]);
> +	val&= ~(BCM2835_GPIO_FSEL_MASK<<  BCM2835_GPIO_FSEL_SHIFT(gpio));
> +	val |= (BCM2835_GPIO_OUTPUT<<  BCM2835_GPIO_FSEL_SHIFT(gpio));
> +	writel(val, reg->gpfsel[BCM2835_GPIO_FSEL_BANK(gpio)]);
> +}
> +
> +int gpio_get_value(unsigned gpio)
> +{
> +	struct bcm_gpio_regs *reg = (struct bcm_gpio_regs *)BCM2835_GPIO_BASE;
> +	unsigned val;
> +
> +	val = readl(&reg->gplev[BCM2835_GPIO_COMMON_BANK(gpio)]);
> +
> +	return (val>>  BCM2835_GPIO_COMMON_SHIFT(gpio))&  0x1;
> +}
> +
> +int gpio_set_value(unsigned gpio, int value)
> +{
> +	struct bcm_gpio_regs *reg = (struct bcm_gpio_regs *)BCM2835_GPIO_BASE;
> +	u32 *output_reg = value ? reg->gpset : reg->gpclr;
> +
> +	writel(1<<  BCM2835_GPIO_COMMON_SHIFT(gpio),
> +				output_reg[BCM2835_GPIO_COMMON_BANK(gpio)]);
> +
> +	return 0;
> +}
> +
Stephen Warren - Aug. 1, 2012, 4:22 a.m.
On 07/31/2012 08:31 PM, Vikram Narayanan wrote:
> On 7/31/2012 11:18 PM, Vikram Narayanan wrote:
>> Driver for BCM2835 SoC. This gives the basic functionality of
>> setting/clearing the output.

>> diff --git a/arch/arm/include/asm/arch-bcm2835/gpio.h

>> +#define BCM2835_GPIO_COUNT    53
> 
> GPIO count should be 54 to make the gpio_is_valid work correctly when
> the gpio is 53.
> Will fix in v4.

Oh dear. I posted an updated version of your patches which fix a bunch
of errors. I guess I'll wait and see if there are any other comments on
other patches in that series, and re-post that series, or just that
patch, with that fixed later.

P.S. There's no need to quote the entire patch just to comment on one line.

Patch

diff --git a/arch/arm/include/asm/arch-bcm2835/gpio.h b/arch/arm/include/asm/arch-bcm2835/gpio.h
new file mode 100644
index 0000000..515456a
--- /dev/null
+++ b/arch/arm/include/asm/arch-bcm2835/gpio.h
@@ -0,0 +1,71 @@ 
+/*
+ * Copyright (C) 2012 Vikram Narayananan
+ * <vikram186@gmail.com>
+ *
+ * See file CREDITS for list of people who contributed to this
+ * project.
+ *
+ * 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; either version 2 of
+ * the License, or (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 59 Temple Place, Suite 330, Boston,
+ * MA 02111-1307 USA
+ */
+
+#ifndef _BCM2835_GPIO_H_
+#define _BCM2835_GPIO_H_
+
+#define BCM2835_GPIO_BASE	0x7E200000
+#define BCM2835_GPIO_COUNT	53
+
+#define BCM2835_GPIO_FSEL_MASK	0x7
+#define BCM2835_GPIO_INPUT		0x0
+#define BCM2835_GPIO_OUTPUT		0x1
+#define BCM2835_GPIO_ALT0		0x2
+#define BCM2835_GPIO_ALT1		0x3
+#define BCM2835_GPIO_ALT2		0x4
+#define BCM2835_GPIO_ALT3		0x5
+#define BCM2835_GPIO_ALT4		0x6
+#define BCM2835_GPIO_ALT5		0x7
+
+#define BCM2835_GPIO_COMMON_BANK(gpio)			((gpio < 32) ? 0 : 1)
+#define BCM2835_GPIO_COMMON_SHIFT(gpio)		(gpio & 0x1f)
+
+#define BCM2835_GPIO_FSEL_BANK(gpio)	(gpio / 10)
+#define BCM2835_GPIO_FSEL_SHIFT(gpio)	((gpio % 10) * 3)
+
+struct bcm_gpio_regs {
+	u32 gpfsel[6];
+	u32 reserved1;
+	u32 gpset[2];
+	u32 reserved2;
+	u32 gpclr[2];
+	u32 reserved3;
+	u32 gplev[2];
+	u32 reserved4;
+	u32 gpeds[2];
+	u32 reserved5;
+	u32 gpren[2];
+	u32 reserved6;
+	u32 gpfen[2];
+	u32 reserved7;
+	u32 gphen[2];
+	u32 reserved8;
+	u32 gplen[2];
+	u32 reserved9;
+	u32 gparen[2];
+	u32 reserved10;
+	u32 gppud;
+	u32 gppudclk[2];
+};
+
+#endif /* _BCM2835_GPIO_H_ */
diff --git a/drivers/gpio/Makefile b/drivers/gpio/Makefile
index 32a2474..8d2f2b2 100644
--- a/drivers/gpio/Makefile
+++ b/drivers/gpio/Makefile
@@ -40,6 +40,7 @@  COBJS-$(CONFIG_TEGRA_GPIO)	+= tegra_gpio.o
 COBJS-$(CONFIG_DA8XX_GPIO)	+= da8xx_gpio.o
 COBJS-$(CONFIG_ALTERA_PIO)	+= altera_pio.o
 COBJS-$(CONFIG_MPC83XX_GPIO)	+= mpc83xx_gpio.o
+COBJS-$(CONFIG_BCM2835_GPIO)	+= bcm2835_gpio.o
 
 COBJS	:= $(COBJS-y)
 SRCS 	:= $(COBJS:.o=.c)
diff --git a/drivers/gpio/bcm2835_gpio.c b/drivers/gpio/bcm2835_gpio.c
new file mode 100644
index 0000000..eb02efa
--- /dev/null
+++ b/drivers/gpio/bcm2835_gpio.c
@@ -0,0 +1,88 @@ 
+/*
+ * Copyright (C) 2012 Vikram Narayananan
+ * <vikram186@gmail.com>
+ *
+ * See file CREDITS for list of people who contributed to this
+ * project.
+ *
+ * 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; either version 2 of
+ * the License, or (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 59 Temple Place, Suite 330, Boston,
+ * MA 02111-1307 USA
+ */
+
+#include <common.h>
+#include <asm/gpio.h>
+#include <asm/io.h>
+
+inline int gpio_is_valid(unsigned gpio)
+{
+	return (gpio < BCM2835_GPIO_COUNT);
+}
+
+int gpio_request(unsigned gpio, const char *label)
+{
+	return gpio_is_valid(gpio);
+}
+
+int gpio_free(unsigned gpio)
+{
+	return 0;
+}
+
+int gpio_direction_input(unsigned gpio)
+{
+	struct bcm_gpio_regs *reg = (struct bcm_gpio_regs *)BCM2835_GPIO_BASE;
+	unsigned val;
+
+	val = readl(&reg->gpfsel[BCM2835_GPIO_FSEL_BANK(gpio)]);
+	val &= ~(BCM2835_GPIO_FSEL_MASK << BCM2835_GPIO_FSEL_SHIFT(gpio));
+	val |= (BCM2835_GPIO_INPUT << BCM2835_GPIO_FSEL_SHIFT(gpio));
+	writel(val, reg->gpfsel[BCM2835_GPIO_FSEL_BANK(gpio)]);
+	}
+
+int gpio_direction_output(unsigned gpio, int value)
+{
+	struct bcm_gpio_regs *reg = (struct bcm_gpio_regs *)BCM2835_GPIO_BASE;
+	unsigned val;
+
+	if (value)
+		gpio_set_value(gpio, value);
+
+	val = readl(&reg->gpfsel[BCM2835_GPIO_FSEL_BANK(gpio)]);
+	val &= ~(BCM2835_GPIO_FSEL_MASK << BCM2835_GPIO_FSEL_SHIFT(gpio));
+	val |= (BCM2835_GPIO_OUTPUT << BCM2835_GPIO_FSEL_SHIFT(gpio));
+	writel(val, reg->gpfsel[BCM2835_GPIO_FSEL_BANK(gpio)]);
+}
+
+int gpio_get_value(unsigned gpio)
+{
+	struct bcm_gpio_regs *reg = (struct bcm_gpio_regs *)BCM2835_GPIO_BASE;
+	unsigned val;
+
+	val = readl(&reg->gplev[BCM2835_GPIO_COMMON_BANK(gpio)]);
+
+	return (val >> BCM2835_GPIO_COMMON_SHIFT(gpio)) & 0x1;
+}
+
+int gpio_set_value(unsigned gpio, int value)
+{
+	struct bcm_gpio_regs *reg = (struct bcm_gpio_regs *)BCM2835_GPIO_BASE;
+	u32 *output_reg = value ? reg->gpset : reg->gpclr;
+
+	writel(1 << BCM2835_GPIO_COMMON_SHIFT(gpio),
+				output_reg[BCM2835_GPIO_COMMON_BANK(gpio)]);
+
+	return 0;
+}
+