Patchwork [U-Boot,2/3] LaCie/common: add support for the GPIO extension bus

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Submitter Simon Guinot
Date June 17, 2013, 8:58 p.m.
Message ID <1371502684-17522-3-git-send-email-simon.guinot@sequanux.org>
Download mbox | patch
Permalink /patch/252059/
State Superseded
Delegated to: Prafulla Wadaskar
Headers show

Comments

Simon Guinot - June 17, 2013, 8:58 p.m.
This patch adds support for the GPIO extension bus found on some LaCie
boards (as the 2Big/5Big Network v2 and the 2Big NAS). This bus allows
to configure the devices (mostly the LEDs) connected to a CPLD via two
GPIO-based registers (address and data).

Signed-off-by: Simon Guinot <simon.guinot@sequanux.org>
---
 board/LaCie/common/gpio-ext.c |   47 +++++++++++++++++++++++++++++++++++++++++
 board/LaCie/common/gpio-ext.h |   24 +++++++++++++++++++++
 2 files changed, 71 insertions(+)
 create mode 100644 board/LaCie/common/gpio-ext.c
 create mode 100644 board/LaCie/common/gpio-ext.h
Prafulla Wadaskar - June 18, 2013, 6:53 a.m.
> -----Original Message-----
> From: Simon Guinot [mailto:simon.guinot@sequanux.org]
> Sent: 18 June 2013 02:28
> To: Prafulla Wadaskar
> Cc: Albert ARIBAUD; u-boot@lists.denx.de
> Subject: [PATCH 2/3] LaCie/common: add support for the
> GPIO extension bus
> 
> This patch adds support for the GPIO extension bus
> found on some LaCie
> boards (as the 2Big/5Big Network v2 and the 2Big NAS).
> This bus allows
> to configure the devices (mostly the LEDs) connected to
> a CPLD via two
> GPIO-based registers (address and data).

Hi Simon
The name given here for the patch as well as files "gpio-ext" is confusing for me.

As you stated here those are the IOs generated by CPLD on your board which can be programmed using bit-banging on two GPIOs.

So to me it those are "cpld_ios".

May you please rename these files accordingly and resend the patch series for better understanding?

To me "gpio-ext" is generic term application for "General purpose IOs"

Regards...
Prafulla . . .
Simon Guinot - June 18, 2013, 10:28 a.m.
On Mon, Jun 17, 2013 at 11:53:53PM -0700, Prafulla Wadaskar wrote:
> 
> 
> > -----Original Message-----
> > From: Simon Guinot [mailto:simon.guinot@sequanux.org]
> > Sent: 18 June 2013 02:28
> > To: Prafulla Wadaskar
> > Cc: Albert ARIBAUD; u-boot@lists.denx.de
> > Subject: [PATCH 2/3] LaCie/common: add support for the
> > GPIO extension bus
> > 
> > This patch adds support for the GPIO extension bus
> > found on some LaCie
> > boards (as the 2Big/5Big Network v2 and the 2Big NAS).
> > This bus allows
> > to configure the devices (mostly the LEDs) connected to
> > a CPLD via two
> > GPIO-based registers (address and data).
> 
> Hi Simon

Hi Prafulla,

Thanks for your quick answer.

> The name given here for the patch as well as files "gpio-ext" is confusing for me.
> 
> As you stated here those are the IOs generated by CPLD on your board which can be programmed using bit-banging on two GPIOs.

Not really bit-banging. Here we have 3 GPIOs used as a kind of address
register and 3 other GPIOs used as a kind of data register. An another
GPIO is used to notify the CPLD than the registers have been updated.
I will update the patch description to make clear that a register may
include several GPIOs.

At LaCie, this kind of bus is called a "GPIO extension bus". It is like
a cheap GPIO expander.

> 
> So to me it those are "cpld_ios".

I am not sure that behind this kind of bus we always have a CPLD. I will
check this. If it is the case, what do you think about cpld-gpio-bus ?

Moreover as this "bus" is really a lacie specific stuff, should I
prepend a "lacie-" prefix ?

Regards,

Simon

> 
> May you please rename these files accordingly and resend the patch series for better understanding?
> 
> To me "gpio-ext" is generic term application for "General purpose IOs"
> 
> Regards...
> Prafulla . . .
Prafulla Wadaskar - June 18, 2013, 11:18 a.m.
> -----Original Message-----
> From: Simon Guinot [mailto:simon.guinot@sequanux.org]
> Sent: 18 June 2013 15:59
> To: Prafulla Wadaskar
> Cc: Albert ARIBAUD; u-boot@lists.denx.de
> Subject: Re: [PATCH 2/3] LaCie/common: add support for
> the GPIO extension bus
> 
> On Mon, Jun 17, 2013 at 11:53:53PM -0700, Prafulla
> Wadaskar wrote:
> >
> >
> > > -----Original Message-----
> > > From: Simon Guinot
> [mailto:simon.guinot@sequanux.org]
> > > Sent: 18 June 2013 02:28
> > > To: Prafulla Wadaskar
> > > Cc: Albert ARIBAUD; u-boot@lists.denx.de
> > > Subject: [PATCH 2/3] LaCie/common: add support for
> the
> > > GPIO extension bus
...snip...

> At LaCie, this kind of bus is called a "GPIO extension
> bus". It is like
> a cheap GPIO expander.
> 
> >
> > So to me it those are "cpld_ios".
> 
> I am not sure that behind this kind of bus we always
> have a CPLD. I will
> check this. If it is the case, what do you think about
> cpld-gpio-bus ?

Even this sounds good to me, better than my suggestion earlier :).

> 
> Moreover as this "bus" is really a lacie specific stuff,
> should I
> prepend a "lacie-" prefix ?

This is not necessary I think.

Regards...
Prafulla . . .

Patch

diff --git a/board/LaCie/common/gpio-ext.c b/board/LaCie/common/gpio-ext.c
new file mode 100644
index 0000000..1e1b7ff
--- /dev/null
+++ b/board/LaCie/common/gpio-ext.c
@@ -0,0 +1,47 @@ 
+/*
+ * gpio-ext.c: provides support for the GPIO extension bus found on some
+ * LaCie boards (as the 2Big/5Big Network v2 and the 2Big NAS). This bus
+ * allows to configure the devices (mostly the LEDs) connected to a CPLD
+ * via two GPIO-based registers (address and data).
+ *
+ * Copyright (C) 2013 Simon Guinot <simon.guinot@sequanux.org>
+ *
+ * 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.
+ */
+
+#include <asm/arch/gpio.h>
+#include "gpio-ext.h"
+
+static void gpio_ext_set_addr(struct gpio_ext *gpio_ext, unsigned addr)
+{
+	int pin;
+
+	for (pin = 0; pin < gpio_ext->num_addr; pin++)
+		kw_gpio_set_value(gpio_ext->addr[pin], (addr >> pin) & 1);
+}
+
+static void gpio_ext_set_data(struct gpio_ext *gpio_ext, unsigned data)
+{
+	int pin;
+
+	for (pin = 0; pin < gpio_ext->num_data; pin++)
+		kw_gpio_set_value(gpio_ext->data[pin], (data >> pin) & 1);
+}
+
+static void gpio_ext_enable_select(struct gpio_ext *gpio_ext)
+{
+	/* The transfer is enabled on the raising edge. */
+	kw_gpio_set_value(gpio_ext->enable, 0);
+	kw_gpio_set_value(gpio_ext->enable, 1);
+}
+
+void gpio_ext_set_value(struct gpio_ext *gpio_ext,
+			unsigned addr, unsigned value)
+{
+	gpio_ext_set_addr(gpio_ext, addr);
+	gpio_ext_set_data(gpio_ext, value);
+	gpio_ext_enable_select(gpio_ext);
+}
diff --git a/board/LaCie/common/gpio-ext.h b/board/LaCie/common/gpio-ext.h
new file mode 100644
index 0000000..09fa271
--- /dev/null
+++ b/board/LaCie/common/gpio-ext.h
@@ -0,0 +1,24 @@ 
+/*
+ * Copyright (C) 2013 Simon Guinot <simon.guinot@sequanux.org>
+ *
+ * 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.
+ */
+
+#ifndef _LACIE_GPIO_EXT_H
+#define _LACIE_GPIO_EXT_H
+
+struct gpio_ext {
+	unsigned *addr;
+	unsigned num_addr;
+	unsigned *data;
+	unsigned num_data;
+	unsigned enable;
+};
+
+void gpio_ext_set_value(struct gpio_ext *gpio_ext,
+			unsigned addr, unsigned value);
+
+#endif /* _LACIE_GPIO_EXT_H */