Commit fdb7e884 authored by Linus Walleij's avatar Linus Walleij Committed by Wolfram Sang
Browse files

i2c: iop: Use GPIO descriptors 



The IOP3xx has some elaborate code to directly slam the
GPIO lines multiplexed with I2C down low before enablement,
apparently a workaround for a hardware bug found in the
early chips.

After consulting the developer documentation for IOP80321
and IOP80331 I can clearly see that this may be useful for
IOP80321 family (mach-iop32x) but it is highly dubious for
any 80331 series or later chip: in these chips the lines
are not multiplexed for UARTs.

We convert the code to pass optional GPIO descriptors
and register these only on the 80321-based boards where
it makes sense, optionally obtain them in the driver and
use the gpiod_set_raw_value() to ascertain the line gets
driven low when needed.

The GPIO driver does not give the GPIO chip a reasonable
label so the patch also adds that so that these machine
descriptor tables can be used.

Signed-off-by: default avatarLinus Walleij <linus.walleij@linaro.org>
Acked-by: default avatarArnd Bergmann <arnd@arndb.de>
Acked-by: default avatarDan Williams <dan.j.williams@intel.com>
Signed-off-by: default avatarWolfram Sang <wsa@the-dreams.de>
parent ed7357c9

arch/arm/include/asm/hardware/iop3xx.h

+2 −0
Original line number Diff line number Diff line
@@ -305,6 +305,8 @@ extern struct platform_device iop3xx_dma_1_channel; 
extern struct platform_device iop3xx_aau_channel;

extern struct platform_device iop3xx_i2c0_device;

extern struct platform_device iop3xx_i2c1_device;

extern struct gpiod_lookup_table iop3xx_i2c0_gpio_lookup;

extern struct gpiod_lookup_table iop3xx_i2c1_gpio_lookup;



#endif

arch/arm/mach-iop32x/em7210.c

+3 −0
Original line number Diff line number Diff line
@@ -24,6 +24,7 @@ 
#include <linux/platform_device.h>

#include <linux/i2c.h>

#include <linux/gpio.h>

#include <linux/gpio/machine.h>

#include <mach/hardware.h>

#include <linux/io.h>

#include <linux/irq.h>
@@ -211,6 +212,8 @@ static void __init em7210_init_machine(void) 
{

	register_iop32x_gpio();

	platform_device_register(&em7210_serial_device);

	gpiod_add_lookup_table(&iop3xx_i2c0_gpio_lookup);

	gpiod_add_lookup_table(&iop3xx_i2c1_gpio_lookup);

	platform_device_register(&iop3xx_i2c0_device);

	platform_device_register(&iop3xx_i2c1_device);

	platform_device_register(&em7210_flash_device);

arch/arm/mach-iop32x/glantank.c

+3 −0
Original line number Diff line number Diff line
@@ -25,6 +25,7 @@ 
#include <linux/i2c.h>

#include <linux/platform_device.h>

#include <linux/io.h>

#include <linux/gpio/machine.h>

#include <mach/hardware.h>

#include <asm/irq.h>

#include <asm/mach/arch.h>
@@ -189,6 +190,8 @@ static void glantank_power_off(void) 
static void __init glantank_init_machine(void)

{

	register_iop32x_gpio();

	gpiod_add_lookup_table(&iop3xx_i2c0_gpio_lookup);

	gpiod_add_lookup_table(&iop3xx_i2c1_gpio_lookup);

	platform_device_register(&iop3xx_i2c0_device);

	platform_device_register(&iop3xx_i2c1_device);

	platform_device_register(&glantank_flash_device);

arch/arm/mach-iop32x/iq31244.c

+3 −0
Original line number Diff line number Diff line
@@ -26,6 +26,7 @@ 
#include <linux/mtd/physmap.h>

#include <linux/platform_device.h>

#include <linux/io.h>

#include <linux/gpio/machine.h>

#include <mach/hardware.h>

#include <asm/cputype.h>

#include <asm/irq.h>
@@ -285,6 +286,8 @@ void ep80219_power_off(void) 
static void __init iq31244_init_machine(void)

{

	register_iop32x_gpio();

	gpiod_add_lookup_table(&iop3xx_i2c0_gpio_lookup);

	gpiod_add_lookup_table(&iop3xx_i2c1_gpio_lookup);

	platform_device_register(&iop3xx_i2c0_device);

	platform_device_register(&iop3xx_i2c1_device);

	platform_device_register(&iq31244_flash_device);

arch/arm/mach-iop32x/iq80321.c

+3 −0
Original line number Diff line number Diff line
@@ -23,6 +23,7 @@ 
#include <linux/mtd/physmap.h>

#include <linux/platform_device.h>

#include <linux/io.h>

#include <linux/gpio/machine.h>

#include <mach/hardware.h>

#include <asm/irq.h>

#include <asm/mach/arch.h>
@@ -172,6 +173,8 @@ static struct platform_device iq80321_serial_device = { 
static void __init iq80321_init_machine(void)

{

	register_iop32x_gpio();

	gpiod_add_lookup_table(&iop3xx_i2c0_gpio_lookup);

	gpiod_add_lookup_table(&iop3xx_i2c1_gpio_lookup);

	platform_device_register(&iop3xx_i2c0_device);

	platform_device_register(&iop3xx_i2c1_device);

	platform_device_register(&iq80321_flash_device);

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