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misc: eeprom_93xx46: Add support for a GPIO 'select' line.

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This commit adds support to the eeprom_93x46 driver allowing a GPIO line
to function as a 'select' or 'enable' signal prior to accessing the
EEPROM.

Signed-off-by: Cory Tusar <cory.tusar@pid1solutions.com>
Tested-by: Chris Healy <chris.healy@zii.aero>
Reviewed-by: Vladimir Zapolskiy <vz@mleia.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
Cory Tusar 2016-02-10 14:32:08 -05:00 committed by Greg Kroah-Hartman
parent e1379b56e9
commit 3ca9b1ac28
2 changed files with 38 additions and 0 deletions
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35
drivers/misc/eeprom/eeprom_93xx46.c
View File

@ -10,11 +10,13 @@
#include <linux/delay.h> #include <linux/delay.h>
#include <linux/device.h> #include <linux/device.h>
#include <linux/gpio/consumer.h>
#include <linux/kernel.h> #include <linux/kernel.h>
#include <linux/module.h> #include <linux/module.h>
#include <linux/mutex.h> #include <linux/mutex.h>
#include <linux/of.h> #include <linux/of.h>
#include <linux/of_device.h> #include <linux/of_device.h>
#include <linux/of_gpio.h>
#include <linux/slab.h> #include <linux/slab.h>
#include <linux/spi/spi.h> #include <linux/spi/spi.h>
#include <linux/sysfs.h> #include <linux/sysfs.h>
@ -343,6 +345,20 @@ static ssize_t eeprom_93xx46_store_erase(struct device *dev,
} }
static DEVICE_ATTR(erase, S_IWUSR, NULL, eeprom_93xx46_store_erase); static DEVICE_ATTR(erase, S_IWUSR, NULL, eeprom_93xx46_store_erase);
static void select_assert(void *context)
{
struct eeprom_93xx46_dev *edev = context;
gpiod_set_value_cansleep(edev->pdata->select, 1);
}
static void select_deassert(void *context)
{
struct eeprom_93xx46_dev *edev = context;
gpiod_set_value_cansleep(edev->pdata->select, 0);
}
static const struct of_device_id eeprom_93xx46_of_table[] = { static const struct of_device_id eeprom_93xx46_of_table[] = {
{ .compatible = "eeprom-93xx46", }, { .compatible = "eeprom-93xx46", },
{ .compatible = "atmel,at93c46d", .data = &atmel_at93c46d_data, }, { .compatible = "atmel,at93c46d", .data = &atmel_at93c46d_data, },
@ -357,6 +373,8 @@ static int eeprom_93xx46_probe_dt(struct spi_device *spi)
struct device_node *np = spi->dev.of_node; struct device_node *np = spi->dev.of_node;
struct eeprom_93xx46_platform_data *pd; struct eeprom_93xx46_platform_data *pd;
u32 tmp; u32 tmp;
int gpio;
enum of_gpio_flags of_flags;
int ret; int ret;
pd = devm_kzalloc(&spi->dev, sizeof(*pd), GFP_KERNEL); pd = devm_kzalloc(&spi->dev, sizeof(*pd), GFP_KERNEL);
@ -381,6 +399,23 @@ static int eeprom_93xx46_probe_dt(struct spi_device *spi)
if (of_property_read_bool(np, "read-only")) if (of_property_read_bool(np, "read-only"))
pd->flags |= EE_READONLY; pd->flags |= EE_READONLY;
gpio = of_get_named_gpio_flags(np, "select-gpios", 0, &of_flags);
if (gpio_is_valid(gpio)) {
unsigned long flags =
of_flags == OF_GPIO_ACTIVE_LOW ? GPIOF_ACTIVE_LOW : 0;
ret = devm_gpio_request_one(&spi->dev, gpio, flags,
"eeprom_93xx46_select");
if (ret)
return ret;
pd->select = gpio_to_desc(gpio);
pd->prepare = select_assert;
pd->finish = select_deassert;
gpiod_direction_output(pd->select, 0);
}
if (of_id->data) { if (of_id->data) {
const struct eeprom_93xx46_devtype_data *data = of_id->data; const struct eeprom_93xx46_devtype_data *data = of_id->data;

3
include/linux/eeprom_93xx46.h
View File

@ -3,6 +3,8 @@
* platform description for 93xx46 EEPROMs. * platform description for 93xx46 EEPROMs.
*/ */
struct gpio_desc;
struct eeprom_93xx46_platform_data { struct eeprom_93xx46_platform_data {
unsigned char flags; unsigned char flags;
#define EE_ADDR8 0x01 /* 8 bit addr. cfg */ #define EE_ADDR8 0x01 /* 8 bit addr. cfg */
@ -21,4 +23,5 @@ struct eeprom_93xx46_platform_data {
*/ */
void (*prepare)(void *); void (*prepare)(void *);
void (*finish)(void *); void (*finish)(void *);
struct gpio_desc *select;
}; };