rtc-v3020: add ability to access v3020 chip with GPIOs
The v3020 RTC can be connected to GPIOs as well as to memory-like interface. Add ability to use GPIO bit-bang for v3020 read-write access. [akpm@linux-foundation.org: fix off-by-one in error path] Signed-off-by: Mike Rapoport <mike@compulab.co.il> Acked-by: Alessandro Zummo <a.zummo@towertech.it> Cc: David Brownell <david-b@pacbell.net> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This commit is contained in:
Mike Rapoport
Linus Torvalds
Родитель
c1c490e017
Коммит
96615841e1
|
|
@ -27,17 +27,162 @@
|
|||
#include <linux/bcd.h>
|
||||
#include <linux/rtc-v3020.h>
|
||||
#include <linux/delay.h>
|
||||
#include <linux/gpio.h>
|
||||
|
||||
#include <linux/io.h>
|
||||
|
||||
#undef DEBUG
|
||||
|
||||
struct v3020;
|
||||
|
||||
struct v3020_chip_ops {
|
||||
int (*map_io)(struct v3020 *chip, struct platform_device *pdev,
|
||||
struct v3020_platform_data *pdata);
|
||||
void (*unmap_io)(struct v3020 *chip);
|
||||
unsigned char (*read_bit)(struct v3020 *chip);
|
||||
void (*write_bit)(struct v3020 *chip, unsigned char bit);
|
||||
};
|
||||
|
||||
#define V3020_CS 0
|
||||
#define V3020_WR 1
|
||||
#define V3020_RD 2
|
||||
#define V3020_IO 3
|
||||
|
||||
struct v3020_gpio {
|
||||
const char *name;
|
||||
unsigned int gpio;
|
||||
};
|
||||
|
||||
struct v3020 {
|
||||
/* MMIO access */
|
||||
void __iomem *ioaddress;
|
||||
int leftshift;
|
||||
|
||||
/* GPIO access */
|
||||
struct v3020_gpio *gpio;
|
||||
|
||||
struct v3020_chip_ops *ops;
|
||||
|
||||
struct rtc_device *rtc;
|
||||
};
|
||||
|
||||
|
||||
static int v3020_mmio_map(struct v3020 *chip, struct platform_device *pdev,
|
||||
struct v3020_platform_data *pdata)
|
||||
{
|
||||
if (pdev->num_resources != 1)
|
||||
return -EBUSY;
|
||||
|
||||
if (pdev->resource[0].flags != IORESOURCE_MEM)
|
||||
return -EBUSY;
|
||||
|
||||
chip->leftshift = pdata->leftshift;
|
||||
chip->ioaddress = ioremap(pdev->resource[0].start, 1);
|
||||
if (chip->ioaddress == NULL)
|
||||
return -EBUSY;
|
||||
|
||||
return 0;
|
||||
}
|
||||
|
||||
static void v3020_mmio_unmap(struct v3020 *chip)
|
||||
{
|
||||
iounmap(chip->ioaddress);
|
||||
}
|
||||
|
||||
static void v3020_mmio_write_bit(struct v3020 *chip, unsigned char bit)
|
||||
{
|
||||
writel(bit << chip->leftshift, chip->ioaddress);
|
||||
}
|
||||
|
||||
static unsigned char v3020_mmio_read_bit(struct v3020 *chip)
|
||||
{
|
||||
return readl(chip->ioaddress) & (1 << chip->leftshift);
|
||||
}
|
||||
|
||||
static struct v3020_chip_ops v3020_mmio_ops = {
|
||||
.map_io = v3020_mmio_map,
|
||||
.unmap_io = v3020_mmio_unmap,
|
||||
.read_bit = v3020_mmio_read_bit,
|
||||
.write_bit = v3020_mmio_write_bit,
|
||||
};
|
||||
|
||||
static struct v3020_gpio v3020_gpio[] = {
|
||||
{ "RTC CS", 0 },
|
||||
{ "RTC WR", 0 },
|
||||
{ "RTC RD", 0 },
|
||||
{ "RTC IO", 0 },
|
||||
};
|
||||
|
||||
static int v3020_gpio_map(struct v3020 *chip, struct platform_device *pdev,
|
||||
struct v3020_platform_data *pdata)
|
||||
{
|
||||
int i, err;
|
||||
|
||||
v3020_gpio[V3020_CS].gpio = pdata->gpio_cs;
|
||||
v3020_gpio[V3020_WR].gpio = pdata->gpio_wr;
|
||||
v3020_gpio[V3020_RD].gpio = pdata->gpio_rd;
|
||||
v3020_gpio[V3020_IO].gpio = pdata->gpio_io;
|
||||
|
||||
for (i = 0; i < ARRAY_SIZE(v3020_gpio); i++) {
|
||||
err = gpio_request(v3020_gpio[i].gpio, v3020_gpio[i].name);
|
||||
if (err)
|
||||
goto err_request;
|
||||
|
||||
gpio_direction_output(v3020_gpio[i].gpio, 1);
|
||||
}
|
||||
|
||||
chip->gpio = v3020_gpio;
|
||||
|
||||
return 0;
|
||||
|
||||
err_request:
|
||||
while (--i >= 0)
|
||||
gpio_free(v3020_gpio[i].gpio);
|
||||
|
||||
return err;
|
||||
}
|
||||
|
||||
static void v3020_gpio_unmap(struct v3020 *chip)
|
||||
{
|
||||
int i;
|
||||
|
||||
for (i = 0; i < ARRAY_SIZE(v3020_gpio); i++)
|
||||
gpio_free(v3020_gpio[i].gpio);
|
||||
}
|
||||
|
||||
static void v3020_gpio_write_bit(struct v3020 *chip, unsigned char bit)
|
||||
{
|
||||
gpio_direction_output(chip->gpio[V3020_IO].gpio, bit);
|
||||
gpio_set_value(chip->gpio[V3020_CS].gpio, 0);
|
||||
gpio_set_value(chip->gpio[V3020_WR].gpio, 0);
|
||||
udelay(1);
|
||||
gpio_set_value(chip->gpio[V3020_WR].gpio, 1);
|
||||
gpio_set_value(chip->gpio[V3020_CS].gpio, 1);
|
||||
}
|
||||
|
||||
static unsigned char v3020_gpio_read_bit(struct v3020 *chip)
|
||||
{
|
||||
int bit;
|
||||
|
||||
gpio_direction_input(chip->gpio[V3020_IO].gpio);
|
||||
gpio_set_value(chip->gpio[V3020_CS].gpio, 0);
|
||||
gpio_set_value(chip->gpio[V3020_RD].gpio, 0);
|
||||
udelay(1);
|
||||
bit = !!gpio_get_value(chip->gpio[V3020_IO].gpio);
|
||||
udelay(1);
|
||||
gpio_set_value(chip->gpio[V3020_RD].gpio, 1);
|
||||
gpio_set_value(chip->gpio[V3020_CS].gpio, 1);
|
||||
|
||||
return bit;
|
||||
}
|
||||
|
||||
static struct v3020_chip_ops v3020_gpio_ops = {
|
||||
.map_io = v3020_gpio_map,
|
||||
.unmap_io = v3020_gpio_unmap,
|
||||
.read_bit = v3020_gpio_read_bit,
|
||||
.write_bit = v3020_gpio_write_bit,
|
||||
};
|
||||
|
||||
static void v3020_set_reg(struct v3020 *chip, unsigned char address,
|
||||
unsigned char data)
|
||||
{
|
||||
|
|
@ -46,7 +191,7 @@ static void v3020_set_reg(struct v3020 *chip, unsigned char address,
|
|||
|
||||
tmp = address;
|
||||
for (i = 0; i < 4; i++) {
|
||||
writel((tmp & 1) << chip->leftshift, chip->ioaddress);
|
||||
chip->ops->write_bit(chip, (tmp & 1));
|
||||
tmp >>= 1;
|
||||
udelay(1);
|
||||
}
|
||||
|
|
@ -54,7 +199,7 @@ static void v3020_set_reg(struct v3020 *chip, unsigned char address,
|
|||
/* Commands dont have data */
|
||||
if (!V3020_IS_COMMAND(address)) {
|
||||
for (i = 0; i < 8; i++) {
|
||||
writel((data & 1) << chip->leftshift, chip->ioaddress);
|
||||
chip->ops->write_bit(chip, (data & 1));
|
||||
data >>= 1;
|
||||
udelay(1);
|
||||
}
|
||||
|
|
@ -67,14 +212,14 @@ static unsigned char v3020_get_reg(struct v3020 *chip, unsigned char address)
|
|||
int i;
|
||||
|
||||
for (i = 0; i < 4; i++) {
|
||||
writel((address & 1) << chip->leftshift, chip->ioaddress);
|
||||
chip->ops->write_bit(chip, (address & 1));
|
||||
address >>= 1;
|
||||
udelay(1);
|
||||
}
|
||||
|
||||
for (i = 0; i < 8; i++) {
|
||||
data >>= 1;
|
||||
if (readl(chip->ioaddress) & (1 << chip->leftshift))
|
||||
if (chip->ops->read_bit(chip))
|
||||
data |= 0x80;
|
||||
udelay(1);
|
||||
}
|
||||
|
|
@ -164,25 +309,23 @@ static int rtc_probe(struct platform_device *pdev)
|
|||
int i;
|
||||
int temp;
|
||||
|
||||
if (pdev->num_resources != 1)
|
||||
return -EBUSY;
|
||||
|
||||
if (pdev->resource[0].flags != IORESOURCE_MEM)
|
||||
return -EBUSY;
|
||||
|
||||
chip = kzalloc(sizeof *chip, GFP_KERNEL);
|
||||
if (!chip)
|
||||
return -ENOMEM;
|
||||
|
||||
chip->leftshift = pdata->leftshift;
|
||||
chip->ioaddress = ioremap(pdev->resource[0].start, 1);
|
||||
if (chip->ioaddress == NULL)
|
||||
if (pdata->use_gpio)
|
||||
chip->ops = &v3020_gpio_ops;
|
||||
else
|
||||
chip->ops = &v3020_mmio_ops;
|
||||
|
||||
retval = chip->ops->map_io(chip, pdev, pdata);
|
||||
if (retval)
|
||||
goto err_chip;
|
||||
|
||||
/* Make sure the v3020 expects a communication cycle
|
||||
* by reading 8 times */
|
||||
for (i = 0; i < 8; i++)
|
||||
temp = readl(chip->ioaddress);
|
||||
temp = chip->ops->read_bit(chip);
|
||||
|
||||
/* Test chip by doing a write/read sequence
|
||||
* to the chip ram */
|
||||
|
|
@ -196,10 +339,17 @@ static int rtc_probe(struct platform_device *pdev)
|
|||
* are all disabled */
|
||||
v3020_set_reg(chip, V3020_STATUS_0, 0x0);
|
||||
|
||||
dev_info(&pdev->dev, "Chip available at physical address 0x%llx,"
|
||||
"data connected to D%d\n",
|
||||
(unsigned long long)pdev->resource[0].start,
|
||||
chip->leftshift);
|
||||
if (pdata->use_gpio)
|
||||
dev_info(&pdev->dev, "Chip available at GPIOs "
|
||||
"%d, %d, %d, %d\n",
|
||||
chip->gpio[V3020_CS].gpio, chip->gpio[V3020_WR].gpio,
|
||||
chip->gpio[V3020_RD].gpio, chip->gpio[V3020_IO].gpio);
|
||||
else
|
||||
dev_info(&pdev->dev, "Chip available at "
|
||||
"physical address 0x%llx,"
|
||||
"data connected to D%d\n",
|
||||
(unsigned long long)pdev->resource[0].start,
|
||||
chip->leftshift);
|
||||
|
||||
platform_set_drvdata(pdev, chip);
|
||||
|
||||
|
|
@ -214,7 +364,7 @@ static int rtc_probe(struct platform_device *pdev)
|
|||
return 0;
|
||||
|
||||
err_io:
|
||||
iounmap(chip->ioaddress);
|
||||
chip->ops->unmap_io(chip);
|
||||
err_chip:
|
||||
kfree(chip);
|
||||
|
||||
|
|
@ -229,7 +379,7 @@ static int rtc_remove(struct platform_device *dev)
|
|||
if (rtc)
|
||||
rtc_device_unregister(rtc);
|
||||
|
||||
iounmap(chip->ioaddress);
|
||||
chip->ops->unmap_io(chip);
|
||||
kfree(chip);
|
||||
|
||||
return 0;
|
||||
|
|
|
|||
|
|
@ -14,6 +14,12 @@
|
|||
* is used depends on the board. */
|
||||
struct v3020_platform_data {
|
||||
int leftshift; /* (1<<(leftshift)) & readl() */
|
||||
|
||||
int use_gpio:1;
|
||||
unsigned int gpio_cs;
|
||||
unsigned int gpio_wr;
|
||||
unsigned int gpio_rd;
|
||||
unsigned int gpio_io;
|
||||
};
|
||||
|
||||
#define V3020_STATUS_0 0x00
|
||||
|
|
|
|||
Загрузка…
Ссылка в новой задаче