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path: root/drivers/i2c/busses/i2c-gpio.c
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Diffstat (limited to 'drivers/i2c/busses/i2c-gpio.c')
-rw-r--r--drivers/i2c/busses/i2c-gpio.c164
1 files changed, 116 insertions, 48 deletions
diff --git a/drivers/i2c/busses/i2c-gpio.c b/drivers/i2c/busses/i2c-gpio.c
index d9aa9a649e3..71a45b210a2 100644
--- a/drivers/i2c/busses/i2c-gpio.c
+++ b/drivers/i2c/busses/i2c-gpio.c
@@ -14,8 +14,15 @@
#include <linux/module.h>
#include <linux/slab.h>
#include <linux/platform_device.h>
-
-#include <asm/gpio.h>
+#include <linux/gpio.h>
+#include <linux/of.h>
+#include <linux/of_gpio.h>
+
+struct i2c_gpio_private_data {
+ struct i2c_adapter adap;
+ struct i2c_algo_bit_data bit_data;
+ struct i2c_gpio_platform_data pdata;
+};
/* Toggle SDA by changing the direction of the pin */
static void i2c_gpio_setsda_dir(void *data, int state)
@@ -78,31 +85,95 @@ static int i2c_gpio_getscl(void *data)
return gpio_get_value(pdata->scl_pin);
}
-static int __devinit i2c_gpio_probe(struct platform_device *pdev)
+static int of_i2c_gpio_get_pins(struct device_node *np,
+ unsigned int *sda_pin, unsigned int *scl_pin)
+{
+ if (of_gpio_count(np) < 2)
+ return -ENODEV;
+
+ *sda_pin = of_get_gpio(np, 0);
+ *scl_pin = of_get_gpio(np, 1);
+
+ if (*sda_pin == -EPROBE_DEFER || *scl_pin == -EPROBE_DEFER)
+ return -EPROBE_DEFER;
+
+ if (!gpio_is_valid(*sda_pin) || !gpio_is_valid(*scl_pin)) {
+ pr_err("%s: invalid GPIO pins, sda=%d/scl=%d\n",
+ np->full_name, *sda_pin, *scl_pin);
+ return -ENODEV;
+ }
+
+ return 0;
+}
+
+static void of_i2c_gpio_get_props(struct device_node *np,
+ struct i2c_gpio_platform_data *pdata)
+{
+ u32 reg;
+
+ of_property_read_u32(np, "i2c-gpio,delay-us", &pdata->udelay);
+
+ if (!of_property_read_u32(np, "i2c-gpio,timeout-ms", &reg))
+ pdata->timeout = msecs_to_jiffies(reg);
+
+ pdata->sda_is_open_drain =
+ of_property_read_bool(np, "i2c-gpio,sda-open-drain");
+ pdata->scl_is_open_drain =
+ of_property_read_bool(np, "i2c-gpio,scl-open-drain");
+ pdata->scl_is_output_only =
+ of_property_read_bool(np, "i2c-gpio,scl-output-only");
+}
+
+static int i2c_gpio_probe(struct platform_device *pdev)
{
+ struct i2c_gpio_private_data *priv;
struct i2c_gpio_platform_data *pdata;
struct i2c_algo_bit_data *bit_data;
struct i2c_adapter *adap;
+ unsigned int sda_pin, scl_pin;
int ret;
- pdata = pdev->dev.platform_data;
- if (!pdata)
- return -ENXIO;
+ /* First get the GPIO pins; if it fails, we'll defer the probe. */
+ if (pdev->dev.of_node) {
+ ret = of_i2c_gpio_get_pins(pdev->dev.of_node,
+ &sda_pin, &scl_pin);
+ if (ret)
+ return ret;
+ } else {
+ if (!dev_get_platdata(&pdev->dev))
+ return -ENXIO;
+ pdata = dev_get_platdata(&pdev->dev);
+ sda_pin = pdata->sda_pin;
+ scl_pin = pdata->scl_pin;
+ }
- ret = -ENOMEM;
- adap = kzalloc(sizeof(struct i2c_adapter), GFP_KERNEL);
- if (!adap)
- goto err_alloc_adap;
- bit_data = kzalloc(sizeof(struct i2c_algo_bit_data), GFP_KERNEL);
- if (!bit_data)
- goto err_alloc_bit_data;
+ ret = devm_gpio_request(&pdev->dev, sda_pin, "sda");
+ if (ret) {
+ if (ret == -EINVAL)
+ ret = -EPROBE_DEFER; /* Try again later */
+ return ret;
+ }
+ ret = devm_gpio_request(&pdev->dev, scl_pin, "scl");
+ if (ret) {
+ if (ret == -EINVAL)
+ ret = -EPROBE_DEFER; /* Try again later */
+ return ret;
+ }
- ret = gpio_request(pdata->sda_pin, "sda");
- if (ret)
- goto err_request_sda;
- ret = gpio_request(pdata->scl_pin, "scl");
- if (ret)
- goto err_request_scl;
+ priv = devm_kzalloc(&pdev->dev, sizeof(*priv), GFP_KERNEL);
+ if (!priv)
+ return -ENOMEM;
+ adap = &priv->adap;
+ bit_data = &priv->bit_data;
+ pdata = &priv->pdata;
+
+ if (pdev->dev.of_node) {
+ pdata->sda_pin = sda_pin;
+ pdata->scl_pin = scl_pin;
+ of_i2c_gpio_get_props(pdev->dev.of_node, pdata);
+ } else {
+ memcpy(pdata, dev_get_platdata(&pdev->dev), sizeof(*pdata));
+ }
if (pdata->sda_is_open_drain) {
gpio_direction_output(pdata->sda_pin, 1);
@@ -139,22 +210,22 @@ static int __devinit i2c_gpio_probe(struct platform_device *pdev)
bit_data->data = pdata;
adap->owner = THIS_MODULE;
- snprintf(adap->name, sizeof(adap->name), "i2c-gpio%d", pdev->id);
+ if (pdev->dev.of_node)
+ strlcpy(adap->name, dev_name(&pdev->dev), sizeof(adap->name));
+ else
+ snprintf(adap->name, sizeof(adap->name), "i2c-gpio%d", pdev->id);
+
adap->algo_data = bit_data;
adap->class = I2C_CLASS_HWMON | I2C_CLASS_SPD;
adap->dev.parent = &pdev->dev;
+ adap->dev.of_node = pdev->dev.of_node;
- /*
- * If "dev->id" is negative we consider it as zero.
- * The reason to do so is to avoid sysfs names that only make
- * sense when there are multiple adapters.
- */
- adap->nr = (pdev->id != -1) ? pdev->id : 0;
+ adap->nr = pdev->id;
ret = i2c_bit_add_numbered_bus(adap);
if (ret)
- goto err_add_bus;
+ return ret;
- platform_set_drvdata(pdev, adap);
+ platform_set_drvdata(pdev, priv);
dev_info(&pdev->dev, "using pins %u (SDA) and %u (SCL%s)\n",
pdata->sda_pin, pdata->scl_pin,
@@ -162,43 +233,40 @@ static int __devinit i2c_gpio_probe(struct platform_device *pdev)
? ", no clock stretching" : "");
return 0;
-
-err_add_bus:
- gpio_free(pdata->scl_pin);
-err_request_scl:
- gpio_free(pdata->sda_pin);
-err_request_sda:
- kfree(bit_data);
-err_alloc_bit_data:
- kfree(adap);
-err_alloc_adap:
- return ret;
}
-static int __devexit i2c_gpio_remove(struct platform_device *pdev)
+static int i2c_gpio_remove(struct platform_device *pdev)
{
+ struct i2c_gpio_private_data *priv;
struct i2c_gpio_platform_data *pdata;
struct i2c_adapter *adap;
- adap = platform_get_drvdata(pdev);
- pdata = pdev->dev.platform_data;
+ priv = platform_get_drvdata(pdev);
+ adap = &priv->adap;
+ pdata = &priv->pdata;
i2c_del_adapter(adap);
- gpio_free(pdata->scl_pin);
- gpio_free(pdata->sda_pin);
- kfree(adap->algo_data);
- kfree(adap);
return 0;
}
+#if defined(CONFIG_OF)
+static const struct of_device_id i2c_gpio_dt_ids[] = {
+ { .compatible = "i2c-gpio", },
+ { /* sentinel */ }
+};
+
+MODULE_DEVICE_TABLE(of, i2c_gpio_dt_ids);
+#endif
+
static struct platform_driver i2c_gpio_driver = {
.driver = {
.name = "i2c-gpio",
.owner = THIS_MODULE,
+ .of_match_table = of_match_ptr(i2c_gpio_dt_ids),
},
.probe = i2c_gpio_probe,
- .remove = __devexit_p(i2c_gpio_remove),
+ .remove = i2c_gpio_remove,
};
static int __init i2c_gpio_init(void)
@@ -219,7 +287,7 @@ static void __exit i2c_gpio_exit(void)
}
module_exit(i2c_gpio_exit);
-MODULE_AUTHOR("Haavard Skinnemoen <hskinnemoen@atmel.com>");
+MODULE_AUTHOR("Haavard Skinnemoen (Atmel)");
MODULE_DESCRIPTION("Platform-independent bitbanging I2C driver");
MODULE_LICENSE("GPL");
MODULE_ALIAS("platform:i2c-gpio");
generated by cgit v1.2.3-70-g09d2 (git 2.46.0) at 2025-11-03 18:29:06 +0000