[PATCH 1/5 v5] i2c/gpio: add DT support
Jean-Christophe PLAGNIOL-VILLARD
plagnioj at jcrosoft.com
Thu Mar 15 11:56:12 EDT 2012
To achieve DT support, we need to populate a custom platform_data in a
private struct from DT information. To simplify code, the adapter and
algorithm are also put into the private struct.
Signed-off-by: Jean-Christophe PLAGNIOL-VILLARD <plagnioj at jcrosoft.com>
Acked-by: Grant Likely <grant.likely at secretlab.ca>
Acked-by: Rob Herring <rob.herring at calxeda.com>
Acked-by: Wolfram Sang <w.sang at pengutronix.de>
Cc: Nicolas Ferre <nicolas.ferre at atmel.com>
---
.../devicetree/bindings/gpio/gpio_i2c.txt | 32 +++++++
drivers/i2c/busses/i2c-gpio.c | 94 +++++++++++++++----
2 files changed, 106 insertions(+), 20 deletions(-)
create mode 100644 Documentation/devicetree/bindings/gpio/gpio_i2c.txt
diff --git a/Documentation/devicetree/bindings/gpio/gpio_i2c.txt b/Documentation/devicetree/bindings/gpio/gpio_i2c.txt
new file mode 100644
index 0000000..4f8ec94
--- /dev/null
+++ b/Documentation/devicetree/bindings/gpio/gpio_i2c.txt
@@ -0,0 +1,32 @@
+Device-Tree bindings for i2c gpio driver
+
+Required properties:
+ - compatible = "i2c-gpio";
+ - gpios: sda and scl gpio
+
+
+Optional properties:
+ - i2c-gpio,sda-open-drain: sda as open drain
+ - i2c-gpio,scl-open-drain: scl as open drain
+ - i2c-gpio,scl-output-only: scl as output only
+ - i2c-gpio,delay-us: delay between GPIO operations (may depend on each platform)
+ - i2c-gpio,timeout-ms: timeout to get data
+
+Example nodes:
+
+i2c at 0 {
+ compatible = "i2c-gpio";
+ gpios = <&pioA 23 0 /* sda */
+ &pioA 24 0 /* scl */
+ >;
+ i2c-gpio,sda-open-drain;
+ i2c-gpio,scl-open-drain;
+ i2c-gpio,delay-us = <2>; /* ~100 kHz */
+ #address-cells = <1>;
+ #size-cells = <0>;
+
+ rv3029c2 at 56 {
+ compatible = "rv3029c2";
+ reg = <0x56>;
+ };
+};
diff --git a/drivers/i2c/busses/i2c-gpio.c b/drivers/i2c/busses/i2c-gpio.c
index a651779..c0330a4 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 <linux/gpio.h>
+#include <linux/of_gpio.h>
+#include <linux/of_i2c.h>
-#include <asm/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)
@@ -78,24 +85,62 @@ static int i2c_gpio_getscl(void *data)
return gpio_get_value(pdata->scl_pin);
}
+static int __devinit of_i2c_gpio_probe(struct device_node *np,
+ struct i2c_gpio_platform_data *pdata)
+{
+ u32 reg;
+
+ if (of_gpio_count(np) < 2)
+ return -ENODEV;
+
+ pdata->sda_pin = of_get_gpio(np, 0);
+ pdata->scl_pin = of_get_gpio(np, 1);
+
+ if (!gpio_is_valid(pdata->sda_pin) || !gpio_is_valid(pdata->scl_pin)) {
+ pr_err("%s: invalid GPIO pins, sda=%d/scl=%d\n",
+ np->full_name, pdata->sda_pin, pdata->scl_pin);
+ return -ENODEV;
+ }
+
+ of_property_read_u32(np, "i2c-gpio,delay-us", &pdata->udelay);
+
+ if (!of_property_read_u32(np, "i2c-gpio,timeout-ms", ®))
+ 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");
+
+ return 0;
+}
+
static int __devinit 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;
int ret;
- pdata = pdev->dev.platform_data;
- if (!pdata)
- return -ENXIO;
+ priv = devm_kzalloc(&pdev->dev, sizeof(*priv), GFP_KERNEL);
+ if (!priv)
+ return -ENOMEM;
+ adap = &priv->adap;
+ bit_data = &priv->bit_data;
+ pdata = &priv->pdata;
- 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;
+ if (pdev->dev.of_node) {
+ ret = of_i2c_gpio_probe(pdev->dev.of_node, pdata);
+ if (ret)
+ return ret;
+ } else {
+ if (!pdev->dev.platform_data)
+ return -ENXIO;
+ memcpy(pdata, pdev->dev.platform_data, sizeof(*pdata));
+ }
ret = gpio_request(pdata->sda_pin, "sda");
if (ret)
@@ -143,6 +188,7 @@ static int __devinit i2c_gpio_probe(struct platform_device *pdev)
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.
@@ -154,7 +200,9 @@ static int __devinit i2c_gpio_probe(struct platform_device *pdev)
if (ret)
goto err_add_bus;
- platform_set_drvdata(pdev, adap);
+ of_i2c_register_devices(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,
@@ -168,34 +216,40 @@ err_add_bus:
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)
{
+ 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),
--
1.7.7
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