i2c/gpio: add DT support
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@jcrosoft.com> Acked-by: Grant Likely <grant.likely@secretlab.ca> Acked-by: Rob Herring <rob.herring@calxeda.com> Acked-by: Wolfram Sang <w.sang@pengutronix.de> Cc: Nicolas Ferre <nicolas.ferre@atmel.com>
This commit is contained in:
Jean-Christophe PLAGNIOL-VILLARD
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86a89f4ff6
commit
8ffaa0f40d
2 changed files with 106 additions and 20 deletions
32
Documentation/devicetree/bindings/gpio/gpio_i2c.txt
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32
Documentation/devicetree/bindings/gpio/gpio_i2c.txt
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@ -0,0 +1,32 @@
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Device-Tree bindings for i2c gpio driver
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Required properties:
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- compatible = "i2c-gpio";
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- gpios: sda and scl gpio
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Optional properties:
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- i2c-gpio,sda-open-drain: sda as open drain
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- i2c-gpio,scl-open-drain: scl as open drain
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- i2c-gpio,scl-output-only: scl as output only
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- i2c-gpio,delay-us: delay between GPIO operations (may depend on each platform)
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- i2c-gpio,timeout-ms: timeout to get data
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Example nodes:
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i2c@0 {
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compatible = "i2c-gpio";
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gpios = <&pioA 23 0 /* sda */
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&pioA 24 0 /* scl */
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>;
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i2c-gpio,sda-open-drain;
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i2c-gpio,scl-open-drain;
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i2c-gpio,delay-us = <2>; /* ~100 kHz */
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#address-cells = <1>;
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#size-cells = <0>;
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rv3029c2@56 {
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compatible = "rv3029c2";
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reg = <0x56>;
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};
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};
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@ -14,8 +14,15 @@
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#include <linux/module.h>
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#include <linux/slab.h>
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#include <linux/platform_device.h>
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#include <linux/gpio.h>
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#include <linux/of_gpio.h>
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#include <linux/of_i2c.h>
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#include <asm/gpio.h>
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struct i2c_gpio_private_data {
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struct i2c_adapter adap;
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struct i2c_algo_bit_data bit_data;
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struct i2c_gpio_platform_data pdata;
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};
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/* Toggle SDA by changing the direction of the pin */
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static void i2c_gpio_setsda_dir(void *data, int state)
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@ -78,24 +85,62 @@ static int i2c_gpio_getscl(void *data)
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return gpio_get_value(pdata->scl_pin);
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}
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static int __devinit of_i2c_gpio_probe(struct device_node *np,
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struct i2c_gpio_platform_data *pdata)
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{
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u32 reg;
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if (of_gpio_count(np) < 2)
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return -ENODEV;
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pdata->sda_pin = of_get_gpio(np, 0);
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pdata->scl_pin = of_get_gpio(np, 1);
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if (!gpio_is_valid(pdata->sda_pin) || !gpio_is_valid(pdata->scl_pin)) {
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pr_err("%s: invalid GPIO pins, sda=%d/scl=%d\n",
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np->full_name, pdata->sda_pin, pdata->scl_pin);
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return -ENODEV;
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}
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of_property_read_u32(np, "i2c-gpio,delay-us", &pdata->udelay);
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if (!of_property_read_u32(np, "i2c-gpio,timeout-ms", ®))
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pdata->timeout = msecs_to_jiffies(reg);
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pdata->sda_is_open_drain =
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of_property_read_bool(np, "i2c-gpio,sda-open-drain");
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pdata->scl_is_open_drain =
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of_property_read_bool(np, "i2c-gpio,scl-open-drain");
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pdata->scl_is_output_only =
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of_property_read_bool(np, "i2c-gpio,scl-output-only");
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return 0;
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}
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static int __devinit i2c_gpio_probe(struct platform_device *pdev)
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{
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struct i2c_gpio_private_data *priv;
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struct i2c_gpio_platform_data *pdata;
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struct i2c_algo_bit_data *bit_data;
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struct i2c_adapter *adap;
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int ret;
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pdata = pdev->dev.platform_data;
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if (!pdata)
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return -ENXIO;
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priv = devm_kzalloc(&pdev->dev, sizeof(*priv), GFP_KERNEL);
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if (!priv)
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return -ENOMEM;
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adap = &priv->adap;
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bit_data = &priv->bit_data;
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pdata = &priv->pdata;
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ret = -ENOMEM;
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adap = kzalloc(sizeof(struct i2c_adapter), GFP_KERNEL);
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if (!adap)
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goto err_alloc_adap;
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bit_data = kzalloc(sizeof(struct i2c_algo_bit_data), GFP_KERNEL);
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if (!bit_data)
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goto err_alloc_bit_data;
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if (pdev->dev.of_node) {
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ret = of_i2c_gpio_probe(pdev->dev.of_node, pdata);
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if (ret)
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return ret;
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} else {
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if (!pdev->dev.platform_data)
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return -ENXIO;
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memcpy(pdata, pdev->dev.platform_data, sizeof(*pdata));
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}
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ret = gpio_request(pdata->sda_pin, "sda");
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if (ret)
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@ -143,6 +188,7 @@ static int __devinit i2c_gpio_probe(struct platform_device *pdev)
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adap->algo_data = bit_data;
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adap->class = I2C_CLASS_HWMON | I2C_CLASS_SPD;
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adap->dev.parent = &pdev->dev;
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adap->dev.of_node = pdev->dev.of_node;
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/*
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* If "dev->id" is negative we consider it as zero.
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@ -154,7 +200,9 @@ static int __devinit i2c_gpio_probe(struct platform_device *pdev)
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if (ret)
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goto err_add_bus;
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platform_set_drvdata(pdev, adap);
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of_i2c_register_devices(adap);
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platform_set_drvdata(pdev, priv);
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dev_info(&pdev->dev, "using pins %u (SDA) and %u (SCL%s)\n",
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pdata->sda_pin, pdata->scl_pin,
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@ -168,34 +216,40 @@ static int __devinit i2c_gpio_probe(struct platform_device *pdev)
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err_request_scl:
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gpio_free(pdata->sda_pin);
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err_request_sda:
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kfree(bit_data);
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err_alloc_bit_data:
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kfree(adap);
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err_alloc_adap:
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return ret;
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}
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static int __devexit i2c_gpio_remove(struct platform_device *pdev)
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{
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struct i2c_gpio_private_data *priv;
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struct i2c_gpio_platform_data *pdata;
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struct i2c_adapter *adap;
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adap = platform_get_drvdata(pdev);
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pdata = pdev->dev.platform_data;
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priv = platform_get_drvdata(pdev);
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adap = &priv->adap;
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pdata = &priv->pdata;
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i2c_del_adapter(adap);
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gpio_free(pdata->scl_pin);
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gpio_free(pdata->sda_pin);
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kfree(adap->algo_data);
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kfree(adap);
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return 0;
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}
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#if defined(CONFIG_OF)
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static const struct of_device_id i2c_gpio_dt_ids[] = {
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{ .compatible = "i2c-gpio", },
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{ /* sentinel */ }
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};
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MODULE_DEVICE_TABLE(of, i2c_gpio_dt_ids);
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#endif
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static struct platform_driver i2c_gpio_driver = {
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.driver = {
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.name = "i2c-gpio",
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.owner = THIS_MODULE,
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.of_match_table = of_match_ptr(i2c_gpio_dt_ids),
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},
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.probe = i2c_gpio_probe,
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.remove = __devexit_p(i2c_gpio_remove),
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