From: Albert Herranz <[email protected]> This patch adds devicetree support to i2c-gpio driver. The allocation of local data is integrated to a private structure, and use devm_* helper for easy cleanup.
It is base on an earlier patch for gc-linux from Albert Herranz <[email protected]>. Signed-off-by: Thomas Chou <[email protected]> CC: Albert Herranz <[email protected]> Acked-by: Haavard Skinnemoen <[email protected]> --- for v2.6.39 v2 move of nodes probing to a hook, which will be optimized out when devicetree is not used. use linux/gpio.h. move binding doc to i2c/i2c-gpio.txt. v3 use speed-hz instead of udelay in dts binding. condition the devicetree probe. v4 simplify private allocation. v5 condition module device table export for of. Documentation/devicetree/bindings/i2c/i2c-gpio.txt | 40 +++++++ drivers/i2c/busses/i2c-gpio.c | 113 ++++++++++++++++---- 2 files changed, 133 insertions(+), 20 deletions(-) create mode 100644 Documentation/devicetree/bindings/i2c/i2c-gpio.txt diff --git a/Documentation/devicetree/bindings/i2c/i2c-gpio.txt b/Documentation/devicetree/bindings/i2c/i2c-gpio.txt new file mode 100644 index 0000000..38ef4f2 --- /dev/null +++ b/Documentation/devicetree/bindings/i2c/i2c-gpio.txt @@ -0,0 +1,40 @@ +GPIO-based I2C + +Required properties: +- compatible : should be "i2c-gpio". +- gpios : should specify GPIOs used for SDA and SCL lines, in that order. +Optional properties: +- sda-is-open-drain : present if SDA gpio is open-drain. +- scl-is-open-drain : present if SCL gpio is open-drain. +- scl-is-output-only : present if the output driver for SCL cannot be + turned off. this will prevent clock stretching from working. +- speed-hz : SCL frequency. +- timeout : clock stretching timeout in milliseconds. + +Example: + +gpio0: starlet-gpio@0d8000c0 { + compatible = "nintendo,starlet-gpio"; + reg = <0d8000c0 4>; + gpio-controller; + #gpio-cells = <2>; +}; + +i2c-video { + #address-cells = <1>; + #size-cells = <0>; + compatible = "i2c-gpio"; + + gpios = <&gpio0 10 0 /* SDA line */ + &gpio0 11 0 /* SCL line */ + >; + sda-is-open-drain; + scl-is-open-drain; + scl-is-output-only; + speed-hz = <250000>; + + audio-video-encoder { + compatible = "nintendo,wii-ave-rvl"; + reg = <70>; + }; +}; diff --git a/drivers/i2c/busses/i2c-gpio.c b/drivers/i2c/busses/i2c-gpio.c index d9aa9a6..6cc5f15 100644 --- a/drivers/i2c/busses/i2c-gpio.c +++ b/drivers/i2c/busses/i2c-gpio.c @@ -14,8 +14,14 @@ #include <linux/module.h> #include <linux/slab.h> #include <linux/platform_device.h> +#include <linux/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 +84,80 @@ static int i2c_gpio_getscl(void *data) return gpio_get_value(pdata->scl_pin); } +#ifdef CONFIG_OF +#include <linux/of_gpio.h> + +/* Check if devicetree nodes exist and build platform data */ +static int i2c_gpio_of_probe(struct platform_device *pdev, + struct i2c_gpio_platform_data *pdata) +{ + struct device_node *np = pdev->dev.of_node; + const __be32 *prop; + int sda_pin, scl_pin; + int len; + + if (!np || of_gpio_count(np) < 2) + return -ENXIO; + + sda_pin = of_get_gpio_flags(np, 0, NULL); + scl_pin = of_get_gpio_flags(np, 1, NULL); + if (sda_pin < 0 || scl_pin < 0) { + pr_err("%s: invalid GPIO pins, sda=%d/scl=%d\n", + np->full_name, sda_pin, scl_pin); + return -ENXIO; + } + + pdata->sda_pin = sda_pin; + pdata->scl_pin = scl_pin; + prop = of_get_property(np, "sda-is-open-drain", NULL); + if (prop) + pdata->sda_is_open_drain = 1; + prop = of_get_property(np, "scl-is-open-drain", NULL); + if (prop) + pdata->scl_is_open_drain = 1; + prop = of_get_property(np, "scl-is-output-only", NULL); + if (prop) + pdata->scl_is_output_only = 1; + prop = of_get_property(np, "speed-hz", &len); + if (prop && len >= sizeof(__be32)) + pdata->udelay = DIV_ROUND_UP(1000000, be32_to_cpup(prop) * 2); + prop = of_get_property(np, "timeout", &len); + if (prop && len >= sizeof(__be32)) + pdata->timeout = msecs_to_jiffies(be32_to_cpup(prop)); + + return 0; +} +#else +static int i2c_gpio_of_probe(struct platform_device *pdev, + struct i2c_gpio_platform_data *pdata) +{ + return -ENXIO; +} +#endif + 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.platform_data) { + *pdata = *(struct i2c_gpio_platform_data *) + pdev->dev.platform_data; + } else { + ret = i2c_gpio_of_probe(pdev, pdata); + if (ret) + return ret; + } ret = gpio_request(pdata->sda_pin, "sda"); if (ret) @@ -143,6 +205,7 @@ 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. @@ -154,13 +217,16 @@ static int __devinit i2c_gpio_probe(struct platform_device *pdev) if (ret) goto err_add_bus; - 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, pdata->scl_is_output_only ? ", no clock stretching" : ""); + /* Now register all the child nodes */ + of_i2c_register_devices(adap); + return 0; err_add_bus: @@ -168,34 +234,41 @@ 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; } +#ifdef CONFIG_OF +static const struct of_device_id i2c_gpio_match[] = { + { .compatible = "i2c-gpio", }, + {}, +}; +MODULE_DEVICE_TABLE(of, i2c_gpio_match); +#else /* CONFIG_OF */ +#define i2c_gpio_match NULL +#endif /* CONFIG_OF */ + static struct platform_driver i2c_gpio_driver = { .driver = { .name = "i2c-gpio", .owner = THIS_MODULE, + .of_match_table = i2c_gpio_match, }, .probe = i2c_gpio_probe, .remove = __devexit_p(i2c_gpio_remove), -- 1.7.4 _______________________________________________ devicetree-discuss mailing list [email protected] https://lists.ozlabs.org/listinfo/devicetree-discuss
