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Re: Fwd: [PATCH 1/3] i2c: Add Device Tree support to the Nomadik I2C driver |
On 15/06/12 12:50, Srinidhi Kasagar wrote:
[...]From: Lee Jones<lee.jones@xxxxxxxxxx> Date: Tue, 17 Apr 2012 16:04:13 +0100 Subject: [PATCH 1/1] i2c: Add Device Tree support to the Nomadik I2C driver Here we apply the bindings required for successful Device Tree probing of the i2c-nomadik driver. We also apply a fall-back configuration in case either one is not provided, or a required element is missing from the one supplied. Cc: linux-i2c@xxxxxxxxxxxxxxx Signed-off-by: Lee Jones<lee.jones@xxxxxxxxxx> --- drivers/i2c/busses/i2c-nomadik.c | 82 +++++++++++++++++++++++++++++++++++++- 1 file changed, 80 insertions(+), 2 deletions(-) diff --git a/drivers/i2c/busses/i2c-nomadik.c b/drivers/i2c/busses/i2c-nomadik.c index a92440d..58e8114 100644 --- a/drivers/i2c/busses/i2c-nomadik.c +++ b/drivers/i2c/busses/i2c-nomadik.c @@ -23,6 +23,7 @@ #include<linux/io.h> #include<linux/regulator/consumer.h> #include<linux/pm_runtime.h> +#include<linux/of.h> #include<plat/i2c.h> @@ -899,15 +900,86 @@ static const struct i2c_algorithm nmk_i2c_algo = { .functionality = nmk_i2c_functionality }; +static struct nmk_i2c_controller u8500_i2c = { + /* + * Slave data setup time; 250ns, 100ns, and 10ns, which + * is 14, 6 and 2 respectively for a 48Mhz i2c clock. + */ + .slsu = 0xe, + .tft = 1, /* Tx FIFO threshold */ + .rft = 8, /* Rx FIFO threshold */ + .clk_freq = 100000, /* std. mode operation */ + .timeout = 200, /* Slave response timeout(ms) */ + .sm = I2C_FREQ_MODE_FAST,How is this possible? you are setting clk_freq as 100kb/s and mode as fast mode which is supposed to be 400kb/s.
That's not how I read it:
enum i2c_freq_mode {
I2C_FREQ_MODE_STANDARD, /* up to 100 Kb/s */
I2C_FREQ_MODE_FAST, /* up to 400 Kb/s */
I2C_FREQ_MODE_HIGH_SPEED, /* up to 3.4 Mb/s */
I2C_FREQ_MODE_FAST_PLUS, /* up to 1 Mb/s */
};
The operative words here are "up to".
+}; + +static int __devinit +nmk_i2c_of_probe(struct device_node *np, struct nmk_i2c_controller *pdata) +{ + of_property_read_u32(np, "clock-frequency", (u32*)&pdata->clk_freq); + if (!pdata->clk_freq) { + pr_warn("%s: Clock frequency not found\n", np->full_name); + return -EINVAL; + } + + of_property_read_u32(np, "stericsson,slsu", (u32*)&pdata->slsu); + if (!pdata->slsu) { + pr_warn("%s: Data line delay not found\n", np->full_name); + return -EINVAL; + } + + of_property_read_u32(np, "stericsson,tft", (u32*)&pdata->tft); + if (!pdata->tft) { + pr_warn("%s: Tx FIFO threshold not found\n", np->full_name); + return -EINVAL; + } + + of_property_read_u32(np, "stericsson,rft", (u32*)&pdata->rft); + if (!pdata->rft) { + pr_warn("%s: Rx FIFO threshold not found\n", np->full_name); + return -EINVAL; + } + + of_property_read_u32(np, "stericsson,timeout", (u32*)&pdata->timeout); + if (!pdata->timeout) { + pr_warn("%s: Timeout not found\n", np->full_name); + return -EINVAL; + } + + if (of_get_property(np, "stericsson,i2c_freq_mode_fast", NULL)) + pdata->sm = I2C_FREQ_MODE_FAST; + else + pdata->sm = I2C_FREQ_MODE_STANDARD;The controller has more modes like fast mode plus and high speed mode. You can't make assumptions like this.
These are currently unsupported. Read the comments in the file:
/* * set the speed mode. Currently we support * only standard and fast mode of operation * TODO - support for fast mode plus (up to 1Mb/s) * and high speed (up to 3.4 Mb/s) */
I can add a similar comment here if it make you feel better?
+ + return 0; +} + static int __devinit nmk_i2c_probe(struct platform_device *pdev) { int ret = 0; struct resource *res; - struct nmk_i2c_controller *pdata = - pdev->dev.platform_data; + struct nmk_i2c_controller *pdata = pdev->dev.platform_data; + struct device_node *np = pdev->dev.of_node; struct nmk_i2c_dev *dev; struct i2c_adapter *adap; + if (np) { + if (!pdata) { + pdata = devm_kzalloc(&pdev->dev, sizeof(*pdata), GFP_KERNEL); + if (!pdata) { + ret = -ENOMEM; + goto err_no_mem; + } + } + ret = nmk_i2c_of_probe(np, pdata); + if (ret) + kfree(pdata); + } + + if (!pdata) + /* No i2c configuration found, using the default. */ + pdata =&u8500_i2c;There are redundant fallback configurations exists in the driver. You might need to remove those, if you want to fallback here.
I only see a fall-back for clk_freq. Are there others?
+ dev = kzalloc(sizeof(struct nmk_i2c_dev), GFP_KERNEL); if (!dev) { dev_err(&pdev->dev, "cannot allocate memory\n"); @@ -1038,11 +1110,17 @@ static int __devexit nmk_i2c_remove(struct platform_device *pdev) return 0; } +static const struct of_device_id nmk_gpio_match[] = { + { .compatible = "st,nomadik-i2c", }, + {}, +}; + static struct platform_driver nmk_i2c_driver = { .driver = { .owner = THIS_MODULE, .name = DRIVER_NAME, .pm =&nmk_i2c_pm, + .of_match_table = nmk_gpio_match, }, .probe = nmk_i2c_probe, .remove = __devexit_p(nmk_i2c_remove), -- 1.7.9.5
Kind regards, Lee -- Lee Jones Linaro ST-Ericsson Landing Team Lead M: +44 77 88 633 515 Linaro.org │ Open source software for ARM SoCs Follow Linaro: Facebook | Twitter | Blog _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@xxxxxxxxxxxxxxxxxxx http://lists.infradead.org/mailman/listinfo/linux-arm-kernel
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