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I2C: MV64XYZ: Add Device Tree support
Extends the driver to get properties from device tree. Rather than pass the N & M factors in DT, use the more standard clock-frequency property. Calculate N & M at run time. In order to do this, we need to know tclk. So the driver uses clk_get() etc in order to get the clock and clk_get_rate() to determine the tclk rate. Not all platforms however have CLK, so some #ifdefery is needed to ensure the driver still compiles when CLK is not available. Signed-off-by: Andrew Lunn <andrew@lunn.ch> [wsa: converted some ints to u32 to match signedness] Signed-off-by: Wolfram Sang <w.sang@pengutronix.de>
This commit is contained in:
Andrew Lunn
Wolfram Sang
parent
6f535b9426
commit
b61d157589
@ -1,4 +1,4 @@
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* I2C
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* Marvell MMP I2C controller
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Required properties :
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@ -32,3 +32,20 @@ Examples:
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interrupts = <58>;
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};
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* Marvell MV64XXX I2C controller
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Required properties :
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- reg : Offset and length of the register set for the device
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- compatible : Should be "marvell,mv64xxx-i2c"
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- interrupts : The interrupt number
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- clock-frequency : Desired I2C bus clock frequency in Hz.
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Examples:
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i2c@11000 {
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compatible = "marvell,mv64xxx-i2c";
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reg = <0x11000 0x20>;
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interrupts = <29>;
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clock-frequency = <100000>;
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};
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@ -18,6 +18,11 @@
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#include <linux/mv643xx_i2c.h>
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#include <linux/platform_device.h>
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#include <linux/io.h>
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#include <linux/of.h>
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#include <linux/of_irq.h>
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#include <linux/of_i2c.h>
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#include <linux/clk.h>
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#include <linux/err.h>
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/* Register defines */
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#define MV64XXX_I2C_REG_SLAVE_ADDR 0x00
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@ -98,6 +103,9 @@ struct mv64xxx_i2c_data {
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int rc;
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u32 freq_m;
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u32 freq_n;
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#if defined(CONFIG_HAVE_CLK)
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struct clk *clk;
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#endif
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wait_queue_head_t waitq;
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spinlock_t lock;
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struct i2c_msg *msg;
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@ -521,6 +529,82 @@ mv64xxx_i2c_unmap_regs(struct mv64xxx_i2c_data *drv_data)
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drv_data->reg_base_p = 0;
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}
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#ifdef CONFIG_OF
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static int __devinit
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mv64xxx_calc_freq(const int tclk, const int n, const int m)
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{
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return tclk / (10 * (m + 1) * (2 << n));
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}
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static bool __devinit
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mv64xxx_find_baud_factors(const u32 req_freq, const u32 tclk, u32 *best_n,
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u32 *best_m)
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{
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int freq, delta, best_delta = INT_MAX;
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int m, n;
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for (n = 0; n <= 7; n++)
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for (m = 0; m <= 15; m++) {
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freq = mv64xxx_calc_freq(tclk, n, m);
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delta = req_freq - freq;
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if (delta >= 0 && delta < best_delta) {
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*best_m = m;
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*best_n = n;
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best_delta = delta;
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}
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if (best_delta == 0)
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return true;
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}
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if (best_delta == INT_MAX)
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return false;
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return true;
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}
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static int __devinit
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mv64xxx_of_config(struct mv64xxx_i2c_data *drv_data,
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struct device_node *np)
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{
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u32 bus_freq, tclk;
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int rc = 0;
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/* CLK is mandatory when using DT to describe the i2c bus. We
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* need to know tclk in order to calculate bus clock
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* factors.
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*/
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#if !defined(CONFIG_HAVE_CLK)
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/* Have OF but no CLK */
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return -ENODEV;
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#else
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if (IS_ERR(drv_data->clk)) {
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rc = -ENODEV;
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goto out;
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}
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tclk = clk_get_rate(drv_data->clk);
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of_property_read_u32(np, "clock-frequency", &bus_freq);
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if (!mv64xxx_find_baud_factors(bus_freq, tclk,
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&drv_data->freq_n, &drv_data->freq_m)) {
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rc = -EINVAL;
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goto out;
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}
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drv_data->irq = irq_of_parse_and_map(np, 0);
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/* Its not yet defined how timeouts will be specified in device tree.
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* So hard code the value to 1 second.
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*/
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drv_data->adapter.timeout = HZ;
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out:
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return rc;
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#endif
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}
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#else /* CONFIG_OF */
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static int __devinit
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mv64xxx_of_config(struct mv64xxx_i2c_data *drv_data,
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struct device_node *np)
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{
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return -ENODEV;
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}
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#endif /* CONFIG_OF */
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static int __devinit
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mv64xxx_i2c_probe(struct platform_device *pd)
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{
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@ -528,7 +612,7 @@ mv64xxx_i2c_probe(struct platform_device *pd)
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struct mv64xxx_i2c_pdata *pdata = pd->dev.platform_data;
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int rc;
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if (!pdata)
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if ((!pdata && !pd->dev.of_node))
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return -ENODEV;
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drv_data = kzalloc(sizeof(struct mv64xxx_i2c_data), GFP_KERNEL);
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@ -546,19 +630,35 @@ mv64xxx_i2c_probe(struct platform_device *pd)
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init_waitqueue_head(&drv_data->waitq);
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spin_lock_init(&drv_data->lock);
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drv_data->freq_m = pdata->freq_m;
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drv_data->freq_n = pdata->freq_n;
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drv_data->irq = platform_get_irq(pd, 0);
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#if defined(CONFIG_HAVE_CLK)
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/* Not all platforms have a clk */
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drv_data->clk = clk_get(&pd->dev, NULL);
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if (!IS_ERR(drv_data->clk)) {
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clk_prepare(drv_data->clk);
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clk_enable(drv_data->clk);
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}
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#endif
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if (pdata) {
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drv_data->freq_m = pdata->freq_m;
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drv_data->freq_n = pdata->freq_n;
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drv_data->irq = platform_get_irq(pd, 0);
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drv_data->adapter.timeout = msecs_to_jiffies(pdata->timeout);
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} else if (pd->dev.of_node) {
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rc = mv64xxx_of_config(drv_data, pd->dev.of_node);
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if (rc)
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goto exit_unmap_regs;
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}
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if (drv_data->irq < 0) {
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rc = -ENXIO;
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goto exit_unmap_regs;
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}
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drv_data->adapter.dev.parent = &pd->dev;
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drv_data->adapter.algo = &mv64xxx_i2c_algo;
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drv_data->adapter.owner = THIS_MODULE;
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drv_data->adapter.class = I2C_CLASS_HWMON | I2C_CLASS_SPD;
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drv_data->adapter.timeout = msecs_to_jiffies(pdata->timeout);
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drv_data->adapter.nr = pd->id;
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drv_data->adapter.dev.of_node = pd->dev.of_node;
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platform_set_drvdata(pd, drv_data);
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i2c_set_adapdata(&drv_data->adapter, drv_data);
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@ -577,11 +677,20 @@ mv64xxx_i2c_probe(struct platform_device *pd)
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goto exit_free_irq;
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}
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of_i2c_register_devices(&drv_data->adapter);
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return 0;
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exit_free_irq:
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free_irq(drv_data->irq, drv_data);
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exit_unmap_regs:
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#if defined(CONFIG_HAVE_CLK)
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/* Not all platforms have a clk */
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if (!IS_ERR(drv_data->clk)) {
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clk_disable(drv_data->clk);
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clk_unprepare(drv_data->clk);
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}
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#endif
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mv64xxx_i2c_unmap_regs(drv_data);
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exit_kfree:
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kfree(drv_data);
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@ -597,17 +706,31 @@ mv64xxx_i2c_remove(struct platform_device *dev)
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rc = i2c_del_adapter(&drv_data->adapter);
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free_irq(drv_data->irq, drv_data);
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mv64xxx_i2c_unmap_regs(drv_data);
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#if defined(CONFIG_HAVE_CLK)
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/* Not all platforms have a clk */
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if (!IS_ERR(drv_data->clk)) {
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clk_disable(drv_data->clk);
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clk_unprepare(drv_data->clk);
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}
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#endif
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kfree(drv_data);
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return rc;
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}
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static const struct of_device_id mv64xxx_i2c_of_match_table[] __devinitdata = {
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{ .compatible = "marvell,mv64xxx-i2c", },
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{}
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};
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MODULE_DEVICE_TABLE(of, mv64xxx_i2c_of_match_table);
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static struct platform_driver mv64xxx_i2c_driver = {
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.probe = mv64xxx_i2c_probe,
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.remove = __devexit_p(mv64xxx_i2c_remove),
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.driver = {
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.owner = THIS_MODULE,
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.name = MV64XXX_I2C_CTLR_NAME,
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.of_match_table = of_match_ptr(mv64xxx_i2c_of_match_table),
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},
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};
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