diff options
Diffstat (limited to 'drivers/i2c/busses/i2c-mv64xxx.c')
| -rw-r--r-- | drivers/i2c/busses/i2c-mv64xxx.c | 133 |
1 files changed, 128 insertions, 5 deletions
diff --git a/drivers/i2c/busses/i2c-mv64xxx.c b/drivers/i2c/busses/i2c-mv64xxx.c index 4f44a33017b..2e9d56719e9 100644 --- a/drivers/i2c/busses/i2c-mv64xxx.c +++ b/drivers/i2c/busses/i2c-mv64xxx.c @@ -18,6 +18,11 @@ #include <linux/mv643xx_i2c.h> #include <linux/platform_device.h> #include <linux/io.h> +#include <linux/of.h> +#include <linux/of_irq.h> +#include <linux/of_i2c.h> +#include <linux/clk.h> +#include <linux/err.h> /* Register defines */ #define MV64XXX_I2C_REG_SLAVE_ADDR 0x00 @@ -98,6 +103,9 @@ struct mv64xxx_i2c_data { int rc; u32 freq_m; u32 freq_n; +#if defined(CONFIG_HAVE_CLK) + struct clk *clk; +#endif wait_queue_head_t waitq; spinlock_t lock; struct i2c_msg *msg; @@ -521,6 +529,82 @@ mv64xxx_i2c_unmap_regs(struct mv64xxx_i2c_data *drv_data) drv_data->reg_base_p = 0; } +#ifdef CONFIG_OF +static int __devinit +mv64xxx_calc_freq(const int tclk, const int n, const int m) +{ + return tclk / (10 * (m + 1) * (2 << n)); +} + +static bool __devinit +mv64xxx_find_baud_factors(const u32 req_freq, const u32 tclk, u32 *best_n, + u32 *best_m) +{ + int freq, delta, best_delta = INT_MAX; + int m, n; + + for (n = 0; n <= 7; n++) + for (m = 0; m <= 15; m++) { + freq = mv64xxx_calc_freq(tclk, n, m); + delta = req_freq - freq; + if (delta >= 0 && delta < best_delta) { + *best_m = m; + *best_n = n; + best_delta = delta; + } + if (best_delta == 0) + return true; + } + if (best_delta == INT_MAX) + return false; + return true; +} + +static int __devinit +mv64xxx_of_config(struct mv64xxx_i2c_data *drv_data, + struct device_node *np) +{ + u32 bus_freq, tclk; + int rc = 0; + + /* CLK is mandatory when using DT to describe the i2c bus. We + * need to know tclk in order to calculate bus clock + * factors. + */ +#if !defined(CONFIG_HAVE_CLK) + /* Have OF but no CLK */ + return -ENODEV; +#else + if (IS_ERR(drv_data->clk)) { + rc = -ENODEV; + goto out; + } + tclk = clk_get_rate(drv_data->clk); + of_property_read_u32(np, "clock-frequency", &bus_freq); + if (!mv64xxx_find_baud_factors(bus_freq, tclk, + &drv_data->freq_n, &drv_data->freq_m)) { + rc = -EINVAL; + goto out; + } + drv_data->irq = irq_of_parse_and_map(np, 0); + + /* Its not yet defined how timeouts will be specified in device tree. + * So hard code the value to 1 second. + */ + drv_data->adapter.timeout = HZ; +out: + return rc; +#endif +} +#else /* CONFIG_OF */ +static int __devinit +mv64xxx_of_config(struct mv64xxx_i2c_data *drv_data, + struct device_node *np) +{ + return -ENODEV; +} +#endif /* CONFIG_OF */ + static int __devinit mv64xxx_i2c_probe(struct platform_device *pd) { @@ -528,7 +612,7 @@ mv64xxx_i2c_probe(struct platform_device *pd) struct mv64xxx_i2c_pdata *pdata = pd->dev.platform_data; int rc; - if ((pd->id != 0) || !pdata) + if ((!pdata && !pd->dev.of_node)) return -ENODEV; drv_data = kzalloc(sizeof(struct mv64xxx_i2c_data), GFP_KERNEL); @@ -546,19 +630,35 @@ mv64xxx_i2c_probe(struct platform_device *pd) init_waitqueue_head(&drv_data->waitq); spin_lock_init(&drv_data->lock); - drv_data->freq_m = pdata->freq_m; - drv_data->freq_n = pdata->freq_n; - drv_data->irq = platform_get_irq(pd, 0); +#if defined(CONFIG_HAVE_CLK) + /* Not all platforms have a clk */ + drv_data->clk = clk_get(&pd->dev, NULL); + if (!IS_ERR(drv_data->clk)) { + clk_prepare(drv_data->clk); + clk_enable(drv_data->clk); + } +#endif + if (pdata) { + drv_data->freq_m = pdata->freq_m; + drv_data->freq_n = pdata->freq_n; + drv_data->irq = platform_get_irq(pd, 0); + drv_data->adapter.timeout = msecs_to_jiffies(pdata->timeout); + } else if (pd->dev.of_node) { + rc = mv64xxx_of_config(drv_data, pd->dev.of_node); + if (rc) + goto exit_unmap_regs; + } if (drv_data->irq < 0) { rc = -ENXIO; goto exit_unmap_regs; } + drv_data->adapter.dev.parent = &pd->dev; drv_data->adapter.algo = &mv64xxx_i2c_algo; drv_data->adapter.owner = THIS_MODULE; drv_data->adapter.class = I2C_CLASS_HWMON | I2C_CLASS_SPD; - drv_data->adapter.timeout = msecs_to_jiffies(pdata->timeout); drv_data->adapter.nr = pd->id; + drv_data->adapter.dev.of_node = pd->dev.of_node; platform_set_drvdata(pd, drv_data); i2c_set_adapdata(&drv_data->adapter, drv_data); @@ -577,11 +677,20 @@ mv64xxx_i2c_probe(struct platform_device *pd) goto exit_free_irq; } + of_i2c_register_devices(&drv_data->adapter); + return 0; exit_free_irq: free_irq(drv_data->irq, drv_data); exit_unmap_regs: +#if defined(CONFIG_HAVE_CLK) + /* Not all platforms have a clk */ + if (!IS_ERR(drv_data->clk)) { + clk_disable(drv_data->clk); + clk_unprepare(drv_data->clk); + } +#endif mv64xxx_i2c_unmap_regs(drv_data); exit_kfree: kfree(drv_data); @@ -597,17 +706,31 @@ mv64xxx_i2c_remove(struct platform_device *dev) rc = i2c_del_adapter(&drv_data->adapter); free_irq(drv_data->irq, drv_data); mv64xxx_i2c_unmap_regs(drv_data); +#if defined(CONFIG_HAVE_CLK) + /* Not all platforms have a clk */ + if (!IS_ERR(drv_data->clk)) { + clk_disable(drv_data->clk); + clk_unprepare(drv_data->clk); + } +#endif kfree(drv_data); return rc; } +static const struct of_device_id mv64xxx_i2c_of_match_table[] __devinitdata = { + { .compatible = "marvell,mv64xxx-i2c", }, + {} +}; +MODULE_DEVICE_TABLE(of, mv64xxx_i2c_of_match_table); + static struct platform_driver mv64xxx_i2c_driver = { .probe = mv64xxx_i2c_probe, .remove = __devexit_p(mv64xxx_i2c_remove), .driver = { .owner = THIS_MODULE, .name = MV64XXX_I2C_CTLR_NAME, + .of_match_table = of_match_ptr(mv64xxx_i2c_of_match_table), }, }; |