diff options
Diffstat (limited to 'drivers/i2c/busses/i2c-ocores.c')
| -rw-r--r-- | drivers/i2c/busses/i2c-ocores.c | 91 |
1 files changed, 79 insertions, 12 deletions
diff --git a/drivers/i2c/busses/i2c-ocores.c b/drivers/i2c/busses/i2c-ocores.c index 7249b5b1e5d0..abf5db7e441e 100644 --- a/drivers/i2c/busses/i2c-ocores.c +++ b/drivers/i2c/busses/i2c-ocores.c @@ -12,6 +12,7 @@ * kind, whether express or implied. */ +#include <linux/clk.h> #include <linux/err.h> #include <linux/kernel.h> #include <linux/module.h> @@ -35,7 +36,9 @@ struct ocores_i2c { int pos; int nmsgs; int state; /* see STATE_ */ - int clock_khz; + struct clk *clk; + int ip_clock_khz; + int bus_clock_khz; void (*setreg)(struct ocores_i2c *i2c, int reg, u8 value); u8 (*getreg)(struct ocores_i2c *i2c, int reg); }; @@ -215,21 +218,34 @@ static int ocores_xfer(struct i2c_adapter *adap, struct i2c_msg *msgs, int num) return -ETIMEDOUT; } -static void ocores_init(struct ocores_i2c *i2c) +static int ocores_init(struct device *dev, struct ocores_i2c *i2c) { int prescale; + int diff; u8 ctrl = oc_getreg(i2c, OCI2C_CONTROL); /* make sure the device is disabled */ oc_setreg(i2c, OCI2C_CONTROL, ctrl & ~(OCI2C_CTRL_EN|OCI2C_CTRL_IEN)); - prescale = (i2c->clock_khz / (5*100)) - 1; + prescale = (i2c->ip_clock_khz / (5 * i2c->bus_clock_khz)) - 1; + prescale = clamp(prescale, 0, 0xffff); + + diff = i2c->ip_clock_khz / (5 * (prescale + 1)) - i2c->bus_clock_khz; + if (abs(diff) > i2c->bus_clock_khz / 10) { + dev_err(dev, + "Unsupported clock settings: core: %d KHz, bus: %d KHz\n", + i2c->ip_clock_khz, i2c->bus_clock_khz); + return -EINVAL; + } + oc_setreg(i2c, OCI2C_PRELOW, prescale & 0xff); oc_setreg(i2c, OCI2C_PREHIGH, prescale >> 8); /* Init the device */ oc_setreg(i2c, OCI2C_CMD, OCI2C_CMD_IACK); oc_setreg(i2c, OCI2C_CONTROL, ctrl | OCI2C_CTRL_IEN | OCI2C_CTRL_EN); + + return 0; } @@ -304,6 +320,8 @@ static int ocores_i2c_of_probe(struct platform_device *pdev, struct device_node *np = pdev->dev.of_node; const struct of_device_id *match; u32 val; + u32 clock_frequency; + bool clock_frequency_present; if (of_property_read_u32(np, "reg-shift", &i2c->reg_shift)) { /* no 'reg-shift', check for deprecated 'regstep' */ @@ -319,12 +337,42 @@ static int ocores_i2c_of_probe(struct platform_device *pdev, } } - if (of_property_read_u32(np, "clock-frequency", &val)) { - dev_err(&pdev->dev, - "Missing required parameter 'clock-frequency'\n"); - return -ENODEV; + clock_frequency_present = !of_property_read_u32(np, "clock-frequency", + &clock_frequency); + i2c->bus_clock_khz = 100; + + i2c->clk = devm_clk_get(&pdev->dev, NULL); + + if (!IS_ERR(i2c->clk)) { + int ret = clk_prepare_enable(i2c->clk); + + if (ret) { + dev_err(&pdev->dev, + "clk_prepare_enable failed: %d\n", ret); + return ret; + } + i2c->ip_clock_khz = clk_get_rate(i2c->clk) / 1000; + if (clock_frequency_present) + i2c->bus_clock_khz = clock_frequency / 1000; + } + + if (i2c->ip_clock_khz == 0) { + if (of_property_read_u32(np, "opencores,ip-clock-frequency", + &val)) { + if (!clock_frequency_present) { + dev_err(&pdev->dev, + "Missing required parameter 'opencores,ip-clock-frequency'\n"); + return -ENODEV; + } + i2c->ip_clock_khz = clock_frequency / 1000; + dev_warn(&pdev->dev, + "Deprecated usage of the 'clock-frequency' property, please update to 'opencores,ip-clock-frequency'\n"); + } else { + i2c->ip_clock_khz = val / 1000; + if (clock_frequency_present) + i2c->bus_clock_khz = clock_frequency / 1000; + } } - i2c->clock_khz = val / 1000; of_property_read_u32(pdev->dev.of_node, "reg-io-width", &i2c->reg_io_width); @@ -368,7 +416,8 @@ static int ocores_i2c_probe(struct platform_device *pdev) if (pdata) { i2c->reg_shift = pdata->reg_shift; i2c->reg_io_width = pdata->reg_io_width; - i2c->clock_khz = pdata->clock_khz; + i2c->ip_clock_khz = pdata->clock_khz; + i2c->bus_clock_khz = 100; } else { ret = ocores_i2c_of_probe(pdev, i2c); if (ret) @@ -402,7 +451,9 @@ static int ocores_i2c_probe(struct platform_device *pdev) } } - ocores_init(i2c); + ret = ocores_init(&pdev->dev, i2c); + if (ret) + return ret; init_waitqueue_head(&i2c->wait); ret = devm_request_irq(&pdev->dev, irq, ocores_isr, 0, @@ -446,6 +497,9 @@ static int ocores_i2c_remove(struct platform_device *pdev) /* remove adapter & data */ i2c_del_adapter(&i2c->adap); + if (!IS_ERR(i2c->clk)) + clk_disable_unprepare(i2c->clk); + return 0; } @@ -458,6 +512,8 @@ static int ocores_i2c_suspend(struct device *dev) /* make sure the device is disabled */ oc_setreg(i2c, OCI2C_CONTROL, ctrl & ~(OCI2C_CTRL_EN|OCI2C_CTRL_IEN)); + if (!IS_ERR(i2c->clk)) + clk_disable_unprepare(i2c->clk); return 0; } @@ -465,9 +521,20 @@ static int ocores_i2c_resume(struct device *dev) { struct ocores_i2c *i2c = dev_get_drvdata(dev); - ocores_init(i2c); + if (!IS_ERR(i2c->clk)) { + unsigned long rate; + int ret = clk_prepare_enable(i2c->clk); - return 0; + if (ret) { + dev_err(dev, + "clk_prepare_enable failed: %d\n", ret); + return ret; + } + rate = clk_get_rate(i2c->clk) / 1000; + if (rate) + i2c->ip_clock_khz = rate; + } + return ocores_init(dev, i2c); } static SIMPLE_DEV_PM_OPS(ocores_i2c_pm, ocores_i2c_suspend, ocores_i2c_resume); |