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author | Max Filippov <jcmvbkbc@gmail.com> | 2015-02-02 18:28:12 +0300 |
---|---|---|
committer | Wolfram Sang <wsa@the-dreams.de> | 2015-02-05 22:29:15 +0100 |
commit | 3a33a85401ecdb0e2c01ea86d9e36a5711ce01d4 (patch) | |
tree | f94aad5c7f9ee69d07a81db4e3fcaa1214202eb8 /drivers/i2c/busses/i2c-ocores.c | |
parent | 8c340f6090e365ce5bac02eed07c1de3aa83f735 (diff) | |
download | linux-3a33a85401ecdb0e2c01ea86d9e36a5711ce01d4.tar.bz2 |
i2c: ocores: fix clock-frequency binding usage
clock-frequency property is meant to control the bus frequency for i2c bus
drivers, but it was incorrectly used to specify i2c controller input clock
frequency.
Introduce new attribute, opencores,ip-clock-frequency, that specifies i2c
controller clock frequency and make clock-frequency attribute compatible
with other i2c drivers. Maintain backwards compatibility in case
opencores,ip-clock-frequency attribute is missing.
Signed-off-by: Max Filippov <jcmvbkbc@gmail.com>
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>
Diffstat (limited to 'drivers/i2c/busses/i2c-ocores.c')
-rw-r--r-- | drivers/i2c/busses/i2c-ocores.c | 55 |
1 files changed, 42 insertions, 13 deletions
diff --git a/drivers/i2c/busses/i2c-ocores.c b/drivers/i2c/busses/i2c-ocores.c index 7249b5b1e5d0..6cbbb134cfb7 100644 --- a/drivers/i2c/busses/i2c-ocores.c +++ b/drivers/i2c/busses/i2c-ocores.c @@ -35,7 +35,8 @@ struct ocores_i2c { int pos; int nmsgs; int state; /* see STATE_ */ - int clock_khz; + 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 +216,34 @@ 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 +318,8 @@ 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 +335,24 @@ 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; + + 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 +396,8 @@ 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 +431,9 @@ 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, @@ -465,9 +496,7 @@ static int ocores_i2c_resume(struct device *dev) { struct ocores_i2c *i2c = dev_get_drvdata(dev); - ocores_init(i2c); - - return 0; + return ocores_init(dev, i2c); } static SIMPLE_DEV_PM_OPS(ocores_i2c_pm, ocores_i2c_suspend, ocores_i2c_resume); |