From 263a5646d88506c82850d824e673b14698ebad6b Mon Sep 17 00:00:00 2001 From: Andy Shevchenko Date: Tue, 24 Mar 2020 14:32:12 +0200 Subject: [PATCH] i2c: core: Allow override timing properties with 0 Some drivers may allow to override properties with 0 value when defaults are not in use, thus, replace memset() with corresponding per property update. Signed-off-by: Andy Shevchenko Tested-by: Wolfram Sang Signed-off-by: Wolfram Sang --- drivers/i2c/busses/i2c-rcar.c | 2 +- drivers/i2c/i2c-core-base.c | 30 +++++++++++++++++------------- 2 files changed, 18 insertions(+), 14 deletions(-) diff --git a/drivers/i2c/busses/i2c-rcar.c b/drivers/i2c/busses/i2c-rcar.c index 879f0e6..c8b57de 100644 --- a/drivers/i2c/busses/i2c-rcar.c +++ b/drivers/i2c/busses/i2c-rcar.c @@ -920,7 +920,7 @@ static int rcar_i2c_probe(struct platform_device *pdev) struct rcar_i2c_priv *priv; struct i2c_adapter *adap; struct device *dev = &pdev->dev; - struct i2c_timings i2c_t; + struct i2c_timings i2c_t = { 0 }; int ret; /* Otherwise logic will break because some bytes must always use PIO */ diff --git a/drivers/i2c/i2c-core-base.c b/drivers/i2c/i2c-core-base.c index 9b2972c..5cc0b0ec5 100644 --- a/drivers/i2c/i2c-core-base.c +++ b/drivers/i2c/i2c-core-base.c @@ -1593,23 +1593,21 @@ EXPORT_SYMBOL(i2c_del_adapter); * @dev: The device to scan for I2C timing properties * @t: the i2c_timings struct to be filled with values * @use_defaults: bool to use sane defaults derived from the I2C specification - * when properties are not found, otherwise use 0 + * when properties are not found, otherwise don't update * * Scan the device for the generic I2C properties describing timing parameters * for the signal and fill the given struct with the results. If a property was * not found and use_defaults was true, then maximum timings are assumed which * are derived from the I2C specification. If use_defaults is not used, the - * results will be 0, so drivers can apply their own defaults later. The latter - * is mainly intended for avoiding regressions of existing drivers which want - * to switch to this function. New drivers almost always should use the defaults. + * results will be as before, so drivers can apply their own defaults before + * calling this helper. The latter is mainly intended for avoiding regressions + * of existing drivers which want to switch to this function. New drivers + * almost always should use the defaults. */ - void i2c_parse_fw_timings(struct device *dev, struct i2c_timings *t, bool use_defaults) { int ret; - memset(t, 0, sizeof(*t)); - ret = device_property_read_u32(dev, "clock-frequency", &t->bus_freq_hz); if (ret && use_defaults) t->bus_freq_hz = I2C_MAX_STANDARD_MODE_FREQ; @@ -1632,19 +1630,25 @@ void i2c_parse_fw_timings(struct device *dev, struct i2c_timings *t, bool use_de t->scl_fall_ns = 120; } - device_property_read_u32(dev, "i2c-scl-internal-delay-ns", &t->scl_int_delay_ns); + ret = device_property_read_u32(dev, "i2c-scl-internal-delay-ns", &t->scl_int_delay_ns); + if (ret && use_defaults) + t->scl_int_delay_ns = 0; ret = device_property_read_u32(dev, "i2c-sda-falling-time-ns", &t->sda_fall_ns); if (ret && use_defaults) t->sda_fall_ns = t->scl_fall_ns; - device_property_read_u32(dev, "i2c-sda-hold-time-ns", &t->sda_hold_ns); + ret = device_property_read_u32(dev, "i2c-sda-hold-time-ns", &t->sda_hold_ns); + if (ret && use_defaults) + t->sda_hold_ns = 0; - device_property_read_u32(dev, "i2c-digital-filter-width-ns", - &t->digital_filter_width_ns); + ret = device_property_read_u32(dev, "i2c-digital-filter-width-ns", &t->digital_filter_width_ns); + if (ret && use_defaults) + t->digital_filter_width_ns = 0; - device_property_read_u32(dev, "i2c-analog-filter-cutoff-frequency", - &t->analog_filter_cutoff_freq_hz); + ret = device_property_read_u32(dev, "i2c-analog-filter-cutoff-frequency", &t->analog_filter_cutoff_freq_hz); + if (ret && use_defaults) + t->analog_filter_cutoff_freq_hz = 0; } EXPORT_SYMBOL_GPL(i2c_parse_fw_timings); -- 2.7.4