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| author | Heiner Kallweit <hkallweit1@gmail.com> | 2023-01-18 22:55:12 +0100 |
|---|---|---|
| committer | Wolfram Sang <wsa@kernel.org> | 2023-01-23 23:18:54 +0100 |
| commit | 8786b095df02c1b881643146869a7d6f80411e6a (patch) | |
| tree | 541f37aca6742f571b6bb44098818675c916d984 /drivers/i2c | |
| parent | i2c: algo: bit: allow getsda to be NULL (diff) | |
| download | linux-8786b095df02c1b881643146869a7d6f80411e6a.tar.xz linux-8786b095df02c1b881643146869a7d6f80411e6a.zip | |
i2c: gpio: support write-only sda/scl w/o pull-up
There are slave devices that understand I2C but have read-only SDA and
SCL. Examples are FD650 7-segment LED controller and its derivatives.
Typical board designs don't even have a pull-up for both pins.
Handle the new attributes for write-only SDA and missing pull-up on
SDA/SCL.
For either pin the open-drain and has-no-pullup properties are
mutually-exclusive, what is documented in the DT property documentation.
We don't add an extra warning here because the open-drain properties
are marked deprecated anyway.
Signed-off-by: Heiner Kallweit <hkallweit1@gmail.com>
[wsa: switched to device properties]
Signed-off-by: Wolfram Sang <wsa@kernel.org>
Diffstat (limited to 'drivers/i2c')
| -rw-r--r-- | drivers/i2c/busses/i2c-gpio.c | 13 |
1 files changed, 10 insertions, 3 deletions
diff --git a/drivers/i2c/busses/i2c-gpio.c b/drivers/i2c/busses/i2c-gpio.c index e4a59840c4fc..1794c0399f22 100644 --- a/drivers/i2c/busses/i2c-gpio.c +++ b/drivers/i2c/busses/i2c-gpio.c @@ -317,6 +317,12 @@ static void i2c_gpio_get_properties(struct device *dev, device_property_read_bool(dev, "i2c-gpio,scl-open-drain"); pdata->scl_is_output_only = device_property_read_bool(dev, "i2c-gpio,scl-output-only"); + pdata->sda_is_output_only = + device_property_read_bool(dev, "i2c-gpio,sda-output-only"); + pdata->sda_has_no_pullup = + device_property_read_bool(dev, "i2c-gpio,sda-has-no-pullup"); + pdata->scl_has_no_pullup = + device_property_read_bool(dev, "i2c-gpio,scl-has-no-pullup"); } static struct gpio_desc *i2c_gpio_get_desc(struct device *dev, @@ -393,7 +399,7 @@ static int i2c_gpio_probe(struct platform_device *pdev) * handle them as we handle any other output. Else we enforce open * drain as this is required for an I2C bus. */ - if (pdata->sda_is_open_drain) + if (pdata->sda_is_open_drain || pdata->sda_has_no_pullup) gflags = GPIOD_OUT_HIGH; else gflags = GPIOD_OUT_HIGH_OPEN_DRAIN; @@ -401,7 +407,7 @@ static int i2c_gpio_probe(struct platform_device *pdev) if (IS_ERR(priv->sda)) return PTR_ERR(priv->sda); - if (pdata->scl_is_open_drain) + if (pdata->scl_is_open_drain || pdata->scl_has_no_pullup) gflags = GPIOD_OUT_HIGH; else gflags = GPIOD_OUT_HIGH_OPEN_DRAIN; @@ -419,7 +425,8 @@ static int i2c_gpio_probe(struct platform_device *pdev) if (!pdata->scl_is_output_only) bit_data->getscl = i2c_gpio_getscl; - bit_data->getsda = i2c_gpio_getsda; + if (!pdata->sda_is_output_only) + bit_data->getsda = i2c_gpio_getsda; if (pdata->udelay) bit_data->udelay = pdata->udelay; |