| Message ID | 20210114174909.399284-1-angelogioacchino.delregno@somainline.org |
|---|---|
| Headers | show |
| Series | QCOM QUP I2C - Add noise rejection, convert to YAML | expand |
On Thu 14 Jan 11:49 CST 2021, AngeloGioacchino Del Regno wrote: > Some I2C devices may be glitchy due to electrical noise coming > from the device itself or because of possible board design issues. > To overcome this issue, the QUP's I2C in Qualcomm SoCs supports > a noise rejection setting for both SCL and SDA lines. > > Introduce a setting for noise rejection through device properties, > "qcom,noise-reject-sda" and "qcom,noise-reject-scl", which will > be used to set the level of noise rejection sensitivity. > If the properties are not specified, noise rejection will not be > enabled. > This looks reasonable, just some small nits below. > Signed-off-by: AngeloGioacchino Del Regno <angelogioacchino.delregno@somainline.org> > --- > drivers/i2c/busses/i2c-qup.c | 17 +++++++++++++++++ > 1 file changed, 17 insertions(+) > > diff --git a/drivers/i2c/busses/i2c-qup.c b/drivers/i2c/busses/i2c-qup.c > index 5a47915869ae..af51234a60ba 100644 > --- a/drivers/i2c/busses/i2c-qup.c > +++ b/drivers/i2c/busses/i2c-qup.c > @@ -8,6 +8,7 @@ > #include <linux/acpi.h> > #include <linux/atomic.h> > #include <linux/clk.h> > +#include <linux/bitfield.h> If you move this one step up you'll maintain the sort order. > #include <linux/delay.h> > #include <linux/dmaengine.h> > #include <linux/dmapool.h> > @@ -39,6 +40,8 @@ > #define QUP_MX_READ_CNT 0x208 > #define QUP_IN_FIFO_BASE 0x218 > #define QUP_I2C_CLK_CTL 0x400 > +#define QUP_I2C_CLK_CTL_SDA_NR GENMASK(27, 26) > +#define QUP_I2C_CLK_CTL_SCL_NR GENMASK(25, 24) > #define QUP_I2C_STATUS 0x404 > #define QUP_I2C_MASTER_GEN 0x408 > > @@ -1663,6 +1666,7 @@ static int qup_i2c_probe(struct platform_device *pdev) > int ret, fs_div, hs_div; > u32 src_clk_freq = DEFAULT_SRC_CLK; > u32 clk_freq = DEFAULT_CLK_FREQ; > + u32 noise_reject_scl = 0, noise_reject_sda = 0; You shouldn't need to initialize these, device_property_read_u32() won't return 0 without updating them. > int blocks; > bool is_qup_v1; > > @@ -1860,6 +1864,19 @@ static int qup_i2c_probe(struct platform_device *pdev) > qup->clk_ctl = ((fs_div / 2) << 16) | (hs_div << 8) | (fs_div & 0xff); > } > > + /* SCL/SDA Noise rejection (optional) */ > + ret = device_property_read_u32(qup->dev, "qcom,noise-reject-scl", > + &noise_reject_scl); > + if (ret == 0) > + qup->clk_ctl |= FIELD_PREP(QUP_I2C_CLK_CTL_SCL_NR, > + noise_reject_scl); I would prefer if you didn't break this line. > + > + ret = device_property_read_u32(qup->dev, "qcom,noise-reject-sda", > + &noise_reject_sda); > + if (ret == 0) > + qup->clk_ctl |= FIELD_PREP(QUP_I2C_CLK_CTL_SDA_NR, > + noise_reject_sda); Ditto. Regards, Bjorn > + > /* > * Time it takes for a byte to be clocked out on the bus. > * Each byte takes 9 clock cycles (8 bits + 1 ack). > -- > 2.29.2 >
Il 14/01/21 18:58, Bjorn Andersson ha scritto: > On Thu 14 Jan 11:49 CST 2021, AngeloGioacchino Del Regno wrote: > >> Document the new noise rejection properties "qcom,noise-reject-sda" >> and "qcom,noise-reject-scl". >> > > I presume these are unit-less levels? > > Yes, there is no unit. Sorry, I've sent v3 before seeing your R-b on this. > Reviewed-by: Bjorn Andersson <bjorn.andersson@linaro.org> > > Regards, > Bjorn > >> Signed-off-by: AngeloGioacchino Del Regno <angelogioacchino.delregno@somainline.org> >> --- >> .../devicetree/bindings/i2c/qcom,i2c-qup.yaml | 14 ++++++++++++++ >> 1 file changed, 14 insertions(+) >> >> diff --git a/Documentation/devicetree/bindings/i2c/qcom,i2c-qup.yaml b/Documentation/devicetree/bindings/i2c/qcom,i2c-qup.yaml >> index c5c7db3ac2a6..3f14dd65c6b9 100644 >> --- a/Documentation/devicetree/bindings/i2c/qcom,i2c-qup.yaml >> +++ b/Documentation/devicetree/bindings/i2c/qcom,i2c-qup.yaml >> @@ -58,6 +58,20 @@ properties: >> '#size-cells': >> const: 0 >> >> + qcom,noise-reject-sda: >> + $ref: /schemas/types.yaml#/definitions/uint32 >> + description: Noise rejection level for the SDA line. >> + minimum: 0 >> + maximum: 3 >> + default: 0 >> + >> + qcom,noise-reject-scl: >> + $ref: /schemas/types.yaml#/definitions/uint32 >> + description: Noise rejection level for the SCL line. >> + minimum: 0 >> + maximum: 3 >> + default: 0 >> + >> required: >> - compatible >> - clocks >> -- >> 2.29.2 >>