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linux_dsm_epyc7002/Documentation/devicetree/bindings/i2c/i2c-davinci.txt

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i2c: davinci: Optimize clock generation on Keystone SoC According to "KeyStone Architecture Inter-IC Control Bus User Guide", fixed additive part of frequency divisors (referred as "d" in the code and datasheet) always equals to 6, independent of module clock prescaler. module clock frequency master clock frequency = ---------------------- (ICCL + 6) + (ICCH + 6) It was not the case with original Davinci IP. Introduce new compatible property "ti,keystone-i2c", which triggers special handling in the driver. Without this change Keystone-based systems (having 204.8MHz input clock) choose prescaler 29 (PSC=28). Using d=5 in this case leads to bus bitrate ~353kHz instead of requested 400kHz. After correction, assuming d=6 bus rate is ~392kHz. This gives ~11% transfer rate increase. Signed-off-by: Alexander Sverdlin <alexander.sverdlin@nokia.com> Reviewed-by: Grygorii Strashko <grygorii.strashko@ti.com> Tested-by: Hemanth Guruva Reddy <hemanth.guruva_reddy@nokia.com> Tested-by: Lukasz Gemborowski <lukasz.gemborowski@nokia.com> Signed-off-by: Wolfram Sang <wsa@the-dreams.de>
2015-09-14 16:03:50 +07:00
* Texas Instruments Davinci/Keystone I2C
i2c: davinci: add OF support add of support for the davinci i2c driver. Signed-off-by: Heiko Schocher <hs@denx.de> Signed-off-by: Sekhar Nori <nsekhar@ti.com> [wsa: fix indentation in the binding description] Signed-off-by: Wolfram Sang <w.sang@pengutronix.de>
2012-07-30 14:21:12 +07:00
This file provides information, what the device node for the
i2c: davinci: Optimize clock generation on Keystone SoC According to "KeyStone Architecture Inter-IC Control Bus User Guide", fixed additive part of frequency divisors (referred as "d" in the code and datasheet) always equals to 6, independent of module clock prescaler. module clock frequency master clock frequency = ---------------------- (ICCL + 6) + (ICCH + 6) It was not the case with original Davinci IP. Introduce new compatible property "ti,keystone-i2c", which triggers special handling in the driver. Without this change Keystone-based systems (having 204.8MHz input clock) choose prescaler 29 (PSC=28). Using d=5 in this case leads to bus bitrate ~353kHz instead of requested 400kHz. After correction, assuming d=6 bus rate is ~392kHz. This gives ~11% transfer rate increase. Signed-off-by: Alexander Sverdlin <alexander.sverdlin@nokia.com> Reviewed-by: Grygorii Strashko <grygorii.strashko@ti.com> Tested-by: Hemanth Guruva Reddy <hemanth.guruva_reddy@nokia.com> Tested-by: Lukasz Gemborowski <lukasz.gemborowski@nokia.com> Signed-off-by: Wolfram Sang <wsa@the-dreams.de>
2015-09-14 16:03:50 +07:00
davinci/keystone i2c interface contains.
i2c: davinci: add OF support add of support for the davinci i2c driver. Signed-off-by: Heiko Schocher <hs@denx.de> Signed-off-by: Sekhar Nori <nsekhar@ti.com> [wsa: fix indentation in the binding description] Signed-off-by: Wolfram Sang <w.sang@pengutronix.de>
2012-07-30 14:21:12 +07:00
Required properties:
i2c: davinci: Optimize clock generation on Keystone SoC According to "KeyStone Architecture Inter-IC Control Bus User Guide", fixed additive part of frequency divisors (referred as "d" in the code and datasheet) always equals to 6, independent of module clock prescaler. module clock frequency master clock frequency = ---------------------- (ICCL + 6) + (ICCH + 6) It was not the case with original Davinci IP. Introduce new compatible property "ti,keystone-i2c", which triggers special handling in the driver. Without this change Keystone-based systems (having 204.8MHz input clock) choose prescaler 29 (PSC=28). Using d=5 in this case leads to bus bitrate ~353kHz instead of requested 400kHz. After correction, assuming d=6 bus rate is ~392kHz. This gives ~11% transfer rate increase. Signed-off-by: Alexander Sverdlin <alexander.sverdlin@nokia.com> Reviewed-by: Grygorii Strashko <grygorii.strashko@ti.com> Tested-by: Hemanth Guruva Reddy <hemanth.guruva_reddy@nokia.com> Tested-by: Lukasz Gemborowski <lukasz.gemborowski@nokia.com> Signed-off-by: Wolfram Sang <wsa@the-dreams.de>
2015-09-14 16:03:50 +07:00
- compatible: "ti,davinci-i2c" or "ti,keystone-i2c";
i2c: davinci: add OF support add of support for the davinci i2c driver. Signed-off-by: Heiko Schocher <hs@denx.de> Signed-off-by: Sekhar Nori <nsekhar@ti.com> [wsa: fix indentation in the binding description] Signed-off-by: Wolfram Sang <w.sang@pengutronix.de>
2012-07-30 14:21:12 +07:00
- reg : Offset and length of the register set for the device
Recommended properties :
- interrupts : standard interrupt property.
- clock-frequency : desired I2C bus clock frequency in Hz.
i2c: davinci: use ICPFUNC to toggle I2C as gpio for bus recovery Having a board where the I2C bus locks up occasionally made it clear that the bus recovery in the i2c-davinci driver will only work on some boards, because on regular boards, this will only toggle GPIO lines that aren't muxed to the actual pins. The I2C controller on SoCs like da850 (and da830), Keystone 2 has the built-in capability to bit-bang its lines by using the ICPFUNC registers of the i2c controller. Implement the suggested procedure by toggling SCL and checking SDA using the ICPFUNC registers of the I2C controller when present. Allow platforms to indicate the presence of the ICPFUNC registers with a has_pfunc platform data flag and add optional DT property "ti,has-pfunc" to indicate the same in DT. Reviewed-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de> Acked-by: Alexander Sverdlin <alexander.sverdlin@nokia.com> Tested-by: Michael Lawnick <michael.lawnick@nokia.com> Signed-off-by: Ben Gardiner <bengardiner@nanometrics.ca> Signed-off-by: Mike Looijmans <milo-software@users.sourceforge.net> [grygorii.strashko@ti.com: combined patches from Ben Gardiner and Mike Looijmans and reimplemented ICPFUNC bus recovery using I2C bus recovery infrastructure] Signed-off-by: Grygorii Strashko <grygorii.strashko@ti.com> Signed-off-by: Wolfram Sang <wsa@the-dreams.de>
2015-04-06 19:38:41 +07:00
- ti,has-pfunc: boolean; if defined, it indicates that SoC supports PFUNC
registers. PFUNC registers allow to switch I2C pins to function as
GPIOs, so they can by toggled manually.
i2c: davinci: add OF support add of support for the davinci i2c driver. Signed-off-by: Heiko Schocher <hs@denx.de> Signed-off-by: Sekhar Nori <nsekhar@ti.com> [wsa: fix indentation in the binding description] Signed-off-by: Wolfram Sang <w.sang@pengutronix.de>
2012-07-30 14:21:12 +07:00
Example (enbw_cmc board):
i2c@1c22000 {
compatible = "ti,davinci-i2c";
reg = <0x22000 0x1000>;
clock-frequency = <100000>;
interrupts = <15>;
interrupt-parent = <&intc>;
#address-cells = <1>;
#size-cells = <0>;
dtt@48 {
compatible = "national,lm75";
reg = <0x48>;
};
};
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