From 374f8436ff3a450a2f95a0c1910a0b17212cede1 Mon Sep 17 00:00:00 2001 From: Peter Rosin Date: Fri, 8 Jul 2016 12:13:12 +0200 Subject: [PATCH 1/8] dt-bindings: i2c: add support for 'i2c-mux' subnode Similar to the new optional 'i2c-bus' subnode from Jon Hunter, this adds an optional 'i2c-mux' subnode, for similar reasons. I.e. it is bad of the i2c mux core to assume that any subnode of an i2c mux device is a potential (when the 'reg' property matches) i2c-mux child bus, given that i2c mux devices might do more than mux i2c traffic. So, if an 'i2c-mux' subnode is present, dictate that all i2c-mux child buses exist beneath that subnode. Acked-by: Rob Herring Reviewed-by: Wolfram Sang Signed-off-by: Peter Rosin --- .../devicetree/bindings/i2c/i2c-mux.txt | 23 +++++++++++++++---- 1 file changed, 18 insertions(+), 5 deletions(-) diff --git a/Documentation/devicetree/bindings/i2c/i2c-mux.txt b/Documentation/devicetree/bindings/i2c/i2c-mux.txt index af84cce5cd7b..212e6779dc5c 100644 --- a/Documentation/devicetree/bindings/i2c/i2c-mux.txt +++ b/Documentation/devicetree/bindings/i2c/i2c-mux.txt @@ -2,19 +2,32 @@ Common i2c bus multiplexer/switch properties. An i2c bus multiplexer/switch will have several child busses that are numbered uniquely in a device dependent manner. The nodes for an i2c bus -multiplexer/switch will have one child node for each child -bus. +multiplexer/switch will have one child node for each child bus. -Required properties: +Optional properties: +- #address-cells = <1>; + This property is required is the i2c-mux child node does not exist. + +- #size-cells = <0>; + This property is required is the i2c-mux child node does not exist. + +- i2c-mux + For i2c multiplexers/switches that have child nodes that are a mixture + of both i2c child busses and other child nodes, the 'i2c-mux' subnode + can be used for populating the i2c child busses. If an 'i2c-mux' + subnode is present, only subnodes of this will be considered as i2c + child busses. + +Required properties for the i2c-mux child node: - #address-cells = <1>; - #size-cells = <0>; -Required properties for child nodes: +Required properties for i2c child bus nodes: - #address-cells = <1>; - #size-cells = <0>; - reg : The sub-bus number. -Optional properties for child nodes: +Optional properties for i2c child bus nodes: - Other properties specific to the multiplexer/switch hardware. - Child nodes conforming to i2c bus binding From e8813c15be0a9e7f2c79c58d3329d92bcf056ecc Mon Sep 17 00:00:00 2001 From: Peter Rosin Date: Fri, 8 Jul 2016 12:12:17 +0200 Subject: [PATCH 2/8] dt-bindings: i2c: add support for 'i2c-arb' subnode This gets rid of the need for a pointless 'reg' property for i2c arbitrators. I.e. this new and more compact style some-arbitrator { i2c-arb { #address-cells = <1>; #size-cells = <0>; some-i2c-device@50 { reg = <0x50>; }; }; }; instead of the old some-arbitrator { #address-cells = <1>; #size-cells = <0>; i2c@0 { reg = <0>; #address-cells = <1>; #size-cells = <0>; some-i2c-device@50 { reg = <0x50>; }; }; }; Acked-by: Rob Herring Reviewed-by: Wolfram Sang Signed-off-by: Peter Rosin --- .../bindings/i2c/i2c-arb-gpio-challenge.txt | 8 ++--- .../devicetree/bindings/i2c/i2c-arb.txt | 35 +++++++++++++++++++ MAINTAINERS | 1 + 3 files changed, 38 insertions(+), 6 deletions(-) create mode 100644 Documentation/devicetree/bindings/i2c/i2c-arb.txt diff --git a/Documentation/devicetree/bindings/i2c/i2c-arb-gpio-challenge.txt b/Documentation/devicetree/bindings/i2c/i2c-arb-gpio-challenge.txt index 71191ff0e781..248a155414c2 100644 --- a/Documentation/devicetree/bindings/i2c/i2c-arb-gpio-challenge.txt +++ b/Documentation/devicetree/bindings/i2c/i2c-arb-gpio-challenge.txt @@ -44,8 +44,7 @@ Required properties: - our-claim-gpio: The GPIO that we use to claim the bus. - their-claim-gpios: The GPIOs that the other sides use to claim the bus. Note that some implementations may only support a single other master. -- Standard I2C mux properties. See i2c-mux.txt in this directory. -- Single I2C child bus node at reg 0. See i2c-mux.txt in this directory. +- I2C arbitration bus node. See i2c-arb.txt in this directory. Optional properties: - slew-delay-us: microseconds to wait for a GPIO to go high. Default is 10 us. @@ -63,8 +62,6 @@ Example: i2c-arbitrator { compatible = "i2c-arb-gpio-challenge"; - #address-cells = <1>; - #size-cells = <0>; i2c-parent = <&{/i2c@12CA0000}>; @@ -74,8 +71,7 @@ Example: wait-retry-us = <3000>; wait-free-us = <50000>; - i2c@0 { - reg = <0>; + i2c-arb { #address-cells = <1>; #size-cells = <0>; diff --git a/Documentation/devicetree/bindings/i2c/i2c-arb.txt b/Documentation/devicetree/bindings/i2c/i2c-arb.txt new file mode 100644 index 000000000000..59abf9277bdc --- /dev/null +++ b/Documentation/devicetree/bindings/i2c/i2c-arb.txt @@ -0,0 +1,35 @@ +Common i2c arbitration bus properties. + +- i2c-arb child node + +Required properties for the i2c-arb child node: +- #address-cells = <1>; +- #size-cells = <0>; + +Optional properties for i2c-arb child node: +- Child nodes conforming to i2c bus binding + + +Example : + + /* + An NXP pca9541 I2C bus master selector at address 0x74 + with a NXP pca8574 GPIO expander attached. + */ + + arb@74 { + compatible = "nxp,pca9541"; + reg = <0x74>; + + i2c-arb { + #address-cells = <1>; + #size-cells = <0>; + + gpio@38 { + compatible = "nxp,pca8574"; + reg = <0x38>; + #gpio-cells = <2>; + gpio-controller; + }; + }; + }; diff --git a/MAINTAINERS b/MAINTAINERS index 0bbe4b105c34..cde3e729df2c 100644 --- a/MAINTAINERS +++ b/MAINTAINERS @@ -5667,6 +5667,7 @@ S: Maintained F: Documentation/i2c/i2c-topology F: Documentation/i2c/muxes/ F: Documentation/devicetree/bindings/i2c/i2c-mux* +F: Documentation/devicetree/bindings/i2c/i2c-arb* F: drivers/i2c/i2c-mux.c F: drivers/i2c/muxes/ F: include/linux/i2c-mux.h From 0ac8eb6452e128abd7af08e5d4a38768833da0ca Mon Sep 17 00:00:00 2001 From: Peter Rosin Date: Fri, 8 Jul 2016 12:13:49 +0200 Subject: [PATCH 3/8] dt-bindings: i2c: add support for 'i2c-gate' subnode Handle i2c gates similarly to how i2c arbitrators are handled. This gets rid of a pointless 'reg' property for i2c gates. I.e. this new and more compact style some-gate { i2c-gate { #address-cells = <1>; #size-cells = <0>; some-i2c-device@50 { reg = <0x50>; }; }; }; instead of the old some-gate { #address-cells = <1>; #size-cells = <0>; i2c@0 { reg = <0>; #address-cells = <1>; #size-cells = <0>; some-i2c-device@50 { reg = <0x50>; }; }; }; Acked-by: Rob Herring Reviewed-by: Wolfram Sang Signed-off-by: Peter Rosin --- .../devicetree/bindings/i2c/i2c-gate.txt | 41 +++++++++++++++++++ MAINTAINERS | 1 + 2 files changed, 42 insertions(+) create mode 100644 Documentation/devicetree/bindings/i2c/i2c-gate.txt diff --git a/Documentation/devicetree/bindings/i2c/i2c-gate.txt b/Documentation/devicetree/bindings/i2c/i2c-gate.txt new file mode 100644 index 000000000000..1846d236e656 --- /dev/null +++ b/Documentation/devicetree/bindings/i2c/i2c-gate.txt @@ -0,0 +1,41 @@ +An i2c gate is useful to e.g. reduce the digital noise for RF tuners connected +to the i2c bus. Gates are similar to arbitrators in that you need to perform +some kind of operation to access the i2c bus past the arbitrator/gate, but +there are no competing masters to consider for gates and therefore there is +no arbitration happening for gates. + +Common i2c gate properties. + +- i2c-gate child node + +Required properties for the i2c-gate child node: +- #address-cells = <1>; +- #size-cells = <0>; + +Optional properties for i2c-gate child node: +- Child nodes conforming to i2c bus binding + + +Example : + + /* + An Invensense mpu9150 at address 0x68 featuring an on-chip Asahi + Kasei ak8975 compass behind a gate. + */ + + mpu9150@68 { + compatible = "invensense,mpu9150"; + reg = <0x68>; + interrupt-parent = <&gpio1>; + interrupts = <18 1>; + + i2c-gate { + #address-cells = <1>; + #size-cells = <0>; + + ax8975@c { + compatible = "ak,ak8975"; + reg = <0x0c>; + }; + }; + }; diff --git a/MAINTAINERS b/MAINTAINERS index cde3e729df2c..353bfe6bbaca 100644 --- a/MAINTAINERS +++ b/MAINTAINERS @@ -5668,6 +5668,7 @@ F: Documentation/i2c/i2c-topology F: Documentation/i2c/muxes/ F: Documentation/devicetree/bindings/i2c/i2c-mux* F: Documentation/devicetree/bindings/i2c/i2c-arb* +F: Documentation/devicetree/bindings/i2c/i2c-gate* F: drivers/i2c/i2c-mux.c F: drivers/i2c/muxes/ F: include/linux/i2c-mux.h From 8f7720b950cf42d316fe5b625867e163a260a83c Mon Sep 17 00:00:00 2001 From: Peter Rosin Date: Mon, 27 Jun 2016 12:01:30 +0200 Subject: [PATCH 4/8] dt-bindings: i2c: add bindings for nxp,pca9541 Fill the gap for this pre-existing driver. Acked-by: Rob Herring Reviewed-by: Wolfram Sang Signed-off-by: Peter Rosin --- .../devicetree/bindings/i2c/nxp,pca9541.txt | 29 +++++++++++++++++++ 1 file changed, 29 insertions(+) create mode 100644 Documentation/devicetree/bindings/i2c/nxp,pca9541.txt diff --git a/Documentation/devicetree/bindings/i2c/nxp,pca9541.txt b/Documentation/devicetree/bindings/i2c/nxp,pca9541.txt new file mode 100644 index 000000000000..0fbbc6970ec5 --- /dev/null +++ b/Documentation/devicetree/bindings/i2c/nxp,pca9541.txt @@ -0,0 +1,29 @@ +* NXP PCA9541 I2C bus master selector + +Required Properties: + + - compatible: Must be "nxp,pca9541" + + - reg: The I2C address of the device. + + The following required properties are defined externally: + + - I2C arbitration bus node. See i2c-arb.txt in this directory. + + +Example: + + i2c-arbitrator@74 { + compatible = "nxp,pca9541"; + reg = <0x74>; + + i2c-arb { + #address-cells = <1>; + #size-cells = <0>; + + eeprom@54 { + compatible = "at,24c08"; + reg = <0x54>; + }; + }; + }; From b2d57b56047b99f2992fc958d7ac5ead283e9088 Mon Sep 17 00:00:00 2001 From: Peter Rosin Date: Sat, 9 Jul 2016 21:53:42 +0200 Subject: [PATCH 5/8] i2c: mux: add support for 'i2c-mux', 'i2c-arb' and 'i2c-gate' DT subnodes Backwards compatibility is preserved; the subnodes are in practice optional. However, the mux core needs to know what subnode it should examine, so add a couple of new flags for i2c_mux_alloc for this purpose. The rule is that if the mux core finds a 'reg' property in the appropriate subnode, e.g. if 'reg' exists in the 'i2c-mux' subnode, then the mux core will assume that this is an old style entry and not an i2c-mux subnode (correspondingly for arbitrators and gates with 'i2c-arb' and 'i2c-gate'). Reviewed-by: Wolfram Sang Signed-off-by: Peter Rosin --- drivers/i2c/i2c-mux.c | 44 +++++++++++++++++++++++++++++++++-------- include/linux/i2c-mux.h | 8 ++++++-- 2 files changed, 42 insertions(+), 10 deletions(-) diff --git a/drivers/i2c/i2c-mux.c b/drivers/i2c/i2c-mux.c index 8eee98634cda..c1ae719d1a7a 100644 --- a/drivers/i2c/i2c-mux.c +++ b/drivers/i2c/i2c-mux.c @@ -255,6 +255,10 @@ struct i2c_mux_core *i2c_mux_alloc(struct i2c_adapter *parent, muxc->dev = dev; if (flags & I2C_MUX_LOCKED) muxc->mux_locked = true; + if (flags & I2C_MUX_ARBITRATOR) + muxc->arbitrator = true; + if (flags & I2C_MUX_GATE) + muxc->gate = true; muxc->select = select; muxc->deselect = deselect; muxc->max_adapters = max_adapters; @@ -335,18 +339,42 @@ int i2c_mux_add_adapter(struct i2c_mux_core *muxc, * nothing if !CONFIG_OF. */ if (muxc->dev->of_node) { - struct device_node *child; + struct device_node *dev_node = muxc->dev->of_node; + struct device_node *mux_node, *child = NULL; u32 reg; - for_each_child_of_node(muxc->dev->of_node, child) { - ret = of_property_read_u32(child, "reg", ®); - if (ret) - continue; - if (chan_id == reg) { - priv->adap.dev.of_node = child; - break; + if (muxc->arbitrator) + mux_node = of_get_child_by_name(dev_node, "i2c-arb"); + else if (muxc->gate) + mux_node = of_get_child_by_name(dev_node, "i2c-gate"); + else + mux_node = of_get_child_by_name(dev_node, "i2c-mux"); + + if (mux_node) { + /* A "reg" property indicates an old-style DT entry */ + if (!of_property_read_u32(mux_node, "reg", ®)) { + of_node_put(mux_node); + mux_node = NULL; } } + + if (!mux_node) + mux_node = of_node_get(dev_node); + else if (muxc->arbitrator || muxc->gate) + child = of_node_get(mux_node); + + if (!child) { + for_each_child_of_node(mux_node, child) { + ret = of_property_read_u32(child, "reg", ®); + if (ret) + continue; + if (chan_id == reg) + break; + } + } + + priv->adap.dev.of_node = child; + of_node_put(mux_node); } /* diff --git a/include/linux/i2c-mux.h b/include/linux/i2c-mux.h index d4c1d12f900d..bd74d5706f3b 100644 --- a/include/linux/i2c-mux.h +++ b/include/linux/i2c-mux.h @@ -32,7 +32,9 @@ struct i2c_mux_core { struct i2c_adapter *parent; struct device *dev; - bool mux_locked; + unsigned int mux_locked:1; + unsigned int arbitrator:1; + unsigned int gate:1; void *priv; @@ -51,7 +53,9 @@ struct i2c_mux_core *i2c_mux_alloc(struct i2c_adapter *parent, int (*deselect)(struct i2c_mux_core *, u32)); /* flags for i2c_mux_alloc */ -#define I2C_MUX_LOCKED BIT(0) +#define I2C_MUX_LOCKED BIT(0) +#define I2C_MUX_ARBITRATOR BIT(1) +#define I2C_MUX_GATE BIT(2) static inline void *i2c_mux_priv(struct i2c_mux_core *muxc) { From 40839590f868d77ab8f84ac6e1b1297f553e3dea Mon Sep 17 00:00:00 2001 From: Peter Rosin Date: Thu, 11 Aug 2016 16:49:54 +0200 Subject: [PATCH 6/8] i2c: mux: inform the i2c mux core about how it is used The i2c mux core can then take appropriate action depending on if it is used for an actual i2c mux, for a gate or for an arbitrator (the last is the case for these drivers). This adds support for the new clearer and more compact devicetree bindings that was added recently. Reviewed-by: Wolfram Sang Signed-off-by: Peter Rosin --- drivers/i2c/muxes/i2c-arb-gpio-challenge.c | 2 +- drivers/i2c/muxes/i2c-mux-pca9541.c | 3 ++- 2 files changed, 3 insertions(+), 2 deletions(-) diff --git a/drivers/i2c/muxes/i2c-arb-gpio-challenge.c b/drivers/i2c/muxes/i2c-arb-gpio-challenge.c index a90bbc4037dd..86fc2d4c081b 100644 --- a/drivers/i2c/muxes/i2c-arb-gpio-challenge.c +++ b/drivers/i2c/muxes/i2c-arb-gpio-challenge.c @@ -130,7 +130,7 @@ static int i2c_arbitrator_probe(struct platform_device *pdev) return -EINVAL; } - muxc = i2c_mux_alloc(NULL, dev, 1, sizeof(*arb), 0, + muxc = i2c_mux_alloc(NULL, dev, 1, sizeof(*arb), I2C_MUX_ARBITRATOR, i2c_arbitrator_select, i2c_arbitrator_deselect); if (!muxc) return -ENOMEM; diff --git a/drivers/i2c/muxes/i2c-mux-pca9541.c b/drivers/i2c/muxes/i2c-mux-pca9541.c index 3cb8af635db5..f052c3067791 100644 --- a/drivers/i2c/muxes/i2c-mux-pca9541.c +++ b/drivers/i2c/muxes/i2c-mux-pca9541.c @@ -349,7 +349,8 @@ static int pca9541_probe(struct i2c_client *client, force = 0; if (pdata) force = pdata->modes[0].adap_id; - muxc = i2c_mux_alloc(adap, &client->dev, 1, sizeof(*data), 0, + muxc = i2c_mux_alloc(adap, &client->dev, 1, sizeof(*data), + I2C_MUX_ARBITRATOR, pca9541_select_chan, pca9541_release_chan); if (!muxc) return -ENOMEM; From a1cbf338abaf4d340b7aee1d8255e20462d11e70 Mon Sep 17 00:00:00 2001 From: Peter Rosin Date: Sat, 9 Jul 2016 20:30:58 +0200 Subject: [PATCH 7/8] i2c: pca9541: add device tree binding No longer rely on the implicit matching with the i2c device name, use an explicit compatible string instead. Reviewed-by: Wolfram Sang Signed-off-by: Peter Rosin --- drivers/i2c/muxes/i2c-mux-pca9541.c | 8 ++++++++ 1 file changed, 8 insertions(+) diff --git a/drivers/i2c/muxes/i2c-mux-pca9541.c b/drivers/i2c/muxes/i2c-mux-pca9541.c index f052c3067791..4ea7e691afc7 100644 --- a/drivers/i2c/muxes/i2c-mux-pca9541.c +++ b/drivers/i2c/muxes/i2c-mux-pca9541.c @@ -85,6 +85,13 @@ static const struct i2c_device_id pca9541_id[] = { MODULE_DEVICE_TABLE(i2c, pca9541_id); +#ifdef CONFIG_OF +static const struct of_device_id pca9541_of_match[] = { + { .compatible = "nxp,pca9541" }, + {} +}; +#endif + /* * Write to chip register. Don't use i2c_transfer()/i2c_smbus_xfer() * as they will try to lock the adapter a second time. @@ -383,6 +390,7 @@ static int pca9541_remove(struct i2c_client *client) static struct i2c_driver pca9541_driver = { .driver = { .name = "pca9541", + .of_match_table = of_match_ptr(pca9541_of_match), }, .probe = pca9541_probe, .remove = pca9541_remove, From 8a191a7ad4ca9022bb838387b20d3de6acc88b72 Mon Sep 17 00:00:00 2001 From: Peter Rosin Date: Sat, 9 Jul 2016 21:21:15 +0200 Subject: [PATCH 8/8] i2c: pca954x: add device tree binding No longer rely on the implicit matching with the i2c device name, use an explicit compatible string instead. Keep a direct pointer to the chip description instead of an index into the chip description array. Reviewed-by: Wolfram Sang Signed-off-by: Peter Rosin --- drivers/i2c/muxes/i2c-mux-pca954x.c | 46 +++++++++++++++++++++-------- 1 file changed, 34 insertions(+), 12 deletions(-) diff --git a/drivers/i2c/muxes/i2c-mux-pca954x.c b/drivers/i2c/muxes/i2c-mux-pca954x.c index 528e755c468f..6dfd31ba29a0 100644 --- a/drivers/i2c/muxes/i2c-mux-pca954x.c +++ b/drivers/i2c/muxes/i2c-mux-pca954x.c @@ -42,6 +42,7 @@ #include #include #include +#include #include #include @@ -58,14 +59,6 @@ enum pca_type { pca_9548, }; -struct pca954x { - enum pca_type type; - - u8 last_chan; /* last register value */ - u8 deselect; - struct i2c_client *client; -}; - struct chip_desc { u8 nchans; u8 enable; /* used for muxes only */ @@ -75,6 +68,14 @@ struct chip_desc { } muxtype; }; +struct pca954x { + const struct chip_desc *chip; + + u8 last_chan; /* last register value */ + u8 deselect; + struct i2c_client *client; +}; + /* Provide specs for the PCA954x types we know about */ static const struct chip_desc chips[] = { [pca_9540] = { @@ -119,6 +120,20 @@ static const struct i2c_device_id pca954x_id[] = { }; MODULE_DEVICE_TABLE(i2c, pca954x_id); +#ifdef CONFIG_OF +static const struct of_device_id pca954x_of_match[] = { + { .compatible = "nxp,pca9540", .data = &chips[pca_9540] }, + { .compatible = "nxp,pca9542", .data = &chips[pca_9542] }, + { .compatible = "nxp,pca9543", .data = &chips[pca_9543] }, + { .compatible = "nxp,pca9544", .data = &chips[pca_9544] }, + { .compatible = "nxp,pca9545", .data = &chips[pca_9545] }, + { .compatible = "nxp,pca9546", .data = &chips[pca_9546] }, + { .compatible = "nxp,pca9547", .data = &chips[pca_9547] }, + { .compatible = "nxp,pca9548", .data = &chips[pca_9548] }, + {} +}; +#endif + /* Write to mux register. Don't use i2c_transfer()/i2c_smbus_xfer() for this as they will try to lock adapter a second time */ static int pca954x_reg_write(struct i2c_adapter *adap, @@ -151,7 +166,7 @@ static int pca954x_select_chan(struct i2c_mux_core *muxc, u32 chan) { struct pca954x *data = i2c_mux_priv(muxc); struct i2c_client *client = data->client; - const struct chip_desc *chip = &chips[data->type]; + const struct chip_desc *chip = data->chip; u8 regval; int ret = 0; @@ -197,6 +212,7 @@ static int pca954x_probe(struct i2c_client *client, int num, force, class; struct i2c_mux_core *muxc; struct pca954x *data; + const struct of_device_id *match; int ret; if (!i2c_check_functionality(adap, I2C_FUNC_SMBUS_BYTE)) @@ -226,14 +242,19 @@ static int pca954x_probe(struct i2c_client *client, return -ENODEV; } - data->type = id->driver_data; + match = of_match_device(of_match_ptr(pca954x_of_match), &client->dev); + if (match) + data->chip = of_device_get_match_data(&client->dev); + else + data->chip = &chips[id->driver_data]; + data->last_chan = 0; /* force the first selection */ idle_disconnect_dt = of_node && of_property_read_bool(of_node, "i2c-mux-idle-disconnect"); /* Now create an adapter for each channel */ - for (num = 0; num < chips[data->type].nchans; num++) { + for (num = 0; num < data->chip->nchans; num++) { bool idle_disconnect_pd = false; force = 0; /* dynamic adap number */ @@ -263,7 +284,7 @@ static int pca954x_probe(struct i2c_client *client, dev_info(&client->dev, "registered %d multiplexed busses for I2C %s %s\n", - num, chips[data->type].muxtype == pca954x_ismux + num, data->chip->muxtype == pca954x_ismux ? "mux" : "switch", client->name); return 0; @@ -299,6 +320,7 @@ static struct i2c_driver pca954x_driver = { .driver = { .name = "pca954x", .pm = &pca954x_pm, + .of_match_table = of_match_ptr(pca954x_of_match), }, .probe = pca954x_probe, .remove = pca954x_remove,