| Message ID | 1369296978-7669-2-git-send-email-b32955@freescale.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
> The WEIM(Wireless External Interface Module) works like a bus. > You can attach many different devices on it, such as NOR, onenand. > > In the case of i.MX6q-sabreauto, the NOR is connected to WEIM. > > This patch also adds the devicetree binding document. > The driver only works when the devicetree is enabled. > > Signed-off-by: Huang Shijie <b32955@freescale.com> > --- > Documentation/devicetree/bindings/bus/imx-weim.txt | 50 +++++++ > drivers/bus/Kconfig | 9 ++ > drivers/bus/Makefile | 1 + > drivers/bus/imx-weim.c | 146 ++++++++++++++++++++ > 4 files changed, 206 insertions(+), 0 deletions(-) > create mode 100644 Documentation/devicetree/bindings/bus/imx-weim.txt > create mode 100644 drivers/bus/imx-weim.c > > diff --git a/Documentation/devicetree/bindings/bus/imx-weim.txt b/Documentation/devicetree/bindings/bus/imx-weim.txt > new file mode 100644 > index 0000000..3db588e > --- /dev/null > +++ b/Documentation/devicetree/bindings/bus/imx-weim.txt > @@ -0,0 +1,50 @@ > +Device tree bindings for i.MX Wireless External Interface Module (WEIM) > + > +The term "wireless" does not imply that the WEIM is literally an interface > +without wires. It simply means that this module was originally designed for > +wireless and mobile applications that use low-power technology. > + > +The actual devices are instantiated from the child nodes of a WEIM node. > + > +Required properties: > + > + - compatible: Should be set to "fsl,imx6q-weim" > + - reg: A resource specifier for the register space > + (see the example below) > + - interrupts: the interrupt number, see the example below. Where interrupt is used in the driver? > + - clocks: the clock, see the example below. > + - #address-cells: Must be set to 2 to allow memory address translation > + - #size-cells: Must be set to 1 to allow CS address passing > + - ranges: Must be set up to reflect the memory layout with four > + integer values for each chip-select line in use: > + > + <cs-number> 0 <physical address of mapping> <size> > + > +Timing property for child nodes. It is mandatory, not optional. > + > + - fsl,weim-cs-timing: The timing array, contains 6 timing values for the > + child node. We can get the CS index from the child > + node's "reg" property. > + > +Example for an imx6q-sabreauto board, the NOR flash connected to the WEIM: > + > + weim: weim@021b8000 { > + compatible = "fsl,imx6q-weim"; > + reg = <0x021b8000 0x4000>; > + interrupts = <0 14 0x04>; > + clocks = <&clks 196>; > + #address-cells = <2>; > + #size-cells = <1>; > + ranges = <0 0 0x08000000 0x08000000>; > + > + nor@0,0 { > + compatible = "cfi-flash"; > + reg = <0 0 0x02000000>; > + #address-cells = <1>; > + #size-cells = <1>; > + bank-width = <2>; > + > + fsl,weim-cs-timing = <0x00620081 0x00000001 0x1C022000 > + 0x0000C000 0x1404a38e 0x00000000>; > + }; > + }; > diff --git a/drivers/bus/Kconfig b/drivers/bus/Kconfig > index b05ecab..488702b 100644 > --- a/drivers/bus/Kconfig > +++ b/drivers/bus/Kconfig > @@ -4,6 +4,15 @@ > > menu "Bus devices" > > +config IMX_WEIM > + tristate "Freescale EIM DRIVER" > + depends on ARCH_MXC > + help > + Driver for i.MX6 WEIM controller. > + The WEIM(Wireless External Interface Module) works like a bus. > + You can attach many different devices on it, such as NOR, onenand. > + But now, we only support the Parallel NOR. > + > config MVEBU_MBUS > bool > depends on PLAT_ORION > diff --git a/drivers/bus/Makefile b/drivers/bus/Makefile > index 3c7b53c..436bbcc 100644 > --- a/drivers/bus/Makefile > +++ b/drivers/bus/Makefile > @@ -2,6 +2,7 @@ > # Makefile for the bus drivers. > # > > +obj-$(CONFIG_IMX_WEIM) += imx-weim.o > obj-$(CONFIG_MVEBU_MBUS) += mvebu-mbus.o > obj-$(CONFIG_OMAP_OCP2SCP) += omap-ocp2scp.o > > diff --git a/drivers/bus/imx-weim.c b/drivers/bus/imx-weim.c > new file mode 100644 > index 0000000..b932add > --- /dev/null > +++ b/drivers/bus/imx-weim.c > @@ -0,0 +1,146 @@ > +/* > + * EIM driver for Freescale's i.MX chips > + * > + * Copyright (C) 2013 Freescale Semiconductor, Inc. > + * > + * This file is licensed under the terms of the GNU General Public > + * License version 2. This program is licensed "as is" without any > + * warranty of any kind, whether express or implied. > + */ > +#include <linux/module.h> > +#include <linux/clk.h> > +#include <linux/io.h> > +#include <linux/of_device.h> > + > +struct imx_weim { > + void __iomem *base; > + struct clk *clk; > +}; > + > +static const struct of_device_id weim_id_table[] = { > + { .compatible = "fsl,imx6q-weim", }, > + {} > +}; > +MODULE_DEVICE_TABLE(of, weim_id_table); > + > +#define CS_TIMING_LEN 6 > +#define CS_REG_RANGE 0x18 > + > +/* Parse and set the timing for this device. */ > +static int > +weim_timing_setup(struct platform_device *pdev, struct device_node *np) > +{ > + struct imx_weim *weim = platform_get_drvdata(pdev); > + u32 value[CS_TIMING_LEN]; > + u32 cs_idx; > + int ret; > + int i; > + > + /* get the CS index from this child node's "reg" property. */ > + ret = of_property_read_u32(np, "reg", &cs_idx); > + if (ret) > + return ret; > + > + /* The weim has four chip selects. */ > + if (cs_idx > 3) > + return -EINVAL; > + > + ret = of_property_read_u32_array(np, "fsl,weim-cs-timing", > + value, CS_TIMING_LEN); > + if (ret) > + return ret; > + > + /* set the timing for WEIM */ > + for (i = 0; i < CS_TIMING_LEN; i++) > + writel(value[i], weim->base + cs_idx * CS_REG_RANGE + i * 4); > + return 0; > +} > + > +static int weim_parse_dt(struct platform_device *pdev) > +{ > + struct device_node *child; > + int ret; > + > + for_each_child_of_node(pdev->dev.of_node, child) { > + if (!child->name) > + continue; > + > + ret = weim_timing_setup(pdev, child); > + if (ret) > + goto parse_fail; > + > + if (!of_platform_device_create(child, NULL, &pdev->dev)) { > + ret = -EINVAL; > + goto parse_fail; > + } > + > + } > + return 0; > + > +parse_fail: > + return ret; > +} > + > +static int weim_probe(struct platform_device *pdev) > +{ > + struct imx_weim *weim; > + struct resource *res; > + int ret = -EINVAL; > + > + weim = devm_kzalloc(&pdev->dev, sizeof(*weim), GFP_KERNEL); > + if (!weim) { > + ret = -ENOMEM; > + goto weim_err; > + } > + platform_set_drvdata(pdev, weim); > + > + /* get the resource */ > + res = platform_get_resource(pdev, IORESOURCE_MEM, 0); > + weim->base = devm_ioremap_resource(&pdev->dev, res); > + if (IS_ERR(weim->base)) { > + ret = PTR_ERR(weim->base); > + goto weim_err; > + } > + > + /* get the clock */ > + weim->clk = devm_clk_get(&pdev->dev, NULL); > + if (IS_ERR(weim->clk)) > + goto weim_err; > + > + clk_prepare_enable(weim->clk); > + > + /* parse the device node */ > + ret = weim_parse_dt(pdev); > + if (ret) { > + clk_disable_unprepare(weim->clk); > + goto weim_err; > + } > + > + dev_info(&pdev->dev, "WEIM driver registered.\n"); > + return 0; > + > +weim_err: > + return ret; > +} > + > +static int weim_remove(struct platform_device *pdev) > +{ > + struct imx_weim *weim = platform_get_drvdata(pdev); > + > + clk_disable_unprepare(weim->clk); > + return 0; > +} > + > +static struct platform_driver weim_driver = { > + .driver = { > + .name = "imx-weim", > + .of_match_table = weim_id_table, > + }, > + .probe = weim_probe, > + .remove = weim_remove, > +}; > + > +module_platform_driver(weim_driver); > +MODULE_AUTHOR("Freescale Semiconductor Inc."); > +MODULE_DESCRIPTION("i.MX EIM Controller Driver"); > +MODULE_LICENSE("GPL"); > -- ---
? 2013?05?23? 16:46, Alexander Shiyan ??:
> Where interrupt is used in the driver?
the driver does not use this interrtupt now, but i am not sure whether
we use it in
the future.
thanks
Huang Shijie
On Thu, May 23, 2013 at 04:16:13PM +0800, Huang Shijie wrote: > The WEIM(Wireless External Interface Module) works like a bus. > You can attach many different devices on it, such as NOR, onenand. > > In the case of i.MX6q-sabreauto, the NOR is connected to WEIM. > > This patch also adds the devicetree binding document. > The driver only works when the devicetree is enabled. > > Signed-off-by: Huang Shijie <b32955@freescale.com> > --- > Documentation/devicetree/bindings/bus/imx-weim.txt | 50 +++++++ > drivers/bus/Kconfig | 9 ++ > drivers/bus/Makefile | 1 + > drivers/bus/imx-weim.c | 146 ++++++++++++++++++++ > 4 files changed, 206 insertions(+), 0 deletions(-) > create mode 100644 Documentation/devicetree/bindings/bus/imx-weim.txt > create mode 100644 drivers/bus/imx-weim.c > > diff --git a/Documentation/devicetree/bindings/bus/imx-weim.txt b/Documentation/devicetree/bindings/bus/imx-weim.txt > new file mode 100644 > index 0000000..3db588e > --- /dev/null > +++ b/Documentation/devicetree/bindings/bus/imx-weim.txt > @@ -0,0 +1,50 @@ > +Device tree bindings for i.MX Wireless External Interface Module (WEIM) > + > +The term "wireless" does not imply that the WEIM is literally an interface > +without wires. It simply means that this module was originally designed for > +wireless and mobile applications that use low-power technology. > + > +The actual devices are instantiated from the child nodes of a WEIM node. > + > + > + - compatible: Should be set to "fsl,imx6q-weim" > + - reg: A resource specifier for the register space > + (see the example below) > + - interrupts: the interrupt number, see the example below. > + - clocks: the clock, see the example below. > + - #address-cells: Must be set to 2 to allow memory address translation > + - #size-cells: Must be set to 1 to allow CS address passing > + - ranges: Must be set up to reflect the memory layout with four > + integer values for each chip-select line in use: > + > + <cs-number> 0 <physical address of mapping> <size> > + > +Timing property for child nodes. It is mandatory, not optional. > + > + - fsl,weim-cs-timing: The timing array, contains 6 timing values for the > + child node. We can get the CS index from the child > + node's "reg" property. This should be more detailed, something like: This contains the values for the registers EIM_CSnGCR1, EIM_CSnGCR2, EIM_CSnRCR1, EIM_CSnRCR2, EIM_CSnWCR1, EIM_CSnWCR2 in this order. > +static int weim_parse_dt(struct platform_device *pdev) > +{ > + struct device_node *child; > + int ret; > + > + for_each_child_of_node(pdev->dev.of_node, child) { > + if (!child->name) > + continue; > + > + ret = weim_timing_setup(pdev, child); > + if (ret) > + goto parse_fail; > + > + if (!of_platform_device_create(child, NULL, &pdev->dev)) { > + ret = -EINVAL; > + goto parse_fail; > + } I would print some warning here for the failures in this loop, but I don't think it's necessary to bail out. No need to make all WEIM devices fail if one has an erroneous device node. > + > + /* get the resource */ > + res = platform_get_resource(pdev, IORESOURCE_MEM, 0); > + weim->base = devm_ioremap_resource(&pdev->dev, res); > + if (IS_ERR(weim->base)) { > + ret = PTR_ERR(weim->base); > + goto weim_err; > + } > + > + /* get the clock */ > + weim->clk = devm_clk_get(&pdev->dev, NULL); > + if (IS_ERR(weim->clk)) > + goto weim_err; > + > + clk_prepare_enable(weim->clk); > + > + /* parse the device node */ > + ret = weim_parse_dt(pdev); > + if (ret) { > + clk_disable_unprepare(weim->clk); > + goto weim_err; > + } > + > + dev_info(&pdev->dev, "WEIM driver registered.\n"); > + return 0; > + > +weim_err: > + return ret; > +} > + > +static int weim_remove(struct platform_device *pdev) > +{ > + struct imx_weim *weim = platform_get_drvdata(pdev); > + > + clk_disable_unprepare(weim->clk); Once again: Is this clock needed for the child devices? If yes, you can't disable it here and leave the child devices registered. Sascha
? 2013?05?23? 17:23, Sascha Hauer ??: > On Thu, May 23, 2013 at 04:16:13PM +0800, Huang Shijie wrote: >> + <cs-number> 0<physical address of mapping> <size> >> + >> +Timing property for child nodes. It is mandatory, not optional. >> + >> + - fsl,weim-cs-timing: The timing array, contains 6 timing values for the >> + child node. We can get the CS index from the child >> + node's "reg" property. > This should be more detailed, something like: > > This contains the values for the registers EIM_CSnGCR1, EIM_CSnGCR2, > EIM_CSnRCR1, EIM_CSnRCR2, EIM_CSnWCR1, EIM_CSnWCR2 in this order. > do you mean i should add some new properties, such as "fsl,eim_csnrcr1", "fsl,eim_csnrcr2" ... >> +static int weim_parse_dt(struct platform_device *pdev) >> +{ >> + struct device_node *child; >> + int ret; >> + >> + for_each_child_of_node(pdev->dev.of_node, child) { >> + if (!child->name) >> + continue; >> + >> + ret = weim_timing_setup(pdev, child); >> + if (ret) >> + goto parse_fail; >> + >> + if (!of_platform_device_create(child, NULL,&pdev->dev)) { >> + ret = -EINVAL; >> + goto parse_fail; >> + } > I would print some warning here for the failures in this loop, but I > don't think it's necessary to bail out. No need to make all WEIM devices > fail if one has an erroneous device node. > ok. >> + >> + /* get the resource */ >> + res = platform_get_resource(pdev, IORESOURCE_MEM, 0); >> + weim->base = devm_ioremap_resource(&pdev->dev, res); >> + if (IS_ERR(weim->base)) { >> + ret = PTR_ERR(weim->base); >> + goto weim_err; >> + } >> + >> + /* get the clock */ >> + weim->clk = devm_clk_get(&pdev->dev, NULL); >> + if (IS_ERR(weim->clk)) >> + goto weim_err; >> + >> + clk_prepare_enable(weim->clk); >> + >> + /* parse the device node */ >> + ret = weim_parse_dt(pdev); >> + if (ret) { >> + clk_disable_unprepare(weim->clk); >> + goto weim_err; >> + } >> + >> + dev_info(&pdev->dev, "WEIM driver registered.\n"); >> + return 0; >> + >> +weim_err: >> + return ret; >> +} >> + >> +static int weim_remove(struct platform_device *pdev) >> +{ >> + struct imx_weim *weim = platform_get_drvdata(pdev); >> + >> + clk_disable_unprepare(weim->clk); > Once again: Is this clock needed for the child devices? If yes, you > can't disable it here and leave the child devices registered. > again. yes. we need this clock. thanks Huang Shijie
On Thursday 23 May 2013, Huang Shijie wrote: > ? 2013?05?23? 17:23, Sascha Hauer ??: > > On Thu, May 23, 2013 at 04:16:13PM +0800, Huang Shijie wrote: > >> + <cs-number> 0<physical address of mapping> <size> > >> + > >> +Timing property for child nodes. It is mandatory, not optional. > >> + > >> + - fsl,weim-cs-timing: The timing array, contains 6 timing values for the > >> + child node. We can get the CS index from the child > >> + node's "reg" property. > > This should be more detailed, something like: > > > > This contains the values for the registers EIM_CSnGCR1, EIM_CSnGCR2, > > EIM_CSnRCR1, EIM_CSnRCR2, EIM_CSnWCR1, EIM_CSnWCR2 in this order. > > > > > do you mean i should add some new properties, such as > "fsl,eim_csnrcr1", "fsl,eim_csnrcr2" ... No, the property is fine, just update the documentation the way that Sascha suggested. > >> +static int weim_remove(struct platform_device *pdev) > >> +{ > >> + struct imx_weim *weim = platform_get_drvdata(pdev); > >> + > >> + clk_disable_unprepare(weim->clk); > > Once again: Is this clock needed for the child devices? If yes, you > > can't disable it here and leave the child devices registered. > > But weim_remove will not be called as long as there are children registered, right? Arnd
On Thu, May 23, 2013 at 04:16:13PM +0800, Huang Shijie wrote: > + /* get the clock */ > + weim->clk = devm_clk_get(&pdev->dev, NULL); > + if (IS_ERR(weim->clk)) > + goto weim_err; > + > + clk_prepare_enable(weim->clk); I notice people are getting lazy about this. clk_prepare_enable() can return an error...
On Thu, May 23, 2013 at 11:53:37AM +0200, Arnd Bergmann wrote: > On Thursday 23 May 2013, Huang Shijie wrote: > > ? 2013?05?23? 17:23, Sascha Hauer ??: > > > On Thu, May 23, 2013 at 04:16:13PM +0800, Huang Shijie wrote: > > >> + <cs-number> 0<physical address of mapping> <size> > > >> + > > >> +Timing property for child nodes. It is mandatory, not optional. > > >> + > > >> + - fsl,weim-cs-timing: The timing array, contains 6 timing values for the > > >> + child node. We can get the CS index from the child > > >> + node's "reg" property. > > > This should be more detailed, something like: > > > > > > This contains the values for the registers EIM_CSnGCR1, EIM_CSnGCR2, > > > EIM_CSnRCR1, EIM_CSnRCR2, EIM_CSnWCR1, EIM_CSnWCR2 in this order. > > > > > > > > > do you mean i should add some new properties, such as > > "fsl,eim_csnrcr1", "fsl,eim_csnrcr2" ... > > No, the property is fine, just update the documentation the way that > Sascha suggested. Yes, that's what I meant. > > > >> +static int weim_remove(struct platform_device *pdev) > > >> +{ > > >> + struct imx_weim *weim = platform_get_drvdata(pdev); > > >> + > > >> + clk_disable_unprepare(weim->clk); > > > Once again: Is this clock needed for the child devices? If yes, you > > > can't disable it here and leave the child devices registered. > > > > > But weim_remove will not be called as long as there are children > registered, right? But then weim_remove would never be called since nobody unregisters the children, right? Sascha
On Thursday 23 May 2013, Sascha Hauer wrote: > > > >> +static int weim_remove(struct platform_device *pdev) > > > >> +{ > > > >> + struct imx_weim *weim = platform_get_drvdata(pdev); > > > >> + > > > >> + clk_disable_unprepare(weim->clk); > > > > Once again: Is this clock needed for the child devices? If yes, you > > > > can't disable it here and leave the child devices registered. > > > > > > > > But weim_remove will not be called as long as there are children > > registered, right? > > But then weim_remove would never be called since nobody unregisters the > children, right? > Ah, right. That is actually another problem: if the probe() function creates the child devices, the remove() function should tear them down again. If we do that, we can ensure that the clock is only turned off after the last child is gone. OTOH, I agree that it would be nicer if the clk could remain turned off as long as no children are active. Can we do a clk_disable() after setting up the timings for the children and then expect those to actually start up the clk again when they need it? Or to take things further: would it make sense to represent WEIM itself as a clock driver and perform the settings for each child only when it sets up its own clk? I guess it would also make sense to use of_platform_populate() instead of of_platform_device_create() when creating the children, so we actually create the entire hierarchy in case of the children itself is a "simple-bus". Arnd
? 2013?05?23? 18:19, Russell King - ARM Linux ??: > On Thu, May 23, 2013 at 04:16:13PM +0800, Huang Shijie wrote: >> + /* get the clock */ >> + weim->clk = devm_clk_get(&pdev->dev, NULL); >> + if (IS_ERR(weim->clk)) >> + goto weim_err; >> + >> + clk_prepare_enable(weim->clk); > I notice people are getting lazy about this. clk_prepare_enable() can > return an error... > i will add the error check in next version. thanks Huang Shijie
? 2013?05?23? 21:09, Arnd Bergmann ??: > OTOH, I agree that it would be nicer if the clk could remain turned > off as long as no children are active. Can we do a clk_disable() > after setting up the timings for the children and then expect those > to actually start up the clk again when they need it? > > Or to take things further: would it make sense to represent WEIM > itself as a clock driver and perform the settings for each child > only when it sets up its own clk? > If the child's subsystem supports it, we can do it. The mtd nand does support this feature, it has @select_chip() hook. We can enable/disable the clock in the @select_chip(). But the mtd NOR does _not_ supports it. Please read the /drivers/mtd/maps/physmap_of.c and /drivers/mtd/chips/cfi_cmd_set_xxx.c. Of course, we can add the feature to NOR subsystem. But that's another issue. So the weim should enable the clock all the time now. > I guess it would also make sense to use of_platform_populate() instead > of of_platform_device_create() when creating the children, so we actually I tried the of_platform_populate(), but failed. firstly, we should set the timing for the device _before_ we do the of_platform_populate(). and i rewrite the weim_parse_dt() to: ------------------------------------------------------------------------------------------ static void weim_parse_dt(struct platform_device *pdev) { struct device_node *child; for_each_child_of_node(pdev->dev.of_node, child) { if (!child->name) continue; if (weim_timing_setup(pdev, child)) { dev_err(&pdev->dev, "%s set timing failed.\n", child->full_name); continue; } } if (!of_platform_populate(pdev->dev.of_node, NULL, NULL, &pdev->dev)) dev_err(&pdev->dev, "%s device create failed.\n", child->full_name); } ------------------------------------------------------------------------------------------ The system hang at : +++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ ## Booting kernel from Legacy Image at 10800000 ... Image Name: Linux Image Type: ARM Linux Kernel Image (uncompressed) Data Size: 4259851 Bytes = 4.1 MB Load Address: 10008000 Entry Point: 10008000 Verifying Checksum ... OK Loading Kernel Image ... OK OK Starting kernel ... ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++== thanks Huang Shijie
On Fri, May 24, 2013 at 03:16:53PM +0800, Huang Shijie wrote: > ? 2013?05?23? 21:09, Arnd Bergmann ??: > >OTOH, I agree that it would be nicer if the clk could remain turned > >off as long as no children are active. Can we do a clk_disable() > >after setting up the timings for the children and then expect those > >to actually start up the clk again when they need it? > > > >Or to take things further: would it make sense to represent WEIM > >itself as a clock driver and perform the settings for each child > >only when it sets up its own clk? > > > If the child's subsystem supports it, we can do it. > > The mtd nand does support this feature, it has @select_chip() hook. > We can enable/disable the clock in the @select_chip(). > > But the mtd NOR does _not_ supports it. > Please read the /drivers/mtd/maps/physmap_of.c and > /drivers/mtd/chips/cfi_cmd_set_xxx.c. > Of course, we can add the feature to NOR subsystem. But that's > another issue. > > So the weim should enable the clock all the time now. Personally I'm fine with this, but you should not disable the clock when the children are active, so either make sure - the WEIM driver can't be unloaded, or - the WEIM driver unregisters its children, or - just leave the clock enabled. > ------------------------------------------------------------------------------------------ > > The system hang at : > +++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ > > ## Booting kernel from Legacy Image at 10800000 ... > Image Name: Linux > Image Type: ARM Linux Kernel Image (uncompressed) > Data Size: 4259851 Bytes = 4.1 MB > Load Address: 10008000 > Entry Point: 10008000 > Verifying Checksum ... OK > Loading Kernel Image ... OK > OK > > Starting kernel ... > ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++== Use EARLY_PRINTK or move your driver init to a late_initcall to make it initialize after the console. Sascha
diff --git a/Documentation/devicetree/bindings/bus/imx-weim.txt b/Documentation/devicetree/bindings/bus/imx-weim.txt new file mode 100644 index 0000000..3db588e --- /dev/null +++ b/Documentation/devicetree/bindings/bus/imx-weim.txt @@ -0,0 +1,50 @@ +Device tree bindings for i.MX Wireless External Interface Module (WEIM) + +The term "wireless" does not imply that the WEIM is literally an interface +without wires. It simply means that this module was originally designed for +wireless and mobile applications that use low-power technology. + +The actual devices are instantiated from the child nodes of a WEIM node. + +Required properties: + + - compatible: Should be set to "fsl,imx6q-weim" + - reg: A resource specifier for the register space + (see the example below) + - interrupts: the interrupt number, see the example below. + - clocks: the clock, see the example below. + - #address-cells: Must be set to 2 to allow memory address translation + - #size-cells: Must be set to 1 to allow CS address passing + - ranges: Must be set up to reflect the memory layout with four + integer values for each chip-select line in use: + + <cs-number> 0 <physical address of mapping> <size> + +Timing property for child nodes. It is mandatory, not optional. + + - fsl,weim-cs-timing: The timing array, contains 6 timing values for the + child node. We can get the CS index from the child + node's "reg" property. + +Example for an imx6q-sabreauto board, the NOR flash connected to the WEIM: + + weim: weim@021b8000 { + compatible = "fsl,imx6q-weim"; + reg = <0x021b8000 0x4000>; + interrupts = <0 14 0x04>; + clocks = <&clks 196>; + #address-cells = <2>; + #size-cells = <1>; + ranges = <0 0 0x08000000 0x08000000>; + + nor@0,0 { + compatible = "cfi-flash"; + reg = <0 0 0x02000000>; + #address-cells = <1>; + #size-cells = <1>; + bank-width = <2>; + + fsl,weim-cs-timing = <0x00620081 0x00000001 0x1C022000 + 0x0000C000 0x1404a38e 0x00000000>; + }; + }; diff --git a/drivers/bus/Kconfig b/drivers/bus/Kconfig index b05ecab..488702b 100644 --- a/drivers/bus/Kconfig +++ b/drivers/bus/Kconfig @@ -4,6 +4,15 @@ menu "Bus devices" +config IMX_WEIM + tristate "Freescale EIM DRIVER" + depends on ARCH_MXC + help + Driver for i.MX6 WEIM controller. + The WEIM(Wireless External Interface Module) works like a bus. + You can attach many different devices on it, such as NOR, onenand. + But now, we only support the Parallel NOR. + config MVEBU_MBUS bool depends on PLAT_ORION diff --git a/drivers/bus/Makefile b/drivers/bus/Makefile index 3c7b53c..436bbcc 100644 --- a/drivers/bus/Makefile +++ b/drivers/bus/Makefile @@ -2,6 +2,7 @@ # Makefile for the bus drivers. # +obj-$(CONFIG_IMX_WEIM) += imx-weim.o obj-$(CONFIG_MVEBU_MBUS) += mvebu-mbus.o obj-$(CONFIG_OMAP_OCP2SCP) += omap-ocp2scp.o diff --git a/drivers/bus/imx-weim.c b/drivers/bus/imx-weim.c new file mode 100644 index 0000000..b932add --- /dev/null +++ b/drivers/bus/imx-weim.c @@ -0,0 +1,146 @@ +/* + * EIM driver for Freescale's i.MX chips + * + * Copyright (C) 2013 Freescale Semiconductor, Inc. + * + * This file is licensed under the terms of the GNU General Public + * License version 2. This program is licensed "as is" without any + * warranty of any kind, whether express or implied. + */ +#include <linux/module.h> +#include <linux/clk.h> +#include <linux/io.h> +#include <linux/of_device.h> + +struct imx_weim { + void __iomem *base; + struct clk *clk; +}; + +static const struct of_device_id weim_id_table[] = { + { .compatible = "fsl,imx6q-weim", }, + {} +}; +MODULE_DEVICE_TABLE(of, weim_id_table); + +#define CS_TIMING_LEN 6 +#define CS_REG_RANGE 0x18 + +/* Parse and set the timing for this device. */ +static int +weim_timing_setup(struct platform_device *pdev, struct device_node *np) +{ + struct imx_weim *weim = platform_get_drvdata(pdev); + u32 value[CS_TIMING_LEN]; + u32 cs_idx; + int ret; + int i; + + /* get the CS index from this child node's "reg" property. */ + ret = of_property_read_u32(np, "reg", &cs_idx); + if (ret) + return ret; + + /* The weim has four chip selects. */ + if (cs_idx > 3) + return -EINVAL; + + ret = of_property_read_u32_array(np, "fsl,weim-cs-timing", + value, CS_TIMING_LEN); + if (ret) + return ret; + + /* set the timing for WEIM */ + for (i = 0; i < CS_TIMING_LEN; i++) + writel(value[i], weim->base + cs_idx * CS_REG_RANGE + i * 4); + return 0; +} + +static int weim_parse_dt(struct platform_device *pdev) +{ + struct device_node *child; + int ret; + + for_each_child_of_node(pdev->dev.of_node, child) { + if (!child->name) + continue; + + ret = weim_timing_setup(pdev, child); + if (ret) + goto parse_fail; + + if (!of_platform_device_create(child, NULL, &pdev->dev)) { + ret = -EINVAL; + goto parse_fail; + } + + } + return 0; + +parse_fail: + return ret; +} + +static int weim_probe(struct platform_device *pdev) +{ + struct imx_weim *weim; + struct resource *res; + int ret = -EINVAL; + + weim = devm_kzalloc(&pdev->dev, sizeof(*weim), GFP_KERNEL); + if (!weim) { + ret = -ENOMEM; + goto weim_err; + } + platform_set_drvdata(pdev, weim); + + /* get the resource */ + res = platform_get_resource(pdev, IORESOURCE_MEM, 0); + weim->base = devm_ioremap_resource(&pdev->dev, res); + if (IS_ERR(weim->base)) { + ret = PTR_ERR(weim->base); + goto weim_err; + } + + /* get the clock */ + weim->clk = devm_clk_get(&pdev->dev, NULL); + if (IS_ERR(weim->clk)) + goto weim_err; + + clk_prepare_enable(weim->clk); + + /* parse the device node */ + ret = weim_parse_dt(pdev); + if (ret) { + clk_disable_unprepare(weim->clk); + goto weim_err; + } + + dev_info(&pdev->dev, "WEIM driver registered.\n"); + return 0; + +weim_err: + return ret; +} + +static int weim_remove(struct platform_device *pdev) +{ + struct imx_weim *weim = platform_get_drvdata(pdev); + + clk_disable_unprepare(weim->clk); + return 0; +} + +static struct platform_driver weim_driver = { + .driver = { + .name = "imx-weim", + .of_match_table = weim_id_table, + }, + .probe = weim_probe, + .remove = weim_remove, +}; + +module_platform_driver(weim_driver); +MODULE_AUTHOR("Freescale Semiconductor Inc."); +MODULE_DESCRIPTION("i.MX EIM Controller Driver"); +MODULE_LICENSE("GPL");
The WEIM(Wireless External Interface Module) works like a bus. You can attach many different devices on it, such as NOR, onenand. In the case of i.MX6q-sabreauto, the NOR is connected to WEIM. This patch also adds the devicetree binding document. The driver only works when the devicetree is enabled. Signed-off-by: Huang Shijie <b32955@freescale.com> --- Documentation/devicetree/bindings/bus/imx-weim.txt | 50 +++++++ drivers/bus/Kconfig | 9 ++ drivers/bus/Makefile | 1 + drivers/bus/imx-weim.c | 146 ++++++++++++++++++++ 4 files changed, 206 insertions(+), 0 deletions(-) create mode 100644 Documentation/devicetree/bindings/bus/imx-weim.txt create mode 100644 drivers/bus/imx-weim.c