From 85bf6d4e4b100efda8169f6f98fd65d0029c7813 Mon Sep 17 00:00:00 2001 From: Huang Shijie Date: Tue, 28 May 2013 14:20:07 +0800 Subject: [PATCH] drivers: bus: add a new driver for WEIM 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 Acked-by: Sascha Hauer Signed-off-by: Shawn Guo --- .../devicetree/bindings/bus/imx-weim.txt | 49 +++++++ drivers/bus/Kconfig | 9 ++ drivers/bus/Makefile | 1 + drivers/bus/imx-weim.c | 138 ++++++++++++++++++ 4 files changed, 197 insertions(+) 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 000000000000..cedc2a9c4785 --- /dev/null +++ b/Documentation/devicetree/bindings/bus/imx-weim.txt @@ -0,0 +1,49 @@ +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) + - 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: + + 0 + +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 property contains the values + for the registers EIM_CSnGCR1, EIM_CSnGCR2, EIM_CSnRCR1, + EIM_CSnRCR2, EIM_CSnWCR1, EIM_CSnWCR2 in this order. + +Example for an imx6q-sabreauto board, the NOR flash connected to the WEIM: + + weim: weim@021b8000 { + compatible = "fsl,imx6q-weim"; + reg = <0x021b8000 0x4000>; + 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 b05ecab915c4..46cd5bb098a9 100644 --- a/drivers/bus/Kconfig +++ b/drivers/bus/Kconfig @@ -4,6 +4,15 @@ menu "Bus devices" +config IMX_WEIM + bool "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 3c7b53c12091..436bbccf4894 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 000000000000..349f14e886b7 --- /dev/null +++ b/drivers/bus/imx-weim.c @@ -0,0 +1,138 @@ +/* + * 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 +#include +#include +#include + +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) { + dev_err(&pdev->dev, "%s set timing failed.\n", + child->full_name); + return ret; + } + } + + ret = of_platform_populate(pdev->dev.of_node, NULL, NULL, &pdev->dev); + if (ret) + dev_err(&pdev->dev, "%s fail to create devices.\n", + pdev->dev.of_node->full_name); + 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; + + ret = clk_prepare_enable(weim->clk); + if (ret) + goto weim_err; + + /* 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 struct platform_driver weim_driver = { + .driver = { + .name = "imx-weim", + .of_match_table = weim_id_table, + }, + .probe = weim_probe, +}; + +module_platform_driver(weim_driver); +MODULE_AUTHOR("Freescale Semiconductor Inc."); +MODULE_DESCRIPTION("i.MX EIM Controller Driver"); +MODULE_LICENSE("GPL");