Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755192AbaDPRTx (ORCPT ); Wed, 16 Apr 2014 13:19:53 -0400 Received: from mail-lb0-f177.google.com ([209.85.217.177]:43422 "EHLO mail-lb0-f177.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755116AbaDPRTo (ORCPT ); Wed, 16 Apr 2014 13:19:44 -0400 From: Sergei Ianovich To: linux-kernel@vger.kernel.org, linux-arm-kernel@lists.infradead.org Cc: Sergei Ianovich , Rob Herring , Pawel Moll , Mark Rutland , Ian Campbell , Kumar Gala , Randy Dunlap , Arnd Bergmann , Greg Kroah-Hartman , devicetree@vger.kernel.org (open list:OPEN FIRMWARE AND...), linux-doc@vger.kernel.org (open list:DOCUMENTATION) Subject: [PATCH v4 17/21] misc: support for serial slots in LP-8x4x Date: Wed, 16 Apr 2014 21:17:22 +0400 Message-Id: <1397668667-27328-11-git-send-email-ynvich@gmail.com> X-Mailer: git-send-email 1.9.2 In-Reply-To: <1397668667-27328-1-git-send-email-ynvich@gmail.com> References: <1397668411-27162-7-git-send-email-ynvich@gmail.com> <1397668667-27328-1-git-send-email-ynvich@gmail.com> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Serial modules (I-870xxW series) implement DCON protocol which allows one-master-many-slaves configuration over RS-485. When these modules are installed into the device, they could be accessed using the 2nd PXA built-in UART port (/dev/ttyS1). However, it seems that addresses are not processed by the modules. So the parallel bus needs to select which slot is connected. Signed-off-by: Sergei Ianovich --- v3..v4 * move DTS binding to a different patch (8/21) v2..v3 * no changes (except number 12/16 -> 17/21) v0..v2 * use device tree * use devm helpers where possible .../devicetree/bindings/misc/lp8x4x-bus.txt | 2 + Documentation/misc-devices/lp8x4x_bus.txt | 15 +++++- drivers/misc/lp8x4x_bus.c | 63 ++++++++++++++++++++++ 3 files changed, 79 insertions(+), 1 deletion(-) diff --git a/Documentation/devicetree/bindings/misc/lp8x4x-bus.txt b/Documentation/devicetree/bindings/misc/lp8x4x-bus.txt index b0fb145..24a8c62 100644 --- a/Documentation/devicetree/bindings/misc/lp8x4x-bus.txt +++ b/Documentation/devicetree/bindings/misc/lp8x4x-bus.txt @@ -8,6 +8,7 @@ Required properties: - reg: physical base addresses and region lengths of * the rotary switch * the 8bit DIP switch + * the serial slot select register * the slot count register - eeprom-gpios : should point to active-low write enable GPIO @@ -18,6 +19,7 @@ Example: compatible = "icpdas,backplane-lp8x4x"; reg = <0x0 0x2 0x9002 0x2 + 0x9004 0x2 0x9046 0x2>; eeprom-gpios = <&gpio 4 0>; }; diff --git a/Documentation/misc-devices/lp8x4x_bus.txt b/Documentation/misc-devices/lp8x4x_bus.txt index 78ea0a89..7b86797 100644 --- a/Documentation/misc-devices/lp8x4x_bus.txt +++ b/Documentation/misc-devices/lp8x4x_bus.txt @@ -19,13 +19,26 @@ LP-8x4x is an ARM-based industrial computer with a custom parallel bus to connect expansion modules with digital input/output, analog input/output, serial, CAN and other types of ports. -The bus is implemented by a FPGA. +The bus is implemented by a FPGA. There are two major groups of expansion +modules: serial and parallel. + +Serial modules (I-870xxW series) implement DCON protocol which allows one- +master-many-slaves configuration over RS-485. When these modules are installed +into the device, they could be accessed using the 2nd PXA built-in UART port +(/dev/ttyS1). However, it seems that addresses are not processed by +the modules. So the parallel bus needs to select which slot is connected. SYSFS ----- /sys/bus/icpdas/devices/backplane: +active_slot + RW - connects the select slot for serial communications. If there + is a parallel module in the selected slot, it simply ignores + incoming packets. So it is safe to activate any available + slot. + dip RO - shows status of LP-8x4x 8bit DIP switch diff --git a/drivers/misc/lp8x4x_bus.c b/drivers/misc/lp8x4x_bus.c index 567fe078..e805640 100644 --- a/drivers/misc/lp8x4x_bus.c +++ b/drivers/misc/lp8x4x_bus.c @@ -29,6 +29,8 @@ struct lp8x4x_master { void *rotary_addr; void *dip_addr; struct gpio_desc *eeprom_nWE; + unsigned int active_slot; + void *switch_addr; struct device dev; }; @@ -47,6 +49,9 @@ static void lp8x4x_master_release(struct device *dev) struct lp8x4x_master *m = container_of(dev, struct lp8x4x_master, dev); WARN_ON(!dev); + /* Disable serial communications */ + iowrite8(0xff, m->switch_addr); + kfree(m); } @@ -114,11 +119,52 @@ static ssize_t dip_show(struct device *dev, static DEVICE_ATTR_RO(dip); +static ssize_t active_slot_show(struct device *dev, + struct device_attribute *attr, char *buf) +{ + struct lp8x4x_master *m = container_of(dev, struct lp8x4x_master, dev); + + return sprintf(buf, "%u\n", m->active_slot); +} + +static ssize_t active_slot_store(struct device *dev, + struct device_attribute *attr, const char *buf, size_t count) +{ + struct lp8x4x_master *m = container_of(dev, struct lp8x4x_master, dev); + unsigned int active_slot = 0; + int err; + + if (!buf) + return count; + if (0 == count) + return count; + + err = kstrtouint(buf, 10, &active_slot); + if (err != 0 || active_slot > m->slot_count) { + dev_err(dev, "slot number is out of range 1..%u\n", + m->slot_count); + return count; + } + + if (!active_slot) { + m->active_slot = 0; + iowrite8(0xff, m->switch_addr); + return count; + } + + m->active_slot = active_slot; + iowrite8((1 << (m->active_slot - 1)) ^ 0xff, m->switch_addr); + return count; +} + +static DEVICE_ATTR_RW(active_slot); + static struct attribute *master_dev_attrs[] = { &dev_attr_slot_count.attr, &dev_attr_rotary.attr, &dev_attr_eeprom_write_enable.attr, &dev_attr_dip.attr, + &dev_attr_active_slot.attr, NULL, }; ATTRIBUTE_GROUPS(master_dev); @@ -181,6 +227,20 @@ static int __init lp8x4x_bus_probe(struct platform_device *pdev) res = platform_get_resource(pdev, IORESOURCE_MEM, r++); if (!res) { + dev_err(&pdev->dev, "Failed to get slot switch address\n"); + err = -ENODEV; + goto err_free; + } + + m->switch_addr = devm_ioremap_resource(&pdev->dev, res); + if (IS_ERR(m->switch_addr)) { + dev_err(&pdev->dev, "Failed to ioremap switch address\n"); + err = PTR_ERR(m->switch_addr); + goto err_free; + } + + res = platform_get_resource(pdev, IORESOURCE_MEM, r++); + if (!res) { dev_err(&pdev->dev, "could not get slot count address\n"); err = -ENODEV; goto err_free; @@ -223,6 +283,9 @@ static int __init lp8x4x_bus_probe(struct platform_device *pdev) dev_info(&pdev->dev, "found bus with up to %u slots\n", m->slot_count); + /* Disable serial communications until explicitly enabled */ + iowrite8(0xff, m->switch_addr); + err = bus_register(&lp8x4x_bus_type); if (err < 0) { dev_err(&pdev->dev, "failed to register bus type\n"); -- 1.8.4.2 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/