HSI: Introduce Nokia N900 modem driver
The Nokia N900's modem is connected via Synchronous Serial Interface (SSI), which is a legacy version of MIPI's High-speed Synchronous Serial Interface (HSI). The handles the GPIOs for enabling and resetting the modem and instanciates ssi-protocol for data exchange. It does not yet support exchanging voice data with the modem. Signed-off-by: Sebastian Reichel <sre@kernel.org> Reviewed-by: Pavel Machek <pavel@ucw.cz> Tested-By: Ivaylo Dimitrov <ivo.g.dimitrov.75@gmail.com>
This commit is contained in:
Sebastian Reichel
parent
dc7bf5d718
commit
eafaebd987
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@ -0,0 +1,57 @@
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Nokia modem client bindings
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The Nokia modem HSI client follows the common HSI client binding
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and inherits all required properties. The following additional
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properties are needed by the Nokia modem HSI client:
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Required properties:
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- compatible: Should be one of
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"nokia,n900-modem"
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- hsi-channel-names: Should contain the following strings
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"mcsaab-control"
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"speech-control"
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"speech-data"
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"mcsaab-data"
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- gpios: Should provide a GPIO handler for each GPIO listed in
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gpio-names
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- gpio-names: Should contain the following strings
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"cmt_apeslpx"
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"cmt_rst_rq"
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"cmt_en"
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"cmt_rst"
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"cmt_bsi"
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- interrupts: Should be IRQ handle for modem's reset indication
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Example:
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&ssi_port {
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modem: hsi-client {
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compatible = "nokia,n900-modem";
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pinctrl-names = "default";
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pinctrl-0 = <&modem_pins>;
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hsi-channel-ids = <0>, <1>, <2>, <3>;
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hsi-channel-names = "mcsaab-control",
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"speech-control",
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"speech-data",
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"mcsaab-data";
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hsi-speed-kbps = <55000>;
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hsi-mode = "frame";
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hsi-flow = "synchronized";
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hsi-arb-mode = "round-robin";
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interrupts-extended = <&gpio3 8 IRQ_TYPE_EDGE_FALLING>; /* 72 */
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gpios = <&gpio3 6 GPIO_ACTIVE_HIGH>, /* 70 */
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<&gpio3 9 GPIO_ACTIVE_HIGH>, /* 73 */
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<&gpio3 10 GPIO_ACTIVE_HIGH>, /* 74 */
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<&gpio3 11 GPIO_ACTIVE_HIGH>, /* 75 */
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<&gpio5 29 GPIO_ACTIVE_HIGH>; /* 157 */
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gpio-names = "cmt_apeslpx",
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"cmt_rst_rq",
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"cmt_en",
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"cmt_rst",
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"cmt_bsi";
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};
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};
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@ -4,6 +4,15 @@
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comment "HSI clients"
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config NOKIA_MODEM
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tristate "Nokia Modem"
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depends on HSI && SSI_PROTOCOL
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help
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Say Y here if you want to add support for the modem on Nokia
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N900 (Nokia RX-51) hardware.
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If unsure, say N.
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config SSI_PROTOCOL
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tristate "SSI protocol"
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depends on HSI && PHONET && (OMAP_SSI=y || OMAP_SSI=m)
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@ -2,5 +2,6 @@
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# Makefile for HSI clients
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#
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obj-$(CONFIG_NOKIA_MODEM) += nokia-modem.o
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obj-$(CONFIG_SSI_PROTOCOL) += ssi_protocol.o
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obj-$(CONFIG_HSI_CHAR) += hsi_char.o
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/*
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* nokia-modem.c
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*
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* HSI client driver for Nokia N900 modem.
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*
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* Copyright (C) 2014 Sebastian Reichel <sre@kernel.org>
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*
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* This program is free software; you can redistribute it and/or
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* modify it under the terms of the GNU General Public License
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* version 2 as published by the Free Software Foundation.
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*
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* This program is distributed in the hope that it will be useful, but
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* WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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* General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program; if not, write to the Free Software
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* Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA
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* 02110-1301 USA
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*/
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#include <linux/gpio/consumer.h>
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#include <linux/hsi/hsi.h>
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#include <linux/init.h>
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#include <linux/interrupt.h>
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#include <linux/of.h>
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#include <linux/of_irq.h>
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#include <linux/of_gpio.h>
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#include <linux/hsi/ssi_protocol.h>
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static unsigned int pm;
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module_param(pm, int, 0400);
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MODULE_PARM_DESC(pm,
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"Enable power management (0=disabled, 1=userland based [default])");
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struct nokia_modem_gpio {
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struct gpio_desc *gpio;
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const char *name;
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};
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struct nokia_modem_device {
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struct tasklet_struct nokia_modem_rst_ind_tasklet;
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int nokia_modem_rst_ind_irq;
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struct device *device;
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struct nokia_modem_gpio *gpios;
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int gpio_amount;
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struct hsi_client *ssi_protocol;
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};
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static void do_nokia_modem_rst_ind_tasklet(unsigned long data)
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{
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struct nokia_modem_device *modem = (struct nokia_modem_device *)data;
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if (!modem)
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return;
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dev_info(modem->device, "CMT rst line change detected\n");
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if (modem->ssi_protocol)
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ssip_reset_event(modem->ssi_protocol);
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}
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static irqreturn_t nokia_modem_rst_ind_isr(int irq, void *data)
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{
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struct nokia_modem_device *modem = (struct nokia_modem_device *)data;
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tasklet_schedule(&modem->nokia_modem_rst_ind_tasklet);
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return IRQ_HANDLED;
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}
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static void nokia_modem_gpio_unexport(struct device *dev)
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{
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struct nokia_modem_device *modem = dev_get_drvdata(dev);
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int i;
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for (i = 0; i < modem->gpio_amount; i++) {
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sysfs_remove_link(&dev->kobj, modem->gpios[i].name);
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gpiod_unexport(modem->gpios[i].gpio);
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}
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}
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static int nokia_modem_gpio_probe(struct device *dev)
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{
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struct device_node *np = dev->of_node;
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struct nokia_modem_device *modem = dev_get_drvdata(dev);
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int gpio_count, gpio_name_count, i, err;
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gpio_count = of_gpio_count(np);
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if (gpio_count < 0) {
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dev_err(dev, "missing gpios: %d\n", gpio_count);
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return gpio_count;
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}
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gpio_name_count = of_property_count_strings(np, "gpio-names");
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if (gpio_count != gpio_name_count) {
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dev_err(dev, "number of gpios does not equal number of gpio names\n");
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return -EINVAL;
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}
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modem->gpios = devm_kzalloc(dev, gpio_count *
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sizeof(struct nokia_modem_gpio), GFP_KERNEL);
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if (!modem->gpios) {
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dev_err(dev, "Could not allocate memory for gpios\n");
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return -ENOMEM;
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}
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modem->gpio_amount = gpio_count;
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for (i = 0; i < gpio_count; i++) {
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modem->gpios[i].gpio = devm_gpiod_get_index(dev, NULL, i);
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if (IS_ERR(modem->gpios[i].gpio)) {
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dev_err(dev, "Could not get gpio %d\n", i);
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return PTR_ERR(modem->gpios[i].gpio);
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}
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err = of_property_read_string_index(np, "gpio-names", i,
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&(modem->gpios[i].name));
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if (err) {
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dev_err(dev, "Could not get gpio name %d\n", i);
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return err;
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}
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err = gpiod_direction_output(modem->gpios[i].gpio, 0);
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if (err)
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return err;
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err = gpiod_export(modem->gpios[i].gpio, 0);
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if (err)
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return err;
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err = gpiod_export_link(dev, modem->gpios[i].name,
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modem->gpios[i].gpio);
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if (err)
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return err;
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}
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return 0;
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}
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static int nokia_modem_probe(struct device *dev)
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{
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struct device_node *np;
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struct nokia_modem_device *modem;
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struct hsi_client *cl = to_hsi_client(dev);
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struct hsi_port *port = hsi_get_port(cl);
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int irq, pflags, err;
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struct hsi_board_info ssip;
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np = dev->of_node;
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if (!np) {
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dev_err(dev, "device tree node not found\n");
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return -ENXIO;
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}
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modem = devm_kzalloc(dev, sizeof(*modem), GFP_KERNEL);
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if (!modem) {
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dev_err(dev, "Could not allocate memory for nokia_modem_device\n");
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return -ENOMEM;
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}
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dev_set_drvdata(dev, modem);
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irq = irq_of_parse_and_map(np, 0);
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if (irq < 0) {
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dev_err(dev, "Invalid rst_ind interrupt (%d)\n", irq);
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return irq;
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}
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modem->nokia_modem_rst_ind_irq = irq;
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pflags = irq_get_trigger_type(irq);
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tasklet_init(&modem->nokia_modem_rst_ind_tasklet,
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do_nokia_modem_rst_ind_tasklet, (unsigned long)modem);
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err = devm_request_irq(dev, irq, nokia_modem_rst_ind_isr,
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IRQF_DISABLED | pflags, "modem_rst_ind", modem);
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if (err < 0) {
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dev_err(dev, "Request rst_ind irq(%d) failed (flags %d)\n",
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irq, pflags);
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return err;
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}
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enable_irq_wake(irq);
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if(pm) {
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err = nokia_modem_gpio_probe(dev);
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if (err < 0) {
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dev_err(dev, "Could not probe GPIOs\n");
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goto error1;
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}
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}
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ssip.name = "ssi-protocol";
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ssip.tx_cfg = cl->tx_cfg;
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ssip.rx_cfg = cl->rx_cfg;
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ssip.platform_data = NULL;
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ssip.archdata = NULL;
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modem->ssi_protocol = hsi_new_client(port, &ssip);
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if (!modem->ssi_protocol) {
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dev_err(dev, "Could not register ssi-protocol device\n");
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goto error2;
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}
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err = device_attach(&modem->ssi_protocol->device);
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if (err == 0) {
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dev_err(dev, "Missing ssi-protocol driver\n");
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err = -EPROBE_DEFER;
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goto error3;
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} else if (err < 0) {
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dev_err(dev, "Could not load ssi-protocol driver (%d)\n", err);
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goto error3;
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}
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/* TODO: register cmt-speech hsi client */
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dev_info(dev, "Registered Nokia HSI modem\n");
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return 0;
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error3:
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hsi_remove_client(&modem->ssi_protocol->device, NULL);
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error2:
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nokia_modem_gpio_unexport(dev);
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error1:
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disable_irq_wake(modem->nokia_modem_rst_ind_irq);
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tasklet_kill(&modem->nokia_modem_rst_ind_tasklet);
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return err;
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}
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static int nokia_modem_remove(struct device *dev)
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{
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struct nokia_modem_device *modem = dev_get_drvdata(dev);
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if (!modem)
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return 0;
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if (modem->ssi_protocol) {
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hsi_remove_client(&modem->ssi_protocol->device, NULL);
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modem->ssi_protocol = NULL;
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}
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nokia_modem_gpio_unexport(dev);
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dev_set_drvdata(dev, NULL);
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disable_irq_wake(modem->nokia_modem_rst_ind_irq);
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tasklet_kill(&modem->nokia_modem_rst_ind_tasklet);
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return 0;
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}
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#ifdef CONFIG_OF
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static const struct of_device_id nokia_modem_of_match[] = {
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{ .compatible = "nokia,n900-modem", },
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{},
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};
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MODULE_DEVICE_TABLE(of, nokia_modem_of_match);
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#endif
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static struct hsi_client_driver nokia_modem_driver = {
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.driver = {
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.name = "nokia-modem",
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.owner = THIS_MODULE,
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.probe = nokia_modem_probe,
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.remove = nokia_modem_remove,
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.of_match_table = of_match_ptr(nokia_modem_of_match),
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},
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};
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static int __init nokia_modem_init(void)
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{
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return hsi_register_client_driver(&nokia_modem_driver);
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}
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module_init(nokia_modem_init);
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static void __exit nokia_modem_exit(void)
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{
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hsi_unregister_client_driver(&nokia_modem_driver);
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}
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module_exit(nokia_modem_exit);
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MODULE_ALIAS("hsi:nokia-modem");
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MODULE_AUTHOR("Sebastian Reichel <sre@kernel.org>");
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MODULE_DESCRIPTION("HSI driver module for Nokia N900 Modem");
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MODULE_LICENSE("GPL");
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