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Subject[PATCHv3 11/14] HSI: Introduce Nokia N900 modem driver
Date
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>
---
.../devicetree/bindings/hsi/nokia-modem.txt | 58 +++++
drivers/hsi/clients/Kconfig | 9 +
drivers/hsi/clients/Makefile | 1 +
drivers/hsi/clients/nokia-modem.c | 272 +++++++++++++++++++++
4 files changed, 340 insertions(+)
create mode 100644 Documentation/devicetree/bindings/hsi/nokia-modem.txt
create mode 100644 drivers/hsi/clients/nokia-modem.c

diff --git a/Documentation/devicetree/bindings/hsi/nokia-modem.txt b/Documentation/devicetree/bindings/hsi/nokia-modem.txt
new file mode 100644
index 0000000..a8b8b6b
--- /dev/null
+++ b/Documentation/devicetree/bindings/hsi/nokia-modem.txt
@@ -0,0 +1,58 @@
+Nokia modem client bindings
+
+The Nokia modem HSI client follows the common HSI
+client binding and inherits all required properties.
+The following additional properties are needed by
+the Nokia modem HSI client:
+
+Required properties:
+- compatible: Should be one of
+ "nokia,n900-modem"
+- reg-names: Should contain the following strings
+ "mcsaab-control"
+ "speech-control"
+ "speech-data"
+ "mcsaab-data"
+- gpios: Should provide a GPIO handler for each GPIO listed in
+ gpio-names
+- gpio-names: Should contain the following strings
+ "cmt_apeslpx"
+ "cmt_rst_rq"
+ "cmt_en"
+ "cmt_rst"
+ "cmt_bsi"
+- interrupts: Should be IRQ handle for modem's reset indication
+
+Example:
+
+&ssi_port {
+ modem: hsi-client {
+ compatible = "nokia,n900-modem";
+
+ pinctrl-names = "default";
+ pinctrl-0 = <&modem_pins>;
+
+ reg = <0>, <1>, <2>, <3>;
+ reg-names = "mcsaab-control",
+ "speech-control",
+ "speech-data",
+ "mcsaab-data";
+ hsi-speed-kbps = <55000>;
+ hsi-mode = "frame";
+ hsi-flow = "synchronized";
+ hsi-arb-mode = "round-robin";
+
+ interrupts-extended = <&gpio3 8 IRQ_TYPE_EDGE_FALLING>; /* 72 */
+
+ gpios = <&gpio3 6 GPIO_ACTIVE_HIGH>, /* 70 */
+ <&gpio3 9 GPIO_ACTIVE_HIGH>, /* 73 */
+ <&gpio3 10 GPIO_ACTIVE_HIGH>, /* 74 */
+ <&gpio3 11 GPIO_ACTIVE_HIGH>, /* 75 */
+ <&gpio5 29 GPIO_ACTIVE_HIGH>; /* 157 */
+ gpio-names = "cmt_apeslpx",
+ "cmt_rst_rq",
+ "cmt_en",
+ "cmt_rst",
+ "cmt_bsi";
+ };
+};
diff --git a/drivers/hsi/clients/Kconfig b/drivers/hsi/clients/Kconfig
index 0c70861..6ce1ea2 100644
--- a/drivers/hsi/clients/Kconfig
+++ b/drivers/hsi/clients/Kconfig
@@ -4,6 +4,15 @@

comment "HSI clients"

+config NOKIA_MODEM
+ tristate "Nokia Modem"
+ depends on SSI_PROTOCOL
+ help
+ Say Y here if you want to add support for the modem on Nokia
+ N900 (Nokia RX-51) hardware.
+
+ If unsure, say N.
+
config SSI_PROTOCOL
tristate "SSI protocol"
depends on HSI && OMAP_SSI && PHONET
diff --git a/drivers/hsi/clients/Makefile b/drivers/hsi/clients/Makefile
index ccbf768..4d5bc0e 100644
--- a/drivers/hsi/clients/Makefile
+++ b/drivers/hsi/clients/Makefile
@@ -2,5 +2,6 @@
# Makefile for HSI clients
#

+obj-$(CONFIG_NOKIA_MODEM) += nokia-modem.o
obj-$(CONFIG_SSI_PROTOCOL) += ssi_protocol.o
obj-$(CONFIG_HSI_CHAR) += hsi_char.o
diff --git a/drivers/hsi/clients/nokia-modem.c b/drivers/hsi/clients/nokia-modem.c
new file mode 100644
index 0000000..f12ec76
--- /dev/null
+++ b/drivers/hsi/clients/nokia-modem.c
@@ -0,0 +1,272 @@
+/*
+ * nokia-modem.c
+ *
+ * HSI client driver for Nokia N900 modem.
+ *
+ * Copyright (C) 2014 Sebastian Reichel <sre@kernel.org>
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * version 2 as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+ * General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA
+ * 02110-1301 USA
+ */
+
+#include <linux/gpio/consumer.h>
+#include <linux/hsi/hsi.h>
+#include <linux/init.h>
+#include <linux/interrupt.h>
+#include <linux/of.h>
+#include <linux/of_irq.h>
+#include <linux/of_gpio.h>
+#include <linux/hsi/ssi_protocol.h>
+
+struct nokia_modem_gpio {
+ struct gpio_desc *gpio;
+ const char *name;
+};
+
+struct nokia_modem_device {
+ struct tasklet_struct nokia_modem_rst_ind_tasklet;
+ int nokia_modem_rst_ind_irq;
+ struct device *device;
+ struct nokia_modem_gpio *gpios;
+ int gpio_amount;
+ struct hsi_client *ssi_protocol;
+};
+
+static void do_nokia_modem_rst_ind_tasklet(unsigned long data)
+{
+ struct nokia_modem_device *modem = (struct nokia_modem_device *)data;
+
+ if (!modem)
+ return;
+
+ dev_info(modem->device, "*** CMT rst line change detected ***\n");
+
+ if (modem->ssi_protocol)
+ ssip_reset_event(modem->ssi_protocol);
+}
+
+static irqreturn_t nokia_modem_rst_ind_isr(int irq, void *data)
+{
+ struct nokia_modem_device *modem = (struct nokia_modem_device *)data;
+
+ tasklet_schedule(&modem->nokia_modem_rst_ind_tasklet);
+
+ return IRQ_HANDLED;
+}
+
+static void nokia_modem_gpio_unexport(struct device *dev)
+{
+ struct nokia_modem_device *modem = dev_get_drvdata(dev);
+ int i;
+
+ for (i = 0; i < modem->gpio_amount; i++) {
+ sysfs_remove_link(&dev->kobj, modem->gpios[i].name);
+ gpiod_unexport(modem->gpios[i].gpio);
+ }
+}
+
+static int nokia_modem_gpio_probe(struct device *dev)
+{
+ struct device_node *np = dev->of_node;
+ struct nokia_modem_device *modem = dev_get_drvdata(dev);
+ int gpio_count, gpio_name_count, i, err;
+
+ gpio_count = of_gpio_count(np);
+ gpio_name_count = of_property_count_strings(np, "gpio-names");
+
+ if(gpio_count != gpio_name_count) {
+ dev_err(dev, "number of gpios does not equal number of gpio names\n");
+ return -EINVAL;
+ }
+
+ modem->gpios = devm_kzalloc(dev, gpio_count*sizeof(struct nokia_modem_gpio),
+ GFP_KERNEL);
+ if (modem->gpios == NULL) {
+ dev_err(dev, "Could not allocate memory for gpios\n");
+ return -ENOMEM;
+ }
+
+ modem->gpio_amount = gpio_count;
+
+ for (i = 0; i < gpio_count; i++) {
+ modem->gpios[i].gpio = devm_gpiod_get_index(dev, NULL, i);
+ if (IS_ERR(modem->gpios[i].gpio)) {
+ dev_err(dev, "Could not get gpio %d\n", i);
+ return PTR_ERR(modem->gpios[i].gpio);
+ }
+
+ err = of_property_read_string_index(np, "gpio-names", i,
+ &(modem->gpios[i].name));
+ if (err) {
+ dev_err(dev, "Could not get gpio name %d\n", i);
+ return err;
+ }
+
+ err = gpiod_direction_output(modem->gpios[i].gpio, 0);
+ if (err)
+ return err;
+
+ err = gpiod_export(modem->gpios[i].gpio, 0);
+ if (err)
+ return err;
+
+ err = gpiod_export_link(dev, modem->gpios[i].name,
+ modem->gpios[i].gpio);
+ if (err)
+ return err;
+ }
+
+ return 0;
+}
+
+static int nokia_modem_probe(struct device *dev)
+{
+ struct device_node *np;
+ struct nokia_modem_device *modem;
+ struct hsi_client *cl = to_hsi_client(dev);
+ struct hsi_port *port = hsi_get_port(cl);
+ int irq, pflags, err;
+ struct hsi_board_info ssip;
+
+ np = dev->of_node;
+ if (!np) {
+ dev_err(dev, "device tree node not found\n");
+ return -ENXIO;
+ }
+
+ modem = devm_kzalloc(dev, sizeof(*modem), GFP_KERNEL);
+ if (!modem) {
+ dev_err(dev, "Could not allocate memory for nokia_modem_device\n");
+ return -ENOMEM;
+ }
+ dev_set_drvdata(dev, modem);
+
+ irq = irq_of_parse_and_map(np, 0);
+ if (irq < 0) {
+ dev_err(dev, "Invalid nokia_modem_rst_ind interrupt: %d\n", irq);
+ return irq;
+ }
+ modem->nokia_modem_rst_ind_irq = irq;
+ pflags = irq_get_trigger_type(irq);
+
+ tasklet_init(&modem->nokia_modem_rst_ind_tasklet,
+ do_nokia_modem_rst_ind_tasklet, (unsigned long)modem);
+ err = devm_request_irq(dev, irq, nokia_modem_rst_ind_isr,
+ IRQF_DISABLED | pflags, "modem_rst_ind", modem);
+ if (err < 0) {
+ dev_err(dev, "Request modem_rst_ind irq(%d) failed (flags %d)\n",
+ irq, pflags);
+ return err;
+ }
+ enable_irq_wake(irq);
+
+ err = nokia_modem_gpio_probe(dev);
+ if (err < 0) {
+ dev_err(dev, "Could not probe GPIOs\n");
+ goto error1;
+ }
+
+ ssip.name = "ssi-protocol";
+ ssip.tx_cfg = cl->tx_cfg;
+ ssip.rx_cfg = cl->rx_cfg;
+ ssip.platform_data = NULL;
+ ssip.archdata = NULL;
+
+ modem->ssi_protocol = hsi_new_client(port, &ssip);
+ if (modem->ssi_protocol == NULL) {
+ dev_err(dev, "Could not register ssi-protocol device\n");
+ goto error2;
+ }
+
+ err = device_attach(&modem->ssi_protocol->device);
+ if (err == 0) {
+ dev_err(dev, "Missing ssi-protocol driver\n");
+ err = -EPROBE_DEFER;
+ goto error3;
+ } else if (err < 0) {
+ dev_err(dev, "Could not load ssi-protocol driver (%d)\n", err);
+ goto error3;
+ }
+
+ /* TODO: register cmt-speech hsi client */
+
+ dev_info(dev, "Registered Nokia HSI modem\n");
+
+ return 0;
+
+error3:
+ hsi_remove_client(&modem->ssi_protocol->device, NULL);
+error2:
+ nokia_modem_gpio_unexport(dev);
+error1:
+ disable_irq_wake(modem->nokia_modem_rst_ind_irq);
+ tasklet_kill(&modem->nokia_modem_rst_ind_tasklet);
+
+ return err;
+}
+
+static int nokia_modem_remove(struct device *dev)
+{
+ struct nokia_modem_device *modem = dev_get_drvdata(dev);
+
+ if (!modem)
+ return 0;
+
+ if (modem->ssi_protocol) {
+ hsi_remove_client(&modem->ssi_protocol->device, NULL);
+ modem->ssi_protocol = NULL;
+ }
+
+ nokia_modem_gpio_unexport(dev);
+ dev_set_drvdata(dev, NULL);
+ disable_irq_wake(modem->nokia_modem_rst_ind_irq);
+ tasklet_kill(&modem->nokia_modem_rst_ind_tasklet);
+
+ return 0;
+}
+
+#ifdef CONFIG_OF
+static const struct of_device_id nokia_modem_of_match[] = {
+ { .compatible = "nokia,n900-modem", },
+ {},
+};
+MODULE_DEVICE_TABLE(of, nokia_modem_of_match);
+#endif
+
+static struct hsi_client_driver nokia_modem_driver = {
+ .driver = {
+ .name = "nokia-modem",
+ .owner = THIS_MODULE,
+ .probe = nokia_modem_probe,
+ .remove = nokia_modem_remove,
+ .of_match_table = of_match_ptr(nokia_modem_of_match),
+ },
+};
+
+static int __init nokia_modem_init(void)
+{
+ return hsi_register_client_driver(&nokia_modem_driver);
+}
+module_init(nokia_modem_init);
+
+static void __exit nokia_modem_exit(void)
+{
+ hsi_unregister_client_driver(&nokia_modem_driver);
+}
+module_exit(nokia_modem_exit);
+
+MODULE_ALIAS("hsi:nokia-modem");
+MODULE_AUTHOR("Sebastian Reichel <sre@kernel.org>");
+MODULE_DESCRIPTION("HSI driver module for Nokia N900 Modem");
+MODULE_LICENSE("GPL");
--
1.9.0


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