Re: [PATCH v5] media: st-rc: Add ST remote control driver

[Prabhakar Lad]

Hi Srinivas,

Thanks for the patch. Several nits below.

On Fri, Sep 27, 2013 at 2:32 PM, Srinivas KANDAGATLA
<srinivas.kandagatla@xxxxxx> wrote:
> From: Srinivas Kandagatla <srinivas.kandagatla@xxxxxx>
>
> This patch adds support to ST RC driver, which is basically a IR/UHF
> receiver and transmitter. This IP (IRB) is common across all the ST
> parts for settop box platforms. IRB is embedded in ST COMMS IP block.
> It supports both Rx & Tx functionality.
>
> This driver adds only Rx functionality via LIRC codec.
>
> Signed-off-by: Srinivas Kandagatla <srinivas.kandagatla@xxxxxx>
> Acked-by: Sean Young <sean@xxxxxxxx>
> ---
> Hi Chehab,
>
> This is a very simple rc driver for IRB controller found in STi SOCs.
> This driver is a raw driver which feeds data to lirc codec for the user lircd
> to decode the keys.
>
> This patch is based on v3.12-rc1.
>
> Changes since v4:
>         - updated dt bindings doc with suggestions from Stephen W.
>
> Changes since v3:
>         - updated dt bindings doc with suggestions from Mark R.
>
> Changes since v2:
>         - Updated Kconfig dependencies as suggested by Sean and Chehab.
>         - Fixed a logical check spoted by Sean.
>
> Changes since v1:
>         - Device tree bindings cleaned up as suggested by Mark and Pawel
>         - use ir_raw_event_reset under overflow conditions as suggested by Sean.
>         - call ir_raw_event_handle in interrupt handler as suggested by Sean.
>         - correct allowed_protos flag with RC_BIT_ types as suggested by Sean.
>         - timeout and rx resolution added as suggested by Sean.
>
> Thankyou all for reviewing and commenting.
>
> Thanks,
> srini
>  Documentation/devicetree/bindings/media/st-rc.txt |   27 ++
>  drivers/media/rc/Kconfig                          |   10 +
>  drivers/media/rc/Makefile                         |    1 +
>  drivers/media/rc/st_rc.c                          |  396 +++++++++++++++++++++
>  4 files changed, 434 insertions(+), 0 deletions(-)
>  create mode 100644 Documentation/devicetree/bindings/media/st-rc.txt
>  create mode 100644 drivers/media/rc/st_rc.c
>
> diff --git a/Documentation/devicetree/bindings/media/st-rc.txt b/Documentation/devicetree/bindings/media/st-rc.txt
> new file mode 100644
> index 0000000..797ef39
> --- /dev/null
> +++ b/Documentation/devicetree/bindings/media/st-rc.txt
> @@ -0,0 +1,27 @@
> +Device-Tree bindings for ST IRB IP
> +
> +Required properties:
> +       - compatible: Should contain "st,comms-irb".
> +       - reg: Base physical address of the controller and length of memory
> +         mapped region.
> +       - interrupts: interrupt-specifier for the sole interrupt generated by
> +         the device. The interrupt specifier format depends on the interrupt
> +         controller parent.
> +       - rx-mode: can be "infrared" or "uhf". rx-mode should be present iff
> +         the rx pins are wired up.
> +       - tx-mode: should be "infrared". tx-mode should be present iff the tx
> +         pins are wired up.
> +
> +Optional properties:
> +       - pinctrl-names, pinctrl-0: the pincontrol settings to configure muxing
> +         properly for IRB pins.
> +       - clocks : phandle with clock-specifier pair for IRB block.
> +
> +Example node:
> +
> +       rc: rc@fe518000 {
> +               compatible      = "st,comms-irb";
> +               reg             = <0xfe518000 0x234>;
> +               interrupts      = <0 203 0>;
> +               rx-mode         = "infrared";
> +       };
> diff --git a/drivers/media/rc/Kconfig b/drivers/media/rc/Kconfig
> index 11e84bc..557afc5 100644
> --- a/drivers/media/rc/Kconfig
> +++ b/drivers/media/rc/Kconfig
> @@ -322,4 +322,14 @@ config IR_GPIO_CIR
>            To compile this driver as a module, choose M here: the module will
>            be called gpio-ir-recv.
>
> +config RC_ST
> +       tristate "ST remote control receiver"
> +       depends on ARCH_STI && RC_CORE
> +       help
> +        Say Y here if you want support for ST remote control driver
> +        which allows both IR and UHF RX.
> +        The driver passes raw pluse and space information to the LIRC decoder.
> +
s/pluse/pulse

> +        If you're not sure, select N here.
> +
>  endif #RC_DEVICES
> diff --git a/drivers/media/rc/Makefile b/drivers/media/rc/Makefile
> index 56bacf0..f4eb32c 100644
> --- a/drivers/media/rc/Makefile
> +++ b/drivers/media/rc/Makefile
> @@ -30,3 +30,4 @@ obj-$(CONFIG_RC_LOOPBACK) += rc-loopback.o
>  obj-$(CONFIG_IR_GPIO_CIR) += gpio-ir-recv.o
>  obj-$(CONFIG_IR_IGUANA) += iguanair.o
>  obj-$(CONFIG_IR_TTUSBIR) += ttusbir.o
> +obj-$(CONFIG_RC_ST) += st_rc.o
> diff --git a/drivers/media/rc/st_rc.c b/drivers/media/rc/st_rc.c
> new file mode 100644
> index 0000000..e2dad9c
> --- /dev/null
> +++ b/drivers/media/rc/st_rc.c
> @@ -0,0 +1,396 @@
> +/*
> + * Copyright (C) 2013 STMicroelectronics Limited
> + * Author: Srinivas Kandagatla <srinivas.kandagatla@xxxxxx>
> + *
> + * This program is free software; you can redistribute it and/or modify
> + * it under the terms of the GNU General Public License as published by
> + * the Free Software Foundation; either version 2 of the License, or
> + * (at your option) any later version.
> + */
> +#include <linux/kernel.h>
> +#include <linux/clk.h>
> +#include <linux/interrupt.h>
> +#include <linux/module.h>
> +#include <linux/of.h>
> +#include <linux/platform_device.h>
> +#include <media/rc-core.h>
> +#include <linux/pinctrl/consumer.h>
> +
> +struct st_rc_device {
> +       struct device                   *dev;
> +       int                             irq;
> +       int                             irq_wake;
> +       struct clk                      *sys_clock;
> +       void                            *base;  /* Register base address */
> +       void                            *rx_base;/* RX Register base address */
> +       struct rc_dev                   *rdev;
> +       bool                            overclocking;
> +       int                             sample_mult;
> +       int                             sample_div;
> +       bool                            rxuhfmode;
> +};
> +
> +/* Registers */
> +#define IRB_SAMPLE_RATE_COMM   0x64    /* sample freq divisor*/
> +#define IRB_CLOCK_SEL          0x70    /* clock select       */
> +#define IRB_CLOCK_SEL_STATUS   0x74    /* clock status       */
> +/* IRB IR/UHF receiver registers */
> +#define IRB_RX_ON               0x40   /* pulse time capture */
> +#define IRB_RX_SYS              0X44   /* sym period capture */
> +#define IRB_RX_INT_EN           0x48   /* IRQ enable (R/W)   */
> +#define IRB_RX_INT_STATUS       0x4C   /* IRQ status (R/W)   */
> +#define IRB_RX_EN               0x50   /* Receive enablei    */
s/enablei/enable

> +#define IRB_MAX_SYM_PERIOD      0x54   /* max sym value      */
> +#define IRB_RX_INT_CLEAR        0x58   /* overrun status     */
> +#define IRB_RX_STATUS           0x6C   /* receive status     */
> +#define IRB_RX_NOISE_SUPPR      0x5C   /* noise suppression  */
> +#define IRB_RX_POLARITY_INV     0x68   /* polarity inverter  */
> +
generally smaller case hex letters are preferred

> +/**
> + * IRQ set: Enable full FIFO                 1  -> bit  3;
> + *          Enable overrun IRQ               1  -> bit  2;
> + *          Enable last symbol IRQ           1  -> bit  1:
> + *          Enable RX interrupt              1  -> bit  0;
> + */
> +#define IRB_RX_INTS            0x0f
> +#define IRB_RX_OVERRUN_INT     0x04
> + /* maximum symbol period (microsecs),timeout to detect end of symbol train */
> +#define MAX_SYMB_TIME          0x5000
> +#define IRB_SAMPLE_FREQ                10000000
> +#define        IRB_FIFO_NOT_EMPTY      0xff00
> +#define IRB_OVERFLOW           0x4
> +#define IRB_TIMEOUT            0xffff
> +#define IR_ST_NAME "st-rc"
> +
> +static void st_rc_send_lirc_timeout(struct rc_dev *rdev)
> +{
> +       DEFINE_IR_RAW_EVENT(ev);
> +       ev.timeout = true;
> +       ir_raw_event_store(rdev, &ev);
> +}
> +
> +/**
> + * RX graphical example to better understand the difference between ST IR block
> + * output and standard definition used by LIRC (and most of the world!)
> + *
> + *           mark                                     mark
> + *      |-IRB_RX_ON-|                            |-IRB_RX_ON-|
> + *      ___  ___  ___                            ___  ___  ___             _
> + *      | |  | |  | |                            | |  | |  | |             |
> + *      | |  | |  | |         space 0            | |  | |  | |   space 1   |
> + * _____| |__| |__| |____________________________| |__| |__| |_____________|
> + *
> + *      |--------------- IRB_RX_SYS -------------|------ IRB_RX_SYS -------|
> + *
> + *      |------------- encoding bit 0 -----------|---- encoding bit 1 -----|
> + *
> + * ST hardware returns mark (IRB_RX_ON) and total symbol time (IRB_RX_SYS), so
> + * convert to standard mark/space we have to calculate space=(IRB_RX_SYS-mark)
> + * The mark time represents the amount of time the carrier (usually 36-40kHz)
> + * is detected.The above examples shows Pulse Width Modulation encoding where
> + * bit 0 is represented by space>mark.
> + */
> +
> +static irqreturn_t st_rc_rx_interrupt(int irq, void *data)
> +{
> +       unsigned int symbol, mark = 0;
> +       struct st_rc_device *dev = data;
> +       int last_symbol = 0;
> +       u32 status;
> +       DEFINE_IR_RAW_EVENT(ev);
> +
> +       if (dev->irq_wake)
> +               pm_wakeup_event(dev->dev, 0);
> +
> +       status  = readl(dev->rx_base + IRB_RX_STATUS);
> +
> +       while (status & (IRB_FIFO_NOT_EMPTY | IRB_OVERFLOW)) {
> +               u32 int_status = readl(dev->rx_base + IRB_RX_INT_STATUS);
> +               if (unlikely(int_status & IRB_RX_OVERRUN_INT)) {
> +                       /* discard the entire collection in case of errors!  */
> +                       ir_raw_event_reset(dev->rdev);
> +                       dev_info(dev->dev, "IR RX overrun\n");
> +                       writel(IRB_RX_OVERRUN_INT,
> +                                       dev->rx_base + IRB_RX_INT_CLEAR);
> +                       continue;
> +               }
> +
> +               symbol = readl(dev->rx_base + IRB_RX_SYS);
> +               mark = readl(dev->rx_base + IRB_RX_ON);
> +
> +               if (symbol == IRB_TIMEOUT)
> +                       last_symbol = 1;
> +
> +                /* Ignore any noise */
> +               if ((mark > 2) && (symbol > 1)) {
> +                       symbol -= mark;
> +                       if (dev->overclocking) { /* adjustments to timings */
> +                               symbol *= dev->sample_mult;
> +                               symbol /= dev->sample_div;
> +                               mark *= dev->sample_mult;
> +                               mark /= dev->sample_div;
> +                       }
> +
> +                       ev.duration = US_TO_NS(mark);
> +                       ev.pulse = true;
> +                       ir_raw_event_store(dev->rdev, &ev);
> +
> +                       if (!last_symbol) {
> +                               ev.duration = US_TO_NS(symbol);
> +                               ev.pulse = false;
> +                               ir_raw_event_store(dev->rdev, &ev);
> +                       } else  {
> +                               st_rc_send_lirc_timeout(dev->rdev);
> +                       }
> +
> +               }
> +               last_symbol = 0;
> +               status  = readl(dev->rx_base + IRB_RX_STATUS);
> +       }
> +
> +       writel(IRB_RX_INTS, dev->rx_base + IRB_RX_INT_CLEAR);
> +
> +       /* Empty software fifo */
> +       ir_raw_event_handle(dev->rdev);
> +       return IRQ_HANDLED;
> +}
> +
> +static void st_rc_hardware_init(struct st_rc_device *dev)
> +{
> +       int baseclock, freqdiff;
> +       unsigned int rx_max_symbol_per = MAX_SYMB_TIME;
> +       unsigned int rx_sampling_freq_div;
> +
> +       clk_prepare_enable(dev->sys_clock);
> +       baseclock = clk_get_rate(dev->sys_clock);
> +
> +       /* IRB input pins are inverted internally from high to low. */
> +       writel(1, dev->rx_base + IRB_RX_POLARITY_INV);
> +
> +       rx_sampling_freq_div = baseclock / IRB_SAMPLE_FREQ;
> +       writel(rx_sampling_freq_div, dev->base + IRB_SAMPLE_RATE_COMM);
> +
> +       freqdiff = baseclock - (rx_sampling_freq_div * IRB_SAMPLE_FREQ);
> +       if (freqdiff) { /* over clocking, workout the adjustment factors */
> +               dev->overclocking = true;
> +               dev->sample_mult = 1000;
> +               dev->sample_div = baseclock / (10000 * rx_sampling_freq_div);
> +               rx_max_symbol_per = (rx_max_symbol_per * 1000)/dev->sample_div;
> +       }
> +
> +       writel(rx_max_symbol_per, dev->rx_base + IRB_MAX_SYM_PERIOD);
> +}
> +
> +static int st_rc_remove(struct platform_device *pdev)
> +{
> +       struct st_rc_device *rc_dev = platform_get_drvdata(pdev);
> +       clk_disable_unprepare(rc_dev->sys_clock);
> +       rc_unregister_device(rc_dev->rdev);
> +       return 0;
> +}
> +
> +static int st_rc_open(struct rc_dev *rdev)
> +{
> +       struct st_rc_device *dev = rdev->priv;
> +       unsigned long flags;
> +       local_irq_save(flags);
> +       /* enable interrupts and receiver */
> +       writel(IRB_RX_INTS, dev->rx_base + IRB_RX_INT_EN);
> +       writel(0x01, dev->rx_base + IRB_RX_EN);
> +       local_irq_restore(flags);
> +
> +       return 0;
> +}
> +
> +static void st_rc_close(struct rc_dev *rdev)
> +{
> +       struct st_rc_device *dev = rdev->priv;
> +       /* disable interrupts and receiver */
> +       writel(0x00, dev->rx_base + IRB_RX_EN);
> +       writel(0x00, dev->rx_base + IRB_RX_INT_EN);
> +}
> +
> +static int st_rc_probe(struct platform_device *pdev)
> +{
> +       int ret = -EINVAL;
> +       struct rc_dev *rdev;
> +       struct device *dev = &pdev->dev;
> +       struct resource *res;
> +       struct st_rc_device *rc_dev;
> +       struct device_node *np = pdev->dev.of_node;
> +       const char *rx_mode;
> +
> +       rc_dev = devm_kzalloc(dev, sizeof(struct st_rc_device), GFP_KERNEL);
> +
> +       if (!rc_dev)
> +               return -ENOMEM;
> +
> +       rdev = rc_allocate_device();
> +
> +       if (!rdev)
> +               return -ENOMEM;
> +
> +       if (np && !of_property_read_string(np, "rx-mode", &rx_mode)) {
> +
> +               if (!strcmp(rx_mode, "uhf")) {
> +                       rc_dev->rxuhfmode = true;
> +               } else if (!strcmp(rx_mode, "infrared")) {
> +                       rc_dev->rxuhfmode = false;
> +               } else {
> +                       dev_err(dev, "Unsupported rx mode [%s]\n", rx_mode);
> +                       goto err;
> +               }
> +
> +       } else {
> +               goto err;
> +       }
> +
> +       rc_dev->sys_clock = devm_clk_get(dev, NULL);
> +       if (IS_ERR(rc_dev->sys_clock)) {
> +               dev_err(dev, "System clock not found\n");
> +               ret = PTR_ERR(rc_dev->sys_clock);
> +               goto err;
> +       }
> +
> +       rc_dev->irq = platform_get_irq(pdev, 0);
> +       if (rc_dev->irq < 0) {
> +               ret = rc_dev->irq;
> +               goto clkerr;
> +       }
> +
> +       ret = -ENODEV;
Not required

> +       res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
> +       if (!res)
> +               goto clkerr;
> +
This check is not required.

> +       rc_dev->base = devm_ioremap_resource(dev, res);
> +       if (IS_ERR(rc_dev->base))
> +               goto clkerr;
> +
In case of error assin ret to PTR_ERR(rc_dev->base)

> +       if (rc_dev->rxuhfmode)
> +               rc_dev->rx_base = rc_dev->base + 0x40;
> +       else
> +               rc_dev->rx_base = rc_dev->base;
> +
> +       rc_dev->dev = dev;
> +       platform_set_drvdata(pdev, rc_dev);
> +       st_rc_hardware_init(rc_dev);
> +
> +       rdev->driver_type = RC_DRIVER_IR_RAW;
> +       rdev->allowed_protos = RC_BIT_ALL;
> +       /* rx sampling rate is 10Mhz */
> +       rdev->rx_resolution = 100;
> +       rdev->timeout = US_TO_NS(MAX_SYMB_TIME);
> +       rdev->priv = rc_dev;
> +       rdev->open = st_rc_open;
> +       rdev->close = st_rc_close;
> +       rdev->driver_name = IR_ST_NAME;
> +       rdev->map_name = RC_MAP_LIRC;
> +       rdev->input_name = "ST Remote Control Receiver";
> +
> +       /* enable wake via this device */
> +       device_set_wakeup_capable(dev, true);
> +       device_set_wakeup_enable(dev, true);
> +
> +       ret = rc_register_device(rdev);
> +       if (ret < 0)
> +               goto clkerr;
> +
> +       rc_dev->rdev = rdev;
> +       if (devm_request_irq(dev, rc_dev->irq, st_rc_rx_interrupt,
> +                       IRQF_NO_SUSPEND, IR_ST_NAME, rc_dev) < 0) {
> +               dev_err(dev, "IRQ %d register failed\n", rc_dev->irq);
> +               ret = -EINVAL;
> +               goto rcerr;
> +       }
> +
> +       /**
> +        * for LIRC_MODE_MODE2 or LIRC_MODE_PULSE or LIRC_MODE_RAW
> +        * lircd expects a long space first before a signal train to sync.
> +        */
> +       st_rc_send_lirc_timeout(rdev);
> +
> +       dev_info(dev, "setup in %s mode\n", rc_dev->rxuhfmode ? "UHF" : "IR");
> +
> +       return ret;
> +rcerr:
> +       rc_unregister_device(rdev);
> +       rdev = NULL;
> +clkerr:
> +       clk_disable_unprepare(rc_dev->sys_clock);
> +err:
> +       rc_free_device(rdev);
> +       dev_err(dev, "Unable to register device (%d)\n", ret);
> +       return ret;
> +}
> +
> +#ifdef CONFIG_PM
> +static int st_rc_suspend(struct device *dev)
> +{
> +       struct st_rc_device *rc_dev = dev_get_drvdata(dev);
> +
> +       if (device_may_wakeup(dev)) {
> +               if (!enable_irq_wake(rc_dev->irq))
> +                       rc_dev->irq_wake = 1;
> +               else
> +                       return -EINVAL;
> +       } else {
> +               pinctrl_pm_select_sleep_state(dev);
> +               writel(0x00, rc_dev->rx_base + IRB_RX_EN);
> +               writel(0x00, rc_dev->rx_base + IRB_RX_INT_EN);
> +               clk_disable_unprepare(rc_dev->sys_clock);
> +       }
> +
> +       return 0;
> +}
> +
> +static int st_rc_resume(struct device *dev)
> +{
> +       struct st_rc_device *rc_dev = dev_get_drvdata(dev);
> +       struct rc_dev   *rdev = rc_dev->rdev;
> +
> +       if (rc_dev->irq_wake) {
> +               disable_irq_wake(rc_dev->irq);
> +               rc_dev->irq_wake = 0;
> +       } else {
> +               pinctrl_pm_select_default_state(dev);
> +               st_rc_hardware_init(rc_dev);
> +               if (rdev->users) {
> +                       writel(IRB_RX_INTS, rc_dev->rx_base + IRB_RX_INT_EN);
> +                       writel(0x01, rc_dev->rx_base + IRB_RX_EN);
> +               }
> +       }
> +
> +       return 0;
> +}
> +
> +static SIMPLE_DEV_PM_OPS(st_rc_pm_ops, st_rc_suspend, st_rc_resume);
> +#endif
> +
> +#ifdef CONFIG_OF
> +static struct of_device_id st_rc_match[] = {
> +       { .compatible = "st,comms-irb", },
> +       {},
> +};
> +
> +MODULE_DEVICE_TABLE(of, st_rc_match);
> +#endif
> +
> +static struct platform_driver st_rc_driver = {
> +       .driver = {
> +               .name = IR_ST_NAME,
> +               .owner  = THIS_MODULE,
> +               .of_match_table = of_match_ptr(st_rc_match),
> +#ifdef CONFIG_PM
> +               .pm     = &st_rc_pm_ops,
> +#endif
> +       },
> +       .probe = st_rc_probe,
> +       .remove = st_rc_remove,
> +};
> +
> +module_platform_driver(st_rc_driver);
> +
> +MODULE_DESCRIPTION("RC Transceiver driver for STMicroelectronics platforms");
> +MODULE_AUTHOR("STMicroelectronics (R&D) Ltd");
> +MODULE_LICENSE("GPL");
> --

Regards,
--Prabhakar Lad
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