linux/drivers/media/rc/mtk-cir.c

459 lines
12 KiB
C

// SPDX-License-Identifier: GPL-2.0-or-later
/*
* Driver for Mediatek IR Receiver Controller
*
* Copyright (C) 2017 Sean Wang <sean.wang@mediatek.com>
*/
#include <linux/clk.h>
#include <linux/interrupt.h>
#include <linux/module.h>
#include <linux/of_platform.h>
#include <linux/reset.h>
#include <media/rc-core.h>
#define MTK_IR_DEV KBUILD_MODNAME
/* Register to enable PWM and IR */
#define MTK_CONFIG_HIGH_REG 0x0c
/* Bit to enable IR pulse width detection */
#define MTK_PWM_EN BIT(13)
/*
* Register to setting ok count whose unit based on hardware sampling period
* indicating IR receiving completion and then making IRQ fires
*/
#define MTK_OK_COUNT(x) (((x) & GENMASK(23, 16)) << 16)
/* Bit to enable IR hardware function */
#define MTK_IR_EN BIT(0)
/* Bit to restart IR receiving */
#define MTK_IRCLR BIT(0)
/* Fields containing pulse width data */
#define MTK_WIDTH_MASK (GENMASK(7, 0))
/* IR threshold */
#define MTK_IRTHD 0x14
#define MTK_DG_CNT_MASK (GENMASK(12, 8))
#define MTK_DG_CNT(x) ((x) << 8)
/* Bit to enable interrupt */
#define MTK_IRINT_EN BIT(0)
/* Bit to clear interrupt status */
#define MTK_IRINT_CLR BIT(0)
/* Maximum count of samples */
#define MTK_MAX_SAMPLES 0xff
/* Indicate the end of IR message */
#define MTK_IR_END(v, p) ((v) == MTK_MAX_SAMPLES && (p) == 0)
/* Number of registers to record the pulse width */
#define MTK_CHKDATA_SZ 17
/* Sample period in ns */
#define MTK_IR_SAMPLE 46000
enum mtk_fields {
/* Register to setting software sampling period */
MTK_CHK_PERIOD,
/* Register to setting hardware sampling period */
MTK_HW_PERIOD,
};
enum mtk_regs {
/* Register to clear state of state machine */
MTK_IRCLR_REG,
/* Register containing pulse width data */
MTK_CHKDATA_REG,
/* Register to enable IR interrupt */
MTK_IRINT_EN_REG,
/* Register to ack IR interrupt */
MTK_IRINT_CLR_REG
};
static const u32 mt7623_regs[] = {
[MTK_IRCLR_REG] = 0x20,
[MTK_CHKDATA_REG] = 0x88,
[MTK_IRINT_EN_REG] = 0xcc,
[MTK_IRINT_CLR_REG] = 0xd0,
};
static const u32 mt7622_regs[] = {
[MTK_IRCLR_REG] = 0x18,
[MTK_CHKDATA_REG] = 0x30,
[MTK_IRINT_EN_REG] = 0x1c,
[MTK_IRINT_CLR_REG] = 0x20,
};
struct mtk_field_type {
u32 reg;
u8 offset;
u32 mask;
};
/*
* struct mtk_ir_data - This is the structure holding all differences among
various hardwares
* @regs: The pointer to the array holding registers offset
* @fields: The pointer to the array holding fields location
* @div: The internal divisor for the based reference clock
* @ok_count: The count indicating the completion of IR data
* receiving when count is reached
* @hw_period: The value indicating the hardware sampling period
*/
struct mtk_ir_data {
const u32 *regs;
const struct mtk_field_type *fields;
u8 div;
u8 ok_count;
u32 hw_period;
};
static const struct mtk_field_type mt7623_fields[] = {
[MTK_CHK_PERIOD] = {0x10, 8, GENMASK(20, 8)},
[MTK_HW_PERIOD] = {0x10, 0, GENMASK(7, 0)},
};
static const struct mtk_field_type mt7622_fields[] = {
[MTK_CHK_PERIOD] = {0x24, 0, GENMASK(24, 0)},
[MTK_HW_PERIOD] = {0x10, 0, GENMASK(24, 0)},
};
/*
* struct mtk_ir - This is the main datasructure for holding the state
* of the driver
* @dev: The device pointer
* @rc: The rc instrance
* @base: The mapped register i/o base
* @irq: The IRQ that we are using
* @clk: The clock that IR internal is using
* @bus: The clock that software decoder is using
* @data: Holding specific data for vaious platform
*/
struct mtk_ir {
struct device *dev;
struct rc_dev *rc;
void __iomem *base;
int irq;
struct clk *clk;
struct clk *bus;
const struct mtk_ir_data *data;
};
static inline u32 mtk_chkdata_reg(struct mtk_ir *ir, u32 i)
{
return ir->data->regs[MTK_CHKDATA_REG] + 4 * i;
}
static inline u32 mtk_chk_period(struct mtk_ir *ir)
{
u32 val;
/* Period of raw software sampling in ns */
val = DIV_ROUND_CLOSEST(1000000000ul,
clk_get_rate(ir->bus) / ir->data->div);
/*
* Period for software decoder used in the
* unit of raw software sampling
*/
val = DIV_ROUND_CLOSEST(MTK_IR_SAMPLE, val);
dev_dbg(ir->dev, "@pwm clk = \t%lu\n",
clk_get_rate(ir->bus) / ir->data->div);
dev_dbg(ir->dev, "@chkperiod = %08x\n", val);
return val;
}
static void mtk_w32_mask(struct mtk_ir *ir, u32 val, u32 mask, unsigned int reg)
{
u32 tmp;
tmp = __raw_readl(ir->base + reg);
tmp = (tmp & ~mask) | val;
__raw_writel(tmp, ir->base + reg);
}
static void mtk_w32(struct mtk_ir *ir, u32 val, unsigned int reg)
{
__raw_writel(val, ir->base + reg);
}
static u32 mtk_r32(struct mtk_ir *ir, unsigned int reg)
{
return __raw_readl(ir->base + reg);
}
static inline void mtk_irq_disable(struct mtk_ir *ir, u32 mask)
{
u32 val;
val = mtk_r32(ir, ir->data->regs[MTK_IRINT_EN_REG]);
mtk_w32(ir, val & ~mask, ir->data->regs[MTK_IRINT_EN_REG]);
}
static inline void mtk_irq_enable(struct mtk_ir *ir, u32 mask)
{
u32 val;
val = mtk_r32(ir, ir->data->regs[MTK_IRINT_EN_REG]);
mtk_w32(ir, val | mask, ir->data->regs[MTK_IRINT_EN_REG]);
}
static irqreturn_t mtk_ir_irq(int irqno, void *dev_id)
{
struct mtk_ir *ir = dev_id;
u8 wid = 0;
u32 i, j, val;
struct ir_raw_event rawir = {};
/*
* Reset decoder state machine explicitly is required
* because 1) the longest duration for space MTK IR hardware
* could record is not safely long. e.g 12ms if rx resolution
* is 46us by default. There is still the risk to satisfying
* every decoder to reset themselves through long enough
* trailing spaces and 2) the IRQ handler guarantees that
* start of IR message is always contained in and starting
* from register mtk_chkdata_reg(ir, i).
*/
ir_raw_event_reset(ir->rc);
/* First message must be pulse */
rawir.pulse = false;
/* Handle all pulse and space IR controller captures */
for (i = 0 ; i < MTK_CHKDATA_SZ ; i++) {
val = mtk_r32(ir, mtk_chkdata_reg(ir, i));
dev_dbg(ir->dev, "@reg%d=0x%08x\n", i, val);
for (j = 0 ; j < 4 ; j++) {
wid = (val & (MTK_WIDTH_MASK << j * 8)) >> j * 8;
rawir.pulse = !rawir.pulse;
rawir.duration = wid * (MTK_IR_SAMPLE + 1);
ir_raw_event_store_with_filter(ir->rc, &rawir);
}
}
/*
* The maximum number of edges the IR controller can
* hold is MTK_CHKDATA_SZ * 4. So if received IR messages
* is over the limit, the last incomplete IR message would
* be appended trailing space and still would be sent into
* ir-rc-raw to decode. That helps it is possible that it
* has enough information to decode a scancode even if the
* trailing end of the message is missing.
*/
if (!MTK_IR_END(wid, rawir.pulse)) {
rawir.pulse = false;
rawir.duration = MTK_MAX_SAMPLES * (MTK_IR_SAMPLE + 1);
ir_raw_event_store_with_filter(ir->rc, &rawir);
}
ir_raw_event_handle(ir->rc);
/*
* Restart controller for the next receive that would
* clear up all CHKDATA registers
*/
mtk_w32_mask(ir, 0x1, MTK_IRCLR, ir->data->regs[MTK_IRCLR_REG]);
/* Clear interrupt status */
mtk_w32_mask(ir, 0x1, MTK_IRINT_CLR,
ir->data->regs[MTK_IRINT_CLR_REG]);
return IRQ_HANDLED;
}
static const struct mtk_ir_data mt7623_data = {
.regs = mt7623_regs,
.fields = mt7623_fields,
.ok_count = 0xf,
.hw_period = 0xff,
.div = 4,
};
static const struct mtk_ir_data mt7622_data = {
.regs = mt7622_regs,
.fields = mt7622_fields,
.ok_count = 0xf,
.hw_period = 0xffff,
.div = 32,
};
static const struct of_device_id mtk_ir_match[] = {
{ .compatible = "mediatek,mt7623-cir", .data = &mt7623_data},
{ .compatible = "mediatek,mt7622-cir", .data = &mt7622_data},
{},
};
MODULE_DEVICE_TABLE(of, mtk_ir_match);
static int mtk_ir_probe(struct platform_device *pdev)
{
struct device *dev = &pdev->dev;
struct device_node *dn = dev->of_node;
struct resource *res;
struct mtk_ir *ir;
u32 val;
int ret = 0;
const char *map_name;
ir = devm_kzalloc(dev, sizeof(struct mtk_ir), GFP_KERNEL);
if (!ir)
return -ENOMEM;
ir->dev = dev;
ir->data = of_device_get_match_data(dev);
ir->clk = devm_clk_get(dev, "clk");
if (IS_ERR(ir->clk)) {
dev_err(dev, "failed to get a ir clock.\n");
return PTR_ERR(ir->clk);
}
ir->bus = devm_clk_get(dev, "bus");
if (IS_ERR(ir->bus)) {
/*
* For compatibility with older device trees try unnamed
* ir->bus uses the same clock as ir->clock.
*/
ir->bus = ir->clk;
}
res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
ir->base = devm_ioremap_resource(dev, res);
if (IS_ERR(ir->base))
return PTR_ERR(ir->base);
ir->rc = devm_rc_allocate_device(dev, RC_DRIVER_IR_RAW);
if (!ir->rc) {
dev_err(dev, "failed to allocate device\n");
return -ENOMEM;
}
ir->rc->priv = ir;
ir->rc->device_name = MTK_IR_DEV;
ir->rc->input_phys = MTK_IR_DEV "/input0";
ir->rc->input_id.bustype = BUS_HOST;
ir->rc->input_id.vendor = 0x0001;
ir->rc->input_id.product = 0x0001;
ir->rc->input_id.version = 0x0001;
map_name = of_get_property(dn, "linux,rc-map-name", NULL);
ir->rc->map_name = map_name ?: RC_MAP_EMPTY;
ir->rc->dev.parent = dev;
ir->rc->driver_name = MTK_IR_DEV;
ir->rc->allowed_protocols = RC_PROTO_BIT_ALL_IR_DECODER;
ir->rc->rx_resolution = MTK_IR_SAMPLE;
ir->rc->timeout = MTK_MAX_SAMPLES * (MTK_IR_SAMPLE + 1);
ret = devm_rc_register_device(dev, ir->rc);
if (ret) {
dev_err(dev, "failed to register rc device\n");
return ret;
}
platform_set_drvdata(pdev, ir);
ir->irq = platform_get_irq(pdev, 0);
if (ir->irq < 0)
return -ENODEV;
if (clk_prepare_enable(ir->clk)) {
dev_err(dev, "try to enable ir_clk failed\n");
return -EINVAL;
}
if (clk_prepare_enable(ir->bus)) {
dev_err(dev, "try to enable ir_clk failed\n");
ret = -EINVAL;
goto exit_clkdisable_clk;
}
/*
* Enable interrupt after proper hardware
* setup and IRQ handler registration
*/
mtk_irq_disable(ir, MTK_IRINT_EN);
ret = devm_request_irq(dev, ir->irq, mtk_ir_irq, 0, MTK_IR_DEV, ir);
if (ret) {
dev_err(dev, "failed request irq\n");
goto exit_clkdisable_bus;
}
/*
* Setup software sample period as the reference of software decoder
*/
val = (mtk_chk_period(ir) << ir->data->fields[MTK_CHK_PERIOD].offset) &
ir->data->fields[MTK_CHK_PERIOD].mask;
mtk_w32_mask(ir, val, ir->data->fields[MTK_CHK_PERIOD].mask,
ir->data->fields[MTK_CHK_PERIOD].reg);
/*
* Setup hardware sampling period used to setup the proper timeout for
* indicating end of IR receiving completion
*/
val = (ir->data->hw_period << ir->data->fields[MTK_HW_PERIOD].offset) &
ir->data->fields[MTK_HW_PERIOD].mask;
mtk_w32_mask(ir, val, ir->data->fields[MTK_HW_PERIOD].mask,
ir->data->fields[MTK_HW_PERIOD].reg);
/* Set de-glitch counter */
mtk_w32_mask(ir, MTK_DG_CNT(1), MTK_DG_CNT_MASK, MTK_IRTHD);
/* Enable IR and PWM */
val = mtk_r32(ir, MTK_CONFIG_HIGH_REG);
val |= MTK_OK_COUNT(ir->data->ok_count) | MTK_PWM_EN | MTK_IR_EN;
mtk_w32(ir, val, MTK_CONFIG_HIGH_REG);
mtk_irq_enable(ir, MTK_IRINT_EN);
dev_info(dev, "Initialized MT7623 IR driver, sample period = %dus\n",
DIV_ROUND_CLOSEST(MTK_IR_SAMPLE, 1000));
return 0;
exit_clkdisable_bus:
clk_disable_unprepare(ir->bus);
exit_clkdisable_clk:
clk_disable_unprepare(ir->clk);
return ret;
}
static int mtk_ir_remove(struct platform_device *pdev)
{
struct mtk_ir *ir = platform_get_drvdata(pdev);
/*
* Avoid contention between remove handler and
* IRQ handler so that disabling IR interrupt and
* waiting for pending IRQ handler to complete
*/
mtk_irq_disable(ir, MTK_IRINT_EN);
synchronize_irq(ir->irq);
clk_disable_unprepare(ir->bus);
clk_disable_unprepare(ir->clk);
return 0;
}
static struct platform_driver mtk_ir_driver = {
.probe = mtk_ir_probe,
.remove = mtk_ir_remove,
.driver = {
.name = MTK_IR_DEV,
.of_match_table = mtk_ir_match,
},
};
module_platform_driver(mtk_ir_driver);
MODULE_DESCRIPTION("Mediatek IR Receiver Controller Driver");
MODULE_AUTHOR("Sean Wang <sean.wang@mediatek.com>");
MODULE_LICENSE("GPL");