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serial: stm32: add wakeup mechanism
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Add support for wake-up from low power modes. This extends stm32f7.
Introduce new compatible for stm32h7 to manage wake-up capability.

Signed-off-by: Fabrice Gasnier <fabrice.gasnier@st.com>
Signed-off-by: Bich Hemon <bich.hemon@st.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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Fabrice Gasnier authored and Greg Kroah-Hartman committed Jul 30, 2017
1 parent 20e4cfc commit 270e5a7
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Showing 2 changed files with 118 additions and 1 deletion.
90 changes: 89 additions & 1 deletion drivers/tty/serial/stm32-usart.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -26,6 +26,7 @@
#include <linux/of_platform.h>
#include <linux/platform_device.h>
#include <linux/pm_runtime.h>
#include <linux/pm_wakeirq.h>
#include <linux/serial_core.h>
#include <linux/serial.h>
#include <linux/spinlock.h>
Expand Down Expand Up @@ -326,6 +327,10 @@ static irqreturn_t stm32_interrupt(int irq, void *ptr)

sr = readl_relaxed(port->membase + ofs->isr);

if ((sr & USART_SR_WUF) && (ofs->icr != UNDEF_REG))
writel_relaxed(USART_ICR_WUCF,
port->membase + ofs->icr);

if ((sr & USART_SR_RXNE) && !(stm32_port->rx_ch))
stm32_receive_chars(port, false);

Expand Down Expand Up @@ -442,6 +447,7 @@ static int stm32_startup(struct uart_port *port)
{
struct stm32_port *stm32_port = to_stm32_port(port);
struct stm32_usart_offsets *ofs = &stm32_port->info->ofs;
struct stm32_usart_config *cfg = &stm32_port->info->cfg;
const char *name = to_platform_device(port->dev)->name;
u32 val;
int ret;
Expand All @@ -452,6 +458,15 @@ static int stm32_startup(struct uart_port *port)
if (ret)
return ret;

if (cfg->has_wakeup && stm32_port->wakeirq >= 0) {
ret = dev_pm_set_dedicated_wake_irq(port->dev,
stm32_port->wakeirq);
if (ret) {
free_irq(port->irq, port);
return ret;
}
}

val = USART_CR1_RXNEIE | USART_CR1_TE | USART_CR1_RE;
stm32_set_bits(port, ofs->cr1, val);

Expand All @@ -469,6 +484,7 @@ static void stm32_shutdown(struct uart_port *port)
val |= BIT(cfg->uart_enable_bit);
stm32_clr_bits(port, ofs->cr1, val);

dev_pm_clear_wake_irq(port->dev);
free_irq(port->irq, port);
}

Expand Down Expand Up @@ -659,6 +675,7 @@ static int stm32_init_port(struct stm32_port *stm32port,
port->ops = &stm32_uart_ops;
port->dev = &pdev->dev;
port->irq = platform_get_irq(pdev, 0);
stm32port->wakeirq = platform_get_irq(pdev, 1);

res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
port->membase = devm_ioremap_resource(&pdev->dev, res);
Expand Down Expand Up @@ -716,6 +733,8 @@ static const struct of_device_id stm32_match[] = {
{ .compatible = "st,stm32-uart", .data = &stm32f4_info},
{ .compatible = "st,stm32f7-usart", .data = &stm32f7_info},
{ .compatible = "st,stm32f7-uart", .data = &stm32f7_info},
{ .compatible = "st,stm32h7-usart", .data = &stm32h7_info},
{ .compatible = "st,stm32h7-uart", .data = &stm32h7_info},
{},
};

Expand Down Expand Up @@ -865,9 +884,15 @@ static int stm32_serial_probe(struct platform_device *pdev)
if (ret)
return ret;

if (stm32port->info->cfg.has_wakeup && stm32port->wakeirq >= 0) {
ret = device_init_wakeup(&pdev->dev, true);
if (ret)
goto err_uninit;
}

ret = uart_add_one_port(&stm32_usart_driver, &stm32port->port);
if (ret)
goto err_uninit;
goto err_nowup;

ret = stm32_of_dma_rx_probe(stm32port, pdev);
if (ret)
Expand All @@ -881,6 +906,10 @@ static int stm32_serial_probe(struct platform_device *pdev)

return 0;

err_nowup:
if (stm32port->info->cfg.has_wakeup && stm32port->wakeirq >= 0)
device_init_wakeup(&pdev->dev, false);

err_uninit:
clk_disable_unprepare(stm32port->clk);

Expand All @@ -892,6 +921,7 @@ static int stm32_serial_remove(struct platform_device *pdev)
struct uart_port *port = platform_get_drvdata(pdev);
struct stm32_port *stm32_port = to_stm32_port(port);
struct stm32_usart_offsets *ofs = &stm32_port->info->ofs;
struct stm32_usart_config *cfg = &stm32_port->info->cfg;

stm32_clr_bits(port, ofs->cr3, USART_CR3_DMAR);

Expand All @@ -913,6 +943,9 @@ static int stm32_serial_remove(struct platform_device *pdev)
TX_BUF_L, stm32_port->tx_buf,
stm32_port->tx_dma_buf);

if (cfg->has_wakeup && stm32_port->wakeirq >= 0)
device_init_wakeup(&pdev->dev, false);

clk_disable_unprepare(stm32_port->clk);

return uart_remove_one_port(&stm32_usart_driver, port);
Expand Down Expand Up @@ -1018,11 +1051,66 @@ static struct uart_driver stm32_usart_driver = {
.cons = STM32_SERIAL_CONSOLE,
};

#ifdef CONFIG_PM_SLEEP
static void stm32_serial_enable_wakeup(struct uart_port *port, bool enable)
{
struct stm32_port *stm32_port = to_stm32_port(port);
struct stm32_usart_offsets *ofs = &stm32_port->info->ofs;
struct stm32_usart_config *cfg = &stm32_port->info->cfg;
u32 val;

if (!cfg->has_wakeup || stm32_port->wakeirq < 0)
return;

if (enable) {
stm32_clr_bits(port, ofs->cr1, BIT(cfg->uart_enable_bit));
stm32_set_bits(port, ofs->cr1, USART_CR1_UESM);
val = readl_relaxed(port->membase + ofs->cr3);
val &= ~USART_CR3_WUS_MASK;
/* Enable Wake up interrupt from low power on start bit */
val |= USART_CR3_WUS_START_BIT | USART_CR3_WUFIE;
writel_relaxed(val, port->membase + ofs->cr3);
stm32_set_bits(port, ofs->cr1, BIT(cfg->uart_enable_bit));
} else {
stm32_clr_bits(port, ofs->cr1, USART_CR1_UESM);
}
}

static int stm32_serial_suspend(struct device *dev)
{
struct uart_port *port = dev_get_drvdata(dev);

uart_suspend_port(&stm32_usart_driver, port);

if (device_may_wakeup(dev))
stm32_serial_enable_wakeup(port, true);
else
stm32_serial_enable_wakeup(port, false);

return 0;
}

static int stm32_serial_resume(struct device *dev)
{
struct uart_port *port = dev_get_drvdata(dev);

if (device_may_wakeup(dev))
stm32_serial_enable_wakeup(port, false);

return uart_resume_port(&stm32_usart_driver, port);
}
#endif /* CONFIG_PM_SLEEP */

static const struct dev_pm_ops stm32_serial_pm_ops = {
SET_SYSTEM_SLEEP_PM_OPS(stm32_serial_suspend, stm32_serial_resume)
};

static struct platform_driver stm32_serial_driver = {
.probe = stm32_serial_probe,
.remove = stm32_serial_remove,
.driver = {
.name = DRIVER_NAME,
.pm = &stm32_serial_pm_ops,
.of_match_table = of_match_ptr(stm32_match),
},
};
Expand Down
29 changes: 29 additions & 0 deletions drivers/tty/serial/stm32-usart.h
View file
Original file line number Diff line number Diff line change
Expand Up @@ -25,6 +25,7 @@ struct stm32_usart_offsets {
struct stm32_usart_config {
u8 uart_enable_bit; /* USART_CR1_UE */
bool has_7bits_data;
bool has_wakeup;
};

struct stm32_usart_info {
Expand Down Expand Up @@ -75,6 +76,27 @@ struct stm32_usart_info stm32f7_info = {
}
};

struct stm32_usart_info stm32h7_info = {
.ofs = {
.cr1 = 0x00,
.cr2 = 0x04,
.cr3 = 0x08,
.brr = 0x0c,
.gtpr = 0x10,
.rtor = 0x14,
.rqr = 0x18,
.isr = 0x1c,
.icr = 0x20,
.rdr = 0x24,
.tdr = 0x28,
},
.cfg = {
.uart_enable_bit = 0,
.has_7bits_data = true,
.has_wakeup = true,
}
};

/* USART_SR (F4) / USART_ISR (F7) */
#define USART_SR_PE BIT(0)
#define USART_SR_FE BIT(1)
Expand All @@ -94,6 +116,7 @@ struct stm32_usart_info stm32f7_info = {
#define USART_SR_BUSY BIT(16) /* F7 */
#define USART_SR_CMF BIT(17) /* F7 */
#define USART_SR_SBKF BIT(18) /* F7 */
#define USART_SR_WUF BIT(20) /* H7 */
#define USART_SR_TEACK BIT(21) /* F7 */
#define USART_SR_ERR_MASK (USART_SR_LBD | USART_SR_ORE | \
USART_SR_FE | USART_SR_PE)
Expand All @@ -114,6 +137,7 @@ struct stm32_usart_info stm32f7_info = {
/* USART_CR1 */
#define USART_CR1_SBK BIT(0)
#define USART_CR1_RWU BIT(1) /* F4 */
#define USART_CR1_UESM BIT(1) /* H7 */
#define USART_CR1_RE BIT(2)
#define USART_CR1_TE BIT(3)
#define USART_CR1_IDLEIE BIT(4)
Expand Down Expand Up @@ -176,6 +200,9 @@ struct stm32_usart_info stm32f7_info = {
#define USART_CR3_DEM BIT(14) /* F7 */
#define USART_CR3_DEP BIT(15) /* F7 */
#define USART_CR3_SCARCNT_MASK GENMASK(19, 17) /* F7 */
#define USART_CR3_WUS_MASK GENMASK(21, 20) /* H7 */
#define USART_CR3_WUS_START_BIT BIT(21) /* H7 */
#define USART_CR3_WUFIE BIT(22) /* H7 */

/* USART_GTPR */
#define USART_GTPR_PSC_MASK GENMASK(7, 0)
Expand Down Expand Up @@ -204,6 +231,7 @@ struct stm32_usart_info stm32f7_info = {
#define USART_ICR_RTOCF BIT(11) /* F7 */
#define USART_ICR_EOBCF BIT(12) /* F7 */
#define USART_ICR_CMCF BIT(17) /* F7 */
#define USART_ICR_WUCF BIT(20) /* H7 */

#define STM32_SERIAL_NAME "ttyS"
#define STM32_MAX_PORTS 8
Expand All @@ -225,6 +253,7 @@ struct stm32_port {
int last_res;
bool tx_dma_busy; /* dma tx busy */
bool hw_flow_control;
int wakeirq;
};

static struct stm32_port stm32_ports[STM32_MAX_PORTS];
Expand Down

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