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Subject[PATCH 3/5] serial: sprd: Add power management for the Spreadtrum serial controller
Date
From: Lanqing Liu <lanqing.liu@unisoc.com>

This patch adds power management for the Spreadtrum serial controller.

Signed-off-by: Lanqing Liu <lanqing.liu@unisoc.com>
Signed-off-by: Baolin Wang <baolin.wang@linaro.org>
---
drivers/tty/serial/sprd_serial.c | 61 +++++++++++++++++++++++++++++++++++---
1 file changed, 57 insertions(+), 4 deletions(-)

diff --git a/drivers/tty/serial/sprd_serial.c b/drivers/tty/serial/sprd_serial.c
index 1891a45..8f45b66 100644
--- a/drivers/tty/serial/sprd_serial.c
+++ b/drivers/tty/serial/sprd_serial.c
@@ -100,10 +100,12 @@
#define SPRD_IMSR_TX_FIFO_EMPTY BIT(1)
#define SPRD_IMSR_BREAK_DETECT BIT(7)
#define SPRD_IMSR_TIMEOUT BIT(13)
+#define SPRD_DEFAULT_SOURCE_CLK 26000000

struct sprd_uart_port {
struct uart_port port;
char name[16];
+ struct clk *clk;
};

static struct sprd_uart_port *sprd_port[UART_NR_MAX];
@@ -491,6 +493,22 @@ static int sprd_verify_port(struct uart_port *port, struct serial_struct *ser)
return 0;
}

+static void sprd_pm(struct uart_port *port, unsigned int state,
+ unsigned int oldstate)
+{
+ struct sprd_uart_port *sup =
+ container_of(port, struct sprd_uart_port, port);
+
+ switch (state) {
+ case UART_PM_STATE_ON:
+ clk_prepare_enable(sup->clk);
+ break;
+ case UART_PM_STATE_OFF:
+ clk_disable_unprepare(sup->clk);
+ break;
+ }
+}
+
static const struct uart_ops serial_sprd_ops = {
.tx_empty = sprd_tx_empty,
.get_mctrl = sprd_get_mctrl,
@@ -507,6 +525,7 @@ static int sprd_verify_port(struct uart_port *port, struct serial_struct *ser)
.request_port = sprd_request_port,
.config_port = sprd_config_port,
.verify_port = sprd_verify_port,
+ .pm = sprd_pm,
};

#ifdef CONFIG_SERIAL_SPRD_CONSOLE
@@ -671,11 +690,45 @@ static int sprd_remove(struct platform_device *dev)
return 0;
}

+static int sprd_clk_init(struct uart_port *uport)
+{
+ struct clk *clk_uart, *clk_parent;
+ struct sprd_uart_port *u = sprd_port[uport->line];
+
+ clk_uart = devm_clk_get(uport->dev, "uart");
+ if (IS_ERR(clk_uart)) {
+ dev_warn(uport->dev, "uart%d can't get uart clock\n",
+ uport->line);
+ clk_uart = NULL;
+ }
+
+ clk_parent = devm_clk_get(uport->dev, "source");
+ if (IS_ERR(clk_parent)) {
+ dev_warn(uport->dev, "uart%d can't get source clock\n",
+ uport->line);
+ clk_parent = NULL;
+ }
+
+ if (!clk_uart || clk_set_parent(clk_uart, clk_parent))
+ uport->uartclk = SPRD_DEFAULT_SOURCE_CLK;
+ else
+ uport->uartclk = clk_get_rate(clk_uart);
+
+ u->clk = devm_clk_get(uport->dev, "enable");
+ if (IS_ERR(u->clk)) {
+ if (PTR_ERR(u->clk) != -EPROBE_DEFER)
+ dev_err(uport->dev, "uart%d can't get enable clock\n",
+ uport->line);
+ return PTR_ERR(u->clk);
+ }
+
+ return 0;
+}
+
static int sprd_probe(struct platform_device *pdev)
{
struct resource *res;
struct uart_port *up;
- struct clk *clk;
int irq;
int index;
int ret;
@@ -704,9 +757,9 @@ static int sprd_probe(struct platform_device *pdev)
up->ops = &serial_sprd_ops;
up->flags = UPF_BOOT_AUTOCONF;

- clk = devm_clk_get(&pdev->dev, NULL);
- if (!IS_ERR_OR_NULL(clk))
- up->uartclk = clk_get_rate(clk);
+ ret = sprd_clk_init(up);
+ if (ret)
+ return ret;

res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
up->membase = devm_ioremap_resource(&pdev->dev, res);
--
1.7.9.5
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