[PATCH v2 2/3] serial: lantiq: Make IRQ & ISR assignment dynamic

From: Rahul Tanwar
Date: Thu Aug 08 2019 - 06:02:24 EST


This driver/IP is reused across multiple SoCs. Older SoCs supported three
separate IRQs for tx, rx & err interrupts. Newer Lightning Mountain SoC
supports single IRQ for all of tx/rx/err interrupts. This patch modifies
the driver design to support dynamic assignment of IRQ resources & ISRs
based on devicetree node compatible entries.

Suggested-by: Andy Shevchenko <andriy.shevchenko@xxxxxxxxx>
Signed-off-by: Rahul Tanwar <rahul.tanwar@xxxxxxxxxxxxxxx>
---
drivers/tty/serial/lantiq.c | 141 ++++++++++++++++++++++++++++++--------------
1 file changed, 96 insertions(+), 45 deletions(-)

diff --git a/drivers/tty/serial/lantiq.c b/drivers/tty/serial/lantiq.c
index 660d21db57dc..b129531dfb9a 100644
--- a/drivers/tty/serial/lantiq.c
+++ b/drivers/tty/serial/lantiq.c
@@ -100,6 +100,12 @@ static void lqasc_tx_chars(struct uart_port *port);
static struct ltq_uart_port *lqasc_port[MAXPORTS];
static struct uart_driver lqasc_reg;

+struct ltq_soc_data {
+ int (*fetch_irq)(struct device *dev, struct ltq_uart_port *ltq_port);
+ int (*request_irq)(struct uart_port *port);
+ void (*free_irq)(struct uart_port *port);
+};
+
struct ltq_uart_port {
struct uart_port port;
/* clock used to derive divider */
@@ -110,6 +116,8 @@ struct ltq_uart_port {
unsigned int rx_irq;
unsigned int err_irq;
spinlock_t lock; /* exclusive access for multi core */
+
+ const struct ltq_soc_data *soc;
};

static inline void asc_update_bits(u32 clear, u32 set, void __iomem *reg)
@@ -343,35 +351,12 @@ lqasc_startup(struct uart_port *port)

spin_unlock_irqrestore(&ltq_port->lock, flags);

- retval = request_irq(ltq_port->tx_irq, lqasc_tx_int,
- 0, "asc_tx", port);
- if (retval) {
- pr_err("failed to request lqasc_tx_int\n");
+ retval = ltq_port->soc->request_irq(port);
+ if (retval)
return retval;
- }
-
- retval = request_irq(ltq_port->rx_irq, lqasc_rx_int,
- 0, "asc_rx", port);
- if (retval) {
- pr_err("failed to request lqasc_rx_int\n");
- goto err1;
- }
-
- retval = request_irq(ltq_port->err_irq, lqasc_err_int,
- 0, "asc_err", port);
- if (retval) {
- pr_err("failed to request lqasc_err_int\n");
- goto err2;
- }

__raw_writel(ASC_IRNREN_RX | ASC_IRNREN_ERR | ASC_IRNREN_TX,
port->membase + LTQ_ASC_IRNREN);
- return 0;
-
-err2:
- free_irq(ltq_port->rx_irq, port);
-err1:
- free_irq(ltq_port->tx_irq, port);
return retval;
}

@@ -381,9 +366,7 @@ lqasc_shutdown(struct uart_port *port)
struct ltq_uart_port *ltq_port = to_ltq_uart_port(port);
unsigned long flags;

- free_irq(ltq_port->tx_irq, port);
- free_irq(ltq_port->rx_irq, port);
- free_irq(ltq_port->err_irq, port);
+ ltq_port->soc->free_irq(port);

spin_lock_irqsave(&ltq_port->lock, flags);
__raw_writel(0, port->membase + LTQ_ASC_CON);
@@ -705,24 +688,98 @@ static struct uart_driver lqasc_reg = {
.cons = &lqasc_console,
};

+static int fetch_irq_lantiq(struct device *dev, struct ltq_uart_port *ltq_port)
+{
+ struct uart_port *port = &ltq_port->port;
+ struct resource irqres[3];
+ int ret;
+
+ ret = of_irq_to_resource_table(dev->of_node, irqres, 3);
+ if (ret != 3) {
+ dev_err(dev,
+ "failed to get IRQs for serial port\n");
+ return -ENODEV;
+ }
+ ltq_port->tx_irq = irqres[0].start;
+ ltq_port->rx_irq = irqres[1].start;
+ ltq_port->err_irq = irqres[2].start;
+ port->irq = irqres[0].start;
+
+ return 0;
+}
+
+static int request_irq_lantiq(struct uart_port *port)
+{
+ struct ltq_uart_port *ltq_port = to_ltq_uart_port(port);
+ int retval;
+
+ retval = request_irq(ltq_port->tx_irq, lqasc_tx_int,
+ 0, "asc_tx", port);
+ if (retval) {
+ dev_err(port->dev, "failed to request asc_tx\n");
+ return retval;
+ }
+
+ retval = request_irq(ltq_port->rx_irq, lqasc_rx_int,
+ 0, "asc_rx", port);
+ if (retval) {
+ dev_err(port->dev, "failed to request asc_rx\n");
+ goto err1;
+ }
+
+ retval = request_irq(ltq_port->err_irq, lqasc_err_int,
+ 0, "asc_err", port);
+ if (retval) {
+ dev_err(port->dev, "failed to request asc_err\n");
+ goto err2;
+ }
+ return 0;
+
+err2:
+ free_irq(ltq_port->rx_irq, port);
+err1:
+ free_irq(ltq_port->tx_irq, port);
+ return retval;
+}
+
+static void free_irq_lantiq(struct uart_port *port)
+{
+ struct ltq_uart_port *ltq_port = to_ltq_uart_port(port);
+
+ free_irq(ltq_port->tx_irq, port);
+ free_irq(ltq_port->rx_irq, port);
+ free_irq(ltq_port->err_irq, port);
+}
+
static int __init
lqasc_probe(struct platform_device *pdev)
{
struct device_node *node = pdev->dev.of_node;
struct ltq_uart_port *ltq_port;
struct uart_port *port;
- struct resource *mmres, irqres[3];
+ struct resource *mmres;
int line;
int ret;

mmres = platform_get_resource(pdev, IORESOURCE_MEM, 0);
- ret = of_irq_to_resource_table(node, irqres, 3);
- if (!mmres || (ret != 3)) {
+ if (!mmres) {
dev_err(&pdev->dev,
- "failed to get memory/irq for serial port\n");
+ "failed to get memory for serial port\n");
return -ENODEV;
}

+ ltq_port = devm_kzalloc(&pdev->dev, sizeof(struct ltq_uart_port),
+ GFP_KERNEL);
+ if (!ltq_port)
+ return -ENOMEM;
+
+ port = &ltq_port->port;
+
+ ltq_port->soc = of_device_get_match_data(&pdev->dev);
+ ret = ltq_port->soc->fetch_irq(&pdev->dev, ltq_port);
+ if (ret)
+ return ret;
+
/* get serial id */
line = of_alias_get_id(node, "serial");
if (line < 0) {
@@ -743,13 +800,6 @@ lqasc_probe(struct platform_device *pdev)
return -EBUSY;
}

- ltq_port = devm_kzalloc(&pdev->dev, sizeof(struct ltq_uart_port),
- GFP_KERNEL);
- if (!ltq_port)
- return -ENOMEM;
-
- port = &ltq_port->port;
-
port->iotype = SERIAL_IO_MEM;
port->flags = UPF_BOOT_AUTOCONF | UPF_IOREMAP;
port->ops = &lqasc_pops;
@@ -758,7 +808,6 @@ lqasc_probe(struct platform_device *pdev)
port->line = line;
port->dev = &pdev->dev;
/* unused, just to be backward-compatible */
- port->irq = irqres[0].start;
port->mapbase = mmres->start;

if (IS_ENABLED(CONFIG_LANTIQ) && !IS_ENABLED(CONFIG_COMMON_CLK))
@@ -778,10 +827,6 @@ lqasc_probe(struct platform_device *pdev)
else
ltq_port->clk = devm_clk_get(&pdev->dev, "asc");

- ltq_port->tx_irq = irqres[0].start;
- ltq_port->rx_irq = irqres[1].start;
- ltq_port->err_irq = irqres[2].start;
-
spin_lock_init(&ltq_port->lock);
lqasc_port[line] = ltq_port;
platform_set_drvdata(pdev, ltq_port);
@@ -791,8 +836,14 @@ lqasc_probe(struct platform_device *pdev)
return ret;
}

+static const struct ltq_soc_data soc_data_lantiq = {
+ .fetch_irq = fetch_irq_lantiq,
+ .request_irq = request_irq_lantiq,
+ .free_irq = free_irq_lantiq,
+};
+
static const struct of_device_id ltq_asc_match[] = {
- { .compatible = "lantiq,asc" },
+ { .compatible = "lantiq,asc", .data = &soc_data_lantiq },
{},
};

--
2.11.0