[PATCH 0/6] serial: max310x: Improve driver. Part 1.

[PATCH 0/6] serial: max310x: Improve driver. Part 1.

[Alexander Shiyan]

This patchset provide various improvements/fixes for MAX310X
serial driver.

Alexander Shiyan (6):
  serial: max310x: Allow driver to be compiled as module
  serial: max310x: Setup baud rate generator more precisely
  serial: max310x: Remove init() and exit() callbacks
  serial: max310x: Remove excess port configure at startup
  serial: max310x: Add the loopback mode support
  serial: max310x: Remove IRQ validation

 drivers/tty/serial/Kconfig            |  2 +-
 drivers/tty/serial/max310x.c          | 76 +++++++++++++++++------------------
 include/linux/platform_data/max310x.h |  5 ---
 3 files changed, 39 insertions(+), 44 deletions(-)

-- 
1.8.3.2

[PATCH 1/6] serial: max310x: Allow driver to be compiled as module

[Alexander Shiyan]

Signed-off-by: Alexander Shiyan <shc_work@mail.ru>
---
 drivers/tty/serial/Kconfig | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/tty/serial/Kconfig b/drivers/tty/serial/Kconfig
index a3815ea..d261d76 100644
--- a/drivers/tty/serial/Kconfig
+++ b/drivers/tty/serial/Kconfig
@@ -289,7 +289,7 @@ config SERIAL_MAX3100
 	  MAX3100 chip support
 
 config SERIAL_MAX310X
-	bool "MAX310X support"
+	tristate "MAX310X support"
 	depends on SPI_MASTER
 	select SERIAL_CORE
 	select REGMAP_SPI if SPI_MASTER
-- 
1.8.3.2

[PATCH 2/6] serial: max310x: Setup baud rate generator more precisely

[Alexander Shiyan]

This patch provide more precisely setup of baud rate generator.
If the result of division has a remainder, we use the multiplier
for the base frequency. Additionally, we report result baud rate
back to serial core.

Signed-off-by: Alexander Shiyan <shc_work@mail.ru>
---
 drivers/tty/serial/max310x.c | 32 ++++++++++++++++++++------------
 1 file changed, 20 insertions(+), 12 deletions(-)

diff --git a/drivers/tty/serial/max310x.c b/drivers/tty/serial/max310x.c
index 8d71e40..313bdf0 100644
--- a/drivers/tty/serial/max310x.c
+++ b/drivers/tty/serial/max310x.c
@@ -1,7 +1,7 @@
 /*
  *  Maxim (Dallas) MAX3107/8/9, MAX14830 serial driver
  *
- *  Copyright (C) 2012-2013 Alexander Shiyan <shc_work@mail.ru>
+ *  Copyright (C) 2012-2014 Alexander Shiyan <shc_work@mail.ru>
  *
  *  Based on max3100.c, by Christian Pellegrin <chripell@evolware.org>
  *  Based on max3110.c, by Feng Tang <feng.tang@intel.com>
@@ -504,25 +504,33 @@ static bool max310x_reg_precious(struct device *dev, unsigned int reg)
 	return false;
 }
 
-static void max310x_set_baud(struct uart_port *port, int baud)
+static int max310x_set_baud(struct uart_port *port, int baud)
 {
-	unsigned int mode = 0, div = port->uartclk / baud;
+	unsigned int mode = 0, clk = port->uartclk, div = clk / baud;
 
-	if (!(div / 16)) {
+	/* Check for minimal value for divider */
+	if (div < 16)
+		div = 16;
+
+	if (clk % baud && (div / 16) < 0x8000) {
 		/* Mode x2 */
 		mode = MAX310X_BRGCFG_2XMODE_BIT;
-		div = (port->uartclk * 2) / baud;
-	}
-
-	if (!(div / 16)) {
-		/* Mode x4 */
-		mode = MAX310X_BRGCFG_4XMODE_BIT;
-		div = (port->uartclk * 4) / baud;
+		clk = port->uartclk * 2;
+		div = clk / baud;
+
+		if (clk % baud && (div / 16) < 0x8000) {
+			/* Mode x4 */
+			mode = MAX310X_BRGCFG_4XMODE_BIT;
+			clk = port->uartclk * 4;
+			div = clk / baud;
+		}
 	}
 
 	max310x_port_write(port, MAX310X_BRGDIVMSB_REG, (div / 16) >> 8);
 	max310x_port_write(port, MAX310X_BRGDIVLSB_REG, div / 16);
 	max310x_port_write(port, MAX310X_BRGCFG_REG, (div % 16) | mode);
+
+	return DIV_ROUND_CLOSEST(clk, div);
 }
 
 static int max310x_update_best_err(unsigned long f, long *besterr)
@@ -875,7 +883,7 @@ static void max310x_set_termios(struct uart_port *port,
 				  port->uartclk / 4);
 
 	/* Setup baudrate generator */
-	max310x_set_baud(port, baud);
+	baud = max310x_set_baud(port, baud);
 
 	/* Update timeout according to new baud rate */
 	uart_update_timeout(port, termios->c_cflag, baud);
-- 
1.8.3.2

[PATCH 3/6] serial: max310x: Remove init() and exit() callbacks

[Alexander Shiyan]

These callbacks were previously used for the IC power initialization.
If this initialization will be needed in the future, it should be
implemented with the regulator API.

Signed-off-by: Alexander Shiyan <shc_work@mail.ru>
---
 drivers/tty/serial/max310x.c          | 7 -------
 include/linux/platform_data/max310x.h | 4 ----
 2 files changed, 11 deletions(-)

diff --git a/drivers/tty/serial/max310x.c b/drivers/tty/serial/max310x.c
index 313bdf0..202c1fb 100644
--- a/drivers/tty/serial/max310x.c
+++ b/drivers/tty/serial/max310x.c
@@ -1135,10 +1135,6 @@ static int max310x_probe(struct device *dev, int is_spi,
 		return PTR_ERR(s->regmap);
 	}
 
-	/* Board specific configure */
-	if (s->pdata->init)
-		s->pdata->init();
-
 	/* Check device to ensure we are talking to what we expect */
 	ret = devtype->detect(dev);
 	if (ret)
@@ -1265,9 +1261,6 @@ static int max310x_remove(struct device *dev)
 		ret = gpiochip_remove(&s->gpio);
 #endif
 
-	if (s->pdata->exit)
-		s->pdata->exit();
-
 	return ret;
 }
 
diff --git a/include/linux/platform_data/max310x.h b/include/linux/platform_data/max310x.h
index dd11dcd..5f4b35d 100644
--- a/include/linux/platform_data/max310x.h
+++ b/include/linux/platform_data/max310x.h
@@ -55,10 +55,6 @@ struct max310x_pdata {
 	const int		frequency;
 	/* GPIO base number (can be negative) */
 	const int		gpio_base;
-	/* Called during startup */
-	void (*init)(void);
-	/* Called before finish */
-	void (*exit)(void);
 };
 
 #endif
-- 
1.8.3.2

[PATCH 4/6] serial: max310x: Remove excess port configure at startup

[Alexander Shiyan]

Serial core calls set_termios() after port startup, so there are
no reason to setup port twice.

Signed-off-by: Alexander Shiyan <shc_work@mail.ru>
---
 drivers/tty/serial/max310x.c | 6 ------
 1 file changed, 6 deletions(-)

diff --git a/drivers/tty/serial/max310x.c b/drivers/tty/serial/max310x.c
index 202c1fb..1fb3895 100644
--- a/drivers/tty/serial/max310x.c
+++ b/drivers/tty/serial/max310x.c
@@ -896,12 +896,6 @@ static int max310x_startup(struct uart_port *port)
 
 	s->devtype->power(port, 1);
 
-	/* Configure baud rate, 9600 as default */
-	max310x_set_baud(port, 9600);
-
-	/* Configure LCR register, 8N1 mode by default */
-	max310x_port_write(port, MAX310X_LCR_REG, MAX310X_LCR_WORD_LEN_8);
-
 	/* Configure MODE1 register */
 	max310x_port_update(port, MAX310X_MODE1_REG,
 			    MAX310X_MODE1_TRNSCVCTRL_BIT,
-- 
1.8.3.2

[PATCH 5/6] serial: max310x: Add the loopback mode support

[Alexander Shiyan]

This patch replaces loopback mode support from platform data to
dynamic setup with TIOCMSET ioctl.

Signed-off-by: Alexander Shiyan <shc_work@mail.ru>
---
 drivers/tty/serial/max310x.c          | 25 ++++++++++++++++++-------
 include/linux/platform_data/max310x.h |  1 -
 2 files changed, 18 insertions(+), 8 deletions(-)

diff --git a/drivers/tty/serial/max310x.c b/drivers/tty/serial/max310x.c
index 1fb3895..3c93814 100644
--- a/drivers/tty/serial/max310x.c
+++ b/drivers/tty/serial/max310x.c
@@ -283,6 +283,7 @@ struct max310x_devtype {
 struct max310x_one {
 	struct uart_port	port;
 	struct work_struct	tx_work;
+	struct work_struct	md_work;
 };
 
 struct max310x_port {
@@ -790,11 +791,21 @@ static unsigned int max310x_get_mctrl(struct uart_port *port)
 	return TIOCM_DSR | TIOCM_CAR;
 }
 
+static void max310x_md_proc(struct work_struct *ws)
+{
+	struct max310x_one *one = container_of(ws, struct max310x_one, md_work);
+
+	max310x_port_update(&one->port, MAX310X_MODE2_REG,
+			    MAX310X_MODE2_LOOPBACK_BIT,
+			    (one->port.mctrl & TIOCM_LOOP) ?
+			    MAX310X_MODE2_LOOPBACK_BIT : 0);
+}
+
 static void max310x_set_mctrl(struct uart_port *port, unsigned int mctrl)
 {
-	/* DCD and DSR are not wired and CTS/RTS is hadnled automatically
-	 * so do nothing
-	 */
+	struct max310x_one *one = container_of(port, struct max310x_one, port);
+
+	schedule_work(&one->md_work);
 }
 
 static void max310x_break_ctl(struct uart_port *port, int break_state)
@@ -904,8 +915,6 @@ static int max310x_startup(struct uart_port *port)
 
 	/* Configure MODE2 register */
 	val = MAX310X_MODE2_RXEMPTINV_BIT;
-	if (s->pdata->uart_flags[line] & MAX310X_LOOPBACK)
-		val |= MAX310X_MODE2_LOOPBACK_BIT;
 	if (s->pdata->uart_flags[line] & MAX310X_ECHO_SUPRESS)
 		val |= MAX310X_MODE2_ECHOSUPR_BIT;
 
@@ -1176,8 +1185,7 @@ static int max310x_probe(struct device *dev, int is_spi,
 		s->p[i].port.irq	= irq;
 		s->p[i].port.type	= PORT_MAX310X;
 		s->p[i].port.fifosize	= MAX310X_FIFO_SIZE;
-		s->p[i].port.flags	= UPF_SKIP_TEST | UPF_FIXED_TYPE |
-					  UPF_LOW_LATENCY;
+		s->p[i].port.flags	= UPF_FIXED_TYPE | UPF_LOW_LATENCY;
 		s->p[i].port.iotype	= UPIO_PORT;
 		s->p[i].port.iobase	= i * 0x20;
 		s->p[i].port.membase	= (void __iomem *)~0;
@@ -1193,6 +1201,8 @@ static int max310x_probe(struct device *dev, int is_spi,
 				    MAX310X_MODE1_IRQSEL_BIT);
 		/* Initialize queue for start TX */
 		INIT_WORK(&s->p[i].tx_work, max310x_wq_proc);
+		/* Initialize queue for changing mode */
+		INIT_WORK(&s->p[i].md_work, max310x_md_proc);
 		/* Register port */
 		uart_add_one_port(&s->uart, &s->p[i].port);
 		/* Go to suspend mode */
@@ -1244,6 +1254,7 @@ static int max310x_remove(struct device *dev)
 
 	for (i = 0; i < s->uart.nr; i++) {
 		cancel_work_sync(&s->p[i].tx_work);
+		cancel_work_sync(&s->p[i].md_work);
 		uart_remove_one_port(&s->uart, &s->p[i].port);
 		s->devtype->power(&s->p[i].port, 0);
 	}
diff --git a/include/linux/platform_data/max310x.h b/include/linux/platform_data/max310x.h
index 5f4b35d..9d5f69b 100644
--- a/include/linux/platform_data/max310x.h
+++ b/include/linux/platform_data/max310x.h
@@ -46,7 +46,6 @@ struct max310x_pdata {
 #define MAX310X_EXT_CLK		(0x00000001)	/* External clock enable */
 	/* Flags global to UART port */
 	const u8		uart_flags[MAX310X_MAX_UARTS];
-#define MAX310X_LOOPBACK	(0x00000001)	/* Loopback mode enable */
 #define MAX310X_ECHO_SUPRESS	(0x00000002)	/* Enable echo supress */
 #define MAX310X_AUTO_DIR_CTRL	(0x00000004)	/* Enable Auto direction
 						 * control (RS-485)
-- 
1.8.3.2

[PATCH 6/6] serial: max310x: Remove IRQ validation

[Alexander Shiyan]

This patch removes excess IRQ checks at driver probe().
IRQ validation is already provided by request_threaded_irq().

Signed-off-by: Alexander Shiyan <shc_work@mail.ru>
---
 drivers/tty/serial/max310x.c | 6 ------
 1 file changed, 6 deletions(-)

diff --git a/drivers/tty/serial/max310x.c b/drivers/tty/serial/max310x.c
index 3c93814..ac1d54c 100644
--- a/drivers/tty/serial/max310x.c
+++ b/drivers/tty/serial/max310x.c
@@ -1081,12 +1081,6 @@ static int max310x_probe(struct device *dev, int is_spi,
 	struct max310x_pdata *pdata = dev_get_platdata(dev);
 	int i, ret, uartclk;
 
-	/* Check for IRQ */
-	if (irq <= 0) {
-		dev_err(dev, "No IRQ specified\n");
-		return -ENOTSUPP;
-	}
-
 	if (!pdata) {
 		dev_err(dev, "No platform data supplied\n");
 		return -EINVAL;
-- 
1.8.3.2