On Thu, 25 May 2023, Hugo Villeneuve wrote:
> From: Hugo Villeneuve <hvilleneuve@xxxxxxxxxxxx>
>
> Commit 679875d1d880 ("sc16is7xx: Separate GPIOs from modem control lines")
> and commit 21144bab4f11 ("sc16is7xx: Handle modem status lines")
> changed the function of the GPIOs pins to act as modem control
> lines without any possibility of selecting GPIO function.
>
> As a consequence, applications that depends on GPIO lines configured
> by default as GPIO pins no longer work as expected.
>
> Also, the change to select modem control lines function was done only
> for channel A of dual UART variants (752/762). This was not documented
> in the log message.
>
> This new patch allows to specify GPIO or modem control line function
> in the device tree, and for each of the ports (A or B).
>
> This is done by using the new device-tree property named
> "modem-control-line-ports" (property added in separate patch).
>
> We also now reduce the number of exported GPIOs according to the
> modem-status-line-port DT property.
>
> Boards that need to have GPIOS configured as modem control lines
> should add that property to their device tree. Here is a list of
> boards using the sc16is7xx driver in their device tree and that may
> need to be modified:
> arm64/boot/dts/freescale/fsl-ls1012a-frdm.dts
> mips/boot/dts/ingenic/cu1830-neo.dts
> mips/boot/dts/ingenic/cu1000-neo.dts
>
> Fixes: 679875d1d880 ("sc16is7xx: Separate GPIOs from modem control lines")
> Fixes: 21144bab4f11 ("sc16is7xx: Handle modem status lines")
> Signed-off-by: Hugo Villeneuve <hvilleneuve@xxxxxxxxxxxx>
> ---
> drivers/tty/serial/sc16is7xx.c | 65 +++++++++++++++++++++++-----------
> 1 file changed, 44 insertions(+), 21 deletions(-)
>
> diff --git a/drivers/tty/serial/sc16is7xx.c b/drivers/tty/serial/sc16is7xx.c
> index a5d8af0f6da0..97ec532a0a19 100644
> --- a/drivers/tty/serial/sc16is7xx.c
> +++ b/drivers/tty/serial/sc16is7xx.c
> @@ -236,7 +236,8 @@
>
> /* IOControl register bits (Only 75x/76x) */
> #define SC16IS7XX_IOCONTROL_LATCH_BIT (1 << 0) /* Enable input latching */
> -#define SC16IS7XX_IOCONTROL_MODEM_BIT (1 << 1) /* Enable GPIO[7:4] as modem pins */
> +#define SC16IS7XX_IOCONTROL_MODEM_A_BIT (1 << 1) /* Enable GPIO[7:4] as modem A pins */
> +#define SC16IS7XX_IOCONTROL_MODEM_B_BIT (1 << 2) /* Enable GPIO[3:0] as modem B pins */
> #define SC16IS7XX_IOCONTROL_SRESET_BIT (1 << 3) /* Software Reset */
>
> /* EFCR register bits */
> @@ -301,12 +302,12 @@
> /* Misc definitions */
> #define SC16IS7XX_FIFO_SIZE (64)
> #define SC16IS7XX_REG_SHIFT 2
> +#define SC16IS7XX_GPIOS_PER_BANK 4
>
> struct sc16is7xx_devtype {
> char name[10];
> int nr_gpio;
> int nr_uart;
> - int has_mctrl;
> };
>
> #define SC16IS7XX_RECONF_MD (1 << 0)
> @@ -336,6 +337,7 @@ struct sc16is7xx_port {
> struct clk *clk;
> #ifdef CONFIG_GPIOLIB
> struct gpio_chip gpio;
> + int gpio_configured;
> #endif
> unsigned char buf[SC16IS7XX_FIFO_SIZE];
> struct kthread_worker kworker;
> @@ -447,35 +449,30 @@ static const struct sc16is7xx_devtype sc16is74x_devtype = {
> .name = "SC16IS74X",
> .nr_gpio = 0,
> .nr_uart = 1,
> - .has_mctrl = 0,
> };
>
> static const struct sc16is7xx_devtype sc16is750_devtype = {
> .name = "SC16IS750",
> - .nr_gpio = 4,
> + .nr_gpio = 8,
> .nr_uart = 1,
> - .has_mctrl = 1,
> };
>
> static const struct sc16is7xx_devtype sc16is752_devtype = {
> .name = "SC16IS752",
> - .nr_gpio = 0,
> + .nr_gpio = 8,
> .nr_uart = 2,
> - .has_mctrl = 1,
> };
>
> static const struct sc16is7xx_devtype sc16is760_devtype = {
> .name = "SC16IS760",
> - .nr_gpio = 4,
> + .nr_gpio = 8,
> .nr_uart = 1,
> - .has_mctrl = 1,
> };
>
> static const struct sc16is7xx_devtype sc16is762_devtype = {
> .name = "SC16IS762",
> - .nr_gpio = 0,
> + .nr_gpio = 8,
> .nr_uart = 2,
> - .has_mctrl = 1,
> };
>
> static bool sc16is7xx_regmap_volatile(struct device *dev, unsigned int reg)
> @@ -1396,6 +1393,10 @@ static int sc16is7xx_probe(struct device *dev,
> return -ENOMEM;
> }
>
> +#ifdef CONFIG_GPIOLIB
> + s->gpio_configured = devtype->nr_gpio;
> +#endif /* CONFIG_GPIOLIB */
> +
> /* Always ask for fixed clock rate from a property. */
> device_property_read_u32(dev, "clock-frequency", &uartclk);
>
> @@ -1473,12 +1474,6 @@ static int sc16is7xx_probe(struct device *dev,
> SC16IS7XX_EFCR_RXDISABLE_BIT |
> SC16IS7XX_EFCR_TXDISABLE_BIT);
>
> - /* Use GPIO lines as modem status registers */
> - if (devtype->has_mctrl)
> - sc16is7xx_port_write(&s->p[i].port,
> - SC16IS7XX_IOCONTROL_REG,
> - SC16IS7XX_IOCONTROL_MODEM_BIT);
> -
> /* Initialize kthread work structs */
> kthread_init_work(&s->p[i].tx_work, sc16is7xx_tx_proc);
> kthread_init_work(&s->p[i].reg_work, sc16is7xx_reg_proc);
> @@ -1514,10 +1509,38 @@ static int sc16is7xx_probe(struct device *dev,
> prop, p, u)
> if (u < devtype->nr_uart)
> s->p[u].irda_mode = true;
> +
> + val = 0;
> +
> + of_property_for_each_u32(dev->of_node, "nxp,modem-control-line-ports",
> + prop, p, u)
> + if (u < devtype->nr_uart) {
Reverse logic + use continue. It will help with the indentation levels.
> + /* Use GPIO lines as modem control lines */
> + if (u == 0)
> + val |= SC16IS7XX_IOCONTROL_MODEM_A_BIT;
> + else if (u == 1)
> + val |= SC16IS7XX_IOCONTROL_MODEM_B_BIT;
> +
> +#ifdef CONFIG_GPIOLIB
> + if (s->gpio_configured >=
> + SC16IS7XX_GPIOS_PER_BANK)
> + s->gpio_configured -=
> + SC16IS7XX_GPIOS_PER_BANK;
> +#endif /* CONFIG_GPIOLIB */
> + }
Please use braces for of_property_for_each_u32 block.
> +
> + if (val)
> + regmap_update_bits(
> + s->regmap,
> + SC16IS7XX_IOCONTROL_REG << SC16IS7XX_REG_SHIFT,
> + SC16IS7XX_IOCONTROL_MODEM_A_BIT |
> + SC16IS7XX_IOCONTROL_MODEM_B_BIT, val);
> }
>
> #ifdef CONFIG_GPIOLIB
> - if (devtype->nr_gpio) {
> + dev_dbg(dev, "GPIOs to configure: %d\n", s->gpio_configured);
> +
> + if (s->gpio_configured) {
> /* Setup GPIO controller */
> s->gpio.owner = THIS_MODULE;
> s->gpio.parent = dev;
> @@ -1527,7 +1550,7 @@ static int sc16is7xx_probe(struct device *dev,
> s->gpio.direction_output = sc16is7xx_gpio_direction_output;
> s->gpio.set = sc16is7xx_gpio_set;
> s->gpio.base = -1;
> - s->gpio.ngpio = devtype->nr_gpio;
> + s->gpio.ngpio = s->gpio_configured;
> s->gpio.can_sleep = 1;
> ret = gpiochip_add_data(&s->gpio, s);
> if (ret)
> @@ -1555,7 +1578,7 @@ static int sc16is7xx_probe(struct device *dev,
> return 0;
>
> #ifdef CONFIG_GPIOLIB
> - if (devtype->nr_gpio)
> + if (s->gpio_configured)
> gpiochip_remove(&s->gpio);
>
> out_thread:
> @@ -1581,7 +1604,7 @@ static void sc16is7xx_remove(struct device *dev)
> int i;
>
> #ifdef CONFIG_GPIOLIB
> - if (s->devtype->nr_gpio)
> + if (s->gpio_configured)
> gpiochip_remove(&s->gpio);
> #endif
>
>
--
i.
