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Message-Id: <20230525111937.e0d3a96d8f95c7a523cdb006@hugovil.com>
Date: Thu, 25 May 2023 11:19:37 -0400
From: Hugo Villeneuve <hugo@...ovil.com>
To: Ilpo Järvinen <ilpo.jarvinen@...ux.intel.com>
Cc: Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
robh+dt@...nel.org, krzysztof.kozlowski+dt@...aro.org,
conor+dt@...nel.org, Jiri Slaby <jirislaby@...nel.org>,
jringle@...dpoint.com, tomasz.mon@...lingroup.com,
l.perczak@...lintechnologies.com,
linux-serial <linux-serial@...r.kernel.org>,
devicetree@...r.kernel.org, LKML <linux-kernel@...r.kernel.org>,
linux-gpio@...r.kernel.org,
Hugo Villeneuve <hvilleneuve@...onoff.com>
Subject: Re: [PATCH v3 08/11] serial: sc16is7xx: fix regression with GPIO
configuration
On Thu, 25 May 2023 15:03:41 +0300 (EEST)
Ilpo Järvinen <ilpo.jarvinen@...ux.intel.com> wrote:
> On Thu, 25 May 2023, Hugo Villeneuve wrote:
>
> > From: Hugo Villeneuve <hvilleneuve@...onoff.com>
> >
> > 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@...onoff.com>
> > ---
> > 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.
Good suggestion, done.
> > + /* 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.
Done
> > +
> > + 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.
>
>
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