target/linux/ramips/patches-5.4/111-gpio-mmio-introduce-BGPIOF_NO_SET_ON_INPUT.patch

   1 From 5d7b644aad721ecca20bd8976b38fb243fdc84f9 Mon Sep 17 00:00:00 2001
   2 From: Chuanhong Guo <gch981213@gmail.com>
   3 Date: Sun, 15 Mar 2020 20:13:37 +0800
   4 Subject: [PATCH] gpio: mmio: introduce BGPIOF_NO_SET_ON_INPUT
   5 MIME-Version: 1.0
   6 Content-Type: text/plain; charset=UTF-8
   7 Content-Transfer-Encoding: 8bit
   8
   9 Some gpio controllers ignores pin value writing when that pin is
  10 configured as input mode. As a result, bgpio_dir_out should set
  11 pin to output before configuring pin values or gpio pin values
  12 can't be set up properly.
  13 Introduce two variants of bgpio_dir_out: bgpio_dir_out_val_first
  14 and bgpio_dir_out_dir_first, and assign direction_output according
  15 to a new flag: BGPIOF_NO_SET_ON_INPUT.
  16
  17 Signed-off-by: Chuanhong Guo <gch981213@gmail.com>
  18 Tested-by: René van Dorst <opensource@vdorst.com>
  19 Reviewed-by: Sergio Paracuellos <sergio.paracuellos@gmail.com>
  20 Signed-off-by: Bartosz Golaszewski <bgolaszewski@baylibre.com>
  21 ---
  22  drivers/gpio/gpio-mmio.c    | 23 +++++++++++++++++++----
  23  include/linux/gpio/driver.h |  1 +
  24  2 files changed, 20 insertions(+), 4 deletions(-)
  25
  26 --- a/drivers/gpio/gpio-mmio.c
  27 +++ b/drivers/gpio/gpio-mmio.c
  28 @@ -381,12 +381,10 @@ static int bgpio_get_dir(struct gpio_chi
  29         return 1;
  30  }
  31
  32 -static int bgpio_dir_out(struct gpio_chip *gc, unsigned int gpio, int val)
  33 +static void bgpio_dir_out(struct gpio_chip *gc, unsigned int gpio, int val)
  34  {
  35         unsigned long flags;
  36
  37 -       gc->set(gc, gpio, val);
  38 -
  39         spin_lock_irqsave(&gc->bgpio_lock, flags);
  40
  41         gc->bgpio_dir |= bgpio_line2mask(gc, gpio);
  42 @@ -397,7 +395,21 @@ static int bgpio_dir_out(struct gpio_chi
  43                 gc->write_reg(gc->reg_dir_out, gc->bgpio_dir);
  44
  45         spin_unlock_irqrestore(&gc->bgpio_lock, flags);
  46 +}
  47
  48 +static int bgpio_dir_out_dir_first(struct gpio_chip *gc, unsigned int gpio,
  49 +                                  int val)
  50 +{
  51 +       bgpio_dir_out(gc, gpio, val);
  52 +       gc->set(gc, gpio, val);
  53 +       return 0;
  54 +}
  55 +
  56 +static int bgpio_dir_out_val_first(struct gpio_chip *gc, unsigned int gpio,
  57 +                                  int val)
  58 +{
  59 +       gc->set(gc, gpio, val);
  60 +       bgpio_dir_out(gc, gpio, val);
  61         return 0;
  62  }
  63
  64 @@ -530,7 +542,10 @@ static int bgpio_setup_direction(struct
  65         if (dirout || dirin) {
  66                 gc->reg_dir_out = dirout;
  67                 gc->reg_dir_in = dirin;
  68 -               gc->direction_output = bgpio_dir_out;
  69 +               if (flags & BGPIOF_NO_SET_ON_INPUT)
  70 +                       gc->direction_output = bgpio_dir_out_dir_first;
  71 +               else
  72 +                       gc->direction_output = bgpio_dir_out_val_first;
  73                 gc->direction_input = bgpio_dir_in;
  74                 gc->get_direction = bgpio_get_dir;
  75         } else {
  76 --- a/include/linux/gpio/driver.h
  77 +++ b/include/linux/gpio/driver.h
  78 @@ -567,6 +567,7 @@ int bgpio_init(struct gpio_chip *gc, str
  79  #define BGPIOF_BIG_ENDIAN_BYTE_ORDER   BIT(3)
  80  #define BGPIOF_READ_OUTPUT_REG_SET     BIT(4) /* reg_set stores output value */
  81  #define BGPIOF_NO_OUTPUT               BIT(5) /* only input */
  82 +#define BGPIOF_NO_SET_ON_INPUT         BIT(6)
  83
  84  int gpiochip_irq_map(struct irq_domain *d, unsigned int irq,
  85                      irq_hw_number_t hwirq);