target/linux/bcm27xx/patches-4.19/950-0606-i2c-bcm2835-Ensure-clock-exists-when-probing.patch

   1 From 1a5122f1756ef4fc5779324ad26b6a04142166b5 Mon Sep 17 00:00:00 2001
   2 From: Annaliese McDermond <nh6z@nh6z.net>
   3 Date: Fri, 21 Jun 2019 03:52:50 -0700
   4 Subject: [PATCH] i2c: bcm2835: Ensure clock exists when probing
   5
   6 Commit 9de93b04df16b055824e3f1f13fedb90fbcf2e4f upstream.
   7
   8 Probe function fails to recognize that upstream clock actually
   9 doesn't yet exist because clock driver has not been initialized.
  10 Actually try to go get the clock and test for its existence
  11 before trying to set up a downstream clock based upon it.
  12
  13 This fixes a bug that causes the i2c driver not to work with
  14 monolithic kernels.
  15
  16 Fixes: bebff81fb8b9 ("i2c: bcm2835: Model Divider in CCF")
  17 Signed-off-by: Annaliese McDermond <nh6z@nh6z.net>
  18 Acked-by: Stefan Wahren <wahrenst@gmx.net>
  19 Signed-off-by: Wolfram Sang <wsa@the-dreams.de>
  20 ---
  21  drivers/i2c/busses/i2c-bcm2835.c | 16 ++++++++++++----
  22  1 file changed, 12 insertions(+), 4 deletions(-)
  23
  24 --- a/drivers/i2c/busses/i2c-bcm2835.c
  25 +++ b/drivers/i2c/busses/i2c-bcm2835.c
  26 @@ -244,15 +244,18 @@ static const struct clk_ops clk_bcm2835_
  27  };
  28
  29  static struct clk *bcm2835_i2c_register_div(struct device *dev,
  30 -                                       const char *mclk_name,
  31 +                                       struct clk *mclk,
  32                                         struct bcm2835_i2c_dev *i2c_dev)
  33  {
  34         struct clk_init_data init;
  35         struct clk_bcm2835_i2c *priv;
  36         char name[32];
  37 +       const char *mclk_name;
  38
  39         snprintf(name, sizeof(name), "%s_div", dev_name(dev));
  40
  41 +       mclk_name = __clk_get_name(mclk);
  42 +
  43         init.ops = &clk_bcm2835_i2c_ops;
  44         init.name = name;
  45         init.parent_names = (const char* []) { mclk_name };
  46 @@ -505,8 +508,8 @@ static int bcm2835_i2c_probe(struct plat
  47         struct resource *mem, *irq;
  48         int ret;
  49         struct i2c_adapter *adap;
  50 -       const char *mclk_name;
  51         struct clk *bus_clk;
  52 +       struct clk *mclk;
  53         u32 bus_clk_rate;
  54
  55         i2c_dev = devm_kzalloc(&pdev->dev, sizeof(*i2c_dev), GFP_KERNEL);
  56 @@ -521,9 +524,14 @@ static int bcm2835_i2c_probe(struct plat
  57         if (IS_ERR(i2c_dev->regs))
  58                 return PTR_ERR(i2c_dev->regs);
  59
  60 -       mclk_name = of_clk_get_parent_name(pdev->dev.of_node, 0);
  61 +       mclk = devm_clk_get(&pdev->dev, NULL);
  62 +       if (IS_ERR(mclk)) {
  63 +               if (PTR_ERR(mclk) != -EPROBE_DEFER)
  64 +                       dev_err(&pdev->dev, "Could not get clock\n");
  65 +               return PTR_ERR(mclk);
  66 +       }
  67
  68 -       bus_clk = bcm2835_i2c_register_div(&pdev->dev, mclk_name, i2c_dev);
  69 +       bus_clk = bcm2835_i2c_register_div(&pdev->dev, mclk, i2c_dev);
  70
  71         if (IS_ERR(bus_clk)) {
  72                 dev_err(&pdev->dev, "Could not register clock\n");