From 9de93b04df16b055824e3f1f13fedb90fbcf2e4f Mon Sep 17 00:00:00 2001 From: Annaliese McDermond Date: Fri, 21 Jun 2019 03:52:50 -0700 Subject: [PATCH] i2c: bcm2835: Ensure clock exists when probing Probe function fails to recognize that upstream clock actually doesn't yet exist because clock driver has not been initialized. Actually try to go get the clock and test for its existence before trying to set up a downstream clock based upon it. This fixes a bug that causes the i2c driver not to work with monolithic kernels. Fixes: bebff81fb8b9 ("i2c: bcm2835: Model Divider in CCF") Signed-off-by: Annaliese McDermond Acked-by: Stefan Wahren Signed-off-by: Wolfram Sang --- drivers/i2c/busses/i2c-bcm2835.c | 16 ++++++++++++---- 1 file changed, 12 insertions(+), 4 deletions(-) diff --git a/drivers/i2c/busses/i2c-bcm2835.c b/drivers/i2c/busses/i2c-bcm2835.c index 512c638..67752f7 100644 --- a/drivers/i2c/busses/i2c-bcm2835.c +++ b/drivers/i2c/busses/i2c-bcm2835.c @@ -154,15 +154,18 @@ static const struct clk_ops clk_bcm2835_i2c_ops = { }; static struct clk *bcm2835_i2c_register_div(struct device *dev, - const char *mclk_name, + struct clk *mclk, struct bcm2835_i2c_dev *i2c_dev) { struct clk_init_data init; struct clk_bcm2835_i2c *priv; char name[32]; + const char *mclk_name; snprintf(name, sizeof(name), "%s_div", dev_name(dev)); + mclk_name = __clk_get_name(mclk); + init.ops = &clk_bcm2835_i2c_ops; init.name = name; init.parent_names = (const char* []) { mclk_name }; @@ -400,8 +403,8 @@ static int bcm2835_i2c_probe(struct platform_device *pdev) struct resource *mem, *irq; int ret; struct i2c_adapter *adap; - const char *mclk_name; struct clk *bus_clk; + struct clk *mclk; u32 bus_clk_rate; i2c_dev = devm_kzalloc(&pdev->dev, sizeof(*i2c_dev), GFP_KERNEL); @@ -416,9 +419,14 @@ static int bcm2835_i2c_probe(struct platform_device *pdev) if (IS_ERR(i2c_dev->regs)) return PTR_ERR(i2c_dev->regs); - mclk_name = of_clk_get_parent_name(pdev->dev.of_node, 0); + mclk = devm_clk_get(&pdev->dev, NULL); + if (IS_ERR(mclk)) { + if (PTR_ERR(mclk) != -EPROBE_DEFER) + dev_err(&pdev->dev, "Could not get clock\n"); + return PTR_ERR(mclk); + } - bus_clk = bcm2835_i2c_register_div(&pdev->dev, mclk_name, i2c_dev); + bus_clk = bcm2835_i2c_register_div(&pdev->dev, mclk, i2c_dev); if (IS_ERR(bus_clk)) { dev_err(&pdev->dev, "Could not register clock\n"); -- 2.7.4