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path: root/drivers/video/fbdev/simplefb.c
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Diffstat (limited to 'drivers/video/fbdev/simplefb.c')
-rw-r--r--drivers/video/fbdev/simplefb.c120
1 files changed, 119 insertions, 1 deletions
diff --git a/drivers/video/fbdev/simplefb.c b/drivers/video/fbdev/simplefb.c
index 52c5c7e63b52..48ccf6db62a2 100644
--- a/drivers/video/fbdev/simplefb.c
+++ b/drivers/video/fbdev/simplefb.c
@@ -28,7 +28,10 @@
#include <linux/platform_device.h>
#include <linux/clk.h>
#include <linux/clk-provider.h>
+#include <linux/of.h>
#include <linux/of_platform.h>
+#include <linux/parser.h>
+#include <linux/regulator/consumer.h>
static struct fb_fix_screeninfo simplefb_fix = {
.id = "simple",
@@ -174,6 +177,10 @@ struct simplefb_par {
int clk_count;
struct clk **clks;
#endif
+#if defined CONFIG_OF && defined CONFIG_REGULATOR
+ u32 regulator_count;
+ struct regulator **regulators;
+#endif
};
#if defined CONFIG_OF && defined CONFIG_COMMON_CLK
@@ -269,6 +276,110 @@ static int simplefb_clocks_init(struct simplefb_par *par,
static void simplefb_clocks_destroy(struct simplefb_par *par) { }
#endif
+#if defined CONFIG_OF && defined CONFIG_REGULATOR
+
+#define SUPPLY_SUFFIX "-supply"
+
+/*
+ * Regulator handling code.
+ *
+ * Here we handle the num-supplies and vin*-supply properties of our
+ * "simple-framebuffer" dt node. This is necessary so that we can make sure
+ * that any regulators needed by the display hardware that the bootloader
+ * set up for us (and for which it provided a simplefb dt node), stay up,
+ * for the life of the simplefb driver.
+ *
+ * When the driver unloads, we cleanly disable, and then release the
+ * regulators.
+ *
+ * We only complain about errors here, no action is taken as the most likely
+ * error can only happen due to a mismatch between the bootloader which set
+ * up simplefb, and the regulator definitions in the device tree. Chances are
+ * that there are no adverse effects, and if there are, a clean teardown of
+ * the fb probe will not help us much either. So just complain and carry on,
+ * and hope that the user actually gets a working fb at the end of things.
+ */
+static int simplefb_regulators_init(struct simplefb_par *par,
+ struct platform_device *pdev)
+{
+ struct device_node *np = pdev->dev.of_node;
+ struct property *prop;
+ struct regulator *regulator;
+ const char *p;
+ int count = 0, i = 0, ret;
+
+ if (dev_get_platdata(&pdev->dev) || !np)
+ return 0;
+
+ /* Count the number of regulator supplies */
+ for_each_property_of_node(np, prop) {
+ p = strstr(prop->name, SUPPLY_SUFFIX);
+ if (p && p != prop->name)
+ count++;
+ }
+
+ if (!count)
+ return 0;
+
+ par->regulators = devm_kcalloc(&pdev->dev, count,
+ sizeof(struct regulator *), GFP_KERNEL);
+ if (!par->regulators)
+ return -ENOMEM;
+
+ /* Get all the regulators */
+ for_each_property_of_node(np, prop) {
+ char name[32]; /* 32 is max size of property name */
+
+ p = strstr(prop->name, SUPPLY_SUFFIX);
+ if (!p || p == prop->name)
+ continue;
+
+ strlcpy(name, prop->name,
+ strlen(prop->name) - strlen(SUPPLY_SUFFIX) + 1);
+ regulator = devm_regulator_get_optional(&pdev->dev, name);
+ if (IS_ERR(regulator)) {
+ if (PTR_ERR(regulator) == -EPROBE_DEFER)
+ return -EPROBE_DEFER;
+ dev_err(&pdev->dev, "regulator %s not found: %ld\n",
+ name, PTR_ERR(regulator));
+ continue;
+ }
+ par->regulators[i++] = regulator;
+ }
+ par->regulator_count = i;
+
+ /* Enable all the regulators */
+ for (i = 0; i < par->regulator_count; i++) {
+ ret = regulator_enable(par->regulators[i]);
+ if (ret) {
+ dev_err(&pdev->dev,
+ "failed to enable regulator %d: %d\n",
+ i, ret);
+ devm_regulator_put(par->regulators[i]);
+ par->regulators[i] = NULL;
+ }
+ }
+
+ return 0;
+}
+
+static void simplefb_regulators_destroy(struct simplefb_par *par)
+{
+ int i;
+
+ if (!par->regulators)
+ return;
+
+ for (i = 0; i < par->regulator_count; i++)
+ if (par->regulators[i])
+ regulator_disable(par->regulators[i]);
+}
+#else
+static int simplefb_regulators_init(struct simplefb_par *par,
+ struct platform_device *pdev) { return 0; }
+static void simplefb_regulators_destroy(struct simplefb_par *par) { }
+#endif
+
static int simplefb_probe(struct platform_device *pdev)
{
int ret;
@@ -340,6 +451,10 @@ static int simplefb_probe(struct platform_device *pdev)
if (ret < 0)
goto error_unmap;
+ ret = simplefb_regulators_init(par, pdev);
+ if (ret < 0)
+ goto error_clocks;
+
dev_info(&pdev->dev, "framebuffer at 0x%lx, 0x%x bytes, mapped to 0x%p\n",
info->fix.smem_start, info->fix.smem_len,
info->screen_base);
@@ -351,13 +466,15 @@ static int simplefb_probe(struct platform_device *pdev)
ret = register_framebuffer(info);
if (ret < 0) {
dev_err(&pdev->dev, "Unable to register simplefb: %d\n", ret);
- goto error_clocks;
+ goto error_regulators;
}
dev_info(&pdev->dev, "fb%d: simplefb registered!\n", info->node);
return 0;
+error_regulators:
+ simplefb_regulators_destroy(par);
error_clocks:
simplefb_clocks_destroy(par);
error_unmap:
@@ -373,6 +490,7 @@ static int simplefb_remove(struct platform_device *pdev)
struct simplefb_par *par = info->par;
unregister_framebuffer(info);
+ simplefb_regulators_destroy(par);
simplefb_clocks_destroy(par);
framebuffer_release(info);