[PATCH v4] ARM: tegra: emc: convert tegra2_emc to a platform driver
Olof Johansson
olof at lixom.net
Thu Jan 5 20:42:43 EST 2012
This is the first step in making it device-tree aware and get rid of the
in-kernel EMC tables (of which there are none in mainline, thankfully).
Changes since v3:
* moved to devm_request_and_ioremap() in probe()
*
Changes since v2:
* D'oh -- missed a couple of variables that were added, never used and then
later removed in a later patch.
Changes since v1:
* Fixed messed up indentation
* Removed code that should be gone (was added here and removed later in series)
Signed-off-by: Olof Johansson <olof at lixom.net>
---
arch/arm/mach-tegra/tegra2_emc.c | 92 +++++++++++++++++++++++--------
arch/arm/mach-tegra/tegra2_emc.h | 11 +--
include/linux/platform_data/tegra_emc.h | 34 +++++++++++
3 files changed, 107 insertions(+), 30 deletions(-)
create mode 100644 include/linux/platform_data/tegra_emc.h
diff --git a/arch/arm/mach-tegra/tegra2_emc.c b/arch/arm/mach-tegra/tegra2_emc.c
index 0f7ae6e..e6229bb 100644
--- a/arch/arm/mach-tegra/tegra2_emc.c
+++ b/arch/arm/mach-tegra/tegra2_emc.c
@@ -16,10 +16,13 @@
*/
#include <linux/kernel.h>
+#include <linux/device.h>
#include <linux/clk.h>
#include <linux/err.h>
#include <linux/io.h>
#include <linux/module.h>
+#include <linux/platform_device.h>
+#include <linux/platform_data/tegra_emc.h>
#include <mach/iomap.h>
@@ -32,18 +35,17 @@ static bool emc_enable;
#endif
module_param(emc_enable, bool, 0644);
-static void __iomem *emc = IO_ADDRESS(TEGRA_EMC_BASE);
-static const struct tegra_emc_table *tegra_emc_table;
-static int tegra_emc_table_size;
+static struct platform_device *emc_pdev;
+static void __iomem *emc_regbase;
static inline void emc_writel(u32 val, unsigned long addr)
{
- writel(val, emc + addr);
+ writel(val, emc_regbase + addr);
}
static inline u32 emc_readl(unsigned long addr)
{
- return readl(emc + addr);
+ return readl(emc_regbase + addr);
}
static const unsigned long emc_reg_addr[TEGRA_EMC_NUM_REGS] = {
@@ -98,15 +100,15 @@ static const unsigned long emc_reg_addr[TEGRA_EMC_NUM_REGS] = {
/* Select the closest EMC rate that is higher than the requested rate */
long tegra_emc_round_rate(unsigned long rate)
{
+ struct tegra_emc_pdata *pdata;
int i;
int best = -1;
unsigned long distance = ULONG_MAX;
- if (!tegra_emc_table)
+ if (!emc_pdev)
return -EINVAL;
- if (!emc_enable)
- return -EINVAL;
+ pdata = emc_pdev->dev.platform_data;
pr_debug("%s: %lu\n", __func__, rate);
@@ -116,10 +118,10 @@ long tegra_emc_round_rate(unsigned long rate)
*/
rate = rate / 2 / 1000;
- for (i = 0; i < tegra_emc_table_size; i++) {
- if (tegra_emc_table[i].rate >= rate &&
- (tegra_emc_table[i].rate - rate) < distance) {
- distance = tegra_emc_table[i].rate - rate;
+ for (i = 0; i < pdata->num_tables; i++) {
+ if (pdata->tables[i].rate >= rate &&
+ (pdata->tables[i].rate - rate) < distance) {
+ distance = pdata->tables[i].rate - rate;
best = i;
}
}
@@ -127,9 +129,9 @@ long tegra_emc_round_rate(unsigned long rate)
if (best < 0)
return -EINVAL;
- pr_debug("%s: using %lu\n", __func__, tegra_emc_table[best].rate);
+ pr_debug("%s: using %lu\n", __func__, pdata->tables[best].rate);
- return tegra_emc_table[best].rate * 2 * 1000;
+ return pdata->tables[best].rate * 2 * 1000;
}
/*
@@ -142,37 +144,81 @@ long tegra_emc_round_rate(unsigned long rate)
*/
int tegra_emc_set_rate(unsigned long rate)
{
+ struct tegra_emc_pdata *pdata;
int i;
int j;
- if (!tegra_emc_table)
+ if (!emc_pdev)
return -EINVAL;
+ pdata = emc_pdev->dev.platform_data;
+
/*
* The EMC clock rate is twice the bus rate, and the bus rate is
* measured in kHz
*/
rate = rate / 2 / 1000;
- for (i = 0; i < tegra_emc_table_size; i++)
- if (tegra_emc_table[i].rate == rate)
+ for (i = 0; i < pdata->num_tables; i++)
+ if (pdata->tables[i].rate == rate)
break;
- if (i >= tegra_emc_table_size)
+ if (i >= pdata->num_tables)
return -EINVAL;
pr_debug("%s: setting to %lu\n", __func__, rate);
for (j = 0; j < TEGRA_EMC_NUM_REGS; j++)
- emc_writel(tegra_emc_table[i].regs[j], emc_reg_addr[j]);
+ emc_writel(pdata->tables[i].regs[j], emc_reg_addr[j]);
+
+ emc_readl(pdata->tables[i].regs[TEGRA_EMC_NUM_REGS - 1]);
+
+ return 0;
+}
+
+static int __devinit tegra_emc_probe(struct platform_device *pdev)
+{
+ struct tegra_emc_pdata *pdata;
+ struct resource *res;
+
+ if (!emc_enable) {
+ dev_err(&pdev->dev, "disabled per module parameter\n");
+ return -ENODEV;
+ }
+
+ pdata = pdev->dev.platform_data;
- emc_readl(tegra_emc_table[i].regs[TEGRA_EMC_NUM_REGS - 1]);
+ if (!pdata) {
+ dev_err(&pdev->dev, "missing platform data\n");
+ return -ENXIO;
+ }
+
+ res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+ if (!res) {
+ dev_err(&pdev->dev, "missing register base\n");
+ return -ENOMEM;
+ }
+
+ emc_regbase = devm_request_and_ioremap(&pdev->dev, res);
+ if (!emc_regbase) {
+ dev_err(&pdev->dev, "failed to remap registers\n");
+ return -ENOMEM;
+ }
+ emc_pdev = pdev;
return 0;
}
-void tegra_init_emc(const struct tegra_emc_table *table, int table_size)
+static struct platform_driver tegra_emc_driver = {
+ .driver = {
+ .name = "tegra-emc",
+ .owner = THIS_MODULE,
+ },
+ .probe = tegra_emc_probe,
+};
+
+static int __init tegra_emc_init(void)
{
- tegra_emc_table = table;
- tegra_emc_table_size = table_size;
+ return platform_driver_register(&tegra_emc_driver);
}
+device_initcall(tegra_emc_init);
diff --git a/arch/arm/mach-tegra/tegra2_emc.h b/arch/arm/mach-tegra/tegra2_emc.h
index 19f08cb..f61409b 100644
--- a/arch/arm/mach-tegra/tegra2_emc.h
+++ b/arch/arm/mach-tegra/tegra2_emc.h
@@ -15,13 +15,10 @@
*
*/
-#define TEGRA_EMC_NUM_REGS 46
-
-struct tegra_emc_table {
- unsigned long rate;
- u32 regs[TEGRA_EMC_NUM_REGS];
-};
+#ifndef __MACH_TEGRA_TEGRA2_EMC_H_
+#define __MACH_TEGRA_TEGRA2_EMC_H
int tegra_emc_set_rate(unsigned long rate);
long tegra_emc_round_rate(unsigned long rate);
-void tegra_init_emc(const struct tegra_emc_table *table, int table_size);
+
+#endif
diff --git a/include/linux/platform_data/tegra_emc.h b/include/linux/platform_data/tegra_emc.h
new file mode 100644
index 0000000..df67505
--- /dev/null
+++ b/include/linux/platform_data/tegra_emc.h
@@ -0,0 +1,34 @@
+/*
+ * Copyright (C) 2011 Google, Inc.
+ *
+ * Author:
+ * Colin Cross <ccross at android.com>
+ * Olof Johansson <olof at lixom.net>
+ *
+ * This software is licensed under the terms of the GNU General Public
+ * License version 2, as published by the Free Software Foundation, and
+ * may be copied, distributed, and modified under those terms.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ *
+ */
+
+#ifndef __TEGRA_EMC_H_
+#define __TEGRA_EMC_H_
+
+#define TEGRA_EMC_NUM_REGS 46
+
+struct tegra_emc_table {
+ unsigned long rate;
+ u32 regs[TEGRA_EMC_NUM_REGS];
+};
+
+struct tegra_emc_pdata {
+ int num_tables;
+ struct tegra_emc_table *tables;
+};
+
+#endif
--
1.7.8.GIT
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