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Commit 17711dbf authored by Olof Johansson's avatar Olof Johansson
Browse files

ARM: tegra: emc: convert tegra2_emc to a platform driver 



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: default avatarOlof Johansson <olof@lixom.net>
Acked-by: default avatarStephen Warren <swarren@nvidia.com>
parent dee47183

arch/arm/mach-tegra/tegra2_emc.c

+69 −23
Original line number Diff line number Diff line
@@ -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);

arch/arm/mach-tegra/tegra2_emc.h

+4 −7
Original line number Diff line number Diff line
@@ -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

include/linux/platform_data/tegra_emc.h

0 → 100644
+34 −0
Original line number Diff line number Diff line 
/*

 * Copyright (C) 2011 Google, Inc.

 *

 * Author:

 *	Colin Cross <ccross@android.com>

 *	Olof Johansson <olof@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