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path: root/drivers/nvmem/lpc18xx_eeprom.c
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Diffstat (limited to 'drivers/nvmem/lpc18xx_eeprom.c')
-rw-r--r--drivers/nvmem/lpc18xx_eeprom.c280
1 files changed, 280 insertions, 0 deletions
diff --git a/drivers/nvmem/lpc18xx_eeprom.c b/drivers/nvmem/lpc18xx_eeprom.c
new file mode 100644
index 000000000..a0275b29a
--- /dev/null
+++ b/drivers/nvmem/lpc18xx_eeprom.c
@@ -0,0 +1,280 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * NXP LPC18xx/LPC43xx EEPROM memory NVMEM driver
+ *
+ * Copyright (c) 2015 Ariel D'Alessandro <ariel@vanguardiasur.com>
+ */
+
+#include <linux/clk.h>
+#include <linux/device.h>
+#include <linux/delay.h>
+#include <linux/err.h>
+#include <linux/io.h>
+#include <linux/module.h>
+#include <linux/mod_devicetable.h>
+#include <linux/nvmem-provider.h>
+#include <linux/platform_device.h>
+#include <linux/reset.h>
+
+/* Registers */
+#define LPC18XX_EEPROM_AUTOPROG 0x00c
+#define LPC18XX_EEPROM_AUTOPROG_WORD 0x1
+
+#define LPC18XX_EEPROM_CLKDIV 0x014
+
+#define LPC18XX_EEPROM_PWRDWN 0x018
+#define LPC18XX_EEPROM_PWRDWN_NO 0x0
+#define LPC18XX_EEPROM_PWRDWN_YES 0x1
+
+#define LPC18XX_EEPROM_INTSTAT 0xfe0
+#define LPC18XX_EEPROM_INTSTAT_END_OF_PROG BIT(2)
+
+#define LPC18XX_EEPROM_INTSTATCLR 0xfe8
+#define LPC18XX_EEPROM_INTSTATCLR_PROG_CLR_ST BIT(2)
+
+/* Fixed page size (bytes) */
+#define LPC18XX_EEPROM_PAGE_SIZE 0x80
+
+/* EEPROM device requires a ~1500 kHz clock (min 800 kHz, max 1600 kHz) */
+#define LPC18XX_EEPROM_CLOCK_HZ 1500000
+
+/* EEPROM requires 3 ms of erase/program time between each writing */
+#define LPC18XX_EEPROM_PROGRAM_TIME 3
+
+struct lpc18xx_eeprom_dev {
+ struct clk *clk;
+ void __iomem *reg_base;
+ void __iomem *mem_base;
+ struct nvmem_device *nvmem;
+ unsigned reg_bytes;
+ unsigned val_bytes;
+ int size;
+};
+
+static inline void lpc18xx_eeprom_writel(struct lpc18xx_eeprom_dev *eeprom,
+ u32 reg, u32 val)
+{
+ writel(val, eeprom->reg_base + reg);
+}
+
+static inline u32 lpc18xx_eeprom_readl(struct lpc18xx_eeprom_dev *eeprom,
+ u32 reg)
+{
+ return readl(eeprom->reg_base + reg);
+}
+
+static int lpc18xx_eeprom_busywait_until_prog(struct lpc18xx_eeprom_dev *eeprom)
+{
+ unsigned long end;
+ u32 val;
+
+ /* Wait until EEPROM program operation has finished */
+ end = jiffies + msecs_to_jiffies(LPC18XX_EEPROM_PROGRAM_TIME * 10);
+
+ while (time_is_after_jiffies(end)) {
+ val = lpc18xx_eeprom_readl(eeprom, LPC18XX_EEPROM_INTSTAT);
+
+ if (val & LPC18XX_EEPROM_INTSTAT_END_OF_PROG) {
+ lpc18xx_eeprom_writel(eeprom, LPC18XX_EEPROM_INTSTATCLR,
+ LPC18XX_EEPROM_INTSTATCLR_PROG_CLR_ST);
+ return 0;
+ }
+
+ usleep_range(LPC18XX_EEPROM_PROGRAM_TIME * USEC_PER_MSEC,
+ (LPC18XX_EEPROM_PROGRAM_TIME + 1) * USEC_PER_MSEC);
+ }
+
+ return -ETIMEDOUT;
+}
+
+static int lpc18xx_eeprom_gather_write(void *context, unsigned int reg,
+ void *val, size_t bytes)
+{
+ struct lpc18xx_eeprom_dev *eeprom = context;
+ unsigned int offset = reg;
+ int ret;
+
+ /*
+ * The last page contains the EEPROM initialization data and is not
+ * writable.
+ */
+ if ((reg > eeprom->size - LPC18XX_EEPROM_PAGE_SIZE) ||
+ (reg + bytes > eeprom->size - LPC18XX_EEPROM_PAGE_SIZE))
+ return -EINVAL;
+
+
+ lpc18xx_eeprom_writel(eeprom, LPC18XX_EEPROM_PWRDWN,
+ LPC18XX_EEPROM_PWRDWN_NO);
+
+ /* Wait 100 us while the EEPROM wakes up */
+ usleep_range(100, 200);
+
+ while (bytes) {
+ writel(*(u32 *)val, eeprom->mem_base + offset);
+ ret = lpc18xx_eeprom_busywait_until_prog(eeprom);
+ if (ret < 0)
+ return ret;
+
+ bytes -= eeprom->val_bytes;
+ val += eeprom->val_bytes;
+ offset += eeprom->val_bytes;
+ }
+
+ lpc18xx_eeprom_writel(eeprom, LPC18XX_EEPROM_PWRDWN,
+ LPC18XX_EEPROM_PWRDWN_YES);
+
+ return 0;
+}
+
+static int lpc18xx_eeprom_read(void *context, unsigned int offset,
+ void *val, size_t bytes)
+{
+ struct lpc18xx_eeprom_dev *eeprom = context;
+
+ lpc18xx_eeprom_writel(eeprom, LPC18XX_EEPROM_PWRDWN,
+ LPC18XX_EEPROM_PWRDWN_NO);
+
+ /* Wait 100 us while the EEPROM wakes up */
+ usleep_range(100, 200);
+
+ while (bytes) {
+ *(u32 *)val = readl(eeprom->mem_base + offset);
+ bytes -= eeprom->val_bytes;
+ val += eeprom->val_bytes;
+ offset += eeprom->val_bytes;
+ }
+
+ lpc18xx_eeprom_writel(eeprom, LPC18XX_EEPROM_PWRDWN,
+ LPC18XX_EEPROM_PWRDWN_YES);
+
+ return 0;
+}
+
+
+static struct nvmem_config lpc18xx_nvmem_config = {
+ .name = "lpc18xx-eeprom",
+ .stride = 4,
+ .word_size = 4,
+ .reg_read = lpc18xx_eeprom_read,
+ .reg_write = lpc18xx_eeprom_gather_write,
+};
+
+static int lpc18xx_eeprom_probe(struct platform_device *pdev)
+{
+ struct lpc18xx_eeprom_dev *eeprom;
+ struct device *dev = &pdev->dev;
+ struct reset_control *rst;
+ unsigned long clk_rate;
+ struct resource *res;
+ int ret;
+
+ eeprom = devm_kzalloc(dev, sizeof(*eeprom), GFP_KERNEL);
+ if (!eeprom)
+ return -ENOMEM;
+
+ res = platform_get_resource_byname(pdev, IORESOURCE_MEM, "reg");
+ eeprom->reg_base = devm_ioremap_resource(dev, res);
+ if (IS_ERR(eeprom->reg_base))
+ return PTR_ERR(eeprom->reg_base);
+
+ res = platform_get_resource_byname(pdev, IORESOURCE_MEM, "mem");
+ eeprom->mem_base = devm_ioremap_resource(dev, res);
+ if (IS_ERR(eeprom->mem_base))
+ return PTR_ERR(eeprom->mem_base);
+
+ eeprom->clk = devm_clk_get(&pdev->dev, "eeprom");
+ if (IS_ERR(eeprom->clk)) {
+ dev_err(&pdev->dev, "failed to get eeprom clock\n");
+ return PTR_ERR(eeprom->clk);
+ }
+
+ ret = clk_prepare_enable(eeprom->clk);
+ if (ret < 0) {
+ dev_err(dev, "failed to prepare/enable eeprom clk: %d\n", ret);
+ return ret;
+ }
+
+ rst = devm_reset_control_get_exclusive(dev, NULL);
+ if (IS_ERR(rst)) {
+ dev_err(dev, "failed to get reset: %ld\n", PTR_ERR(rst));
+ ret = PTR_ERR(rst);
+ goto err_clk;
+ }
+
+ ret = reset_control_assert(rst);
+ if (ret < 0) {
+ dev_err(dev, "failed to assert reset: %d\n", ret);
+ goto err_clk;
+ }
+
+ eeprom->val_bytes = 4;
+ eeprom->reg_bytes = 4;
+
+ /*
+ * Clock rate is generated by dividing the system bus clock by the
+ * division factor, contained in the divider register (minus 1 encoded).
+ */
+ clk_rate = clk_get_rate(eeprom->clk);
+ clk_rate = DIV_ROUND_UP(clk_rate, LPC18XX_EEPROM_CLOCK_HZ) - 1;
+ lpc18xx_eeprom_writel(eeprom, LPC18XX_EEPROM_CLKDIV, clk_rate);
+
+ /*
+ * Writing a single word to the page will start the erase/program cycle
+ * automatically
+ */
+ lpc18xx_eeprom_writel(eeprom, LPC18XX_EEPROM_AUTOPROG,
+ LPC18XX_EEPROM_AUTOPROG_WORD);
+
+ lpc18xx_eeprom_writel(eeprom, LPC18XX_EEPROM_PWRDWN,
+ LPC18XX_EEPROM_PWRDWN_YES);
+
+ eeprom->size = resource_size(res);
+ lpc18xx_nvmem_config.size = resource_size(res);
+ lpc18xx_nvmem_config.dev = dev;
+ lpc18xx_nvmem_config.priv = eeprom;
+
+ eeprom->nvmem = devm_nvmem_register(dev, &lpc18xx_nvmem_config);
+ if (IS_ERR(eeprom->nvmem)) {
+ ret = PTR_ERR(eeprom->nvmem);
+ goto err_clk;
+ }
+
+ platform_set_drvdata(pdev, eeprom);
+
+ return 0;
+
+err_clk:
+ clk_disable_unprepare(eeprom->clk);
+
+ return ret;
+}
+
+static int lpc18xx_eeprom_remove(struct platform_device *pdev)
+{
+ struct lpc18xx_eeprom_dev *eeprom = platform_get_drvdata(pdev);
+
+ clk_disable_unprepare(eeprom->clk);
+
+ return 0;
+}
+
+static const struct of_device_id lpc18xx_eeprom_of_match[] = {
+ { .compatible = "nxp,lpc1857-eeprom" },
+ { },
+};
+MODULE_DEVICE_TABLE(of, lpc18xx_eeprom_of_match);
+
+static struct platform_driver lpc18xx_eeprom_driver = {
+ .probe = lpc18xx_eeprom_probe,
+ .remove = lpc18xx_eeprom_remove,
+ .driver = {
+ .name = "lpc18xx-eeprom",
+ .of_match_table = lpc18xx_eeprom_of_match,
+ },
+};
+
+module_platform_driver(lpc18xx_eeprom_driver);
+
+MODULE_AUTHOR("Ariel D'Alessandro <ariel@vanguardiasur.com.ar>");
+MODULE_DESCRIPTION("NXP LPC18xx EEPROM memory Driver");
+MODULE_LICENSE("GPL v2");